Will the increase in atmospheric carbon dioxide lead to larger insects?

Will the increase in atmospheric carbon dioxide lead to larger insects?

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From my understanding, the increase in atmospheric carbon dioxide will also increase oxygen levels. That makes me wonder if in the near future insects will grow larger than they are today, since their maximum size is limited by how deeply oxygen is able to diffuse into their body.

There is the supported theory that insects during the Paleozoic period were larger in size because of the increased oxygen content in the air.

The study adds support to the theory that some insects were much larger during the late Paleozoic period because they had a much richer oxygen supply.

The Paleozoic period, about 300 million years ago, was a time of huge and abundant plant life and rather large insects - dragonflies had two-and-a-half-foot wing spans, for example. The air's oxygen content was 35% during this period, compared to the 21% we breathe now, Kaiser said. Researchers have speculated that the higher oxygen concentration allowed insects to grow much bigger.

It is because when the oxygen concentration in the atmosphere is high, the insect needs smaller quantities of air to meet its oxygen demands. The tracheal diameter can be narrower and still deliver enough oxygen for a much larger insect, Kaiser concluded.

There are similar papers that investigate the relationship between oxygen and maximum potential size, such as this article published in Nature (1999):

The tendency of some animals to be larger at higher latitudes ('polar gigantism') has not been explained, although it has often been attributed to low temperature and metabolism. [… ] We have analysed length data for 1,853 species of benthic amphipod crustaceans from 12 sites worldwide, from polar to tropical and marine (continental shelf) to freshwater environments. We find that maximum potential size (MPS) is limited by oxygen availability.

Another paper published in Proceedings further supports this theory:

[… ] A variety of recent empirical findings support a link between oxygen and insect size, including: (i) most insects develop smaller body sizes in hypoxia, and some develop and evolve larger sizes in hyperoxia; (ii) insects developmentally and evolutionarily reduce their proportional investment in the tracheal system when living in higher PO2, suggesting that there are significant costs associated with tracheal system structure and function; and (iii) larger insects invest more of their body in the tracheal system, potentially leading to greater effects of a PO2 on larger insects.

The question you propose is very interesting, although I am sure it would take thousands of years for these insects to adapt to this oxygen level change (which in itself, to reach prehistoric levels, would take a long time) and in turn become larger.

This article, based on the original APS paper, seems to think larger insects could appear in the future if the limiting factor (in this case low oxygen levels) is removed.

Image from Biotic interactions modify the effects of oxygen on insect gigantism (PNAS, Chown 2012).

How Does Carbon Dioxide Affect the Environment?

Carbon dioxide is essential to the survival of plants and animals. Too much, however, can cause all life on Earth to die. Not only do plants and animals need to ingest carbon dioxide, but they also rely on the gas to keep them warm, as it is an essential component to Earth's atmosphere.

TLDR (Too Long Didn't Read)

Carbon dioxide plays a key role in plant life and helps keep the earth warm. Increasing levels of carbon dioxide in the atmosphere, though, are linked to global warming.

Giant insects might reign if only there was more oxygen in the air

VIRGINIA BEACH, VA (October 11, 2006) - The delicate lady bug in your garden could be frighteningly large if only there was a greater concentration of oxygen in the air, a new study concludes. The study adds support to the theory that some insects were much larger during the late Paleozoic period because they had a much richer oxygen supply, said the study's lead author Alexander Kaiser.

The study, "No giants today: tracheal oxygen supply to the legs limits beetle size,'' will be presented Oct. 10 and 11 at Comparative Physiology 2006: Integrating Diversity. The conference will be held Oct. 8-11 in Virginia Beach. The research was carried out by Alexander Kaiser and Michael C. Quinlan of Midwestern University, Glendale, Arizona J. Jake Socha and Wah-Keat Lee, Argonne National Laboratory, Argonne, IL and Jaco Klok and Jon F. Harrison, Arizona State University, Tempe, AZ. Harrison is the principal investigator.

The Paleozoic period, about 300 million years ago, was a time of huge and abundant plant life and rather large insects -- dragonflies had two-and-a-half-foot wing spans, for example. The air's oxygen content was 35% during this period, compared to the 21% we breathe now, Kaiser said. Researchers have speculated that the higher oxygen concentration allowed insects to grow much bigger.

First, a bit of background: Insects don't breathe like we do and don't use blood to transport oxygen. They take in oxygen and expel carbon dioxide through holes in their bodies called spiracles. These holes connect to branching and interconnecting tubes, called tracheae, Kaiser explained.

Whereas humans have one trachea, insects have a whole tracheal system that transports oxygen to all areas of their bodies and removes carbon dioxide. As the insect grows, tracheal tubes get longer to reach central tissue, and get wider or more numerous to meet the additional oxygen demands of a larger body.

Insects can limit oxygen flow by closing their spiracles. In fact, one reason insects are so hardy is that they can close their spiracles and live off the oxygen they already have in their tracheae. Kaiser recalled a caterpillar that fell into a bucket of water in his lab. When the creature was discovered the next day, lab workers thought it had drowned. But when they removed its apparently lifeless little body from the water, they were surprised to see it crawl away.

Tracheae grow disproportionately

This experiment was designed to find out:

  • how much room the tracheal system takes up in the bodies of different-sized beetles
  • whether tracheal dimensions increase proportionately as the beetles get larger
  • whether there is a limit to the size a beetle could grow in the current atmosphere

The researchers used x-ray images to compare the tracheal dimensions of four species of beetles, ranging in size from 3mm (Tribolium castaneum, about one-tenth of an inch) to about 3.5 cm (Eleodes obscura, about 1.5 inches). Beetles were not in existence during the Paleozoic period, but Kaiser's team used the insect because they are much easier to maintain in the laboratory than dragonflies, which are quite difficult.

The study found that the tracheae of the larger beetles take up a greater proportion of their bodies, about 20% more, than the increase in their body size would predict, Kaiser said. This is because the tracheal system is not only becoming longer to reach longer limbs, but the tubes increase in diameter or number to take in more air to handle the additional oxygen demands.

The disproportionate increase in tracheal size reaches a critical point at the opening where the leg and body meet, the researchers found. This opening can get only so big, and limits the size of the trachea that runs through it. When tracheal size is limited, so is oxygen supply and so is growth, Kaiser explained.

Using the disproportional increases they observed among the beetles, the researchers calculated that beetles could not grow larger than about 15 centimeters. And this is the size of the largest beetle known: the Titanic longhorn beetle, Titanus giganteus, from South America, which grows 15-17 cm, Kaiser said.

And why wouldn't the opening between the body and the leg limit insect size in the Paleozoic era, too? After all, dragonflies and some other insects back then had the same body architecture, but they were much bigger.

It is because when the oxygen concentration in the atmosphere is high, the insect needs smaller quantities of air to meet its oxygen demands. The tracheal diameter can be narrower and still deliver enough oxygen for a much larger insect, Kaiser concluded.

Embargoed until October 11, 2006

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Question on the part on "simple accounting":

I assume if we set HE to 0, then NE-NA would result in a deltaC of 0, representing the pre-industrial equilibrum. This puzzles me: Why is nature (oceans, plants, soils) suddenly able to absorb 15 billion tons more CO2 with an atmosphere with

400ppm, as opposed to the pre-industrial equilibrium with

If we say there was pre-industrial equilibrium with 280ppm CO2 by volume, NE-NA=0, but the natural carbon cycle is still at work. NE=NA= 770 GtCO2 pa.

Now we are at 400ppm having pumped something like 2,200 GtCO2 into the atmosphere over the previous century or so and seen a little over half of it get absorbed by the oceans and biosphere, if we stopped emitting tomorrow (HE=0), equilibrium will not be achieved for a millenium or so. The eventual level of atmospheric CO2 would be somewhere near 340ppm.

Archer et al 2009 is usually seen as a pretty definitive study on the subject.

Falkenherz to add to what MA ROger has already said, if you want a specific mechanism, the transport of carbon dioxide between the atmosphere and surface oceans is proportional to the difference in partial pressure of CO2 between air and ocean. Therefore if we increase the partial pressure of CO2 in the atmosphere (e.g. by burning fossil fuels) then this difference increases, and more CO2 passes from atmosphere to the ocean than in the other direction. This causes the oceans to take up more CO2 until the partial pressures are in equilibrium again.

David Archer has written a very good primer on the carbon cycle, which is well worth a read.

Thanks for the answers and sorry for the double-post, no idea how that happened.

[Dikran Marsupial] no problem, easily fixed.

3) or maybe it is greed:


Simple Accounting Revisted "It's the Animals"

The simple accounting demonstration that CO2 increase is manmade is pure crap.
Animals and plants produce more than 220 GT of CO2 per year. Let&rsquos just change a few words. Let humans be part of the nature term NE (as we are) and let a group of animal species A be the one that produce some extra CO2 by an amount of 30 GT (we can certainly find some species to be blamed). Then we have the same result,
NE-NA = -15
but now the added CO2 is blamed on animals, not humans. Why should humans be solely responsible for all CO2 production added to the atmosphere? Is this some sort conspiracy against humans? Why not share the blame among all species, animals and humans included?

In any way, the NE and NA terms will balance in the future (CO2 will stabilize as it always did in history) and humans and animals will keep on living. As is well known, CO2 levels have been much higher in the history of the planet and life kept growing despite of it. I'm just sick of alarmists and skeptics bashing against those who have another perspective about this whole topic and who, ironically, are also skeptics. Skeptics against skeptics. How uglier can it get?

[TD] Please do not use all caps, because it is the web equivalent of yelling. Instead use the bold and italic formatting controls.

Chris, plants take carbon out of the atmosphere. Animals eat plants. Animals breathe out CO2. In general, animals are carbon neutral, just as human breathing is carbon-neutral. Humans, however, are also digging up and burning billions of tons of carbon that has been stored in the Earth over hundreds of millions of years. We're adding the carbon of the past to the present (and future).

You are not doing the accounting correctly. It's not enough to simply produce CO2. You have to have a net exchange from one reservoir to the other.

So, for your example to work, the respiring organisms would have to cause a net loss of plant carbon to the atmosphere. To match the observed increase in atmospheric CO2, you would have to move about 250 petagrams of carbon from the terrestrial biosphere to the atmopshere (current - preindustrial atmsopheric CO2 = 850 Pg - 600 Pg).

That is 40-60% of current living terrestrial plant biomass (terrestrial plant C

450 - 650p petagrams C according to the IPCC.) About 2/3s of that deline in terrestrial biomass would have occured since 1970. There is large uncertainty around estimates of plant biomass for sure, but you bet we would have noticed such a massive decline over such a short period of time.

As indicated in the post, the CO2 accumulating in the atmosphere is highly depleted in 14 C. We know it is therefore tens of thousands of years old because that is how long it takes for 14 C to decay completely. That age rules out everything except fossil fuels.

It is simple accounting in the end. Really, scientists are not so stupid to miss something so obvious. If individuals had been, you can bet their competitors would take them to task!

Chris636: Of course the CO2 level eventually will stabilize--when humans eventually run out of fossil fuels to burn. The problem is that the ill effects of those high CO2 levels will get much, much worse, for a very, very long time in the time scale of human lives, civilization, and even species. See RealClimate for a couple of relevant posts.

Chris626 wrote "The simple accounting demonstration that CO2 increase is manmade is pure crap."

so all of the worlds carbon cycle specialists are wrong, no hubris there then! o)

"Let humans be part of the nature term NE (as we are)"

This is just silly, if you define humans as part of nature the word "anthropogenic", "artificial" and ultimately "natural" have no meaning.

" let a group of animal species A be the one that produce some extra CO2 by an amount of 30 GT "

The flaw in this argument is obvious. The carbon dioxide that animals produce through respiration is directly (in the case of herbivores) or indirectly (in the case of carnivores) derived from plant matter, which is contructed from carbon dioxide taken out of the atmosphere. Thus all animals merely return to atmosphere the carbon that was taken out of it via photosynthesis, and hence are essentially carbon neutral. Now if you can identify an animal species where this is not the case and is increasing the amount of carbon moving through the carbon cycle, then you might have the beginings of an argument.

"Why should humans be solely responsible for all CO2 production added to the atmosphere? Is this some sort conspiracy against humans? Why not share the blame among all species, animals and humans included?"

because humans are the only animals that introduce additional carbon into the carbon cycle by extracting it (in the form of fossil fuels) from the lithosphere and burn it, which puts it in the atmosphere.

Rather ironic thatyou should ask that, given you started your post by calling the work of eminent scientists "crap".

It is sad that there are skeptics that can't even accept that the increase in atmospheric CO2 is due to anthropogenic emissions when the evidence is unambiguous and unequivocal. If the natural environment (including all the animals) were a net carbon source, the atmospheric CO2 would be rising faster than anthropogenic emisssions as both nature and mankind would be net sources. However we know for sure that this is not the case, the observations rule that out completely.

I dont want to dogpile, but Chris626 is only looking at one of the lines of evidence presented (getting the accounting wrong). If it is "crap" then explain the isotopic evidence and ocean acidification.

While the planet might have had higher levels in past, (but also different solar input) the problem is rate of change (because adaption takes a long time), not the final temperature.

All: Please do not dogpile any future comments posted by Chris626. Dogpiling is both unnecessary and unseemly. Furthermore, it is prohibited by the SkS Comments Policy.

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Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

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Sorry John..being a skeptic is fine but in this case you're incorrect..I'm not saying only mankind is contributing but I'm saying what they manufacture,since the Industrial revolution has contributed could it not?? btw I taught several volunteer FYI college classes at night several years back to mostly adults who had no idea what it was all about. my saying to those who must deny "well I guess we'll just have to wait and see"..yep it's moving along a good deal faster than old mother nature had in mind..have a swell day..glad I found and joined this site..ciao

I agree with the CO2, 13C and 14C could be attributed to fossil fuel burning. But the oxygen isotopes in the CO2 molecule are not mentioned in the explanations.

Can anyone explain why CO2, 13C and 14C isotopes follow a trend while 18O isotopes of CO2 do not show a clear trend?

[RH] Fixed image width. Please keep your images down to 500px.

jlfqam @16, total oxygen content in the atmosphere is showing a trend, as shown in this graph from the 2001 IPCC TAR:

You will notice that the trend is in parts per million. The graph you show of the d 18 O isotope is in parts per mill, ie, parts per thousand. A reduction of 30 ppm over 10 years (as shown above),ie, three parts per hundred of the scale, will not register on a graph scaled in parts per thousand.

Thanks for the figure of the evolution of atmospheric O2 concentration.

A comparison of simultaneous variation O2(atm) with CO2(atm) can be seen in the plots from Scripps measurements

I am sorry, I did not explain properly the figures, the fourth plot refers to the Oxygen isotope composition of O atom in the atmospheric CO2 molecule,

the isotope ratio 18O/16O, in this molecule refers to the ratio of 12C18O16O+12C18O2(less abundant) over 12C16O2, for example.

According to two possible sources of CO2, biomass/fossil fuel burning or ocean sources: (equations are not stoichiometric)

In the first case, burning, the oxygen source is atmospheric Oxygen (O2), which is produced by photosynthesis, and ultimately bears the isotope composition of the water used

by photsynthetic organisms during the water photolysis reaction: H2O=>O2 + (2H --->sugars (CnH2nO))

combustion #CnH(2n+x)+*O2=> #C*O2+H2*O

#C has the isotope signature of the fuel organic Carbon, and is measured in the 13C and 14C plots in the previous posting.

*O is the isotope signature of the O2 used in the combustion, and is represented in the 18O plot from Scripps CO2(atm) measurements.

The second case, the marine source of CO2, has also isotope signatures

remineralisation of organic matter from ocean bottom organic rich sediments $CnH(2n+x)+^O2=> $C^O2+H2^O

$C has the isotope signature of the marine biomass remineralised, as it's of biogenic origin is depleted in 13C, and since it's old, it's mostly depleted in 14C, hence in principle it's difficult to distinguish from fossil fuel carbon

^O is the isotope signature of ocean waters, either deep or shallow, as bicarbonate or dissolved CO2 rapidly equilibrate with water.

In principle the measurement of the 18O isotope ratio in atmospheric CO2 should tell us which of the two sources is the dominant.

Which one of the two sources can explain the plots in the previous posting 16.jlfqam

jlfqam @18, fossil fuels are completely depleted in C14. That is, there &Delta 14 C = -1000 per mill, as per this chart:

In contrast, the &Delta 14 C of abyssal oceanic waters averages about -160 per mill, with minimum values of about -240 per mill (See figure 1 here). Taking those minimum values, you would need an increase in atmospheric CO2 4.2 times greater than has been observed to obtain an equivalent reduction in atmosperic C14 to that which has been observed as a result of the combustion of fossil fuels. Therefore the C14 evidence by itself is sufficient to show the primary source of the increased CO2 is from the combustion of fossil fuels.

That being said, it is a bad practise to relly on a single indicator in making these sorts of determinations. In fact there are at least 10 different lines of evidence that help us determine the source of the increase in atmospheric C14. Some lines only provide evidence regarding a single potential source, while some provide relevant evidence for all four "major" theories. Overall, only a fossil fuel source is not contradicted by any line of evidence. Further, it is strongly supported by five of the ten lines of evidence, and given moderate support by a further two. This evidence is discussed here, and summarized by this chart:

I have not come across a discussion of &Delta 18 O in this connection, but given the strength of the evidence from other sources, I would be flabberghasted were it to show anything different.

I will post the answer in the corresponding forum page. I am sorry I did not find it first.

In your post (29th November 2016, #19 above) you wrote:

That being said, it is a bad practise to relly on a single indicator in making these sorts of determinations. In fact there are at least 10 different lines of evidence that help us determine the source of the increase in atmospheric C14.

My understanding was that the levels (or actually ratio) of C14 were decreasing as they come from a fossil source. Am I wrong, or could you possibly have meant CO2?

KalleH @21, you are quite correct that I intended to write ". determine the source of the [decrease] in atmospheric C14". Thankyou for picking up on my error.

In general, I believe that many things happen naturally. But naturally, cause a very little amount of effect if we compare to human activities. CO2 or carbon dioxide is a colorless gas consisting of carbon and oxygen. It occurs naturally in the atmosphere. Plants use it and animals also produce it in respiration. It is a major greenhouse gas emitted by fossil fuel combustion. Burning fossil fuels is one of the causes that make CO2 increase so we can't say that iCO2 came from natural because human is the one who controls everything even we can control that in next 50 years what we want our world gonna be like. The science researcher says that humans are emitting CO2 at a rate twice as fast as the atmospheric increase (natural sinks are absorbing the other half).Nature is absorbing more CO2 than it is emitting. So, the percent that CO2 increases in our world today caused by human activities whether directly or indirectly way. It has more effect than natural.

MY question is this: Since the total annual amount of CO2 has increased on an annual basis, the amount of CO2 from Earth keeps going up as well. I've seen reports that say "our" Co2 is absorbed to the rate of about 55%. That is consistently evey year. If, as some assume, all of earth's CO2 is absorbed, in ever larger amounts, how come our 45% is always left over?

The 45% isn't written in stone. Using the MLO data for atmospheric CO2 and the emissions estimates from Global Carbon Project, the 45% value has remained pretty much the multi-decadal value since 1990. Over the period 1960-90, the Airborne Fraction had been slowly increasing from an early value of 35%.

There are a lot of waggles along the way. Over the period since 1959, annual Airborne Fractions have varied from 20% all the way up to 80%. The El Nino is one big factor in these waggles, as are big tropical volcanoes. Taking multi-year averages, the percentage is still a bit waggly. After the rise to 1990, there was a short sharp dip caused by the eruption of Pinatubo in the early 1990s, a rise into the 2000s due to the high incidence of El Ninos then a dip into the 2010s due to all the La Ninas.

Where the Airborne Fraction goes in coming years? If we begin to reduce the acceleration of our emissions, it should start to drop, and drop quicker if our emissions begin to fall. Mind, all the waggles will prevent a clear sight of any such a drop for some time.

I'm having a little trouble getting some math to come out right. CO2 concentration is rising by 2 ppmv/year. The net flux is given as 15 gigatons/year.

For the surface area of the earth I take a radius of 6.4e6 meters to get an area of 171e12 m 2 . I convert 14.7 lb/in 2 atmospheric pressure at sea level to a metric value of 10.35e3 kg/m 2 or 10.35 ton/m 2 . When I multiply those together, it comes out to 1.771e15 tons for the total weight of the atmosphere. One ppm of that would weigh 1.771e9 tons or 1.771 gigatons.

The atmosphere is primarily molecular nitrogen. Each molecule has a weight of 28. The weight for CO2 is 44. This brings the weight of one ppm by volume up to 2.78 gigatons. The increase of concentration given in the article, 2ppmv/year would represent a weight of 5.56 gigatons. This is low by a factor of almost three from the value of 15 given in the article.

Area wrong. Should be pi times 4 , not pi times 4/3 .

Thank-you. It has been a few years. I was confusing the area and volume formulas.

The arguments presented are helpful and fairly comprehensive, but I was surprised the author, dana1981, did not address what, in my view, is the most important scientific publication on this issue: &ldquoThe phase relation between atmospheric carbon dioxide and global temperature&rdquo by Ole Humlum, Kjell Stordahl and Jan-Erik Solheim in Global and Planetary Change 100: 51-69, 2013. These authors showed, using published temperature time series from multiple sources and global CO2 and anthropogenic CO2 data that, for the years 1980 to 2011:

1. There was a good temporal correlation between global CO2 and ocean temp, land temp, global temp and lower troposphere temp BUT the global CO2 FOLLOWED the ocean temp, then the land temp, then the lower troposphere temp, in that order, with lags of 9-12 months.

2. In contrast, there was poor temporal correlation between anthropogenic CO2 emissions and both global CO2 and temperature.

3. While anthropogenic CO2 was emitted overwhelmingly from the northern hemisphere, the time sequence of ocean temperature variation commenced in the Southern Hemisphere, reasonably close to the equator, then spread north and south to the poles, always preceding the global CO2 time sequence.

These carefully determined temporal sequences and correlations, based squarely on the published temperature and CO2 data, clearly indicate a causal sequence in which global temperature changes PRECEDE global CO2 changes by 9-12 months, commencing with changes in the ocean surface temperature, then the land temperature, then the lower troposphere temperature. These observations are the complete OPPOSITE of what should be expected if anthropogenic CO2 emissions were driving both the global CO2 levels and then causing a secondary increase in temperatures.

So, while I appreciate the energy balance and other arguments advanced above, causality requires a demonstrated temporal sequence of changes that the data I describe here simply do not support. I would be very interested in your explanation for these observations.

[TD] Humlum is wrong. Type "Humlum" into the Search field at the top left of this (or any) SkepticalScience page.

mkrichew:Having difficulty understanding how 2.4 ppm change annually ( or 19 billion tons ) atmospheric CO2 translates to delta Catm = 18 billion tons.

I would say it is a bit lax to substitute 18 for 19 within the OP but given the situation the OP describes, it makes zero difference to the argument presented. The "19 billion tons" figure in the OP is described as "roughly" the &DeltaCatm required to give a +2.4ppm(v) increase which is given as the rate of CO2 increase "recently."

We could be more precise and say that a +2.4ppm increase would require &DeltaCatm = 18.7 Gt(CO2), but given the wobbles caused by ENSO to the annual increase in atmospheric CO2, it is impossible to be that precise about it. The OP was written in 2012 and the source of the MLO CO2 data cited ESRL give a value for the 2012 annual MLO CO2 increase as +2.61ppm = 20.4Gt(CO2) although if the average of the 12-month increases through 2012 is used to calculate a value the result is +2.20ppm. Or if the ESRL Global data is used instead of MLO data, &DeltaCatm for 2012 is given by ESRL as +2.39ppm while tha average of the months yields +2.00ppm =15.6Gt(CO2). Or an alternative source of the value would be the Global Carbon Project's 2012 &DeltaCatm of 5.07Gt(C) = 18.6Gt(CO2) (altough note the 2012 LOC emissions are a long way from zero which is the assumption made in the the OP).

Thank you for your kind response. As you may have guessed I am the author of the Mike Krichew Theory of What Causes Ice Ages which I wrote sometime after Al Gore released his documentary "An Inconvenient Truth" and conservative elements responded as President Trump did, suggesting a conspiracy. At the time I suggested a comet tail reflecting sunlight might account for the increased insolation that would warm the oceans causing an increase in the atmospheric CO2 levels which would warm the atmosphere and further warm the oceans. At the time I was not much of a believer in the Milankovitch cycles theory. However, the other day it occurred to me that if the earth is indeed an oblate speroid or ellipsoid in shape then it may be possible for the earth to present different size cross-sectional areas to the sun during the cycle. This would result in different insolations. Someone with a talent for mathematics might show the different cross-sectional areas if it has not already been done. Someone else with an interest in celestial science might calculate where the minimums and maximums of cross-section occur and plot them on the slightly sinusoidal graph of climate change over time. If there is any correlation, it should then be possible to calculate and model the increased insolation that occurs during the cycle. If this has already been done, a reference would be nice.

[TD] Please copy and paste your comment into a relevant thread you find by typing Milankovich into the Search field at the top left of the page--for example, this one.

I have responded to mkrichew in the appropriate place.

Higher Carbon Dioxide Levels Prompt More Plant Growth, But Fewer Nutrients

COLUMBUS, Ohio — It might seem there’s an upside to the rising levels of carbon dioxide in the atmosphere. Plants are growing faster.

However, in many species of plants, quantity is not quality. Most plants are growing faster, but they have on average more starch, less protein and fewer key vitamins in them, said James Metzger, a professor and chair of the Department of Horticulture and Crop Science in The Ohio State University’s College of Food, Agricultural, and Environmental Sciences (CFAES).

This change is happening because the current level of carbon dioxide in the atmosphere is 400 parts per million, nearly double what it was in the middle of the 18 th century, the start of the industrial revolution. And it keeps rising, spurred by the burning of fuels.

Taking in carbon dioxide and light, a plant forms sugars and starches first, then other nutrients including protein, fat and antioxidants. Though carbon dioxide is necessary for plants to live, too much carbon dioxide can reduce the amount of valuable nutrients the plant produces including iron, zinc and vitamin C.

“The loss of nutrients, particularly protein, is serious,” Metzger said. “That does not help in the effort for people to eat more balanced diets and increase their nutrition.”

Animal meat and dairy products are a significant source of protein for humans. So, if animals aren’t getting sufficient protein from plants, that will affect what they can produce as food.

What’s happening is that a higher level of carbon dioxide in the atmosphere reduces the amount of photorespiration that occurs in plants. During photorespiration, plants take in oxygen from the environment, release carbon dioxide and produce waste products including glycolic acid, which a plant can’t use. In order for the plant to turn the glycolic acid into a product it can use, the plant has to do more photosynthesis, the process through which plants use sunlight, water and carbon dioxide to create glucose, a form of sugar that plants need to survive.

Low rates of photorespiration, caused by the higher amounts of carbon dioxide, are associated with low stress levels in plants, which ironically is not a good thing. That’s because stressed plants respond by producing antioxidants such as vitamins C and E, as well as higher protein levels. So, as carbon dioxide levels in the atmosphere rise, there is less photorespiration and therefore less stress on plants. And the reduced stress means increased growth, but at a cost, a decline in the nutritional quality of the plants.

“This has been observed in many different species of plants,” Metzger said.

If the plant is not producing enough antioxidants, that’s not just less healthy for people who later eat the plant, but also for the plant’s ability to fend off diseases, Metzger said. Plants can become more vulnerable to diseases as well as insects. With fewer nutrients in the plants, the insects have to devour more of them to get the same nutritional value.

Not all plants react to the rising carbon dioxide levels in the same way. Some crops, including corn and sugar cane, do not decrease in nutritional value in the midst of higher carbon dioxide levels. That’s because their photosynthesis process differs from that of most other plants.

Temperature is a factor as well. Depending on the temperature, plants can react in different ways to high carbon dioxide levels. The rising carbon dioxide levels that are triggering more photosynthesis can hinder the growth of some plants cultivated in temperatures below 59 degrees Fahrenheit, such as winter wheat, said Katrina Cornish, Ohio Research Scholar and Endowed Chair in Bio-based Emergent Materials with CFAES.

Plants grown in hot weather conditions can also be impeded by elevated carbon dioxide. In hot temperatures, many plants stay cool by opening wide the pores on the underside of their leaves. But in an atmosphere with high carbon dioxide, the pores do not open as wide, so plants are not able to keep themselves cool, Cornish said. This could cause “the plants to become crispy critters and die, when they were OK at lower carbon dioxide levels,” she said.

“Plants need time to adapt to the increase in carbon dioxide levels. And the increase is happening so quickly, plants are not going to have a chance to adapt.”

In the short term, the additional photosynthesis spurred by higher carbon dioxide levels may bring about small gains in the amount of leaves, stem and shoots that are produced by a crop but not necessarily in the portion of the crop that can be harvested. And in the long term, it’s going to do more harm to plants than good, Cornish said.

“There’s going to be a tipping point, and that tipping point is different for each crop,” Cornish said.

Already, rice plants grown in elevated carbon dioxide have been shown to produce more tillers, which include the stems and leaves of the plant, but fewer and smaller grains.

One way to prevent the higher carbon dioxide levels from affecting plant growth and yield is through plant crossbreeding and gene manipulation, Metzger pointed out. Both could lead to the creation of varieties of plants whose growth and nutrient levels will be less affected by the higher amounts of carbon dioxide in the environment.

More research is needed to figure out how a plant produces antioxidants, Metzger said.

“I think it’s important that we put some effort into really understanding how those biochemical pathways are controlled and how we can manipulate them without any harmful effects on the plant.”

How Exactly Does Carbon Dioxide Cause Global Warming?

“You Asked” is a series where Earth Institute experts tackle reader questions on science and sustainability. Over the past few years, we’ve received a lot of questions about carbon dioxide — how it traps heat, how it can have such a big effect if it only makes up a tiny percentage of the atmosphere, and more. With the help of Jason Smerdon, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory, we answer several of those questions here.

How does carbon dioxide trap heat?

You’ve probably already read that carbon dioxide and other greenhouse gases act like a blanket or a cap, trapping some of the heat that Earth might have otherwise radiated out into space. That’s the simple answer. But how exactly do certain molecules trap heat? The answer there requires diving into physics and chemistry.

Simplified diagram showing how Earth transforms sunlight into infrared energy. Greenhouse gases like carbon dioxide and methane absorb the infrared energy, re-emitting some of it back toward Earth and some of it out into space. Credit: A loose necktie on Wikimedia Commons

When sunlight reaches Earth, the surface absorbs some of the light’s energy and reradiates it as infrared waves, which we feel as heat. (Hold your hand over a dark rock on a warm sunny day and you can feel this phenomenon for yourself.) These infrared waves travel up into the atmosphere and will escape back into space if unimpeded.

Oxygen and nitrogen don’t interfere with infrared waves in the atmosphere. That’s because molecules are picky about the range of wavelengths that they interact with, Smerdon explained. For example, oxygen and nitrogen absorb energy that has tightly packed wavelengths of around 200 nanometers or less, whereas infrared energy travels at wider and lazier wavelengths of 700 to 1,000,000 nanometers. Those ranges don’t overlap, so to oxygen and nitrogen, it’s as if the infrared waves don’t even exist they let the waves (and heat) pass freely through the atmosphere.

A diagram showing the wavelengths of different types of energy. Energy from the Sun reaches Earth as mostly visible light. Earth reradiates that energy as infrared energy, which has a longer, slower wavelength. Whereas oxygen and nitrogen do not respond to infrared waves, greenhouse gases do. Credit: NASA

With CO2 and other greenhouse gases, it’s different. Carbon dioxide, for example, absorbs energy at a variety of wavelengths between 2,000 and 15,000 nanometers — a range that overlaps with that of infrared energy. As CO2 soaks up this infrared energy, it vibrates and re-emits the infrared energy back in all directions. About half of that energy goes out into space, and about half of it returns to Earth as heat, contributing to the ‘greenhouse effect.’

By measuring the wavelengths of infrared radiation that reaches the surface, scientists know that carbon dioxide, ozone, and methane are significantly contributing to rising global temperatures. Credit: Evans 2006 via Skeptical Science

Smerdon says that the reason why some molecules absorb infrared waves and some don’t “depends on their geometry and their composition.” He explained that oxygen and nitrogen molecules are simple — they’re each made up of only two atoms of the same element — which narrows their movements and the variety of wavelengths they can interact with. But greenhouse gases like CO2 and methane are made up of three or more atoms, which gives them a larger variety of ways to stretch and bend and twist. That means they can absorb a wider range of wavelengths — including infrared waves.

How can I see for myself that CO2 absorbs heat?

As an experiment that can be done in the home or the classroom, Smerdon recommends filling one soda bottle with CO2 (perhaps from a soda machine) and filling a second bottle with ambient air. “If you expose them both to a heat lamp, the CO2 bottle will warm up much more than the bottle with just ambient air,” he says. He recommends checking the bottle temperatures with a no-touch infrared thermometer. You’ll also want to make sure that you use the same style of bottle for each, and that both bottles receive the same amount of light from the lamp.

A more logistically challenging experiment that Smerdon recommends involves putting an infrared camera and a candle at opposite ends of a closed tube. When the tube is filled with ambient air, the camera picks up the infrared heat from the candle clearly. But once the tube is filled with carbon dioxide, the infrared image of the flame disappears, because the CO2 in the tube absorbs and scatters the heat from the candle in all directions, and therefore blurs out the image of the candle. There are several videos of the experiment online, including this one:

Why does carbon dioxide let heat in, but not out?

Energy enters our atmosphere as visible light, whereas it tries to leave as infrared energy. In other words, “energy coming into our planet from the Sun arrives as one currency, and it leaves in another,” said Smerdon.

CO2 molecules don’t really interact with sunlight’s wavelengths. Only after the Earth absorbs sunlight and reemits the energy as infrared waves can the CO2 and other greenhouse gases absorb the energy.

How can CO2 trap so much heat if it only makes up 0.04% of the atmosphere? Aren’t the molecules spaced too far apart?

Before humans began burning fossil fuels, naturally occurring greenhouse gases helped to make Earth’s climate habitable. Without them, the planet’s average temperature would be below freezing. So we know that even very low, natural levels of carbon dioxide and other greenhouse gases can make a huge difference in Earth’s climate.

Today, CO2 levels are higher than they have been in at least 3 million years. And although they still account for only 0.04% of the atmosphere, that still adds up to billions upon billions of tons of heat-trapping gas. For example, in 2019 alone, humans dumped 36.44 billion tonnes of CO2 into the atmosphere, where it will linger for hundreds of years. So there are plenty of CO2 molecules to provide a heat-trapping blanket across the entire atmosphere.

In addition, “trace amounts of a substance can have a large impact on a system,” explains Smerdon. Borrowing an analogy from Penn State meteorology professor David Titley, Smerdon said that “If someone my size drinks two beers, my blood alcohol content will be about 0.04 percent. That is right when the human body starts to feel the effects of alcohol.” Commercial drivers with a blood alcohol content of 0.04% can be convicted for driving under the influence.

“Similarly, it doesn’t take that much cyanide to poison a person,” adds Smerdon. “It has to do with how that specific substance interacts with the larger system and what it does to influence that system.”

In the case of greenhouse gases, the planet’s temperature is a balance between how much energy comes in versus how much energy goes out. Ultimately, any increase in the amount of heat-trapping means that the Earth’s surface gets hotter. (For a more advanced discussion of the thermodynamics involved, check out this NASA page.)

If there’s more water than CO2 in the atmosphere, how do we know that water isn’t to blame for climate change?

Water is indeed a greenhouse gas. It absorbs and re-emits infrared radiation, and thus makes the planet warmer. However, Smerdon says the amount of water vapor in the atmosphere is a consequence of warming rather than a driving force, because warmer air holds more water.

“We know this on a seasonal level,” he explains. “It’s generally drier in the winter when our local atmosphere is colder, and it’s more humid in the summer when it’s warmer.”

As carbon dioxide and other greenhouse gases heat up the planet, more water evaporates into the atmosphere, which in turn raises the temperature further. However, a hypothetical villain would not be able to exacerbate climate change by trying to pump more water vapor into the atmosphere, says Smerdon. “It would all rain out because temperature determines how much moisture can actually be held by the atmosphere.”

Similarly, it makes no sense to try to remove water vapor from the atmosphere, because natural, temperature-driven evaporation from plants and bodies of water would immediately replace it. To reduce water vapor in the atmosphere, we must lower global temperatures by reducing other greenhouse gases.

If Venus has an atmosphere that’s 95% CO2, shouldn’t it be a lot hotter than Earth?

Thick clouds of sulfuric acid surround Venus and prevent 75% of sunlight from reaching the planet’s surface. Without these clouds, Venus would be even hotter than it already is. Credit: NASA

The concentration of CO2 in Venus’ atmosphere is about 2,400 times higher than that of Earth. Yet the average temperature of Venus is only about 15 times higher. What gives?

Interestingly enough, part of the answer has to do with water vapor. According to Smerdon, scientists think that long ago, Venus experienced a runaway greenhouse effect that boiled away almost all of the planet’s water — and water vapor, remember, is also a heat-trapping gas.

“It doesn’t have water vapor in its atmosphere, which is an important factor,” says Smerdon. “And then the other important factor is Venus has all these crazy sulfuric acid clouds.”

High up in Venus’ atmosphere, he explained, clouds of sulfuric acid block about 75% of incoming sunlight. That means the vast majority of sunlight never gets a chance to reach the planet’s surface, return to the atmosphere as infrared energy, and get trapped by all that CO2 in the atmosphere.

Won’t the plants, ocean, and soil just absorb all the excess CO2?

Eventually … in several thousand years or so.

Plants, the oceans, and soil are natural carbon sinks — they remove some carbon dioxide from the atmosphere and store it underground, underwater, or in roots and tree trunks. Without human activity, the vast amounts of carbon in coal, oil, and natural gas deposits would have remained stored underground and mostly separate from the rest of the carbon cycle. But by burning these fossil fuels, humans are adding a lot more carbon into the atmosphere and ocean, and the carbon sinks don’t work fast enough to clean up our mess.

A simplified diagram showing the carbon cycle. Credit: Jack Cook/Woods Hole Oceanographic Institution

It’s like watering your garden with a firehose. Even though plants absorb water, they can only do so at a set rate, and if you keep running the firehose, your yard is going to flood. Currently our atmosphere and ocean are flooded with CO2, and we can see that the carbon sinks can’t keep up because the concentrations of CO2 in the atmosphere and oceans are rising quickly.

The amount of carbon dioxide in the atmosphere (raspberry line) has increased along with human emissions (blue line) since the start of the Industrial Revolution in 1750. Credit: NOAA

Unfortunately, we don’t have thousands of years to wait for nature to absorb the flood of CO2. By then, billions of people would have suffered and died from the impacts of climate change there would be mass extinctions, and our beautiful planet would become unrecognizable. We can avoid much of that damage and suffering through a combination of decarbonizing our energy supply, pulling CO2 out the atmosphere, and developing more sustainable ways of thriving.

Starving grasshoppers? How rising carbon dioxide levels may promote an ‘insect apocalypse’

Empty calories may be grasshoppers’ downfall. Many insect populations are declining, and a provocative new hypothesis suggests one problem is that rising levels of atmospheric carbon dioxide (CO2) are making plants less nutritious. That could spell trouble not just for insects, but for plant eaters of all sizes.

Over the past 5 years, several studies have documented dwindling insect populations, prompting “insect apocalypse” headlines and calls for increased conservation efforts. Not everyone was convinced insect populations can have booms and busts, and the trends might vary depending on the species. Just last week, for example, a meta-analysis of 166 insect populations found that although terrestrial species are indeed declining overall, aquatic insects seem to be doing fine. But a study on the Kansas prairie has convinced Michael Kaspari, an ecologist at the University of Oklahoma, that the decline is real—and that “nutrient dilution” in plants could be a major problem.

“The insect decline papers thus far haven’t been testing particular mechanisms for the declines they purport to show, so this proposed mechanism with concrete data is extremely powerful,” says Chelse Prather, a conservation biologist at the University of Dayton. Nutrient dilution “could be a global problem,” adds Roel van Klink, an entomologist at the German Centre for Integrative Biodiversity Research, whose team did last week’s analysis of insect trends.

Ellen Welti, Kaspari’s postdoc, had been analyzing data on 44 species of grasshoppers at the Konza Prairie Biological Station, a 3487-hectare native tallgrass preserve in northeastern Kansas that is the site of a long-term ecological research (LTER) program. She tracked population trends in two surveys of grasshopper abundance, one done in undisturbed habitats from 1996 to 2017 and another done from 2002 to 2017 where bison grazed. Population booms and busts coincided with major climatic events, such as El Niño, a Pacific Ocean disturbance that alters temperature and rainfall. But when Welti factored out those events, it became clear to her and Kaspari that over the long term, the grasshoppers were declining, by 30% over 2 decades. “I was actually quite surprised,” Welti recalls.

She and other researchers have assumed that habitat loss and pesticides underlie most of the reported drops in insect numbers. But those factors are not thought to be in play on the Konza Prairie.

Kaspari and Welti wondered whether another global trend could be responsible. Increasing CO2 concentrations in the air speed plant growth. But as Harvard University planetary health scientist Samuel Myers and his colleagues demonstrated in 2014, plants including wheat, maize, rice, and other major crops grown under expected future CO2 levels accumulate less nitrogen, phosphorous, sodium, zinc, and other nutrients than they do under current CO2 levels. The thinking is that roots cannot keep up with the growth stimulated by the extra carbon and therefore don’t provide adequate supplies of other elements.

Since then, most of the concern about nutrient dilution has focused on human health. Given the predicted rises in CO2, “diluted” plants could increase the number of people worldwide who are not getting enough nutrients in their diet—already 1 billion or so—by hundreds of millions, Myers says.

But he and others have wondered about the broader ecological impact. It “is an enormously important question,” Myers says. “As humans we have a lot of choices about what we eat, but there are a lot of animals that just eat what they eat.”

At the Kansas LTER, other researchers had collected and stored samples of the various grass species each year. So, Welti determined concentrations of 30 elements in those samples. The biomass of the grasses doubled over the past 30 years, but the plants’ nitrogen content declined about 42%, phosphorous by 58%, potassium by 54%, and sodium by 90%, Kaspari’s team reported recently in the Proceedings of the National Academy of Sciences. “This paper is a good red flag for the scientific community,” says biologist Arianne Cease at Arizona State University, Tempe.

Sebastian Seibold, a conservation biologist at the Technical University of Munich who has been studying insect declines for the past 10 years, cautions that the idea needs to be tested in different ecosystems. “We cannot derive general conclusions from it,” he says. “In German landscapes, there is no evidence for nutrient shortage,” adds Wolfgang Wägele, a taxonomist at the Zoological Research Museum Alexander Koenig.

Yet others suspect the work signals a sea change. “The study nicely demonstrates how climate change adds to the global problem of insect decline, even in presumably undisturbed areas,” says Lars Krogmann, a systematic entomologist at the University of Hohenheim.

Kaspari predicts that as investigators analyse the data sets van Klink pulled together for last week’s study, they will find that plant eaters are among the species most devastated in this decline. At the Konza Prairie, Welti hopes to bolster the hypothesis by looking for a decline in nutrients in the grasshoppers’ own tissues. Larger plant eaters, such as elephants, pandas, and elk, may also be at risk, Prather says. “If nutrient dilution is widespread, this has enormous implications for herbivorous organisms all over."

Will rising carbon dioxide levels really boost plant growth?

Credit: Shutterstock

Plants have become an unlikely subject of political debate. Many projections suggest that burning fossil fuels and the resulting climate change will make it harder to grow enough food for everyone in the coming decades. But some groups opposed to limiting our emissions claim that higher levels of carbon dioxide (CO₂) will boost plants' photosynthesis and so increase food production.

New research published in Science suggests that predicting the effects of increasing CO₂ levels on plant growth may actually be more complicated than anyone had expected.

To understand what the researchers have found out requires a bit of background information about photosynthesis. This is the process that uses light energy to power the conversion of CO₂ into the sugars that fuel plant growth and ultimately provide the food we depend on. Unfortunately, photosynthesis is flawed.

Molecules of CO₂ and oxygen are similar shapes and the key mechanism that harvests CO₂, an enzyme with the catchy name of RuBisCO, sometimes mistakes an oxygen molecule for one of CO₂. This wasn't a problem when RuBisCO first evolved. But about 30m years ago CO₂ levels in the atmosphere dropped to less than one-third of what they had been. With less CO₂ around, plants began mistakenly trying to harvest oxygen molecules more often. Today this is often a substantial drain upon a plant's energy and resources.

As it gets hotter, RuBisCO becomes even more prone to errors. Water also evaporates faster, forcing plants to take measures to avoid drying out. Unfortunately, stopping water getting out of their leaves also stops CO₂ getting in and, as RuBisCO becomes starved of CO₂, it wastes more and more of the plant's resources by using oxygen instead. At 25°C, this can consume one-quarter of what the plant produces – and the problem becomes more extreme as temperatures rise further.

However, some plants developed a way to avoid the problem by pumping CO₂ to the cells where the RuBisCO is located to turbocharge photosynthesis. These are known as C4 plants, as opposed to normal C3 plants which can't do this. C4 plants can be much more productive, especially under hot and dry conditions. They came to dominate Earth's tropical grasslands from 5m to 10m years ago, probably because the world became drier at this time and their water use is more efficient.

Maize (corn) and sugar cane are C4 plants but most crops are not, although a project initially funded by the Bill and Melinda Gates Foundation has been seeking to improve yields in rice by adding C4 machinery to it.

Most models of how plant growth and crop yields will be affected by the CO₂ released by burning fossil fuels have assumed that regular C3 plants may perform better. Meanwhile, the RuBisCO in C4 plants already gets enough CO₂ and so increases should have little effect on them. This has been supported by previous short-term studies.

The new Science paper reports data from a project that has been comparing C3 and C4 plants for the past 20 years. Their findings are surprising. As was expected, for the first ten years, C3 grasses grown under extra CO₂ did better – but their C4 equivalents did not. However, in the second decade of the experiment the situation reversed, with the C3 plants producing less biomass under higher levels of CO₂ and the C4 plants producing more.

It seems that this perplexing result may be because as time went by, less nitrogen was available to fertilise growth of plants in the C3 plots and more in the C4 plots. So the effect was not just due to the plants themselves but also to their interactions with the chemistry of the soil and its microbes.

These results suggest that the way that changes in CO₂ affect established ecosystems are likely to be complex and hard to predict. They may hint that, as CO₂ in the atmosphere increases, C4 tropical grasslands could perhaps absorb more carbon than expected, and forests, which are predominantly C3, might absorb less. But the exact picture is likely to depend on local conditions.

What this means for food production may be more straightforward and less comforting than at first glance. These results are from grasses that survive and continue to grow year on year. But current cereal crops are "annual plants" that die after one season and have to be replanted.

As a result, they don't have the opportunity to build up the soil interactions that seem to have boosted growth of the C4 plants in the experiment. We can't expect that our food security problems will be solved by C4 crop yields increasing in response to CO₂ as they did in the experiment. Similarly, the eventual fall in biomass seen in the C3 plots shouldn't happen in C3 annual crops.

But, as we know, C3 plants waste a lot more resources at higher temperatures, so any increase in photosynthesis from rising CO₂ levels seems likely to be at least cancelled out by the effects of the global warming it will cause. And that's without factoring in changes to rainfall patterns such as more frequent droughts. Solutions that seem to be too good to be true generally are – and, for the moment, that still seems to be the case for the idea that CO₂ enhanced crop yields will feed the world.


Zheutlin, A. R., Adar, S. D. & Park, S. K. Carbon dioxide emissions and change in prevalence of obesity and diabetes in the United States: an ecological study. Environ. Int. 73, 111–116 (2014).

Zappulla, D. Environmental stress, erythrocyte dysfunctions, inflammation, and the metabolic syndrome: adaptations to CO2 increases? J. Cardiometab. Syndr. 3, 30–34 (2008).

Costello, A. et al. Managing the health effects of climate change. Lancet 373, 1693–1733 (2009).

Mora, C. et al. Global risk of deadly heat. Nat. Clim. Change 7, 501–506 (2017).

Spengler, J. et al. in Climate Change, the Indoor Environment, and Health (eds Spengler, J. et al.) Ch. 4 (The National Academies Press, 2011).

Hönisch, B., Hemming, N. G., Archer, D., Siddall, M. & McManus, J. F. Atmospheric carbon dioxide concentration across the mid-Pleistocene transition. Science 324, 1551–1554 (2009).

Hayhoe, K. et al. in Climate Science Special Report: Fourth National Climate Assessment (eds Wuebbles, D. J. et al.) 133–160 (US Global Change Research Program, 2017).

Gall, E., Cheung, T., Luhung, I., Schiavon, S. & Nazaroff, W. Real-time monitoring of personal exposures to carbon dioxide. Build. Environ. 104, 59–67 (2016).

Kriebel, D. et al. The precautionary principle in environmental science. Environ. Health Perspect. 109, 871–876 (2001).

Crump, D. Climate Change—Health Impacts due to Changes in the Indoor Environment (Institute of Environment and Health, 2011).

Klepeis, N. E. et al. The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. J. Expo. Anal. Environ. Epidemiol. 11, 231–252 (2001).

Schweizer, C. et al. Indoor time–microenvironment–activity patterns in seven regions of Europe. J. Expo. Sci. Environ. Epidemiol. 17, 170–181 (2007).

Standard 62. 1–2013 Ventilation for Acceptable Indoor Air Quality (ANSI/ASHRAE, 2013).

Persily, A. Challenges in developing ventilation and indoor air quality standards: the story of ASHRAE Standard 62. Build. Environ. 91, 61–69 (2015).

Erdmann, C. A., Steiner, K. C. & Apte, M. G. Indoor carbon dioxide concentrations and sick building syndrome symptoms in the BASE study revisited: analyses of the 100 building dataset. Proc. Indoor Air 2002 3, 443–448 (2002).

Nazaroff, W. W. Exploring the consequences of climate change for indoor air quality. Environ. Res. Lett. 8, 015022 (2013).

Abdel-Salam, M. M. Investigation of PM2.5 and carbon dioxide levels in urban homes. J. Air Waste Manag. Assoc. 65, 930–936 (2015).

Seppänen, O. A., Fisk, W. J. & Mendell, M. J. Association of ventilation rates and CO2 concentrations with health and other responses in commercial and institutional buildings. Indoor Air 9, 226–252 (1999).

Fisk, W. J. The ventilation problem in schools: literature review. Indoor Air 27, 1039–1051 (2017).

Newsham, G. R. et al. Do ‘green’ buildings have better indoor environments? New evidence. Build. Res. Inf. 41, 415–434 (2013).

Liang, H.-H. et al. Satisfaction of occupants toward indoor environment quality of certified green office buildings in Taiwan. Build. Environ. 72, 232–242 (2014).

Colton, M. D. et al. Indoor air quality in green vs conventional multifamily low-income housing. Environ. Sci. Technol. 48, 7833–7841 (2014).

Persily, A. & de Jonge, L. Carbon dioxide generation rates for building occupants. Indoor Air 27, 868–879 (2017).

Becerra, M., Jerez, A., Valenzuela, M., Garces, H. & Demarco, R. Life quality disparity: analysis of indoor comfort gaps for Chilean households. Energy Policy 121, 190–201 (2018).

Mendell, M. J. & Heath, G. A. Do indoor pollutants and thermal conditions in schools influence student performance? A critical review of the literature. Indoor Air 15, 27–52 (2005).

Boor, B. E., Spilak, M. P., Laverge, J., Novoselac, A. & Xu, Y. Human exposure to indoor air pollutants in sleep microenvironments: a literature review. Build. Environ. 125, 528–555 (2017).

Strøm-Tejsen, P., Zukowska, D., Wargocki, P. & Wyon, D. P. The effects of bedroom air quality on sleep and next-day performance. Indoor Air 26, 679–686 (2016).

Mishra, A. K., van Ruitenbeek, A. M., Loomans, M. G. L. C. & Kort, H. S. M. Window/door opening-mediated bedroom ventilation and its impact on sleep quality of healthy, young adults. Indoor Air 28, 339–351 (2018).

Balvis, E., Sampedro, O., Zaragoza, S., Paredes, A. & Michinel, H. A simple model for automatic analysis and diagnosis of environmental thermal comfort in energy efficient buildings. Appl. Energy 177, 60–70 (2016).

Ghahramani, A. et al. Personal CO2 bubble: context-dependent variations and wearable sensors usability. J. Build. Eng. 22, 295–304 (2019).

Law, J., Watkins, S. & Alexander, D. In-Flight Carbon Dioxide Exposures and Related Symptoms: Association, Susceptibility, and Operational Implications (NASA Johnson Space Center, 2010).

Richardson, E. T. et al. Forced removals embodied as tuberculosis. Soc. Sci. Med. 161, 13–18 (2016).

Hudda, N. & Fruin, S. A. Carbon dioxide accumulation inside vehicles: the effect of ventilation and driving conditions. Sci. Total Environ. 610–611, 1448–1456 (2018).

Constantin, D., Mazilescu, C.-A., Nagi, M., Draghici, A. & Mihartescu, A.-A. Perception of cabin air quality among drivers and passengers. Sustainability 8, 852 (2016).

Cao, X. et al. The on-board carbon dioxide concentrations and ventilation performance in passenger cabins of US domestic flights. Indoor Built Environ. 28, 761–771 (2019).

Jacobson, M. Z. Enhancement of local air pollution by urban CO2 domes. Environ. Sci. Technol. 44, 2497–2502 (2010).

Velasco, E. & Roth, M. Cities as net sources of CO2: review of atmospheric CO2 exchange in urban environments measured by eddy covariance technique. Geogr. Compass 4, 1238–1259 (2010).

Ward, H. C. et al. Effects of urban density on carbon dioxide exchanges: observations of dense urban, suburban and woodland areas of southern England. Environ. Pollut. 198, 186–200 (2015).

Bergeron, O. & Strachan, I. B. CO2 sources and sinks in urban and suburban areas of a northern mid-latitude city. Atmos. Environ. 45, 1564–1573 (2011).

Idso, C. D., Idso, S. B. & Balling, R. C. Jr An intensive two-week study of an urban CO2 dome in Phoenix, Arizona, USA. Atmos. Environ. 35, 995–1000 (2001).

Idso, C. D., Idos, S. B. & Balling, R. C. Jr The urban CO2 dome of Phoenix, Arizona. Phys. Geogr. 19, 95–108 (1998).

Wang, P. et al. Emission characteristics of atmospheric carbon dioxide in Xi’an, China based on the measurements of CO2 concentration, Δ 14 C and δ 13 C. Sci. Total Environ. 619–620, 1163–1169 (2018).

W orld Urbanization Prospects: The 2018 Revision (Economic and Social Affairs, United Nations, 2018).

George, K., Ziska, L. H., Bunce, J. A. & Quebedeaux, B. Elevated atmospheric CO2 concentration and temperature across an urban–rural transect. Atmos. Environ. 41, 7654–7665 (2007).

Esquivel-Hernandez, G. et al. Near surface carbon dioxide and methane in urban areas of Costa Rica. Open J. Air Pollut. 4, 208–223 (2015).

Briber, B., Hutyra, L., Dunn, A., Raciti, S. & Munger, J. W. Variations in atmospheric CO2 mixing ratios across a Boston, MA urban to rural gradient. Land 3, 304–327 (2013).

Lee, J. K., Christen, A., Ketler, R. & Nesic, Z. A mobile sensor network to map carbon dioxide emissions in urban environments. Atmos. Meas. Tech. 10, 645–665 (2017).

Sahay, S. & Ghosh, C. Monitoring variation in greenhouse gases concentration in urban environment of Delhi. Environ. Monit. Assess. 185, 123–142 (2013).

Majumdar, D., Rao, P. & Maske, N. Inter-seasonal and spatial distribution of ground-level greenhouse gases (CO2, CH4, N2O) over Nagpur in India and their management roadmap. Environ. Monit. Assess. 189, 121 (2017).

Gratani, L. & Varone, L. Atmospheric carbon dioxide concentration variations in Rome: relationship with traffic level and urban park size. Urban Ecosyst. 17, 501–511 (2014).

Persily, A. Evaluating building IAQ and ventilation with carbon dioxide. ASHRAE Trans. 103, 193–204 (1997).

Keun Kim, M. & Choi, J. Can increased outdoor CO2 concentrations impact on the ventilation and energy in buildings? A case study in Shanghai, China. Atmos. Environ. 210, 220–230 (2019).

Okobia, L. E., Hassan, S. M. & Peter, A. Increase in outdoor carbon dioxide and its effects on the environment and human health in Kuje FCT Nigeria. Environ. Health Rev. 60, 104–112 (2017).

Arceo, E., Hanna, R. & Oliva, P. Does the effect of pollution on infant mortality differ between developing and developed countries? Evidence from Mexico City. Econ. J. 126, 257–280 (2016).

Lu, R. & Turco, R. P. Air pollutant transport in a coastal environment. Part 1: Two-dimensional simulations of sea-breeze and mountain effects. J. Atmos. Sci. 51, 2285–2308 (1994).

Bell, M. L. & Davis, D. L. Reassessment of the lethal London fog of 1952: novel indicators of acute and chronic consequences of acute exposure to air pollution. Environ. Health Perspect. 109, 389–394 (2001).

Rendon, A. M., Salazar, J. F. & Palacio, C. A. Effects of urbanization on the temperature inversion breakup in a mountain valley with implications for air quality. J. Appl. Meteorol. Climatol. 53, 840–858 (2014).

Gago, E. J., Roldan, J., Pacheco-Torres, R. & Ordonez, J. The city and urban heat islands: a review of strategies to mitigate adverse effects. Renew. Sustain. Energy Rev. 25, 749–758 (2013).

Lietzke, B. & Vogt, R. Variability of CO2 concentrations and fluxes in and above an urban street canyon. Atmos. Environ. 74, 60–72 (2013).

Velasco, E. et al. Sources and sinks of carbon dioxide in a neighborhood of Mexico City. Atmos. Environ. 97, 226–238 (2014).

Robertson, D. S. The rise in the atmospheric concentration of carbon dioxide and the effects on human health. Med. Hypotheses 56, 513–518 (2001).

Spengler, J. D. Climate change, indoor environments, and health. Indoor Air 22, 89–95 (2012).

Lowe, R. J., Huebner, G. M. & Oreszczyn, T. Possible future impacts of elevated levels of atmospheric CO2 on human cognitive performance and on the design and operation of ventilation systems in buildings. Build. Serv. Eng. Res. Technol. 39, 698–711 (2018).

Carlton, E. J. et al. Relationships between home ventilation rates and respiratory health in the Colorado Home Energy Efficiency and Respiratory Health (CHEER) study. Environ. Res. 169, 297–307 (2019).

Chen, J., Brager, G. S., Augenbroe, G. & Song, X. Impact of outdoor air quality on the natural ventilation usage of commercial buildings in the US. Appl. Energy 235, 673–684 (2019).

Shrubsole, C. et al. Bridging the gap: the need for a systems thinking approach in understanding and addressing energy and environmental performance in buildings. Indoor Built Environ. 28, 100–117 (2019).

Vardoulakis, S. et al. Impact of climate change on the domestic indoor environment and associated health risks in the UK. Environ. Int. 85, 299–313 (2015).

Steinemann, A., Wargocki, P. & Rismanchi, B. Ten questions concerning green buildings and indoor air quality. Build. Environ. 112, 351–358 (2016).

Zappulla, D. in Air Pollution - Sources, Prevention, and Health Effects (ed. Sethi, R.) Ch. 16 (Nova Science, 2013).

Leung, D. Y. C. Outdoor-indoor air pollution in urban environment: challenges and opportunity. Front. Environ. Sci. 2, 69 (2015).

Fitzpatrick, M. C. & Dunn, R. R. Contemporary climatic analogs for 540 North American urban areas in the late 21st century. Nat. Commun. 10, 614 (2019).

King, A. D. & Harrington, L. J. The inequality of climate change from 1.5 to 2 °C of global warming. Geophys. Res. Lett. 45, 5030–5033 (2018).

Zhang, X., Wargocki, P. & Lian, Z. Physiological responses during exposure to carbon dioxide and bioeffluents at levels typically occurring indoors. Indoor Air 27, 65–77 (2017).

Zhang, X., Wargocki, P., Lian, Z. & Thyregod, C. Effects of exposure to carbon dioxide and bioeffluents on perceived air quality, self-assessed acute health symptoms, and cognitive performance. Indoor Air 27, 47–64 (2017).

Zhang, X., Wargocki, P. & Lian, Z. Human responses to carbon dioxide, a follow-up study at recommended exposure limits in non-industrial environments. Build. Environ. 100, 162–171 (2016).

Shiraram, S., Ramamurthy, K. & Ramakrishnan, S. Effect of occupant-induced indoor CO2 concentration and bioeffluents on human phyiology using a spirometric test. Build. Environ. 149, 58–67 (2019).

Vehvilainen, T. et al. High indoor CO2 concentrations in an office environment increases the transcutaneous CO2 level and sleepiness during cognitive work. J. Occup. Environ. Hyg. 13, 19–29 (2016).

Hughson, R. L., Yee, N. J. & Greaves, D. K. Elevated end-tidal PCO2 during long-duration spaceflight. Aerosp. Med. Hum. Perform. 87, 894–897 (2016).

Law, J. et al. Relationship between carbon dioxide levels and reported headaches on the international space station. J. Occup. Environ. Med. 56, 477–483 (2014).

Thom, S. R., Bhopale, V. M., Hu, J. & Yang, M. Inflammatory responses to acute elevations of carbon dioxide in mice. J. Appl. Physiol. 123, 297–302 (2017).

Thom, S. R., Bhopale, V. M., Hu, J. & Yang, M. Increased carbon dioxide levels stimulate neutrophils to produce microparticles and activate the nucleotide-binding domain-like receptor 3 inflammasome. Free Radic. Biol. Med. 106, 406–416 (2017).

Schneberger, D., DeVasure, J. M., Bailey, K. L., Romberger, D. J. & Wyatt, T. A. Effect of low-level CO2 on innate inflammatory protein response to organic dust from swine confinement barns. J. Occup. Med. Toxicol. 12, 9 (2017).

Hutter, H. P. et al. Semivolatile compounds in schools and their influence on cognitive performance of children. Int. J. Occup. Med. Environ. Health 26, 628–635 (2013).

Azuma, K., Kagi, N., Yanagi, U. & Osawa, H. Effects of low-level inhalation exposure to carbon dioxide in indoor environments: a short review on human health and pscyhomotor performance. Environ. Int. 121, 51–56 (2018).

Kajtar, L. & Herczeg, L. Influence of carbon-dioxide concentration on human well-being and intensity of mental work. Idojaras 116, 145–169 (2012).

Satish, U. et al. Is CO2 an indoor pollutant? Direct effects of low-to-moderate CO2 concentrations on human decision-making performance. Environ. Health Perspect. 120, 1671–1677 (2012).

Allen, J. G. et al. Associations of cognitive function scores with carbon dioxide, ventilation, and volatile organic compound exposures in office workers: a controlled exposure study of green and conventional office environments. Environ. Health Perspect. 124, 805–812 (2016).

Allen, J. G. et al. Airplane pilot flight performance on 21 maneuvers in a flight simulator under varying carbon dioxide concentrations. J. Expo. Sci. Environ. Epidemiol. 29, 457–468 (2019).

Cao, X. et al. Heart rate variability and performance of commercial airline pilots during flight simulations. Int. J. Environ. Res. Public Health 16, 237 (2019).

Snow, S. et al. Exploring the physiological, neurophysiological and cognitive performance effects of elevated carbon dioxide concentrations indoors. Build. Environ. 156, 243–252 (2019).

Rodeheffer, C. D., Chabal, S., Clarke, J. M. & Fothergill, D. M. Acute exposure to low-to-moderate carbon dioxide levels and submariner decision making. Aerosp. Med. Hum. Perform. 89, 520–525 (2018).

Snow, S. et al. Using EEG to characterise drowsiness during short duration exposure to elevated indoor carbon dioxide concentrations. Preprint at bioRxiv (2018).

MacNaughton, P. et al. Environmental perceptions and health before and after relocation to a green building. Build. Environ. 104, 138–144 (2016).

Miller, A. H. & Raison, C. L. The role of inflammation in depression: from evolutionary imperative to modern treatment target. Nat. Rev. Immunol. 16, 22–34 (2016).

Cronym, P. D., Watkins, S. & Alexander, D. J. Chronic Exposure to Moderately Elevated CO 2 During Long-Duration Space Flight (NASA Center for AeroSpace Information, 2012).

Bloch-Salisbury, E., Lansing, R. & Shea, S. A. Acute changes in carbon dioxide levels alter the electroencephalogram without affecting cognitive function. Psychophysiology 37, 418–426 (2000).

Zouboules, S. M. & Day, T. A. The exhausting work of acclimating to chronically elevated CO2. J. Physiol. 597, 1421–1423 (2019).

Wang, D., Thomas, R. J., Yee, B. J. & Grunstein, R. R. Hypercapnia is more important than hypoxia in the neuro-outcomes of sleep-disordered breathing. J. Appl. Physiol. 120, 1484–1486 (2016).

Burgraff, N. J. et al. Ventilatory and integrated physiological responses to chronic hypercapnia in goats. J. Physiol. 596, 5343–5363 (2018).

Miller, J. et al. Comorbidity, systemic inflammation and outcomes in the ECLIPSE cohort. Resp. Med. 107, 1376–1384 (2013).

Beheshti, A., Cekanaviciute, E., Smith, D. J. & Costes, S. V. Global transcriptomic analysis suggests carbon dioxide as an environmental stressor in spaceflight: a systems biology GeneLab case study. Sci. Rep. 8, 4191 (2018).

Schaefer, K. E. Effects of increased ambient CO2 levels on human and animal health. Experientia 38, 1163–1168 (1982).

Schaefer, K. E., Douglas, W. H. J., Messier, A. A., Shea, M. L. & Gohman, P. A. Effect of prolonged exposure to 0.5% CO2 on kidney calcification and ultrastructure of lungs. Undersea Biomed. Res. 6, S155–S161 (1979).

Wade, C. E., Wang, T. J., Lang, K. C., Corbin, B. J. & Steele, M. K. Rat growth, body composition, and renal function during 30 days increased ambient CO2 exposure. Aviat. Space Environ. Med. 71, 599–609 (2000).

Hacquemand, R. et al. Effects of CO2 inhalation exposure on mice vomeronasal epithelium. Cell Biol. Toxicol. 26, 309–317 (2010).

Robertson, D. S. Health effects of increase in concentration of carbon dioxide in the atmosphere. Curr. Sci. 90, 1607–1609 (2006).

Robertson, D. S. Palaeo-variations in the atmospheric concentration of carbon dioxide and the relationship to extinctions. Speculat. Sci. Technol. 21, 171–185 (1999).

Guais, A. et al. Toxicity of carbon dioxide: a review. Chem. Res. Toxicol. 24, 2061–2070 (2011).

Carnauba, R. A., Baptistella, A. B., Paschoal, V. & Hübscher, G. H. Diet-induced low-grade metabolic acidosis and clinical outcomes: a review. Nutrients 9, 538 (2017).

Frassetto, L., Banerjee, T., Powe, N. & Sebastian, A. Acid balance, dietary acid load, and bone effects-a controversial subject. Nutrients 10, 517 (2018).

Martrette, J. M. et al. Effects of prolonged exposure to CO2 on behaviour, hormone secretion and respiratory muscles in young female rats. Physiol. Behav. 177, 257–262 (2017).

Kiray, M. et al. Effects of carbon dioxide exposure on early brain development in rats. Biotech. Histochem. 89, 371–383 (2014).

Hersoug, L. G., Sjödin, A. & Astrup, A. A proposed potential role for increasing atmospheric CO2 as a promoter of weight gain and obesity. Nutr. Diabetes 2, e31 (2012).

Kikuchi, R. et al. Hypercapnia accelerates adipogenesis: a novel role of high CO2 in exacerbating obesity. Am. J. Resp. Cell Mol. Biol. 57, 570–580 (2017).

Medinas, D. B., Cerchiaro, G., Trindade, D. F. & Augusto, O. The carbonate radical and related oxidants derived from bicarbonate buffer. IUBMB Life 59, 255–262 (2007).

Ezraty, B., Chabalier, M., Ducret, A., Maisonneuve, E. & Dukan, S. CO2 exacerbates oxygen toxicity. EMBO Rep. 12, 321–326 (2011).

Veselá, A. & Wilhelm, J. The role of carbon dioxide in free radical reactions of the organism. Physiol. Res. 51, 335–339 (2002).

Zuj, K. A. et al. Impaired cerebrovascular autoregulation and reduced CO2 reactivity after long duration spaceflight. Am. J. Physiol. Heart Circ. Physiol. 302, H2592–H2598 (2012).

Zwart, S. R. et al. Astronaut ophthalmic syndrome. FASEB J. 31, 3746–3756 (2017).

Michael, A. P. & Marshall-Bowman, K. Spaceflight-induced intracranial hypertension. Aerosp. Med. Hum. Perform. 86, 557–562 (2015).

Laurie, S. S. et al. Effects of short-term mild hypercapnia during head-down tilt on intracranial pressure and ocular structures in healthy human subjects. Physiol. Rep. 5, e13302 (2017).

Faustman, E. M., Silbernagel, S. M., Fenske, R. A., Burbacher, T. M. & Ponce, R. A. Mechanisms underlying children’s susceptibility to environmental toxicants. Environ. Health Perspect. 108, 13–21 (2000).

Rice, S. A. Human health risk assessment of CO2: survivors of acute high-level exposure and populations sensitive to prolonged low-level exposure. In Third Annual Conference on Carbon Sequestration (2004)

Glodzik, L., Randall, C., Rusinek, H. & de Leon, M. J. Cerebrovascular reactivity to carbon dioxide in Alzheimer’s disease. J. Alzheimers Dis. 35, 427–440 (2013).

Holy, X., Collombet, J. M., Labarthe, F., Granger-Veyron, N. & Bégot, L. Effects of seasonal vitamin D deficiency and respiratory acidosis on bone metabolism markers in submarine crewmembers during prolonged patrols. J. Appl. Physiol. 112, 587–596 (2012).

Battaglia, M. & Khan, W. U. in Biomarkers in Psychiatry. Current Topics in Behavioral Neurosciences Vol. 40 (eds Pratt, J. & Hall, J.) 195–217 (Springer, 2018).

Kim, J., Kong, M., Hong, T., Jeong, K. & Lee, M. Physiological response of building occupants based on their activity and the indoor environmental quality condition changes. Build. Environ. 145, 96–103 (2018).

Anderson, D. E. Cardiorenal effects of behavioral inhibition of breathing. Biol. Psychol. 49, 151–163 (1998).

Anderson, D. E. & Chesney, M. A. Gender-specific association of perceived stress and inhibited breathing pattern. Int. J. Behav. Med. 9, 216–227 (2002).

Scholz, L. et al. Miniature low-cost carbon dioxide sensor for mobile devices. IEEE Sens. J. 17, 2889–2895 (2017).

Stingone, J. A. et al. Toward greater implementation of the exposome research paradigm within environmental epidemiology. Annu. Rev. Public Health 38, 315–327 (2017).

Go, Y. M., Chandler, J. D. & Jones, D. P. The cysteine proteome. Free Radic. Biol. Med. 84, 227–245 (2015).

Ghaffarianhoseini, A. et al. Sick building syndrome: are we doing enough? Archit. Sci. Rev. 61, 99–121 (2018).

Heidari, L., Younger, M., Chandler, G., Gooch, J. & Schramm, P. Integrating health into buildings of the future. ASME J. Sol. Energy Eng. 139, 010802 (2017).

Carrer, P. et al. On the development of health-based ventilation guidelines: principles and framework. Int. J. Environ. Res. Public Health 15, 1360 (2018).

MacNaughton, P. et al. The impact of working in a green certified building on cognitive function and health. Build. Environ. 114, 178–186 (2017).

Shrubsole, C. Systems thinking in the built environment: seeing the bigger picture, understanding the detail. Indoor Built Environ. 27, 439–441 (2018).


This work used eddy covariance data acquired and shared by the FLUXNET community, including these networks: AmeriFlux, AfriFlux, AsiaFlux, CarboAfrica, CarboEuropeIP, CarboItaly, CarboMont, ChinaFlux, Fluxnet-Canada, GreenGrass, ICOS, KoFlux, LBA, NECC, OzFlux-TERN, TCOS-Siberia, and USCCC. The FLUXNET eddy covariance data processing and harmonization was carried out by the European Fluxes Database Cluster, AmeriFlux Management Project, and Fluxdata project of FLUXNET.

Support for this research was provided by the California Department of Water Resources, the US Department of Energy, Office of Science and Biological and Environmental Research, and the European Research Council Synergy grant ERC-SyG-2013-610028 IMBALANCE-P.

Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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