Arguments
Fact brief - Can CO2 be ignored because it’s just a trace gas?
Posted on 18 January 2025 by Guest Author
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Can CO2 be ignored because it’s just a trace gas?
While carbon dioxide is a small part of the atmosphere, it has a large impact on climate as a greenhouse gas.
Nitrogen and oxygen make up around 99% of the atmosphere, but neither traps heat. Less than 0.05% of the atmosphere is made up of greenhouse gases, which do.
Without greenhouse gases, the Earth would be too cold to support most life, with average temperatures 2° F below zero (-18° C).
On the other hand, increasing greenhouse gas concentrations elevates temperatures. Human activities such as fossil fuel burning have raised CO2 concentrations from 280 parts per million in pre-industrial times to 424 parts per million in 2024. Over the same period, the planet has warmed 2° F (1.3° C) on average.
Climate scientists agree that emissions of CO2 and other greenhouse gases are responsible for this observed rise in temperature despite their relatively low concentration in the atmosphere.
Go to full rebuttal on Skeptical Science or to the fact brief on Gigafact
This fact brief is responsive to conversations such as this one.
Sources
NASA Carbon Dioxide
MIT Climate Portal How do greenhouse gases trap heat in the atmosphere?
Columbia Climate School You Asked: If CO2 Is Only 0.04% of the Atmosphere, How Does it Drive Global Warming?
NASA Steamy Relationships: How Atmospheric Water Vapor Amplifies Earth’s Greenhouse Effect
EIA Energy and the environment explained
Carbon Brief State of the climate: 2024 sets a new record as the first year above 1.5C
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Carbon dioxide is a trace gas, but to put that in perspective, the amount of CO2 in the atmosphere is not physically insubstantial.
Focusing on parts per million to the exclusion of actual amounts is employing a mathematical sleight of hand. A sleight of hand that suits those who don't accept the scientific orthodoxy behind the 'warming' role of CO2.
Which is why "trace" amounts of CO2 supports the massive amount of plant life on land and in water.
Noel:
An illustration of why ppm is a bad set of units to look at the radiative effects of CO2 forms part of the discussion in this blog post I did a few years ago. (To toot my own horn.)
https://skepticalscience.com/from-email-bag-beer-lambert.html
Nicely stated Noel.
"Which is why "trace" amounts of CO2 supports the massive amount of plant life on land and in water."
Thanks for the reminder Bob of your very interesting and illustrative paper.
Yes, indeed, Evan (and Noel).
It is always interesting to see how the contrarians can both argue that "CO2 is a trace gas" and can't possibly imagine that it can have any effect - yet at the same time they argue that the CO2 effect is saturated, so adding more can't have any additional effect. And then turn around and do the "CO2 is plant food" dance.
If Elon Musk wanted to give me 0.04% of his net worth, I'm sure I could live a long and wealthy life on "trace money".
Noel Yrrep,
In addition to your well presented questioning of the questionable claims made-up by people who are resistant to learning how CO2 levels in the atmosphere significantly affect the global average surface temperature, the ‘hard of learning’ would struggle to explain:
How the surface is so much warmer than it would be without ‘trace amounts of ghg’ in the atmosphere. What evidence-based, independently verifiable, alternative understanding do they offer?
Some might claim that God made it this way, in a way that humans cannot ruin, therefore, it is not necessary for people to understand how it works. Others may claim that the activity in free market capitalism (the developed economy) will naturally be the best way to identify and solve any developed or developing problems if it is free from external observation and influences. Still Others may claim that popularity of a belief justifies it. And some may claim that everyone's personal opinion is as valid as any other opinion.
Those would be arguments based on orthodoxy (which means ‘the right opinion’).
Science is not a matter of opinion. Science, done scientifically, develops evidence-based improved understandings of what is going on.
So I would recommend that instead of “...those who don't accept the scientific orthodoxy behind the 'warming' role of CO2.”, you should say something like “...those who resist improving their awareness and understanding of the scientifically developed knowledge regarding the 'warming' role of CO2.”
One of the fundamental problems for understanding how a "trace" gas can have such a large impact is that most people don't understand how delicately balanced our ecosystem is. Consider that the orbits of Jupiter and Saturn, over 100,000-yr cycles (i.e., Milankovitch cycles), cause sealevel to go up and down 400 ft! That is a delicately-balanced system!
Evan @6,
Your make a good point about the sensitivity of our amazing planet’s global climate conditions. It has prompted the following thoughts regarding attempts to ignore or dismiss CO2 impacts ...
The warming impact of increased levels of CO2 have been understood for more than 125 years. And the natural causes of glaciation and inter-glacial periods, like the Milankovitch cycles, have been reasonably understood for more than 80 years.
A challenging understanding, an inconvenient truth, is that human CO2 impacts causing global warming may be helpful in the future but are not helpful now. Those distant future actions could make the next natural glaciation event more ‘livable’.
The next glaciation is expected to naturally happen about 50,000 years from now. But studies, like the one reported in the Carbon Brief in 2016: Human emissions will delay next ice age by 50,000 years, indicate that the human caused increased CO2 levels have likely delayed the next glaciation by 50,000 years. That is nothing to be proud of. It was Too Much Too Soon.
It would be ‘great’ if lots of easy to access fossil fuels were still available for future humans to use to limit the negative impacts of future glaciations.
Fossil fuels are undeniably non-renewable. Future generations cannot benefit from burning them as much as current generations do. Rapidly ending fossil fuel use would leave more ‘limited resources’ for the benefit of future generations and reduce the climate change harm done to people today and to future generations. However, the ‘competitive marketplace’ fails to ‘naturally’ develop towards those understandably ‘great’ objectives. In fact, there is ample evidence that the marketplace developed, and continues to develop, misinformation efforts against the development of such ’helpful external influences on the marketplace’.
The undeniable marketplace efforts against learning to be less harmful and more helpful to Others clarifies what competitive free market activity can be expected to accomplish. The fundamental market function is managing the distribution and benefits from the use of scarce resources. It develops replacement alternatives as resources become scarcer. However, the marketplace will only seriously develop replacements that are less expensive than the increased cost of the activities that rely on scarcer resources (note political efforts to reduce the costs of fossil fuels).
More importantly, the market is unlikely to care to reduce harm or ensure that harm done is repaired. Limiting harm done, and avoiding the challenge of getting the beneficiaries of harm done to repair the damage done, requires external influence to make the more harmful ways less popular, more difficult, and more expensive.
Hopefully efforts to limit the success of misinformation, not just regarding climate science, will result in more helpful and less harmful political action. It is common sense that political actions need to be less likely to cycle in ways that are significantly negative for the future of humanity. However, limiting the sensitivity of political actions to harmful misunderstandings is likely less certain than improving the understanding of the sensitivity of the climate on this amazing planet to the impacts of human activity.
Scientific understanding is certain to be constantly improving the ability to develop sustainable improvements and limit harm done - The politics of popularity of beliefs is not certain to develop sustainable improvements or limit harm done.
OPOF@7, whereas you make good points that I think most of agree with, they represent a global perspective with the benefit of a broad scientific overview, shared by a relatively small percentage of our planet. The bulk of humans operate within a very narrow sphere of understanding, more concerned about meeting their daily needs than planning for long-term effects.
And then, of course, there are the complications of greed and self interest. I don't see any of these conditions changing. So whereas I agree conceptually with your analysis, I don't see enough of the world adopting viewpoints such as you present to really slow down the steady buildup of GHGs in the atmosphere.
As always, I hope I'm wrong, and I hope more people adopt your well-stated viewpoints.
Evan @8,
I understand that I am ‘not the norm’. I am a retired professional engineer with an MBA who, decades ago, ‘took to heart’ the ethical obligation to learn to ‘protect the public interests from the potential harms of interests that are opposed to learning to be less harmful and more helpful to others’.
There is a reason I concluded my comment @7 the way I did.
I agree that the future is likely to continue to get worse while ‘potentially appearing to be getting better’. Global interests can indeed be harmfully influenced by ‘Us (me) vs Others’-ism (not just nationalism). There needs to be a systemic change of the ‘developed dominance of misleading marketing in the competitions for perceptions of superiority’.
The ‘popularity of beliefs’ needs to be governed by learning to be less harmful and more helpful to others. Developed socioeconomic systems have been significantly influenced by misunderstandings that keep people from learning how to be less harmful and more helpful to others.
The problem has always been the many ways that popularity of instinctive, first-impression, emotion-triggered, gut-reaction misunderstandings can ‘be more popular’ than rational unemotional thoughtful considerate (critical thinking) pursuits of learning to be less harmful and more helpful to others. Note that changing this fundamental dynamic is an uphill battle. The science (knowledge) of how to win by being misleading is very advanced and continues to quickly advance.
It is important for people to learn where the blame lies (intentionally chosen term):
I also hope that the future of humanity will be sustainably improved. However, I share your concern that climate change impact mitigation is not happening as rapidly as is need to responsibly limit the harm done. Responsible considerate leadership could have accomplished significantly more mitigation by now.
My more global concern is that we could be witnessing the early days of a powerful resurgence leading to many decades, possibly centuries, of global humanity being dominated by extremely harmful misunderstandings.
The success of misleaders can be sensitive to small changes of awareness and understanding. Every vote and consumer choice matters.
The more 'common sense, or normal, understanding' needs to be that anyone aware of misleading messages regarding climate science has no excuse for supporting the misleaders (as customers or voters) regardless of other interests. ‘Pursuers of popularity’ who are misleading about climate science are likely harmfully misleading about many other things.
Evan @8, and OPOF @9
Interesting. I agree with OPOFs views on the climate issue, in a theoretical sense. For example, it is obvious to me high income people can mostly cut their consumption significantly and still have a decent enough life, and that leaders of society should set an example. However I share Evans concern that greed and self interest get in the way, and human nature is unlikely to change.
But the situation is quite nuanced because most people are not hugely greedy. They clearly make personal sacrifices for a good cause, up to a limit, on average over the population. For example they donate to charity and help others. The majority of people have accepted things like carbon taxes or emissions trading schemes up to a certain extent, knowing this is ultimately a personal sacrifice. This has helped build renewable energy.
I think our job is to persuade people to make as much sacrifice as possible in terms of things like accepting carbon taxes or government subsidy schemes. But it seems unlikely we would get people to make huge personal sacrifices of the type where they stop flying, or turn thermostats down low in the middle of winter and cycle everywhere. These things can become very uncomfortable and have various downsides. This is all why I tend to promote the renewables and electric cars side of the equation. I dont fly much myself , but for many people travel is viewed almost as an essential of life.
The energy consumption issue has another dimension as well. If we cut our levels of energy use too much and too fast it could cause a severe recession and unemployment, as demand is sucked out of the economy. And this means its unlikely such a policy would gain traction. This is why I tend to think we are mostly or almost completely reliant on an energy substitiution process of building renewables and EV's. Im not saying this is the ideal perfect solution - just that is likely the only workable solution in the real world.
I think the misinformation thing is a different issue, although it is used to make greed sound acceptable.
OPOF: "My more global concern is that we could be witnessing the early days of a powerful resurgence leading to many decades, possibly centuries, of global humanity being dominated by extremely harmful misunderstandings."
It has shocked me how 50% of people could support a leader who spreads huge volumes of misinformation. Its really a bit depressing and shows how thin the veneer of civilisation is. However its hard to say how long harmful misunderstandings would last. If a harmful misunderstanding causes a global trajedy like a nuclear war the pendulum might quickly swing back to the need to truth and accuracy. Or maybe people will just tire of all the misinformation and normality will be restored quite quickly. But in the medieval period of human history, the middle ages, people believed in complete nonsense and it was a dark time that lasted over 1000 years. It kind of self corrected as people slowly realised their lack of accurate information was holding them back and science emerged to promote accurate information. But that was a slow process. Maybe a centuries long period of misinformation could happen again especially if there is a huge drop in trust in science. We must do all we can to counter that.
Trace is a flexile concept. For climate change deniers 400 parts per million is a trace. What then is 200 parts in 100 million million? 200 nanograms is the weight of purified botulinus toxin required to kill a 100 kilogram or 100 million million nanogram human. That is 400 parts per 200 million million. In the natural world of climate change science and biology unimaginably tiny amounts of substances have profound effects that are readily observed by the intelligent. Climate change denial, though, relies on widespread ignorance. Unfortunately, in my country, Australia, and Trump’s America it’s been an incredibly successful strategy.
nigelj @10,
I have reasons to disagree regarding greed and self-interest being ‘ human nature that is unlikely to change’.
I will start by presenting an important perspective on economic development (aligned with the understanding presented in the 2012 book “Why Nations Fail”).
A competitive marketplace (of products, services, ideas, science, politics...) can develop amazing improvements. That is the positive-sum game (vs. zero-sum game) potential of marketplace competition. And the ways it happens include creative disruption or creative destruction of the developed status-quo (links are to Wikipedia. Note that “Why Nations Fail” is mentioened in the creative destruction Wikipedia item). However, competition for personal benefit and perceptions of superiority relative to others can produce negative-sum disruptive-destructive results.
When creative disruption-destruction is not responsibly governed by learning to be less harmful and more helpful to others the collective result can be worse than it needed to be. If people in the competition can get away with winning by being more harmful and less helpful to others then ‘greed and selfishness are encouraged to develop’ rather than being ‘human nature’.
The winners in the negative-sum game may be worse off than they would have been in the positive-sum alternative. But they pursue ‘their interest’ which is ‘increasing their perceived status relative to others’. They would think that others benefiting reduces ‘their’ potential ‘relative’ superiority.
The sensitivity of the climate on this amazing planet to human impacts on seemingly minor aspects of what is going on, like the trace amount of CO2, is tragically affected by the sensitivity of people to temptations to misunderstand matters in ways that make them like being greedier and more selfish.
Today’s situation is worse than it needed to be. The fossil fuel collective has successfully misled resistance to the creative disruption of developed energy systems. As a result there is more damage done and increasing need for creative disruption-destruction. The feedback response to increased need for rapid creative disruption-destruction is ‘increased resistance to change’.
What is required is getting people to change their mind about understandably unsustainable and harmful actions they have developed a liking for and related misunderstandings that promote and excuse those actions. And the manitude and speed of the required changes is continuing to increase.
Misinformation is a serious problem, especially, but not only, regarding climate change. This NPR article “The Doomsday Clock has never been closer to metaphorical midnight. What does it mean?” includes the following:
This year, it cited continuing trends in multiple "global existential threats" including nuclear weapons, climate change, AI, infectious diseases and conflicts in Ukraine and the Middle East. It also pointed to the spread of misinformation and conspiracy theories as a "potent threat multiplier" that undermines public discourse in general and about these very issues.
While these threats are not new, the scientists said that "despite unmistakable signs of danger, national leaders and their societies have failed to do what is needed to change course."
They are particularly concerned about the U.S., China and Russia, countries they say have the "collective power to destroy civilization" and the "prime responsibility to pull the world back from the brink."