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Monday 4 December 2023 Dublin: 3°C

Debunked: No, excess carbon dioxide in the atmosphere is not down to natural causes

Spurious claims were made by an Australian climate change denier

A MISLEADING ARGUMENT made by an Australian climate change denier has been spread by Irish social media users, along with a claim that the Irish Green Party are “environmental deniers”.

An assertion made to back up the argument is that carbon dioxide (CO2) makes up about 0.04% of the earth’s atmosphere, which is true. But this does not support the theory that human activity has not begun to alter the planet’s climate.

Suggestions that large amounts of CO2 are released naturally are also true, though they lack context.

The cumulative effect of additional CO2 released by human activity has shifted atmospheric levels out of balance, which has resulted in changing weather patterns.

Australian broadcaster

The argument was made in a video clip from a television show featuring Australian broadcaster Alan Jones who, previous to this, had called climate change a hoax multiple times.

The original footage was broadcast live by the Australian Broadcasting Corporation in May 2019.

An edited clip was viewed more than 105,000 times after being shared on an Irish anti-government campaigner’s Facebook page  along with the claim that the Green Party is “destroying your quality of life and risking your food and energy security because they are a cult of environmental deniers and must be stopped”.

The edited clip zooms and pans across the image and adds music. However, it does not appear to have changed or omitted any of the statements made in that section of the original broadcast.

In the video, Jones repeatedly asks: “What percentage of the atmosphere is made up of carbon dioxide?” He goes on to give an answer: “It’s 0.04 of a percent. And of that 0.04 of a percent, human beings around the world create 3%. And of that 3%, Australia creates 1.3%. So for the 1.3% of 3% of 0.04%, we then decide to have a national economic suicide?”

Climate science

It is notable that Jones was previously ordered to undertake basic journalism training by the Australian Communications and Media Authority in 2012, after no evidence was provided he had tried to verify whether a similar, false claim was true: that “human beings produce 0.001% of carbon dioxide in the atmosphere”.  

But one of the figures cited by Jones in the claim we’re looking at is correct: NASA puts the current concentration of carbon dioxide in Earth’s atmosphere is about 412 parts per million (ppm), or 0.0412%, roughly the 0.04% cited by Jones.

However, it should not be thought that just because carbon dioxide comprises a small part of the atmosphere, it has a small effect.

When more carbon is released into the atmosphere than can be absorbed back into the Earth, it leads to a concentration of carbon in the atmosphere, which has now risen to about 50% compared to pre-industrial levels, according to Ireland’s Environmental Protection Agency (EPA).

Furthermore, it is unclear where Jones’s figure that human beings create only 3% of the CO2 in the atmosphere was sourced.

The Intergovernmental Panel on Climate Change (IPCC), the United Nations body for understanding climate change, gives a breakdown of the entire climate cycle from 2010 to 2019.

This includes vast amounts of carbon that would be released even without human intervention, such as 111.1 billion tonnes from land sources such as fire, as well as 54.6 billion tonnes exuded in Ocean-atmosphere gas exchange.

CO2 budget Credit: IPCC

But humans have also released 9.4 billion tonnes of CO2 by burning fossil fuels in that time. That figure alone exceeds the 3% figure cited by Jones.

More importantly, these are only gross figures; land and oceans also absorb carbon dioxide through photosynthesis and gas exchange. They are net absorbers, meaning that overall, they reduce the levels of CO2 in the atmosphere. The same is not true for most human activities.

A climate change expert consulted by The Journal also explained why Jones’s argument is misleading.

“I’m not sure even where to start with the levels of wrong here,” Peter Thorne, a Professor in Physical Geography (Climate Change) at Maynooth University in Ireland and Director of the Irish Climate Analysis and Research UnitS group (ICARUS), said.

Thorne outlined how the carbon produced by human activity compared with the output of natural sources such as land and oceans. 

“The natural components have long been in balance [in terms of giving back the carbon dioxide they emit].

“It’s a bit like not raising the minimum wage and yet increasing the cost of living. The debt simply keeps accumulating.

“It will take many thousands of years for the earth system to fully sequester the carbon we have already emitted.”

The effect of humans on their environment

The EPA also stated that the increase in carbon dioxide in the atmosphere is down to mankind.

“The increase in atmospheric carbon dioxide levels is directly attributable to human activities. It is most responsible for global warming and is essentially irreversible on century timescales,” the agency told The Journal through email.

“The sources for Ireland are similar to the global sources with almost 90% of energy used in Ireland being provided by fossil fuel,” a statement continued, also citing heating and transport as sources of emissions.

“Carbon dioxide is the main greenhouse gas emitted by Ireland, at around 60% of the total in 2021.

“Its contribution to increasing global warming will continue until additional CO2 emissions are reduced to zero, ie net-zero CO2, is achieved.”

Further evidence that the carbon dioxide in the atmosphere was not released by natural processes, but by the burning of fossil fuels, formed from ancient organic matter, comes from what is known as the isotopic fingerprint of those fuels.

In brief, carbon isotopes with more neutrons are heavier and decay at a steady rate, meaning that it is possible to estimate the age of the carbon in the atmosphere.

As a result, it is possible to date the rise in carbon dioxide in the atmosphere to a point when humans burning fossil fuels began.

“We know its old carbon because it’s depleted in heavy carbon 13 and carbon 14 isotopes – so we know the source of the increase is fossil carbon reserves,” Professor Peter Thorne explained.

As such, the argument made by Jones in the video is misleading.

It falsely implies that 97% the excess CO2 in the atmosphere was released by natural processes. Rather, it is the cumulative effect of additional CO2 released by human activity that is responsible for driving a change in weather patterns.

The Journal’s FactCheck is a signatory to the International Fact-Checking Network’s Code of Principles. You can read it here. For information on how FactCheck works, what the verdicts mean, and how you can take part, check out our Reader’s Guide here. You can read about the team of editors and reporters who work on the factchecks here.