Fact brief - Are carbon dioxide emissions from human activities enough to affect the climate?

Skeptical Science is partnering with Gigafact to produce fact briefs — bite-sized fact checks of trending claims. This fact brief was updated by John Mason in collaboration with members from the Gigafact team. The initial version was published in 2021 and written by John Cook. You can submit claims you think need checking via the tipline.

Are carbon dioxide emissions from human activities enough to affect the climate?

Neither land nor oceans have been able to adequately absorb the extra CO₂ released by our fossil fuel burning, causing atmospheric CO₂ to rise and affect our climate.

We have understood since the 1850s that adding more CO₂ to our atmosphere will cause global temperatures to rise by making it more difficult for heat to escape the atmosphere.

Earth's carbon cycle naturally exchanges a large amount of CO₂ between the atmosphere, oceans and land surface. Normally, our land and oceans keep CO₂ levels balanced by emitting or absorbing CO2 accordingly. Now, the system is in a state of imbalance.

For over a million years, atmospheric CO₂ swung between 180 and 300 parts per million as glaciations and interglacials came and went. But due to our activities, atmospheric CO₂ reached 420 parts per million in March 2024 - a 50% increase from pre-industrial times.

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 Earth Observatory: The carbon cycle

NASA Vital Signs: Carbon dioxide measurements

Reuters CO2 levels to breach 50% rise from pre-industrial era in 2021 - Met Office

About fact briefs published on Gigafact

Fact briefs are short, credibly sourced summaries that offer “yes/no” answers in response to claims found online. They rely on publicly available, often primary source data and documents. Fact briefs are created by contributors to Gigafact — a nonprofit project looking to expand participation in fact-checking and protect the democratic process. See all of our published fact briefs here.

Posted by John Mason on Saturday, 10 August, 2024

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