Carbon dioxide is a major cause of climate change, although it makes up just 0.04 percent of the atmosphere

Context

A video of U.S. Congressman Doug LaMalfa claiming that measures against climate change are overscaled compared to the amount of carbon dioxide (CO2) present in the Earth's atmosphere has gone viral on social media.

The clip is taken from a recording of a March 28 House Transportation and Infrastructure Committee hearing to review the implementation of the Infrastructure Investment and Jobs Act. LaMalfa asked the panelists, “What percent of our atmosphere is CO2?,” and is informed the answer is 0.04 percent. LaMalfa also stated that the amount has increased from 0.03 percent over the last couple of decades. the congressman then argued that the measures against climate change are overscaled compared to such a small increase and the amount of carbon dioxide in the atmosphere.

On April 21, 2021, U.S. President Joe Biden announced a new target “to achieve a 50-52 percent reduction from 2005 levels in economy-wide net greenhouse gas pollution in 2030.” The bipartisan Infrastructure Investment and Jobs Act aims to tackle climate change through a $550 billion investment in clean energy and in electric vehicle infrastructure to reduce dependence on fossil fuels, signed into law on November 15, 2021.

In Fact

The amount of carbon dioxide in the atmosphere is indeed 0.04 percent. According to NASA “human activities have raised the atmosphere’s carbon dioxide content by 50% in less than 200 years.” Carbon dioxide levels are now higher than at any point in human history. As a greenhouse gas, carbon dioxide emits and absorbs heat, preventing it from escaping into space and instead trapping the heat on Earth's surface, known as the greenhouse effect.

Most scientists agree that the greenhouse effect is the main reason behind climate change. According to the International Energy Agency (IEA) CO2 Emissions in 2022 report carbon dioxide emissions accounted for 89 percent of energy-related greenhouse gas emissions.

The Intergovernmental Panel on Climate Change (IPCC) report from March 2023 affirmed that “human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming.” The increase in carbon dioxide over the last 60 years is 100 times faster than previous natural increases which is primarily caused by the extraction and combustion of fossil fuels such as coal, oil, and natural gas. Although oxygen and nitrogen constitute the majority of the atmosphere they do not have the same effect, because they are not greenhouse gases.

The U.S. is the second biggest carbon dioxide emitter in the world. According to the U.S. Environmental Protection Agency, carbon dioxide makes up 79.4 percent of U.S. greenhouse gas emissions. LaMalfa is correct that the amount of carbon dioxide in the atmosphere is only 0.04 percent, however, it is erroneous to claim an over-stretch in cutting down carbon dioxide emissions since it is the prominent greenhouse gas driving climate change.

Although not expressed by LaMalfa, the video of the hearing has been used to disprove climate change altogether. Logically Facts has previously debunked multiple false and misleading claims about global warming and climate change.

The Verdict

Carbon dioxide accounts for the majority of emitted greenhouse gases trapping heat on Earth's surface. Most scientists agree that the main cause of climate change is the greenhouse effect. Scientific evidence does not support the claim that cutting down carbon dioxide emissions is disproportionate because it makes up 0.04 percent of the atmosphere. Therefore, we marked this claim as misleading.