US congressman misleads on CO2's climate impact

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In a video viewed tens of thousands of times on social media, a US congressman claims the rise in atmospheric carbon dioxide (CO2) is "tiny." This is misleading; while the numbers cited are correct, they fail to account for the fact that even a relatively small proportion of CO2 has a strong warming effect that drives climate change.

"What percent of our atmosphere is CO2?" says Doug LaMalfa, a Republican congressman from the US state of California, in a video shared on Facebook, Instagram, YouTube and Twitter.

The clip shows LaMalfa addressing a panel of experts during a March 28, 2023 hearing of the House Transportation and Infrastructure Committee on the Infrastructure Investment and Jobs Act's implementation.

Panel members responded to his question with a series of incorrect guesses ranging from five to eight percent.

"I ask a lot of people that, because all we hear is climate change, climate change, CO2, CO2," LaMalfa said. "The answer is 0.04 percent. Not one percent, not half of a percent. It's 0.04 percent and it's gone up from 0.03 over the last couple of decades.

"This is what we're being all contorted into doing, is this tiny change in CO2."

Screenshot of a Facebook post taken April 26, 2023

LaMalfa has previously denied the existence of human-caused climate change in public meetings. The lawmaker, who owns a stake in a rice farm in California, has reportedly received donations from logging and fossil fuel companies.

The figures LaMalfa cited are correct -- but his claim omits the fact that CO2 makes an outsized contribution to global warming and climate change.

"CO2 is a minor constituent of the atmosphere. Despite that, it has a big effect on planetary temperature because it absorbs infrared heat radiation," Andrew Watson, an atmosphere specialist at the University of Exeter, previously told AFP.

Change in CO2

Atmospheric CO2 has risen from around 280 parts per million (ppm) in the 1850s to more than 400 ppm, according to data (archived here) published by the US National Oceanic and Atmospheric Administration (NOAA).

NOAA's data (archived here) show CO2 averaged 421 ppm in March 2023 -- an increase of more than 50 percent from pre-industrial levels. Over the past two decades, the greenhouse gas has increased by around 12 percent.

That corresponds with a surge in human-caused emissions and a global rise in temperatures, according to NOAA and the UN Intergovernmental Panel on Climate Change (IPCC).

Screenshot taken April 26, 2023 of an August 2021 IPCC report with charts showing the rise in global temperatures with the impact of human emissions (right)

NASA says the warming effect of CO2 is augmented by other trace greenhouse gases, including nitrous oxide, methane and ozone.

"While these greenhouse gases make up just a tiny percentage of our atmosphere, they play major roles in trapping Earth's radiant heat and keeping it from escaping into space, thereby warming our planet and contributing to Earth's greenhouse effect," the US agency says.

Charging electric vehicles

LaMalfa said during the hearing that some panel members were "looking to change your vehicles to electric even though we don't have the electric grid (capacity)."

The US infrastructure bill passed in 2021 provided $550 billion to boost green transportation and energy, including support for electric vehicles and improvements to the power grid.

California's Air Resources Board ruled in August 2022 that all new cars sold in the state, the most populous in the US, must be zero-emission starting in 2035. The decision followed an executive order from Democratic Governor Gavin Newsom.

The Biden administration has also proposed new auto emissions rules to accelerate the transition, aiming to make two-thirds of the new car market electric by 2032.

An electric vehicle being charged in California in April 2023 ( AFP / Frederic J. BROWN)

An analysis from Yale Climate Connections indicates electric vehicles need not swamp the grid if they are charged during off-peak times. Utilities in states such as California offer discounts for customers who avoid charging their cars during the evening peak period.

Researchers at the Massachusetts Institute of Technology calculated that without mitigation, evening peaks in charging demand could require 20 percent more power generation capacity. However, measures such as adding chargers to workplaces could offset that.

Experts have previously told AFP that electric vehicles produce fewer emissions over their lifespan than gasoline-powered vehicles and that their overall environmental impact is lighter.

AFP has fact-checked other false and misleading claims about climate change here.