Human CO2, not water vapor, is driving climate change


The claim: human-made CO2 is an insignificant contributor to climate change

The latest United Nations intergovernmental panel on climate change the report has been published in August, document dangerous human-made changes to Earth’s climate systems and predict more to come.

Although the report has been described as a “red code for humanity»By UN Secretary General António Guterres, a Claim soon resurfaced on social media, claiming that humanity’s CO2 emissions are too small to have an impact on the climate.

A graphic version of the claim titled “How Climate Alarmists Use Numbers to Deceive” has been posted on Facebook on September 19 and received hundreds of shares. The graph also accuses the Environmental Protection Agency of publishing a misleading pie chart that “exaggerates the role of CO2 as a greenhouse gas.”

“SCIENTIFIC FACT: CO2 of human origin constitutes only 0.1 to 0.2% of atmospheric greenhouse gases. It’s an insignificant contributor to global temperature and climate, ”the post concludes.

This statement, which has been repeatedly demystified, is wrong. Man-made CO2 in the atmosphere causes significant changes in Earth’s climate, scientists say.

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Man-made CO2 changes Earth’s climate

Josh willis, a climatologist at NASA’s Jet Propulsion Laboratory, told USA TODAY that it is a logical error to assume that a proportionately small amount of a substance cannot have a large impact on a system.

“It is a technique commonly used to confuse people,” he said, pointing out that, for example, minute amounts of arsenic can kill an adult.

Willis said that human-generated CO2 does indeed change the Earth’s climate.

Carbon dioxide is a natural part of the atmospheric and biological cycles on Earth. It is not just produced by burning fossil fuels. It is also expelled by animals and volcanic activity, for example.

Once expelled, carbon dioxide is again absorbed or sequestered in forests, grasslands, peatlands, the ocean and other “carbon sinks”, completing the cycle.

In the atmosphere, carbon dioxide and other greenhouse gases trap heat, creating a habitable planet with stable, warm temperatures. This phenomenon is commonly referred to as the “greenhouse effect”.

The problem is, humans are now making it easier to release more carbon dioxide into the atmosphere than ever before, while destroying sinks, like forests. This causes the accumulation of carbon dioxide in the atmosphere in quantities unprecedented for hundreds of thousands of years.

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The amount of carbon dioxide in the atmosphere is proportionately smaller than that of some other gases, such as water vapor. And the amount generated by humans is even smaller than that.

But carbon dioxide also behaves differently from other gases. And several sources of evidence show that the accumulated quantity is sufficient to cause the changes documented by climatologists.

Water vapor and CO2 behave differently in the atmosphere

The social media post correctly states that there may be more water vapor than CO2 in the atmosphere, but it is wrong to claim that CO2 is insignificant.

It’s “an old myth,” Willis said. “This one was demystified Many times.”

The fact that there is generally more water vapor than CO2 in the atmosphere does not change the impact of CO2 on the atmosphere.

Both CO2 and water vapor contribute to the “greenhouse effect” which warms the Earth and makes it habitable. However, they play very different roles. The increase in CO2 levels causes climate change, while the increase in water vapor levels is caused by climate change.

At a given average temperature, the average levels of water vapor in the atmosphere remain relatively constant. Fluctuations are inherently short-lived, as water condenses and rains out of the atmosphere, Susan solomon, an atmospheric chemist and professor at the Massachusetts Institute of Technology, told USA TODAY in an email.

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In a warmer atmosphere, more water collects before it rains. Therefore, a warming atmosphere will see an increase in stable water vapor, which, in turn, will make the warming worse.

However, for this to happen in the first place, Earth’s atmosphere would have to be warming already. This is what is happening, and it is because of the heat trapped by the high human emissions of CO2.

“When the planet gets warmer, we get more water vapor and the planet gets warmer a bit more,” Willis said. Unlike CO2, “humans do not control the amount of water in the atmosphere – it is a reaction to the heat of the planet.”

The publication distorts the EPA pie chart

The post falsely concludes that CO2 is insignificant after claiming that an EPA chart on the subject is misleading.

The unlabeled pie chart shows the percentages of carbon dioxide, methane, nitrous oxide, and fluorinated gases.

“No mention is made that this table includes only ‘human-made’ greenhouse gases,” the accompanying text reads.

The text and image of the post are dated 2014, and USA TODAY could not find the exact pie chart shown in the Facebook post. But the style and content matches a pie chart found on the EPA Inventory of greenhouse gas emissions and sinks in the United States report web page.

The current version of this table is titled “Overview of Greenhouse Gas Emissions in the United States”. It doesn’t explicitly state that the graph shows only human-caused emissions, but elsewhere on the page the report notes that the topic is “total greenhouse gas emissions from all man-made sources in the United States. United”.

The post also states that “excluding water vapor, this graph is very misleading and greatly exaggerates the role of CO2 as a greenhouse gas.”

However, the graph only shows the relative percentages of the various human-made greenhouse gases emitted in the United States. Nowhere on the page does it state that the graph is intended to describe the role or importance of each type of gas in the greenhouse effect. climate effect or change.

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USA TODAY has previously refuted a claim that a similar waterline shown in photos of a beach taken years apart prove that climate change is not real. USA TODAY also discovered that a video purporting to show climate activist Greta Thunberg denying the existence of a climate crisis has been changed.

Our rating: False

Based on our research, we find FALSE the claim that human-made CO2 is an insignificant contributor to climate change. Although human-generated CO2 typically contains a smaller proportion of atmospheric greenhouse gases than water vapor, research has unequivocally shown that it has a large impact and changes the Earth’s climate.

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