U.S. News

Trump revives a misleading claim that global warming isn't happening because it's cold outside

Key Points
  • President Trump has revived a misleading message about climate change.
  • Since at least 2011, Trump has frequently tweeted that bouts of cold undermine the scientific consensus that human activity is changing the Earth's climate.
  • Weather and climate are not the same thing, and extreme cold spells can happen even as global average temperatures rise.
President Donald Trump
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During a blast of blistering wintery weather, Donald Trump took to Twitter to cast doubt on global warming, implying that the cold snap undermined warnings that the Earth's climate is changing due to human activity.

The date was Nov. 1, 2011.

For much of the last six years, Trump has been pushing a misleading message that global warming is in doubt because bouts of extreme cold continue to put a chill on the United States. The tweets seemed to have stopped after Trump declared his bid for the presidency in 2015.

But on Thursday, the president picked up the line after dropping it for more than two years.

To be sure, weather and climate are not the same thing. According to NASA, the difference is a "measure of time." Here's how NASA puts it:

Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere 'behaves' over relatively long periods of time ...

An easy way to remember the difference is that climate is what you expect, like a very hot summer, and weather is what you get, like a hot day with pop-up thunderstorms.

So while average global temperatures have been rising, extreme cold will still hit regions over short periods.

But Trump has long muddled weather and climate with his tweets.

Trump posted 115 tweets expressing climate change denial between November 2011 and October 2015, according to a search conducted by Vox in June. In about a third of those tweets — or roughly 40 posts — Trump argued that climate change cannot be real because it was cold outside.

Tweeting that claim became something of an annual tradition to kick off the cold season. Here are his first tweets on the subject from each fall over five years:

After each of those missives, he tweeted on the subject several more times throughout the winter — with the exception of fall 2015, when he was battling for the Republican nomination for president. He was particularly prolific during the 2013-2014 fall and winter season, tweeting the theme more than a dozen times.

But Trump has also preached the message beyond the winter months. He has repeatedly used unseasonably cold spells as an opportunity to revive his claims during the spring and summer.

A number of climate scientists pushed back on Trump's latest tweet on the climate-weather connection.

The consensus among climate scientists is that global warming is real and is primarily caused by emissions of carbon dioxide and other greenhouse gases from human activity. A report issued by 13 U.S. agencies echoed that conclusion last month.

Despite this, Trump has moved swiftly to deconstruct President Barack Obama's policies aimed at mitigating the impacts of climate change; set in motion a U.S. exit from the Paris climate agreement; and pushed policies to boost coal-fired power generation, a primary contributor to greenhouse gas emissions.

Some of the other themes Trump has tweeted include that global warming is a "hoax," a "canard" and "bulls--t"; China is using the myth of climate change to gain an economic advantage over the United States; and environmentalists started using the phrase "climate change" because "global warming" didn't stick.