This story was originally published on August 3, 2023.
July [2023] was [at that point] the Earth’s hottest month on record. Scientists say that this record-breaking heat is due in large part to climate change caused by burning fossil fuels and other human activities.
Scientists have known for over a century that carbon dioxide and other gases trap heat in the Earth’s atmosphere. And by burning coal, natural gas, and oil, we are pumping more of this insulation into our atmosphere.
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Add in [2023’s] El Nino, a Pacific Ocean warming event that can lead to warmer global temps, and you’ve got a recipe for blistering heat in places like the Southwest U.S., Asia, and Europe, says Richard Alley, a climate scientist at Penn State.
“Getting what we’re seeing without the human influence would have been almost impossible at this point,” said Alley. “And with the human influence, it’s expected.”
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July 6, 2023, was officially [at that time] the hottest day ever recorded on Earth, according to the UN’s World Meteorological Organization. Countries around the world have experienced 120-degree Fahrenheit heat. The average temperature in Phoenix was 102.7 degrees in July 2023, a record. It topped 100 degrees that month in Canada’s Northwest Territories, just below the Arctic Circle.
Alley said weather extremes like heat waves have always happened, but with climate change, the odds of these extremes happening are greater. He used the analogy of weighting a set of dice.
“We’ve had weird weather. It happens,” he said. “But we’re weighting the dice. We’re making it more and more and more likely that they come up hot, and they are.”
A recent study found heat waves in China, Europe and North America were much more likely because of human-caused climate change.
The Earth’s temperature has gone up by around 2 degrees Fahrenheit since the 18th century, and is on pace to increase another three to four degrees Fahrenheit by the end of this century, says Benjamin Cook, a climate scientist with NASA’s Goddard Institute for Space Studies. The main reason is human fossil fuel consumption.
“Contributing to many or all of these heat events and other climate extremes is increases in greenhouse gases because of the burning of fossil fuels,” Cook said. “So it’s all really anthropogenic. All of the warming we’re seeing is driven by human activities.”
What can Pennsylvania expect?
Pennsylvania is expected to have 37 days of 90-degree temperatures in a year by mid-century, up from an average of 5. Southwestern Pennsylvania will see more extremely hot days than anywhere else in the state, according to a state climate assessment.
Scientists say the best way to slow and eventually stop global warming is by reducing or eliminating fossil fuel use. Governments have pledged to do that under the UN’s Paris Agreement; the Biden Administration has pledged to cut US carbon pollution in half by 2030.
In 2022, Biden signed the Inflation Reduction Act, the largest climate commitment in US history. That legislation allocates billions of dollars to $370 billion over 10 years on renewable energy and other low-carbon technologies.
