Scientists have also reported unprecedented melting in both Arctic and Antarctic glaciers. The Greenland ice sheet is losing ice six times faster than it was in the 1980s. Ice melt at the South Pole has increased six-fold, too.
Why climate change leads to more heat waves
When greenhouse gases (emitted by the burning of fossil fuels like oil, gas, and coal) enter the atmosphere, they trap more of the sun's heat on the planet, causing Earth's overall surface temperatures to rise.
As the Earth warms, severely hot days happen more frequently. Think of our planet's temperature range as a bell curve: Climate change shifts that entire curve towards the higher end of the temperature spectrum. The center of the curve may only move slightly, but that still puts a large chunk of potential days into the extreme range.
"So you know, a warming of 1 degree Celsius, which is what we've seen thus far, can lead to a 10-fold increase in the frequency of 100 degree days in New York City for example," climate scientist Michael Mann told the New York Times.
Climate change made the European heat wave of 2003 — which killed 15,000 people in France alone — twice as likely, and it's made heat waves like the one Europe suffered through last year five times more likely. If carbon emissions continue unabated, most of the US could see 20 to 30 more days every year with temperatures above 90 degrees Fahrenheit, according to the Union of Concerned Scientists.
"We have a new normal," Ahira Sánchez-Lugo, a climatologist with the National Oceanic and Atmospheric Administration, told Time Magazine. "Just in the 21st century, we've set a new global world temperature record five times."
Wildfires, too, are made worse by climate change
On Wednesday, Pierre Markuse, a satellite photography expert, posted images online showing wildfires in the Arctic. Colossal pillars of smoke were visible from space above Russia, Alaska, and Greenland.
The Copernicus Atmosphere Monitoring Service said its team has observed more than 100 intense and long-lasting fires in the Arctic Circle since the start of June.
Again, climate change is almost certainly playing a role.
Hot and dry conditions in the Northern Hemisphere, which the World Meteorological Organization (WMO) has called "unprecedented," have created ideal conditions for wildfires in the Arctic.
"Climate change, with rising temperatures and shifts in precipitation patterns, is amplifying the risk of wildfires and prolonging the season," the WMO wrote.
This is because warming leads winter snow cover to melt sooner, and hotter air sucks away the moisture from trees and soil, leading to dryer land. Decreased rainfall also makes for parched forests that are prone to burning.
In the western US, the average wildfire season is 78 days longer than it was 50 years ago, likely due to climate change, the Center for Climate and Energy Solutions reported.
Fires are getting bigger, too.
A recent study found that the portion of California that burns from wildfires every year has increased more than five-fold since 1972. Twelve of the 15 biggest fires in the state's history have occurred since the year 2000.
Large wildfires in the US now burn more than twice the area they did in 1970.
"No matter how hard we try, the fires are going to keep getting bigger, and the reason is really clear," climatologist Park Williams told Columbia University's Center for Climate and Life. "Climate is really running the show in terms of what burns."
Scientists agree that the only way to meaningfully combat climate change is to curb greenhouse emissions.
"This is the biggest crisis humanity has ever faced," Greta Thunberg, a 16-year-old climate activist, told United Nations secretary general António Guterres last year. "First we have to realize this, and then as fast as possible do something to stop the emissions and try to save what we can save."
