- A Northwest heat wave was deemed “virtually impossible” without human-induced climate change.
- Extreme flooding is linked to warmer temperatures, scientists say.
- One-third of France’s wine crop was wiped out by an April cold snap.
From freezing temperatures to heat to flooding to drought and everything in between, this year saw what seemed like a never-ending series of deadly and costly weather events.
Scientists say many of 2021’s weather disasters were exacerbated by climate change, and human-induced global warming made some of them much more likely to occur.
Global temperatures rose nearly 2 degrees between 1901 and 2020 due to greenhouse gas emissions, according to the National Oceanic and Atmospheric Administration. That’s made air and surface temperatures warmer and certain weather events more extreme.
Here’s a look at some of the worst climate disasters of 2021 – including historic drought, deadly heat and devastating wildfires that made NOAA’s annual list of billion-dollar disasters:
Northwest Heat Wave Left Hundreds Dead
Summer 2021 was the hottest for the contiguous United States in records dating back 126 years, according to NOAA.
Parts of the Northwest – where summers aren’t normally hot and not everyone has air conditioning – suffered the most, especially during an extreme heat wave from June 26 to July 2 that brought temperatures well over 100 degrees to many areas, combined with record-high nighttime lows that yielded little to no relief.
At least 126 people died in Washington from heat-related issues during that week, according to the state Department of Health. Another 31 deaths afterward were also connected to the heat.
In Oregon, at least 54 deaths were attributed to heat in the Portland area alone, where the high reached 116.
Hundreds more deaths were reported across the border in British Columbia.
Emergency room visits from June 25 to 30 were 69 times higher than the previous year in Alaska, Idaho, Washington and Oregon, according to the U.S. Centers for Disease Control and Prevention.
The World Weather Attribution initiative, a group of climate scientists from around the world that analyzes the role of climate change in extreme weather events, deemed the 2021 western U.S. heat wave “virtually impossible without human-caused climate change” that drove temperatures higher than ever recorded before.
The WWA stated in its report on the event: “Our results provide a strong warning: Our rapidly warming climate is bringing us into uncharted territory that has significant consequences for health, well-being and livelihoods.”
Historic Drought Parched California
Californians are used to dryness. But this second consecutive year of drought was historic in its extremes. The 12-month period that ended Sept. 30 – known as the water year – was the driest in California in nearly a century and the second-driest ever recorded, according to a report from the California Department of Water Resources and other agencies.
Going back farther, NOAA’s National Centers for Environmental Information said the 18-month period from April 2020 to Sept. 30 was the driest on record in the state.
One big reason? All that heat. Warming temperatures mean that more water evaporates from reservoirs and other sources.
“Temperatures have been high unusually high, by historical standards, for the last decade or so,” Jay Lund, an engineering professor and drought expert at the UC-Davis Center for Watershed Sciences, told weather.com in an interview earlier this year. “So in this drought and the previous drought, we’ve had much higher evaporation from the watersheds and from the reservoirs than we have had historically, so in terms of runoffs, these droughts are even drier than they are in terms of precipitation.”
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California this year saw its warmest spring and summer average temperatures on record.
Those warmer temperatures also increase aridification, the process of drying out land, vegetation and other parts of the landscape.
Despite recent storms, the latest drought monitor report released Dec. 14 shows more than 80% of the state in extreme or exceptional drought, the two highest categories. That’s down from a peak of almost 88% three months ago, but there’s no way to know for sure how the state’s wet season – which typically runs through mid-May and includes rain and snow – will play out.
And it’s not just California. Drought and heat in western and central states cost more than $4.5 billion last year, including widespread crop and livestock losses, according to NOAA. From 2016 to 2019, drought impacts cost more than $10 billion combined.
Wildfires Fueled by Heat and Drought – All the Way Into December
Heat and drought are two key ingredients for wildfires.
More than 57,000 large wildfires burned nearly 12,000 square miles of land in the U.S. this year, mostly in the hot, dry West, according to the National Interagency Fire Center.
While that’s about average for the past 10 years, scientists say fires are burning hotter and faster because of climate change.
“The drier things get, the more intensely they burn, and the more intensely they burn, the more extreme fires that you see,” Daniel Swain, a UCLA climate scientist who studies drought, wildfires and other weather events, told weather.com in an interview for a story in October.
Many factors influence wildfires, but when they burn more intensely, they create more smoke, a major public health hazard. Smoke from western wildfires this summer drifted all the way to New York.
“It’s not the presence of fire on the landscape really that’s the problem,” said Swain. “That’s a natural process. The problem is the magnitude and the intensity of the fires that we’re currently seeing. And it is specifically that aspect of wildfire that is directly influenced by climate change and by warming temperatures through that aridification of the landscape and the drying out of vegetation which is potential wildfire fuel.”
The Dixie Fire, the largest single wildfire in records kept by the California Department of Forestry and Fire Protection, happened this year. And late-season fires in other states, including Texas and Oklahoma, broke out amid unusually high December temperatures.
Extreme European Flooding Was Made More Likely by Climate Change
Germany, Luxembourg and parts of Belgium and the Netherlands saw extreme flooding that killed more than 200 people in July. Houses, roads, bridges and train tracks were swept away, waves of muddy water flowed through main streets and some areas were left completely cut off.
Full data isn’t available for the event because some monitoring sites were washed away, according to the WAA, which concluded that climate change made the extreme flooding event more likely to happen.
Scientists say that some of the same climate change dynamics that make drought worse can also cause more rain. Increased evaporation from warmer temperatures puts more water in the air, which allows storms to produce more intense rainfall events in some locations.
And they say extreme rainfall like that which led to deadly flooding this summer in Tennessee, as well as from remnants of hurricanes Ida and Henri in the Northeast and a November storm in British Columbia, is happening more often because of climate change.
Over the past 30 years, flooding has been America’s worst storm-related killer, claiming an average of 85 lives a year. At least 145 have been killed this year, the most since 2017.
French Vineyards Froze in ‘Agricultural Catastrophe’
First came unusually warm temperatures in March that prompted young, green leaves to sprout earlier than usual.
Then came a frosty cold snap in April, freezing vineyards and fruit trees across a wide swath of France.
The freeze was thought to have wiped out at least a third of France’s wine production, with estimated losses well over $1 billion, the Guardian reported.
“This is probably the greatest agricultural catastrophe of the beginning of the 21st century,” said French agriculture minister Julien Denormandie.
Like the summer flooding and heat, the WWA concluded that global warming made the French freeze disaster more probable.
“We found that although climate change made the temperatures of the observed event less cold than they would have been without the burning of fossil fuels over the last centuries, the fact that climate change has also led to an earlier start of the growing season means that frost damage in young leaves has become more likely due to human-induced climate change,” according to the group’s report.
“Overall, we conclude that human-caused climate change made the 2021 event 20% to 120% more likely.”
December Tornadoes Aren’t the Norm
Pinning a specific tornado to climate change is extremely difficult, according to NOAA.
But, the agency notes, “Warmer winter temperatures attributed to climate change are projected to create conditions that make tornadoes more likely.”
NOAA says those warmer winter temperatures and warm, moist air contributed to the development of thunderstorms that turned into a historic tornado outbreak the night of Dec. 10. Dozens of people were killed across several states, including at a candle factory in Kentucky and an Amazon warehouse in Illinois.
A few days later, a widespread windstorm and severe weather outbreak amid unusual heat from the Rockies and Plains into the upper Midwest spawned more storms and tornadoes, as well as snow and dust storms plus high winds that knocked out power to more than 500,000 homes and businesses and helped spread wildfires.
At least five deaths were blamed on this system, which also brought the first tornado ever documented in Minnesota in December in records dating back to 1950.
“In this and many other ways, this resembled a storm in spring or early fall, rather than a core winter month,” weather.com senior meteorologist Jonathan Erdman wrote. “It’s also one most in the Plains and upper Midwest won’t soon forget.”
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.