How the Warming Arctic Helped Drive a Deep Freeze Into Texas.
The sub-zero temperatures causing blackouts across the southern U.S. are connected to climate change.
The Earth’s poles are warming faster than anywhere on the planet. While the consequences of that aren’t completely understood, it’s becoming apparent that many of the world’s extreme weather events owe the Arctic at least some of the credit.
A blast of cold air that swept out of Canada in mid-February, moving across the Great Plains and deep into the South, has overburdened the electrical grid and triggered widespread power outages in Texas, which like many southern states relies predominantly on electric heating, according to the Energy Information Administration. It was the second time in six months that extreme temperatures have brought grids to their knees—a heatwave across California in August caused a spike in energy demand for cooling equipment, forcing rolling blackouts for the first time since 2001.
Is the Texas cold blast connected to climate change? “I have argued a definitive yes,” said Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research, part of risk analytics firm Verisk, who’s spent more than a decade studying what warming across the Arctic means to weather for the rest of the world.
While Cohen is more confident in making this connection than many in his field, the data show plainly that the region is a warming faster than the rest of the planet. The North Pole has been heating up about twice as fast as the rest of Earth for the last 30 years, according to the National Snow & Ice Data Center. “Most scientists agree that this rapid warming is a signal of human-caused climate change,” the center’s website says.
In the Northern Hemisphere’s summer, this has led to a decrease in the contrast between the heat of the equator and the cold of North Pole. The strength of the summer jet stream, a river of wind that propels weather systems around the globe, depends on extreme temperature differences between these two regions. As the planet warms and this contrast diminishes, the jet stream weakens and can no longer push large weather patterns out of the way. This is what caused wildfires above the Arctic Circle, droughts throughout the world, and record-setting heat waves from Moscow to the U.S.
In the case of the Texas cold snap, the phenomenon began in the first week of January, when air in the stratosphere above the Arctic warmed suddenly. This set up a slow-moving atmospheric chain reaction that weakened the polar vortex, the girdle of winds that keeps frigid air corralled at the North Pole, allowing it to spill out into the temperate regions of Asia, Europe, and North America. Once the cold starts rolling south, very little can stop it.
“As the old saying goes, there is nothing between the Arctic and Dallas but a barbed wire fence,” said Dan Pydynowski, a meteorologist with AccuWeather Inc. “So when you get a direct discharge like this it will go all the way.”
While these events happen about six times per decade, according to the National Oceanic and Atmospheric Administration, Cohen maintains that climate change has increased the frequency with which the polar vortex weakens and allow the cold to air to run amok.
Texas has certainly seen snow before, said Bob Henson, a meteorologist with Yale Climate Connections. But he urged observers not to be distracted by individual anomalies. “We know the climate of the central U.S. can produce events like this,” he said. “The point is, when you sum up all the events that are happening 365 days a year, that is when you see climate change most vividly.”
Across the U.S., severe thunderstorms and hail damage have been rising for decades. Some of that is due to increasing population, but that doesn’t explain the full extent of the increase. While scientists aren’t sure about the precise cause, there’s broad agreement that the weather is changing.
In the past year, many parts of the world’s oceans reached record warm temperatures. The Atlantic produced an all-time high of 30 hurricanes and tropical storms in 2020. Vast areas the west were consumed by wildfires, including parts of Oregon and Washington that were once too wet to produce the required dry brush as fuel. Studies by reinsurers Munich Re and Aon both show weather-related natural disasters around the world increasing over the years, while damage from other events such as earthquakes and volcanoes has remained the same.
The disparity between warming and cooling becomes most apparent in the all-time records. In the last year 292 all-time hot records have been set, according to the National Centers for Environmental Information, compared to three low temperature extremes. Scientists repeatedly point to this to show the world is getting warmer.
“It’s no secret that extreme weather events are happening more frequently,” said Jennifer Francis, senior scientist at the Woodwell Climate Research Center in Woods Hole, Massachusetts. “Climate scientists have been predicting this behavior for years, maybe decades, so it comes as no surprise whatsoever that we’re seeing back-to-back extremes of various types around the globe.”
During the worst of the cold on Monday, 157 million people across the U.S. were living under winter storm warnings or weather advisories, said Brian Hurley, a senior branch forecaster with the U.S. Weather Prediction Center. Dallas was colder than Anchorage, Alaska. The cold itself damaged or forced power suppliers offline in a part of the country ill-prepared for frigid temperatures.
“The sorry state of the U.S. electric grid is a shining a bright light on the glaring need for grid modernization,” Francis said, as well as “mounting vulnerabilities in infrastructure of all sorts.”
Up until about two weeks ago, winter was relatively mild across the U.S. January was the ninth warmest across the 48 contiguous states, with temperatures among the 10 warmest for the month in Washington, Montana, North Dakota, South Dakota, Minnesota, Michigan, and Maine, the Centers for Environmental Information said. December was also mild in most places.
It’s not yet possible to connect the extreme cold of the last few days directly to climate change, but Henson says that doesn’t matter in the bigger picture.
“Climate change is real regardless of an extreme cold outbreak,” he said. “You don’t need to explain every cold and snow outbreak to explain climate change.”
16 February 2021