It's hard to believe in this month of cold and snow, but climate scientists are saying that 2020 is almost tied with 2016 to be the hottest year on record. This past decade has been the hottest ever recorded, and the last five years were the hottest since 1880.
Note that with each new broken heat record, the baseline is now set higher. The heat increases have no end in sight, and so the future will be hotter. This is climate change change.
One example: This summer Phoenix, Arizona experienced a record-breaking 145 days above 100 degrees Fahrenheit. The city also had 15 days above 115 degrees F (double the previous record).
At what point will it be too hot for humans? It's up to us - governments, corporations, individuals - to make decisions to control what happens in the future and to stop the runaway heat increases.
Yale Climate Connections (YCC) has all sorts of climate related articles. (Example:November 2020 among warmest Novembers on record, NOAA and NASA report)
Graph of global (land and ocean) temperature increases over time from 1880 to 2020 at NOAA (National Oceanic and Atmospheric Administration).
Excerpts from NPR: 2020 May Be The Hottest Year On Record. Here's The Damage It Did
With just a few weeks left, 2020 is in a dead-heat tie for the hottest year on record. But whether it claims the top spot misses the point, climate scientists say. There is no shortage of disquieting statistics about what is happening to the Earth.
The hottest decade on record is coming to a close, with the last five years being the hottest since 1880. 2020 is just two-hundredths of a degree cooler than 2016, the hottest year ever recorded. The Earth is nearly 2 degrees Fahrenheit warmer now than it was in the 20th century, and greenhouse gas concentrations in the atmosphere are still rising.
The future will be even hotter, although humans, through the choices governments, corporations and individuals make, will decide exactly how much.
That means more years like 2020, with increasingly powerful hurricanes, more intense wildfires, less ice and longer heat waves. The average yearly number of $1 billion-dollar disasters in the U.S. has quadrupled in the last three decades. As of October 2020, there had been 16 climate-driven disasters that caused at least $1 billion in damage each.
"How many times can we say the word 'unprecedented'?" says Kristina Dahl, climate scientist at the Union of Concerned Scientists. "This is not just something theoretical that we're predicting. It's something that we are living through and that we're already beginning to see."
As President-elect Joe Biden assembles a new administration that promises to reduce greenhouse gas emissions and help people across the country, and around the world, adapt to global warming, NPR's Climate Team asked climate scientists what lessons can be learned at the end of another hot year.
- Dangerous heat waves that don't let up
Weather reports across the Southwest this year featured one number, over and over: 100 degrees.
That's because many cities endured lengthy stretches of relentless heat, breaking long-term temperature records. Phoenix, Arizona experienced a record-breaking 145 days above 100 degrees, the repeated, sustained heat waves made worse by a lack of rain. The city also had 15 days above 115 degrees, double the previous record.
Heat can have deadly consequences. Phoenix also broke the record for the number of heat-related deaths, with almost 300 people dying. Some were killed directly by the heat, while others suffered from cardiac and respiratory problems triggered by heat stress.
The Arctic is warming twice as fast as the rest of the Earth, according to the federal government's 2020 Arctic Report Card. That means sea ice is melting earlier in the spring and freezing later in the fall. Permanently frozen ground is melting, and wildfires in boreal forests and Arctic shrublands are getting more frequent and severe. There was less Arctic sea ice this October than any previous October on record.
In a 2020 study, Hesselbjerg Christensen and his colleagues analyzed how quickly the Arctic is warming now compared to dramatic temperature changes in the distant past, such as when the last Ice Age ended, and found that what's happening now is comparably fast. "The amount of warming that's taking place is quite comparable to what happened at the top of Greenland like 30,000 years ago," he says. "This is almost as abrupt as anything gets."
The West is no stranger to fires, but this year's blazes seemed relentless. More than nine million acres burned and 17,000 homes and buildings were destroyed. Three states experienced the largest wildfires in their recorded history: California, Oregon and Colorado.
The pattern was unsettlingly similar across those states: extreme hot weather and high winds created explosive infernos that sent people fleeing their homes with just minutes to spare. As multiple fires burned, fire-fighting crews were stretched thin with little relief. No state could spare extra personnel to help their Western neighbors. Millions of people inhaled unhealthy air for weeks, as the smoke spread to places far and wide that had not had wildfires.
That created an extremely "thirsty" atmosphere — a key metric that scientists track to measure fire danger. When the air is hot and dry, it acts like a sponge, drawing moisture out of soils and plants. That dry vegetation is highly flammable, creating the conditions for explosive fires.
Climate scientists say as temperatures continue to rise, the West will see more and more days with high fire danger due to a "thirstier" atmosphere.
- Hotter ocean water is bad news in so many ways
Ocean warming was also on full display in 2020, and it was messy. Sections of the Indian Ocean, the Pacific and the Caribbean all had their hottest years ever. Most of the Earth's ocean area was much warmer than average.
Hotter water meant more powerful storms. Warm water on the ocean surface helps storms gain energy as they form, which leads to more destructive wind and storm surge. Hot ocean water also endows some storms with enormous amounts of moisture that falls as rain when the storm hits land.
Record-breaking heat in the Bay of Bengal helped power a devastating cyclone that hit India and Bangladesh in May. By the time the Atlantic Hurricane season began in June, the water in the Gulf of Mexico was also heating up.
That helped fuel a record-breaking number of rapidly intensifying hurricanes whose wind speeds got about 35 miles per hour faster in 24 hours or less. Wind speed indicates how powerful a hurricane is, so the 10 storms that rapidly intensified in 2020 all gained a lot of power very quickly, which made it more difficult for people in their path to prepare.