Earth breaks global annual heat records in 2023

Last year, Earth broke annual heat records, flirted with the globally agreed warming threshold and showed other signs of a feverish planet, the European climate agency said Tuesday.

The European climate agency Copernicus said the year saw a warming of 1.48 degrees Celsius compared to pre-industrial times. That figure is just shy of the 1.5° Celsius limit the world hoped to meet in the 2015 Paris climate agreement to avoid the most severe effects of warming.

And January 2024 is on track to be so hot that, for the first time, a 12-month period will exceed the 1.5° threshold, said Samantha Burgess, deputy director of Copernicus. Scientists have repeatedly said that the Earth would have to warm on average by 1.5° over two or three decades for the threshold to be technically exceeded.

The 1.5° target "must be kept alive because lives are at risk and choices must be made," Burgess said. “And these choices impact not you and me, but our children and our grandchildren.”

Record heat made life miserable and sometimes deadly in Europe, North America, China and many other places last year. But scientists say global warming is also responsible for more extreme weather events, like the long drought that devastated the Horn of Africa, the torrential rains that destroyed dams and killed thousands in Libya, and the wildfires forests in Canada which have polluted the air from North America to Europe.

At another press conference on Tuesday, international climatologists calculated the role of global warming in extreme weather events. Group leader Friederike Otto, a climatologist at Imperial College, said: " Our analysis clearly shows that the hottest year had a significant impact."

The World Weather Attribution team only looks at events that affect at least 1 million people or kill more than 100. But Otto said her team was overwhelmed by more than 160 of these events in 2023 and that it was only able to carry out 14 studies, including a large number on deadly heat waves. “Basically, all the heat waves happening today have been made more likely and hotter because of human-induced climate change,” she said.

Last year, the United States experienced 28 weather disasters that caused at least $1 billion in damage, breaking the previous record of 22 set in 2020, the National Oceanic and Water Administration said Tuesday. atmosphere (National Oceanic and Atmospheric Administration). The number of these costly disasters, which are adjusted for inflation, has skyrocketed, from an average of just three per year in the 1980s and just under six per year. year in the 1990s.

U.S. disasters costing billions of dollars last year included a drought, four floods, 19 severe storms, two hurricanes, a wildfire and a winter storm. Combined, they killed 492 people and caused nearly $93 billion in damage, according to NOAA.

Antarctica's sea ice reached historic lows in 2023 and broke eight monthly records for low sea ice, Copernicus reported.

Copernicus calculated that the global average temperature for 2023 was about one-sixth of a degree Celsius higher than the previous record set in 2016. While that doesn't seem like much for a world record, it's an exceptionally large margin for the new record, Mr. Burgess said. The Earth's average temperature in 2023 was 14.98° Celsius, Copernicus calculated.

"Records were broken for seven months. We had the hottest June, July, August, September, October, November and December," Ms Burgess said. "It's not just one season or one month that was exceptional. It was exceptional for more than half the year. "

Several factors made 2023 the hottest year on record, but by far the biggest is the ever-increasing amount of heat-trapping greenhouse gases in the atmosphere, Burgess said. These gases come from the combustion of coal, oil and natural gas.

Other factors include the natural El Nino phenomenon - a temporary warming of the central Pacific that changes weather patterns around the world - other natural oscillations in the Arctic, Southern and Indian Oceans, increased activity solar energy and the eruption of an underwater volcano in 2022 that sent water vapor into the atmosphere, Burgess said.

Malte Meinshausen, a climatologist at the University of Melbourne, said about 1.3 degrees Celsius of warming is due to greenhouse gases, 0.1 degrees Celsius to El Nino and the rest to smaller causes.

Copernicus data only goes back to 1940 and is based on a combination of observations and forecast models. Other groups, including the U.S. National Oceanic and Atmospheric Administration and NASA, the U.K. Meteorological Office and Berkeley Earth, date back to the mid-1800s and will announce their calculations for 2023 on Friday, hoping for record will be beaten.

The Japan Meteorological Agency, which uses techniques similar to Copernicus and dates back to 1948, estimated late last month that it was the hottest year ever, 1.47 degrees Celsius warmer than pre-industrial levels. The University of Alabama Huntsville's global dataset, which uses satellite measurements rather than ground data and dates back to 1979, also estimated last week that it was the most hot never recorded, but in lesser proportions.

Although actual observations are only less than two centuries old, several scientists say tree rings and ice cores suggest this is the warmest climate Earth has experienced in more than 100,000 years. years.

“This basically means that our cities, our roads, our monuments, our farms, in practice all human activities have never had to deal with such a hot climate,” said Carlo Buontempo, director of Copernicus, during a press conference held Tuesday. “There were simply no cities, books, agriculture or domesticated animals on this planet the last time the temperature was this high.”

For the first time, Copernicus recorded a day when the planet's average temperature exceeded that of the pre-industrial era by at least 2° Celsius. This happened twice and he narrowly missed a third day around Christmas, Burgess said.

For the first time, every day of the year was at least 1° Celsius warmer compared to pre-industrial times. For almost half the year or 173 days, the world was 1.5° warmer than it was in the mid-1800s.

Mr Meinshausen, the Australian climate scientist, said it was natural for the public to wonder whether the 1.5° target was lost. He added that it was important to continue trying to curb warming.

"We don't remove a speed limit because someone exceeded it ," he said. “We are redoubling our efforts to put the brakes on.”

But Mr. Buontempo believes that warming will only increase: “If the current trajectory continues, in a few years, the record year 2023 will probably be remembered as a cold year.”