Record wildfires. A deadly hurricane season. Arctic sea ice at its lowest ever. Drought. Floods. Heatwaves. The World Meteorological Organization’s (WMO) annual climate report, released on Wednesday, reads like a long list of extreme weather and natural disasters. But it may well be a preview of things to come. The report, which includes data from January to October and is based on input from dozens of international experts and organizations, says that 2020 is on course to be one of the three warmest years on record after 2016 and 2019. The average global temperature is set to be about 1.2 degrees Celsius above pre-industrial levels.
Worryingly, 2020 has been unusually hot despite the cooling effect of La Niña. The recurrent climate phenomenon, which developed in August and strengthened in October, is normally associated with below-normal sea surface temperatures in the Pacific Ocean caused by changes in winds, air pressure and rainfall. While La Niña is limited to the Pacific, its effects act to cool the entire planet’s temperatures, like natural air conditioning for Earth. But its impact has been more than offset by heat trapped in the atmosphere by greenhouse gasses, the WMO said. The group’s secretary general Petteri Taalas said that in the past, unusually warm years — such as 2016 — coincided with a strong El Niño event, which is the opposite of La Niña and causes above average sea surface temperatures and thus warmer global temperatures. Not anymore. “Despite the current La Niña conditions, this year has already shown near record heat comparable to the previous record of 2016,” Taalas said in a news release accompanying the main report.
The WMO also said that the period between 2011 and 2020 will be the warmest decade on record, with the warmest six years all being since 2015. The trend is likely set to continue. While emissions fell during the spring lockdown, the concentration of greenhouse gases in the atmosphere surged to a new record high this year. Taalas said there was now at least a one in five chance of average global temperature temporarily exceeding the pre-industrial levels by 1.5 degree Celsius by 2024 — a critical threshold the Paris Agreement aims to limit global warming to. The effects of this rapid warming have been felt around the world throughout the year — from extreme heat and wildfires to floods and a record-breaking Atlantic hurricane season. Taalas summarized 2020 as “yet another extraordinary year for our climate. “Millions of people have been forced to leave their homes — some of them permanently — because of extreme weather and other events caused or exasperated by climate change. Hundreds have died.
Late last year and early this year, Australia suffered what was the worst bushfire season on record. Research has showed that the climate crisis made those fires at least 30% more likely. At least 33 people and an estimated 1 billion animals died in the fires, according to Australia’s parliament. Hundreds more died as a result of smoke exposure. Devastating wildfires in the western US left at least 43 people dead this fall. In October, California recorded the first “gigafire” — a term for a blaze that burns at least a million acres of land — in modern history. South America’s Pantanal, the world’s largest tropical wetlands, was on fire for months. This year also brought plenty of evidence for a trend climate scientists have been warning about for some time: hurricanes, typhoons, and tropical cyclones worldwide are becoming stronger and potentially more deadly as the globe warms due to the climate crisis. The number of tropical cyclones globally was above average in 2020. The north Atlantic hurricane season had its largest number of named storms on record. Many caused death and devastation. At least 100 people died last month when Tropical Depression Eta hit Central America. Hurricane Iota, which hit Nicaragua about three weeks later, was the strongest hurricane of 2020 in the Atlantic and the strongest ever to hit the country. In the US, Hurricane Laura killed at least 27 people in August. In the Philippines, dozens of people died when two back-to-back typhoons hit within 10 days of each other in November.
Crucially, global oceans also continued to get warmer. Oceans serve as a good indicator of the real impact of climate change. Covering almost three quarters of Earth’s surface, they absorb the vast majority of the world’s heat. According to the WMO report, more than 80% of the global ocean experienced a marine heatwave at some time in 2020.The report highlighted the Arctic as an area undergoing “drastic changes” as the global temperature increases. In September, the amount of Arctic sea ice shrunk to the second lowest level since records began in 1978.According to the report, the Greenland ice sheet has continued to lose mass, although at a slower rate than seen in 2019.The ice cover plays a key role in regulating global climate. Its bright surface reflects heat back to the atmosphere. When it melts or doesn’t refreeze, the darker ocean surface absorbs more heat. The WMO said 2020 also brought some unusually strong heatwaves — most notably across northern Asia, particularly the Siberian Arctic. In parts of northern Siberia, the year to date has been 5 degrees Celsius or more warmer than average, the WMO said. South America and much of Europe also experienced heatwaves and prolonged droughts. A number of temperature records fell this year. When the mercury reached 54.4 degrees Celsius in California’s Death Valley in August, it was the highest known temperature in the world in at least the last 80 years. And while some parts of the world experienced heatwaves and drought, other areas suffered deadly flooding. According to the report, more than 2,000 deaths were reported during the flood season in India, Pakistan, Nepal, Bangladesh, Afghanistan and Myanmar.
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