Decade of 'exceptional' heat likely to be hottest on record, experts say
The last decade has been one of “exceptional” heat around the world, and was almost certainly the hottest on record, while the oceans have also warmed to record levels and grown markedly more acidic, the World Meteorological Organization has said.
Temperatures for the years from 2010 to 2019 were about 1.1C above the average for the pre-industrial period, showing how close the world is coming to the 1.5C of warming that scientists say will cause dramatic impacts, extreme weather and the loss of vital ecosystems.
The preliminary findings of the State of the Global Climate, an annual publication by the WMO, show that this year is on course to be the second or third warmest since records began.
Over land, the impacts from January to October have included severe droughts, heatwaves and floods across all inhabited continents, and over the seas there have also been heatwaves.
During the past year, the upper levels of the oceans, measured since the 1950s, have exceeded previous records so far this year, and the ocean experienced about 1.5 months of unusually warm temperatures, with large areas of the north-east Pacific showing severe heatwaves. The Arctic sea ice minimum in September was the third smallest on record. The final version of the report will be published in March.
Petteri Taalas, the WMO secretary general, said the impacts of rising concentrations of carbon in the atmosphere were becoming ever more harmful, as demonstrated in this year’s extreme weather events.
“Heatwaves and floods which used to be once-in-a-century events are becoming more regular occurrences. Countries from the Bahamas to Japan to Mozambique suffered devastating tropical cyclones. Wildfires swept through the Arctic and Australia,” he said.
He warned that more erratic rainfall patterns posed a threat to crop yields, which, combined with population increases, would mean “considerable food security challenges for vulnerable countries in the future”.
The findings came as the world’s governments gathered in Madrid for a critical UN conference on the climate. On Monday, the UN secretary general, António Guterres, warned that though the technology and economic means to fight climate chaos were available, political will was lacking.
He called on world leaders and governments to pay heed to young people, who were “showing remarkable leadership and mobilisation”.
The latest WMO figures showed the pattern of warming was growing stronger, warned Keith Shine, regius professor of meteorology and climate science at the University of Reading.
“Each of the past four decades has been 0.1 to 0.2C warmer than the decade before. Carbon dioxide levels have continued their relentless rise, and methane levels have grown much more rapidly than in the previous decade. Unless things start to change markedly, it is going to get harder and harder to meet the goals of the Paris agreement.”
While average temperatures may seem to be only gradually creeping up over decades, this disguises the true impact on lives, explained Grant Allen, professor of atmospheric physics at the University of Manchester.
“This [temperature rise] does not simply mean slightly warmer summers, it means an increased frequency of extreme weather globally – droughts, heatwaves, flooding and changing patterns in the frequency and intensity of tropical cyclones.
“These impacts are real and happening now and place huge pressures on communities and countries – put simply, these impacts make for a more unstable world, and are already having profound impacts on our ecosystems and biodiversity.”