Key warming mark creeps closer
The world is creeping closer to the warming threshold that international agreements are trying to prevent, with nearly a 50-50 chance that Earth will temporarily hit that temperature mark within the next five years, teams of meteorologists across the globe predict.
With human-made climate change continuing, there’s a 48% chance that the globe will reach a yearly average of 1.5C above pre-industrial levels of the late 1800s at least once between now and 2026, a bright red signal in climate change negotiations and science, the team of 11 different forecast centres has predicted for the World Meteorological Organisation.
Last year, the same forecasters put the odds at closer to 40%. A decade ago, it was only 10%.
The team, coordinated by Britain’s Meteorological Office, in its five-year general outlook, said there was a 93% chance that the world would set a record for hottest year by the end of 2026.
They also said there was a 93% chance that the five years from 2022 to 2026 would be the hottest on record.
‘‘We’re going to see continued warming in line with what is expected with climate change,’’ said UK Met Office senior scientist Leon Hermanson, who coordinated the report.
The forecasts are big-picture global and regional climate predictions on a yearly and seasonal time scale, based on long-term averages and computer simulations.
But even if the world hits that mark of 1.5C above pre-industrial times – the globe has already warmed about 1.1C since the late 1800s – that’s not quite the same as the global threshold first set by international negotiators in the 2015 Paris agreement. In 2018, a major United Nations science report predicted dramatic and dangerous effects on people and the world if warming exceeds 1.5C.
‘‘This is a warning of what will be just average in a few years,’’ said Cornell University climate scientist Natalie Mahowald, who wasn’t part of the forecast teams.
The prediction made sense, given how warm the world already was, and an additional tenth of a degree C was expected because of human-caused climate change in the next five years, said climate scientist Zeke Hausfather of tech company Stripe and Berkeley Earth, who wasn’t part of the forecast teams.
Add to that the likelihood of a strong El Nino – the natural periodic warming of parts of the Pacific, which alters world weather – which could toss another couple of tenths of a degree on top temporarily, and the world gets to 1.5C.
The world is in the second straight year of a La Nina, the opposite of El Nino, which has a slight global cooling effect but isn’t enough to counter the overall warming of heat-trapping gases created by the burning of coal, oil and natural gas. The five-year forecast says that La Nina is likely to end late this year or in 2023.
The greenhouse effect from fossil fuels is like putting global temperatures on a rising escalator. El Nino, La Nina and a handful of other natural weather variations were like taking steps up or down on that escalator, scientists said.
On a regional scale, the Arctic will still be warming during the northern winter, at a rate three times more than the globe on average.
While the American Southwest and southwestern Europe are likely to be drier than normal during the next five years, wetter than normal conditions are expected for Africa’s often arid Sahel region, northern Europe, northeast Brazil and Australia, the report predicts. The forecasters also predict that the devastating fire-prone megadrought in the US Southwest will continue.
The global team has been making these predictions informally for a decade, and formally for about five years. Hermanson said it had greater than 90% accuracy.