Flirting with climate danger: UN forecasts 2 in 3 chance of briefly hitting key heat limit soon

There is a two-in-three chance that within the next five years the world will reach an internationally accepted global temperature threshold to limit the worst effects of climate change, a new World Meteorological Organization report estimates.

The only possibility will be a quick flirtation and less concern with the agreed climate danger point, the UN weather agency said on Wednesday. That’s because scientists expect temporary bursts of heat from El Niño to boost human-caused warming from the burning of coal, oil and gas to new highs and then drop back down.

The 2015 Paris climate agreement set 1.5 C (2.7 F) as a global hedge on atmospheric warming, with countries pledging to try to prevent long-term warming if possible. Scientists in a 2018 UN special report said that crossing that point would be very different and dangerous, with more death, destruction and damage to global ecosystems.

“It will not be this year, probably. Maybe it will be next year or the year after “that year’s average 1.5 C, said the lead report author Leon Hermanson, a climate scientist at the British Met Office.

Why doesn’t that mean we failed to meet our Paris targets

But climate scientists say what happens in the next five years is not the same as failing to meet global targets.

“This report does not mean we will permanently exceed the 1.5 C level set in the Paris Agreement, which indicates long-term warming over many years. However, the WMO is sounding the alarm that we will temporarily breach the 1.5 C level with increasing frequency,” said WMO Secretary General Petteri Taalas in a statement.

“One year doesn’t mean anything,” Hermanson said. Scientists usually use an average of 30 years.

The 66 percent probability of a year reaching that threshold within five years has increased from 48 percent last year, 40 percent the year before that, 20 percent in 2020 and 10 percent about ten years ago. The WMO report is based on calculations by 11 different climate science centers around the world.

The world is approaching the 1.5 C threshold due to human-caused climate change over the years. The temporary warming from this year’s expected El Niño – a phenomenon that begins by warming parts of the central Pacific Ocean and then sloshes around the globe – makes it “possible for us to see a year of more than 1.5 C once a decade before long-term average warming is driven by human emissions of greenhouse gases,” said climate scientist Zeke Hausfather of technology companies Stripe and Berkeley Earth, who were not part of the WMO report.

“We do not expect the long-term average to exceed 1.5 C until the early to mid-2030s,” Hausfather said in an email.

Why is this still big?

But every year at or near 1.5 C is important.

“We see this report as a barometer of how close we are, because the closer we get to the threshold, the more noise that’s bumping up and down will hit you over the threshold randomly,” Hermanson said in an interview. . And he said another random bump through the sign happens, that the world is closer to actually find the threshold.

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The key to all of this is the El Niño cycle. The world is coming off a record triple-dip La Niña – three straight years of El Niño whose cold cousin has hindered the ascent of human warming – and is on the verge of an El Niño that some scientists predict will strengthen.

La Niña has slightly slowed the human-caused warming trend so the world hasn’t broken the annual temperature mark since 2016, in the midst of the last super-sized El Niño, Hermanson said.

Some bad news, some good

And that means a 98 percent chance of breaking the 2016 annual global temperature record between now and 2027, the report said. There is also a 98 percent chance that the next five years will be the five hottest years on record, the report said.

Because of the change from La Niña to El Niño. “Where there was a flood before, there will be a drought and where there was a drought before there will be a flood,” Hermanson said.

The report warns that the Amazon will be abnormally dry over the next five years, while parts of Africa’s Sahel – the transition zone between the Sahara in the north and the savannah in the south – will be wetter.

That’s “one of the positive things that came out of this forecast,” Hermanson said. “It’s not all doom and gloom and heat waves.”

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University of Pennsylvania climate scientist Michael Mann said reports like this put too much emphasis on global surface temperatures, which vary with the El Niño cycle, even if they rise over the long term.

The real concern is deep ocean water, which absorbs the majority of the world’s human-caused warming, leading to a steady increase in ocean heat content and new records being set regularly.

Mann said it is wrong to think that the world will exceed the threshold any time now, because “concerted efforts to lower carbon emissions can still avoid crossing it all,” Mann said. “That’s what we need to focus on.”