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Climate warning signs bright red: top scientists

Taipei Times · last updated

Climate warning signs bright red: top scientists

‘CRUNCH TIME’: Temperatures are reaching a hard cap, with scientists expecting a peak in warming in the next three to four decades, a researcher said

From carbon pollution to sea-level rise to global heating, the pace and level of key climate change indicators are all in uncharted territory, more than 60 top scientists said yesterday.

Greenhouse gas emissions from burning fossil fuels and deforestation hit a new high last year, averaging over the past decade a record 53.6 billion tonnes per year — that is 100,000 tonnes per minute — of carbon dioxide or its equivalent in other gases, they reported in a peer-reviewed update.

Earth’s surface temperature last year breached 1.5°C for the first time, and the additional carbon humanity can emit with a two-thirds chance of staying under that threshold long-term — our 1.5°C “carbon budget” — would be exhausted in a couple of years, they said.

Embers glow at night amid the Basin Fire in the Sierra National Forest in Fresno County, California, on June 26 last year.

Photo: AFP

Investment in clean energy outpaced investment in oil, gas and coal last year two-to-one, but fossil fuels accounted for more than 80 percent of global energy consumption, and growth in renewables still lags behind new demand.

Included in the 2015 Paris Agreement on climate as an aspirational goal, the 1.5°C limit has since been validated by science as necessary for avoiding a catastrophically climate-addled world.

The hard cap on warming to which nearly 200 nations agreed was “well below” 2°C, commonly interpreted to mean 1.7°C to 1.8°C.

“We are already in crunch time for these higher levels of warming,” coauthor Joeri Rogelj, a professor of climate science and policy at Imperial College London, told journalists at a news conference.

“The next three or four decades is pretty much the timeline over which we expect a peak in warming to happen,” he said.

No less alarming than record heat and carbon emissions is the gathering pace at which these and other climate indicators are shifting, according to the study, published in Earth System Science Data.

Human-induced warming increased over the past decade at a rate “unprecedented in the instrumental record,” and well above the 2010-2019 average registered in the UN’s most recent Intergovernmental Panel on Climate Change report in 2021.

“I tend to be an optimistic person,” said lead author Piers Forster, head of the University of Leed’s Priestley Centre for Climate Futures. “But if you look at this year’s update, things are all moving in the wrong direction.”

The rate at which sea levels have shot up in the past few years is also alarming, the scientists said.

After creeping up, on average, well under 2mm per year from 1901 to 2018, global oceans have risen 4.3mm annually since 2019.