Climate change poses an “existential threat” to life on Earth, leading scientists warned on Tuesday, citing this year’s avalanche of record high temperatures and extreme weather that they said hit harder than expected. While 2023 is expected to be the hottest year in history, regions across the planet have been hit by deadly heat waves.

Others were affected by floods or, in some cases, both extremes.

“The truth is that we are shocked by the ferocity of extreme weather events in 2023. We fear the uncharted territory we are now entering,” a coalition of international writers wrote in a new report published in the journal. bioscience.

Their harsh assessment: “Life on planet Earth is under siege.”

With record levels of greenhouse gas and fossil fuel subsidies rising last year, humanity has made “minimal progress” in reducing the emissions that are causing the planet to warm, they said. The provocative assessment came just a month before the UN’s COP28 climate talks in the oil-rich United Arab Emirates.

“We must transform our perspective on the climate emergency from an isolated environmental problem to a systemic, existential threat,” the authors said.

The State of the Climate study examined the latest data on the “vital signs” of 35 planets and found that 20 of them reached record levels this year.

“off schedule”

A temperature increase of just 1.2 degrees Celsius above pre-industrial levels caused a range of damaging and costly consequences. The warming El Nino weather phenomenon also began this year. The European Union’s Copernicus climate change service said the three months to September were the warmest period on record and possibly the warmest in about 120,000 years.

The report stated that many climate-related records were broken “by large margins” in 2023, including temperatures in the oceans that absorbed almost all of the extreme heat caused by human-caused carbon pollution.

Co-author Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said recorded sea surface temperatures were “completely out of line” and scientists could not yet fully explain why. Potentially serious impacts include increased intensity of major tropical storms, as well as threats to marine life and coral reefs, the report said.

This year, people across the planet have faced heat waves and droughts, as well as severe flooding in the United States, China, India and beyond. Record wildfires in Canada, partly linked to climate change, have caused more carbon dioxide emissions than the country’s total greenhouse gas emissions in 2021, according to a report.

1.5C period

By 2023, days when the global average temperature is 1.5°C above pre-industrial levels will be rare, according to the authors. This year, as of mid-September, 38 such days had already been recorded. The Paris Agreement’s more ambitious 1.5C target will be measured in decades.

But lead author William Ripple, a professor at Oregon State University, said we are likely entering a period in which annual temperatures will reach that level or higher, risking dangers from climate feedback loops and tipping points.

“These tipping points, once crossed, could change our climate in ways that are difficult or impossible to reverse,” he told AFP.

This could include the melting of ice sheets in Greenland and West Antarctica, thawing of large areas of permafrost, and the destruction of widespread coral reefs.

“At some tipping points we’re no longer going to avoid them, it’s more about slowing down the damage,” said co-author Tim Lenton, director of the Global Systems Institute at the University of Exeter.

To do this, it is necessary to reduce emissions and prevent temperature rise.

Lenton told AFP that every fraction of a degree counts: “There’s still a lot to play for.” This includes the number of people who may face unbearable conditions such as extreme heat, limited food availability and extreme climates in the coming decades. The report states that by the end of the century, between three and six billion people could be “outside the habitable zone.”

“Many world leaders generally continue to support business as usual rather than implementing policies to curb climate change and sustain life on Earth,” Ripple said.

“We hope that recent extreme weather events will help motivate policymakers at the upcoming COP28 climate conference to support large-scale reductions in fossil fuel emissions and increased financing for climate change adaptation, especially in the world’s most vulnerable regions.” Source