For the first time since record-keeping began, Earth has exceeded a critical temperature threshold that scientists say could trigger the worst effects of climate change.
The planet climbed 2.07 degrees Celsius above pre-industrial levels on Friday, the average from the 1850s to 1900s, according to Europe’s Copernicus climate change service.
Two degrees Celsius – or 3.6 degrees Fahrenheit – is the internationally agreed upper limit of warming, established by the 2015 Paris climate agreement. The agreement aims to keep global temperature increases well below this limit, and preferably below 1.5 degrees Celsius, recognizing that “this would significantly reduce the risks and impacts of climate change”.
Copernicus officials shared their findings in a statement Monday. post on. Assistant principal Samantha Burgess said preliminary data also show that the global temperature on Saturday measured 2.06 degrees Celsius above pre-industrial levels, indicating that there are “now two days in November 2023” where the temperature has exceeded the benchmark.
🌡️ ERA5 data from @CopernicusECMWF indicates that November 17 was the first day that the global temperature exceeded 2°C above pre-industrial levels, reaching 2.07°C above the 1850-1900 average and that the provisional ERA5 value for the 18 November is 2.06°C. pic.twitter.com/lLGwlCsZtP
– Copernicus ECMWF (@CopernicusECMWF) November 20, 2023
Scientists have long warned that sustained warming of 1.5 degrees or more would bring cascading risks to human and planetary systems, including negative impacts on ecosystems, biodiversity, water supplies and food security. Warming land and ocean temperatures are already contributing to rising sea levels, melting ice caps and increased risks such as heat waves, drought and extreme precipitation, according to the Group. intergovernmental experts on climate change.
While significant challenges are expected for many regions and systems with 1.5 degrees of warming, “risks would be greater with 2 degrees Celsius of warming and an even greater effort would be needed to adapt to an increase temperature of this magnitude,” indicates the IPCC.
However, caution is advised when dealing with data from a single day, said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. He noted that the terms of the Paris climate agreement are more about sustained warming over several years at these temperatures.
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Exceeding 2 degrees once or twice does not indicate a point of no return, Schmidt said. But this record weekend is remarkable in the context of broader trends.
“Is the planet warming? Yes,” Schmidt said. “Are we going to see days above 2 degrees before we get weeks above 2 degrees, before we get to months, before we get to years? Yes. And the planet is going through Is there currently an exceptional warming surge? The answer is yes, yes, it is. 2023 is proving to be exceptional both in terms of impacts and measures.
Indeed, Monday’s announcement came just weeks after officials warned that 2023 was on track to become Earth’s hottest year on record following record temperatures in June, July, August, September and October . This latest milestone is remarkable, but it’s also a reminder that it’s not too late to change course, said Zeke Hausfather, a research scientist at Berkeley Earth.
“It’s a warning that we’re starting to get uncomfortably close,” Hausfather said. “The fact that we are seeing 1.5 degrees of warming for months is certainly a sign that this goal is rapidly being abandoned, and if we continue to be complacent over the next decade, we will be in the same state of affairs. ‘mind. place in relation to 2 degrees.
The majority of warming is attributed to greenhouse gas emissions from burning fossil fuels, he and other experts say. But the strengthening of the El Niño phenomenon this year also plays a role, as the climate pattern is associated with warmer global temperatures.
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Researchers also hypothesize that the eruption of the Hunga Tonga-Hunga Ha’apai volcano in the South Pacific could contribute to this year’s extreme warming. The eruption spewed record amounts of heat-trapping water vapor into the atmosphere.
Additionally, a study released this month by renowned climate scientist James Hansen said a recent change in aerosol transport regulations could be a contributing factor. The regulations reduced the amount of sulfur allowed in fuels in an effort to improve air quality, but the change may have had an unintended global warming effect because the aerosols reflected sunlight from Earth.
Hausfather said the volcano’s eruption and change in shipping regulations appear to have played a small role in recent warming trends, but not enough to explain how unusually hot it has been this year. The fact that El Niño arrived so quickly after three rare consecutive years of La Niña, its cooling counterpart, may have caused some of its warming effects to appear earlier and stronger than in previous years.
“Scientists don’t have all the answers right now,” he said. “We’ll be doing a lot of research over the next few years to determine the exact factors, but it’s certainly been an exceptionally warm year so far – and it will be by far the hottest year on record.”
But all hope is not lost. The Fifth National Climate Change Assessment, released last week by the White House, emphasized that every fraction of a degree of warming added or avoided will make a difference.
The report “clearly shows that for every tenth of a degree of warming avoided, we save, we avoid risk, we avoid suffering,” Katharine Hayhoe, one of its authors, told the Times.
The news also comes ahead of COP28, an international climate conference that begins later this month in Dubai.
“We still have time,” Hausfather said, “to avoid the future we got a glimpse of last weekend.”
This story was originally published in the Los Angeles Times.