The Earth’s temperature briefly rose above a crucial threshold that scientists have been warning for decades could have catastrophic and irreversible impacts on the planet and its ecosystems, data shared by a prominent climate scientist shows.
“Our best estimate is that this was the first day when global temperature was more than 2°C above 1850-1900 (or pre-industrial) levels, at 2.06°C,” wrote Samantha Burgess, deputy director of the Copernicus Climate Change Service, based in Europe, on X (former twitter).
For the first time, the global average temperature on Friday last week was more than 2 degrees Celsius hotter than levels before industrialization, according to preliminary data she shared on X.
Media reports including reports by CNN said:
The threshold was crossed just temporarily and does not mean that the world is at a permanent state of warming above 2 degrees, but it is a symptom of a planet getting steadily hotter and hotter, and moving towards a longer-term situation where climate crisis impacts will be difficult — in some cases impossible — to reverse.
Burgess said in her post that global temperatures on Friday averaged 1.17 degrees above 1991-2020 levels, making it the warmest November 17 on record. But compared to pre-industrial times, before humans began burning fossil fuels on a large scale and altering the Earth’s natural climate, the temperature was 2.06 degrees warmer.
The breach of 2 degrees on Friday came two weeks before the start of the UN COP28 climate conference in Dubai, where countries will take stock of their progress towards the Paris Climate Agreement pledge to limit global warming to 2 degrees above pre-industrial levels, with an ambition of limiting it to 1.5 degrees.
One day above 2 degrees of warming “does not mean that the Paris Agreement has been breached,” Burgess told CNN, “but highlights how we are approaching those internationally agreed limits. We can expect to see increasing frequency of 1.5 degree and 2 degree days over the coming months and years.”
Copernicus’ data is preliminary and will require weeks to be confirmed with real-life observations.
The world already looks on track to breach 1.5 degrees of warming on a longer-term basis in the next few years, a threshold beyond which scientists say humans and ecosystems will struggle to adapt.
A UN report published Monday showed that even if countries carried out their current emissions-reduction pledges, the world would reach between 2.5 and 2.9 degrees of warming sometime this century.
But 1.5 is not a cliff edge for the Earth — every fraction of a degree it warms above that, the worse the impacts will be. Warming to 2 degrees puts far more of the population at risk of deadly extreme weather and increases the likelihood of the planet reaching irreversible tipping points, such as the collapse of the polar ice sheets and the mass death of coral reefs.
Richard Allan, professor of climate science at the University of Reading in the UK, called the breach a “canary in the coalmine” which “underscores the urgency of tackling greenhouse gas emissions.”
But he added that it was “entirely expected that single days will surpass 2 degrees above pre-industrial well before the actual 2 degrees Celsius target is breached over many years.”
The data comes on heels of the hottest 12 months on record, and after a year of extreme weather events, supercharged by the climate crisis, including fires in Hawaii, floods in northern Africa and storms in the Mediterranean, all of which have claimed lives.
Scientists are increasingly expressing alarm that data on temperatures are exceeding their predictions.
A string of reports checking the health of the Earth’s climate and humans’ actions to combat it in recent weeks show that the planet is careening toward a dangerous level of warming, and not doing enough to mitigate or adapt to its impacts.
A UN report last week found that according to countries’ climate plans, planet-heating pollution in 2030 will still be 9% higher than it was in 2010. According to the Intergovernmental Panel on Climate Change, the world needs to decrease emissions by 45% by the end of this decade compared to 2010 to have any hope of limiting global warming to 1.5 degrees Celsius above pre-industrial levels. An increase of 9% means that target is way off.
Another UN report also found that the world is planning to blow the fossil fuels production limit that would keep a lid on global heating. By 2030, countries plan to produce more than twice the limit of fossil fuels that would cap warming at 1.5 degrees.
Two degrees Celsius — or 3.6 degree Fahrenheit — is the internationally agreed upon upper limit of warming established by the 2015 Paris climate agreement. The agreement seeks to hold the increase in the global temperature to well below that limit, and preferably below 1.5 degrees Celsius, in recognition that “this would significantly reduce the risks and impacts of climate change.”
Scientists have long warned that sustained warming of 1.5 degrees or more will lead to cascading risks for human and planetary systems, including negative impacts on ecosystems, biodiversity, water supplies and food security. Warming land and ocean temperatures are already contributing to sea level rise, melting ice sheets and increased hazards such as heat waves, drought and extreme precipitation, according to the Intergovernmental Panel on Climate Change.
While significant challenges are expected for many regions and systems at 1.5 degrees of warming, “risks would be larger at 2 degrees Celsius of warming and an even greater effort would be needed for adaptation to a temperature increase of that magnitude,” the IPCC says.
Caution is warranted when it comes to a single day’s data, said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. He noted that the terms of the Paris climate agreement are more concerned with sustained, years-long warming at those temperatures.
Surpassing 2 degrees once or twice does not indicate a point of no return, Schmidt said. But the record-setting weekend is noteworthy in the context of larger 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 is the planet right now going through an exceptional warming spurt? The answer is yes, yes it is. 2023 is proving to be exceptional in both the impacts and in these metrics.”
Indeed, Monday’s announcement came only weeks after officials warned that 2023 is on track to become Earth’s warmest year on record following a record-hot June, July, August, September and October. The latest milestone is noteworthy, but also a reminder that it’s not too late to change course, said Zeke Hausfather, a research scientist with Berkeley Earth.
“It’s a warning that we’re starting to get uncomfortably close,” Hausfather said. “Certainly the fact that we were seeing months on end of 1.5 degrees [warming] is a sign that that target is quickly slipping by the wayside, and if we keep being complacent for the next decade, we’re going to be in the same place regarding 2 degrees.”
The majority of the warming is attributed to greenhouse gas emissions from the burning of fossil fuels, he and other experts say. But this year’s strengthening El Niño is also playing a role, as the climate pattern is associated with warmer global temperatures.
Researchers have also posited that last year’s eruption of the Hunga Tonga-Hunga Ha’apai volcano in the South Pacific may be contributing to extreme warming this year. The eruption shot record amounts of heat-trapping water vapor into the atmosphere.
Additionally, a study published this month by renowned climate scientist James Hansen said a recent change in aerosol shipping 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 planetary warming effect because the aerosols were reflecting sunlight away from Earth.
Hausfather said the volcano eruption and the change in shipping regulations appear to have played a small role in recent warming trends, but not enough to singularly explain how anomalously hot this year has been. That El Niño arrived so quickly after a rare three consecutive years of La Niña, its cooling counterpart, may have made some of its warming effects show up earlier and stronger than in previous years.
“Scientists don’t have all the answers right now,” he said. “Were going to be doing a lot of research in the next few years to dig into the exact drivers, but it certainly has been an exceptionally warm year so far — and it’s going to be the warmest year on record by a fairly large margin.”
Not all hope is lost, however. The Fifth National Climate Change Assessment, released last week by the White House, underscored that every fraction of a degree of warming added or averted will make a difference.
The report “clearly shows that per 10th of a degree of avoided warming, we save, we prevent risk, we prevent suffering,” Katharine Hayhoe, one of its authors, told The Times.
The news also comes ahead of COP28, an international climate conference that will begin later this month in Dubai.
“We still have time,” Hausfather said, “to avoid the future we got a sneak peek of this past weekend.”
