The man known as the godfather of climate science has warned that the internationally agreed threshold to prevent the Earth from entering a new era of overheating will be “for all practical purposes exceeded” by 2024.
James Hansen, the former NASA scientist known for warning the world about the dangers of climate change in the 1980s, said global warming from the burning of fossil fuels, amplified by the naturally recurring El Niño climate event, could see temperatures as much as 1.7C (3F) above pre-industrial averages by May. .
This high temperature, measured in the 12 months through May, alone will not break world governments’ commitment to limit global warming to 1.5°C (2.7°F) above what it was before the dominance of coal, oil and gas. Scientists say that the 1.5-degree ceiling cannot be breached unless this limit is exceeded for several years, with this moment likely to occur at some point in the 2030s.
But even after El Niño, which has increased the average global temperature, subsides, the average for subsequent years will still be around the 1.5°C limit, Hansen said. Earth’s warming from greenhouse gas emissions is amplified by knock-on effects such as melting the planet’s ice, making the surface darker and therefore absorbing more sunlight, Hansen said.
“We are currently in the process of moving to a 1.5 degree world,” Hansen told the Guardian. “You can bet $100 on a donut on this one, and if you find some idiot willing to bet, you can be sure to get a free donut.”
In a newsletter published with two other climate researchers, Hansen states that “the 1.5-degree global warming ceiling has been exceeded for all practical purposes because the massive planetary energy imbalance is driving global temperatures even higher.” Hansen supported a view, discussed by some other climate scientists, that the rate of global warming is increasing due to a widening gap between the amount of energy absorbed by the Earth from the sun and the amount of energy returned to space.
Hansen, known for his role in publicly announcing the start of the greenhouse effect to the US Congress in 1988, added that the impending loss of the 1.5C guardrail should shake the United Nations Intergovernmental Panel on Climate Change (IPCC). The leading climate science body to chart ways to avoid exceeding the target.
“Passing the 1.5-degree world is an important milestone because it shows that the story told by the IPCC, the scientific advisory body of the United Nations, with its approval, is complete nonsense,” Hansen said.
“We are not moving to a 1.5 degree world, we are passing through this world for a short time in 2024. Unless we take conscious actions that will affect the energy balance of the planet, we will move to a 2 degree (3.6 degree) world in the 2030s.”
Last year was the hottest year ever recorded; Scientific institutions in the United States and the European Union are expected to confirm this this week; Global temperatures for 2023 will be 1.5C above pre-industrial levels. El Niño, which warms parts of the Pacific Ocean and normally contributes to overall global temperature, is expected to be even stronger this year than last and then fade away.
Governments meeting at the UN climate talks in Dubai in December reaffirmed their previous commitments made in Paris in 2015 to strive to limit global temperature rise to 1.5°C; high greenhouse gas emissions and ongoing plans for massive oil and gas drilling. Carbon emissions from fossil fuels reached a new record last year.
Although the 1.5 degree target is as political as it is scientific, researchers say that if the world exceeds this temperature, there will be worse effects in terms of heat waves, droughts, floods and other disasters. For developing countries and small island states at existential risk from sea level rise and extreme weather, the agreed goal is a challenging and totemic one; “1.5 for survival” is now a common mantra heard in international climate talks.
Hansen’s claim that this year will herald the beginning of a period of rising 1.5 degrees Celsius drew a cautious response from other scientists contacted by the Guardian. Drew Shindell, a climate scientist at Duke University, said this year has been “unusually warm” due to El Niño, and whether the 1.5 degree target has been eliminated will be best determined in the coming years.
However, he added that the world is approaching this point and the 1.5 degree limit will probably be exceeded: “Given that recent years have warmed very quickly, it is no longer in the 2030s, but in the 2020s. In my opinion, the post-1.5C period is correct.”
“To me, whether it’s 2024 or 2027 doesn’t ultimately make much difference in terms of shaping our actions; We must change course now, otherwise we will lose our ability to stay below 2C as the 1.5C target is now over. reach,” Shindell said.
“I somewhat disagree with Hansen,” said Zeke Hausfather, a climate scientist at Stripe and Berkeley Earth, that global temperatures would not be at least 1.4C warmer than pre-industrial times if La Niña, an El adverse climate condition, were offset. Niño. “But as the Earth continues to warm, such temperatures will no longer be seen in the long term,” Hausfather said, adding that he expects the long-term average to fully exceed 1.5 degrees by the early 2030s.
Andrew Dessler, a climate researcher at Texas A&M University, said he expected it would take “about 10 years” to break the 1.5C limit, but said Hansen’s views should be taken seriously. “Jim is probably the greatest climate scientist in history, so I’m hesitant to agree with him because maybe he’ll be right,” Dessler said.
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Researchers emphasize that even if the earth’s temperature exceeds the 1.5 degree limit, this does not mean that everything will be irreversibly lost, that every fraction of a degree matters or does not matter in shaping the severity of climate impacts. With the current government pledging to reduce emissions (albeit without actual actions to date), the world is still heading for at least 2.5°C (4.5°F) of warming by the end of this century.
“I think we’re addressing the wrong question by worrying about a certain threshold,” said Kerry Emanuel, a climate and meteorologist at the Massachusetts Institute of Technology. “There are no magic numbers in climate change; there are only rapidly increasing risks.”
Emanuel noted that recent severe heat waves, fires and storms have been exacerbated by global warming, which is about 1.2°C (2.1°F) more than just over a century ago. “Maybe when half the population of the planet experiences at least one of these weather disasters, they can mobilize their leaders,” Emanuel said. “I hope you don’t suffer this much.”