The 2°C climate target, set out by the 2015 Paris Agreement and internationally accepted, is “dead,” according to climate scientist Dr. James Hansen.
Hansen and his colleagues recently concluded that the climate’s sensitivity to fossil fuel use and emissions is greater than previously thought. If Hansen’s analysis is correct, while being more extreme than other estimates, extreme weather events will occur with more frequency and intensity going forward, and more “tipping points” will be reached, from which the Earth won’t be able to heal.
Hansen is a former NASA scientist and is considered the father of global awareness of climate change. He famously called the Paris Agreement, a result of the UN Climate Change Conference in December 2015, a “fraud.”
The Paris Agreement set out the overarching goal of limiting global warming to under 2°C compared to pre-industrial levels.
“It’s just bullshit for them to say: ‘We’ll have a 2°C warming target and then try to do a little better every five years,’” said Hansen in response to the conference. “It’s just worthless words. There is no action, just promises. As long as fossil fuels appear to be the cheapest fuels out there, they will be continued to be burned.”
Ten years later, Hansen’s statements ring harsh but true, as 2024 was the warmest year on record according to the World Meteorological Organization. The past ten years all rank in the top ten warmest in history.
Now, almost a decade after the 2°C target was set, Hansen is even more pessimistic. “The Intergovernmental Panel on Climate Change (IPCC) defined a scenario which gives a 50% chance to keep warming under 2°C – that scenario is now impossible,” he said. “The 2°C target is dead, because the global energy use is rising, and it will continue to rise.”
The new analysis by Hansen and his team predicts that global warming will likely reach that threshold by 2045.
Extreme weather has already caused devastation around the globe, with temperatures now around 1.3°C warmer than pre-industrial records on average. An increase to 2°C would likely catalyze further damage.
Professor Jeffery Sachs, a colleague of Hansen’s at Columbia, stated that a “shocking rise of warming has been exposed by, ironically, a reduction of pollutants, but we now have a new baseline and trajectory for where we are.”
Sachs is referring to the reduction in certain pollutants, such as those from shipping pollution, that blocked the sun’s warming rays. Now that their use is on the decline, warming is occurring more rapidly than many experts thought.
In their analysis, Hansen and his team state: “Failure to be realistic in climate assessment and failure to call out the fecklessness of current policies to stem global warming is not helpful to young people.”
Experts not involved in the study still acknowledge the importance of its claims. Dr. Zeke Hausfather, a renowned climate scientist, responded to the publication by saying that it’s “important to emphasise that both of these issues – [pollution cuts] and climate sensitivity – are areas of deep scientific uncertainty.”
Still, Hausfather recognized the significance of the analysis, adding that “[w]hile Hansen et al are on the high end of available estimates, we cannot say with any confidence that they are wrong, rather that they just represent something closer to a worst-case outcome.”
The continued rise in global temperatures has been in large part due to the increasing CO2 emissions around the world, as accepted by most experts today. This has been compounded over the past two years by the natural El Niño climate cycle, which raises ocean surface temperatures.
However, despite El Niño ending in mid-2024, the abnormally high temperatures around the globe persisted. Hansen and his team, as well as other experts, have focused on shipping emissions as a potential culprit.
Suphite particles produced by burning fuel for ships have long blocked sunlight from reaching the surface of the Earth. But new environmental policies, passed in 2020, have resulted in an 80% reduction in the level of sulphur in fuels, which means there are now fewer pollution particles blocking the sun’s rays. More sun is now reaching the Earth’s surface, meaning higher temperatures.
Hansen’s analysis measured 0.5 watts per square metre (W/m2) of sunlight reaching the Earth’s surface. Recent studies found the range to between 0.07 and 0.15 W/m2, a significantly lower estimate.
Hansen’s team came to their figure by looking at changes in the reflectiveness of the ocean, a more top-down approach than was typically used in previous analyses.
This difference has led some to question Hansen’s latest report.
Dr. Gavin Schmidt, the director of NASA’s Goddard Institute for Space Studies, disagreed with the findings. “Both approaches are useful and often complementary,” he said. “But I think in this case, Hansen’s approach is too simple and doesn’t factor in changes in Chinese emissions, or internal variability.”
The analysis from Hansen and his team, published in the journal Environment: Science and Policy for Sustainable Development, also predicts a point of no return should things not change.
“As a result, shutdown of the Atlantic Meridional Overturning Circulation (Amoc) is likely within the next 20-30 years, unless actions are taken to reduce global warming — in contradiction to conclusions of IPCC.”
Amoc refers to the system of ocean currents that lead to warm water heading south and cold water heading north. A collapse of these ocean currents would undoubtedly lead to the melting of the Arctic ice.
“If Amoc is allowed to shut down, it will lock in major problems including sea level rise of several metres — thus, we describe Amoc shutdown as the ‘point of no return.’”
Previous studies have estimated the timing of this Amoc collapse to be 2050.
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Still, it was not all doom and gloom from Hansen and colleagues, who claim this “point of no return” could be avoided. Hansen suggests a carbon fee and dividend policy, taxing fossil fuels and putting the revenue back into the public.
More directly, Hansen supports the use of nuclear power, an emission-free source of energy. He also supports using geoengineering techniques to block sunlight from reaching the Earth’s surface. While controversial, as many see it as a solution to only the symptoms of climate change, Hansen calls it “purposeful global cooling.”
The overarching threat of climate change remains existential in the eyes of many experts, even if Hansen’s view on the immediacy of the situation is extreme. The analysis calls for fundamental political change to effectively face the climate crisis.
“Special interests have assumed far too much power in our political systems,” says Hansen. “In democratic countries the power should be with the voter, not with the people who have the money. That requires fixing some of our democracies, including the US.”
“Today, with rising crises including global climate change, we have reached a point where we must address the problem of special interests,” state the joint authors of the report, emphasizing that they remained “optimistic.”
Editor’s Note: The opinions expressed here by the authors are their own, not those of Impakter.com — Cover Photo Credit: Mika Baumeister.
