Climate change target of 2C is ‘dead’, says renowned climate scientist 

The pace of global heating has been significantly underestimated, according to renowned climate scientist Prof James Hansen, who said the international 2C target is “dead”.A new analysis by Hansen and colleagues concludes that both the impact of recent cuts in sun-blocking shipping pollution, which has raised temperatures, and the sensitivity of the climate to increasing fossil fuels emissions are greater than thought.The group’s results are at the high end of estimates from mainstream climate science but cannot be ruled out, independent experts said. If correct, they mean even worse extreme weather will come sooner and a greater risk of passing global tipping points, such as the collapse of the critical Atlantic ocean currents.Hansen, at Columbia University in the US, sounded the alarm to the general public about climate breakdown in testimony he gave to a UN congressional committee in 1988.“The Intergovernmental Panel on Climate Change (IPPC) defined a scenario which gives a 50% chance to keep warming under 2C – that scenario is now impossible,” he said. “The 2C target is dead, because the global energy use is rising, and it will continue to rise.” The new analysis said global heating is likely to reach 2C by 2045, unless solar geoengineering is deployed.The world’s nations pledged in Paris in 2015 to keep global temperature rise below 2C above preindustrial levels and pursue efforts to limit it to 1.5C. The climate crisis has already supercharged extreme weather across the world with just 1.3C of heating on average in recent years, destroying lives and livelihoods – 2C would be far worse.Prof Jeffrey Sachs, also at Columbia University, said: “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.”Climate scientist Dr Zeke Hausfather, who was not part of the study, said it was a useful contribution. “It’s important to emphasise that both of these issues – [pollution cuts] and climate sensitivity – are areas of deep scientific uncertainty,” he said. “While 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.”In the new study, published in the journal Environment: Science and Policy for Sustainable Development, Hansen’s team said: “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.” They said the IPCC analysis was heavily reliant on computer models and that the complementary approach they took of making more use of observations and climate analogues from the distant past was needed.The world has seen extraordinary temperatures over the last two years. The primary cause is the relentless rise in CO2 emissions from the burning of fossil fuels. The peak of the El Niño cli