Scientists have warned that the carbon budget remaining to limit the climate crisis to 1.5C of global heating is now “tiny”, sending a “dire” message about the adequacy of climate action.
The carbon budget is known to be the maximum amount of carbon emissions that can be released while restricting global temperature rise to the limits of the Paris agreement. The new figure is half the size of the budget estimated in 2020 and would be exhausted in six years at current levels of emissions.
Temperature records have been obliterated in 2023, with extreme weather supercharged by global heating hitting lives and livelihoods across the world, according to latest reports. At the imminent UN Cop28 climate summit in the United Arab Emirates there are likely to be disputes over calls for a phaseout of fossil fuels.
Among other things, the analysis found the carbon budget remaining for a 50% chance of keeping global temperature rise below 1.5C is about 250bn tonnes. Global emissions are expected to reach a record high this year of about 40bn tonnes. To retain the 50% chance of a 1.5C limit, emissions would have to plunge to net zero by 2034, far faster than even the most radical scenarios.
Although existing policies are far from delivering this ambition, the current UN ambition is to cut emissions by half by 2030 and reach net zero by 2050. If it was achieved, however, it would mean only about a 40% chance of staying below 1.5C, the scientists said, so breaking the limit would be more likely than not.
Read also: Leaders meet to protect tropical forests, combat climate change
But the scientists warned that for every 10th of a degree of extra heat caused more human suffering and therefore keeping as close as possible to 1.5C was crucial.
The new carbon budget estimate is the most recent and comprehensive analysis to date. The main reasons the budget has shrunk so markedly since 2020 are the continued high emissions from human activities and a better understanding of how reducing air pollution increases heating by blocking less sunlight.
In his reaction, Prof Joeri Rogelj, at Imperial College London, UK, and one the study’s authors, said: “The budget is so small, and the urgency of meaningful action for limiting warming is so high, [that] the message from [the carbon budget] is dire.
Speaking further, he said “having a 50% or higher likelihood that we limit warming to 1.5C is out of the window, irrespective of how much political action and policy action there is.” He said it was “remarkable” how much risk humanity appeared willing to take with global heating.
Story was adapted from the Guardian.
