Earth could warm by more than 3.5 C, leading to extreme weather: research

BONN, Germany — Climate researchers said Thursday the planet could warm by more than 3.5 C, boosting the risk of drought, flood and rising seas.

The United Nations’ target is a 2 C limit on warming from pre- industrial levels in the belief that that amount of climate change would be manageable. But in a report issued here during the latest round of UN talks, scientists said the Earth’s average global temperature rise could exceed the dangerous 3.5 C warming they had flagged only six months ago.

Marion Vieweg, a policy researcher with German firm Climate Analytics, said the 3.5 C estimate had been based on the assumption that all countries will meet their pledges, in themselves inadequate to meet the 2 C limit, to reduce greenhouse- gas emissions.

New research has found this is not “a realistic assumption,” she said, adding that right now “we can’t quantify yet how much above” 3.5 C Earth will warm.

The monitoring tool is called Climate Action Tracker ( CAT), a joint project of Climate Analytics, Ecofys and the Potsdam Institute for Climate Impact Research in Germany.

Her colleague, Bill Hare, said the gap between countries’ promised interventions and the reality was “getting bigger.”

Projections are for a greenhousegas overshoot of between nine and 11 billion tonnes a year beyond the annual 44- billion- tonne ceiling needed by 2020 to achieve the 2 C target.

At the moment, the world emits about 48 billion tonnes of these gases, including CO2 and methane.

The United States accounts for six billion tonnes, China seven billion and the European Union five billion, the CAT said.