The coal-fired Plant Scherer, one of America's top carbon dioxide emitters AP
The world has three years to start making significant reductions in greenhouse gas emissions or face the prospect of dangerous global warming, experts have warned in an article in the prestigious journal Nature.
Calling for world leaders to be guided by the scientific evidence rather than “hide their heads in the sand”, they said “entire ecosystems” were already beginning to collapse, summer sea ice was disappearing in the Arctic and coral reefs were dying from the heat.
The world could emit enough carbon to bust the Paris Agreement target of between 1.5 to 2 degrees Celsius in anything from four to 26 years if current levels continue, the article said.
Global emissions had been rising rapidly but have plateaued in recent years. The experts, led by Christiana Figueres, who as Executive Secretary of the United Nations Framework Convention on Climate Change played a key role in the Paris Agreement, said they must start to fall rapidly from 2020 at the latest.
“The year 2020 is crucially important for another reason, one that has more to do with physics than politics,” they said.
Citing a report published in April, they added: “Should emissions continue to rise beyond 2020, or even remain level, the temperature goals set in Paris become almost unattainable.
“Lowering emissions globally is a monumental task, but research tells us that it is necessary, desirable and achievable.”
The article was signed by more than 60 scientists, such as Professor Michael Mann of Pennsylvania State University, politicians, including former Mexican President Felipe Calderon and ex-Irish President Mary Robinson, businesspeople like Paul Polman, chief executive of Unilever, investment managers, environmental campaigners and others.
Since the 1880s, the world’s temperature has risen by about 1C because of greenhouse gases resulting from human activity – a process predicted by a Swedish Nobel Prize-winning scientist in 1895.