MIAMI - Fossil fuel burning has unnaturally propelled the Earth to a temperature range that was last seen 115,000 to 130,000 years ago, saddling future generations with risky, unproven technologies that could cost hundreds of trillions of dollars, according to a paper submitted by a former senior Nasa climate scientist.
World-renowned climate scientist James Hansen warned that the global average temperature is already 1.3 deg C warmer than during pre-industrial times, defined as from 1880 to 1920 - following a trend where the world has heated up at a rate of 0.18 deg C per decade over the past 45 years.
"The science has become crystal clear," he told reporters yesterday on a conference call to discuss his latest research paper, titled Young People's Burden: The Requirement Of Negative CO2 Emissions.
The paper, published yesterday in Earth Systems Dynamics Discussion, has not yet been peer-reviewed, but Dr Hansen said he wanted it released now because time is of the essence.
"Some people might object to discussing such a paper before it has gone through the peer-review process, but I am going to do that simply because we are running out of time on the climate issue," he said.
The paper, authored by Dr Hansen and 11 prominent climate scientists, warned that the planet's three most dangerous greenhouse gases - carbon dioxide, methane and nitrous oxide - are all rising, ensuring more global warming in the years to come.
As a result, glaciers and ice sheets are melting, the oceans are acidifying and rising seas will engulf coastal cities worldwide in the coming centuries.
The paper said fossil fuels must be taxed to protect children from the costly turmoil.
Otherwise, young people face the "dubious" proposition of somehow sucking carbon dioxide from the air at a price tag of between US$104 trillion (S$142 trillion) and US$570 trillion in the next century, said Dr Hansen, who leads the climate science programme at Columbia University's Earth Institute.
"That's not fair. Today's adults benefit from fossil fuel burning and leave the waste for young people to clean up," said Dr Hansen's granddaughter Sophie Kivlehan, 18, in a video message released along with the paper.
"The assumption that young (people) will somehow figure out a way to undo the deeds of their forebears has crept into and spread like a cancer through United Nations climate scenarios," said the paper.