Climate clock ticks closer to 2045 catastrophe

A different kind of “doomsday clock” launched by Oxford University is ticking toward 2045, the year at which it’s estimated — under a “business as usual” scenario — we’ll emit the trillionth tonne of carbon and tip the scales in the direction of catastrophic climate change.

As of today, the clock shows we’ve spewed nearly 532 billion tonnes of carbon into the atmosphere since the start of the Industrial Revolution. Recent research suggests that, once that figure reaches one trillion, we’ve put ourselves on track for global warming in excess of 2°C.

Hosted by the Oxford e-Research Centre, trillionthtonne.org currently predicts that the trillionth tonne will be reached in March 2045, but this date is advancing as manmade carbon emissions gradually accelerate.

The launch of the website coincides with a one tonne heap of anthracite coal — representing the trillionth tonne of carbon to be released into the atmosphere through human activity since industrialisation began — going on display at the Science Museum in London. The display is launched alongside “Prove It! All the evidence you need to believe in climate change,” a new Science Museum exhibit on the facts about climate change and the coming global warming talks in Copenhagen this December.

“The trillionth tonne symbolises the way carbon dioxide emissions accumulate in the atmosphere,” said Myles Allen of Oxford University’s Department of Physics, who proposed the idea based on a paper he and co-authors published in Nature earlier this year. “It is sobering to think that it could be vaporised into carbon dioxide within my lifetime, committing the Earth to a most likely warming of more than two degrees, widely regarded as a threshold for the most dangerous impacts of climate change.”

Allen continued, “If we make deep cuts in emissions, perhaps our children will be able to show their grandchildren the trillionth tonne. But even that will not be enough: because of their cumulative effect on climate, net carbon dioxide emissions eventually have to cease altogether. Only when our great, great, great grandchildren are still gazing at the trillionth tonne, sitting safely intact in the Science Museum in 150 years time, will the saga of human-induced climate change be passing into history.”

In April 2009, a team led by Oxford University scientists showed how emitting carbon dioxide more slowly will not prevent dangerous climate change unless it involves phasing out carbon dioxide emissions altogether, before we reach an upper limit of one trillion tonnes of carbon. Two studies published in Nature showed that the risk of dangerous climate change is primarily determined by the accumulation of carbon dioxide emissions over time, not by short-term emission rates.

The original “Doomsday Clock,” maintained by the Bulletin of the Atomic Scientists, was last pushed closer to midnight in 2007, due to both accelerating climate change and nuclear threats from Russia, North Korea and Iran. The time on that clock currently stands at 5 minutes to midnight.