Climate Change

Are we headed for ‘hothouse’ Earth?

‘THE WOLVES ARE NOW IN SIGHT’ *Are we headed for ‘hothouse’ Earth?*

Warren Murray

[image: Thermometer in the sun]
Melting ice in Greenland disrupts the Gulf Stream current, raising sea levels and pumping heat into the Southern Ocean. There, it speeds up the loss of ice from the Antarctic. As the heat rises, more rain falls in forested regions and the wettened soil is less able to trap planet-warming methane. Ocean floors give up even more methane, heating the planet further still.
We will pause there to explain this is not a sequel to The Day After Tomorrow but an illustration of what leading climate scientists fear could happen if “positive feedback loops” are allowed to take hold <click.mail.theguardian.com/?qs=12d489361b4507d94079ac8c2b23106b9beed1b34e5dc4ab62a68b291741bd60e541fd068facab2eaa8f1415311b083a> – by which warming temperatures release new sources of greenhouse gases or destroy the Earth’s ability to absorb carbon and reflect heat, causing a spiral into a “hothouse” world. They ask whether the planet’s temperature can stabilise at 2C above pre-industrial levels, or whether it will tip towards being 4C warmer and far less supportive of human life.
“I do hope we are wrong, but as scientists we have a responsibility to explore whether this is real,” said Johan Rockström, one of the authors of a paper published in the Proceedings of the National Academy of Sciences <click.mail.theguardian.com/?qs=12d489361b4507d95f0c2611bbb21dff07a9ee371cbc65a6fd78d4b4b6161a21a940d9947d6d215eeff616f8a07bcb2a>. “We could end up delivering the Paris agreement and keep to 2C of warming, but then face an ugly surprise if the system starts to slip away.” Dr Phil Williamson, a climate researcher at the University of East Anglia, said: “In the context of the summer of 2018, this is definitely not a case of crying wolf, raising a false alarm: the wolves are now in sight.”
The Guardian 7/8/18