Science Daily has a piece on a new study of data gleaned from Tahitian corals laid down during the BÃ¸lling warming event around 14,000 years ago. Then, high latitudes of the Northern hemisphere warmed as much as 15 degrees Celsius in a few tens of decades and the new study indicates that freshwater from melting ice shelfs contributed to a rise of over 14 meters (45 feet) in sea levels.
Meanwhile, over at New Scientist, there’s worrying news about Artic ice melt.
The disappearance of Arctic sea ice has crossed a “tipping point” that could soon make ice-free summers a regular feature across most of the Arctic Ocean, says a British climate scientist who is setting up an early warning system for dangerous climate tipping points.
Tim Lenton at the University of Exeter has carried out a day-by-day assessment of Arctic ice-cover data collected since satellite observation began in 1979. He presented his hotly anticipated findings for the first time at the Planet Under Pressure conference in London on Monday.
Up until 2007, sea ice systematically fluctuated between extensive cover in winter and lower cover in summer. But since then, says Lenton, the difference between winter and summer ice cover has been a million square kilometres greater than it was before, as a result of unprecedented summer melting. These observations are in contrast to what models predict should have happened.
One of the consequences, according to a study by Euan Nisbet of Royal Holloway, University of London, is that gas hydrates on the seabed are melting.
This could trigger landslides on steep submarine slopes in the area, unleashing tsunamis capable of hitting the UK, and releasing buried methane that could amplify global warming. Something similar happened off Norway 8000 years ago in a similar geological setting, Nisbet told New Scientist.
These studies come on the back of a 2010 one that suggests that the West Antarctic Ice Sheet might be close to a tipping point at which it would rapidly disintigrate, dropping enough fresh water into the world’s oceans to quickly raise sea levels by more than ten feet.
With a crowd-sourced study involving over 10,000 simulations strongly suggesting that we’re in for more warming in decades to come than the most pessimistic “official” climate predictions, such tipping points are likely to come thick and fast. For example, an estimated 5.6 million trees have already died of drought in Texas urban areas alone, decreasing shade cover dramatically and increasing heat evaporation which will deplete scarce water resources even faster as we head towards a new dustbowl. Rising sea levels will swamp much of the Texas coast while flooding cities worldwide which are homes to 27 million people, from Mumbai to Miami.
But Rick Perry is upset about UK ‘meddling’ in his denialism. Go figure.