New Scientist is a British science weekly that’s not cheap but is well worth the subscription price. Its environmental coverage in particular doesn’t mince words. Here’s a sampling of recent articles, all of which appear to point to rising climatic instability — and an ever-bigger market for alternative energy.
Errors and lies thrive in cold weather
14 January 2010 by Michael Le PageHERE’S the question to put to all those who confidently declare that the recent severe winter conditions prove that global warming is nonsense: “Next time there’s a heatwave in summer or an unusually mild spell in winter, will you publicly accept that the ‘warmists’ were right all along? If not, why not? If a cold snap means the climate is getting colder, surely a spell of hot weather proves it is getting warmer?”
The point, of course, is that a bout of extreme weather does not prove anything about climate change. Climate is the average weather over decades.
That said, it is perfectly reasonable to ask why, if the world is warming, have so many places in the northern hemisphere been experiencing record lows? The answer is that for the past few decades cold Arctic air has mostly stayed in the Arctic over winter, trapped by strong winds spinning around the pole. This winter the vortex has weakened and in many places cold air is spilling further south than usual.
The result has been freezing weather for places as far afield as Florida, China and the UK. However, the Arctic, Greenland, much of the Mediterranean and southern Asia have been warmer than usual. So overall the northern hemisphere winter may be no colder than in previous years, it’s just that the heat is distributed differently. Indeed, the average surface temperature of the entire planet during January may yet turn out to be one of the warmest on record.
The surface temperature of the planet in January may turn out to be one of the warmest on record
Most atmospheric scientists regard the recent weather as nothing more than the kind of extreme event that happens from time to time. Others are not so sure. Xiangdong Zhang of the International Arctic Research Center in Fairbanks, Alaska, has found that atmospheric circulation patterns in the Arctic are changing drastically as it warms. He says these changes might have contributed to the recent unusual weather.
Either way, some areas could have more cold weather in the future. That will not change the big picture: the world warmed over the 20th century and it is going to get warmer still. Anyone who tells you a cold spell proves otherwise is either intellectually challenged or plain dishonest.
Major Antarctic glacier is ‘past its tipping point’
13 January 2010 by Shanta BarleyA major Antarctic glacier has passed its tipping point, according to a new modelling study. After losing increasing amounts of ice over the past decades, it is poised to collapse in a catastrophe that could raise global sea levels by 24 centimetres.
Pine Island glacier (PIG) is one of many at the fringes of the West Antarctic ice sheet. In 2004, satellite observations showed that it had started to thin, and that ice was flowing into the Amundsen Sea 25 per cent faster than it had 30 years before.
Now, the first study to model changes in an ice sheet in three dimensions shows that PIG has probably passed a critical “tipping point” and is irreversibly on track to lose 50 per cent of its ice in as little as 100 years, significantly raising global sea levels.
The team that carried out the study admits their model can represent only a simplified version of the physics that govern changes in glaciers, but say that if anything, the model is optimistic and PIG will disappear faster than it projects.
Richard Katz of the University of Oxford and colleagues developed the model to explore whether the retreat of the “grounding line” – the undersea junction at which a floating ice shelf becomes an ice sheet grounded on the sea bed – could cause ice sheets to collapse.
Warm seas
Climate change is warming the Amundsen Sea, which is at the southern margin of the Pacific Ocean. As rising sea levels push the warm water beneath the ice shelves, it melts them from below, pushing the grounding line higher up the continental shelf.
By raising sea levels, and therefore the grounding line, in their model, Katz’s team were able to find the point of no return beyond which the glacier would be unable to recover. That’s because the Antarctic sea bed has a small lip in it: it rises slowly up the continental shelf, then makes a slight dip before rising again to the shoreline. The researchers found that as long as the grounding line is on the outer rise of the sea bed, before the lip, small changes in climate lead to correspondingly small changes in the glacier’s ice volume.
But as soon as the grounding line moves over the lip and starts to move down into the dip in the sea bed, the situation changes critically. “Once the grounding line passes the crest, a small change in the climate causes a rapid and irreversible loss of ice,” says Katz.
Past the point of no return
According to Katz’s model, the grounding line probably passed over the crest in 1996 and is now poised to enter a period of accelerated shrinking.
The model suggests that within 100 years, PIG’s grounding line could have retreated over 200 kilometres. “Before the retreating grounding line comes to a rest at some unknown point on the inner slope, PIG will have lost 50 per cent of its ice, contributing 24 centimetres to global sea levels,” says Richard Hindmarsh of the British Antarctic Survey, who did not participate in the study.
This assumes that the grounding line does eventually stabilise, after much of PIG is gone. In reality, PIG could disappear entirely, says Hindmarsh. “If Thwaite’s glacier, which sits alongside PIG, also retreats, PIG’s grounding line could retreat even further back to a second crest, causing sea levels to rise by 52 centimetres.” The model suggests Thwaite’s glacier has also passed its tipping point.
Observations already show that the model severely underestimates the rate at which PIG’s grounding line is retreating, says Katz. “Ours is a simple model of an ice sheet that neglects some important physics,” says Katz. “The take-home message is that we should be concerned about tipping points in West Antarctica and we should do a lot more work to investigate,” he says.
Journal reference: Proceedings of the Royal Society A, DOI: 10.1098/rspa.2009.0434
Avoiding dangerous warming by 2100 ‘barely feasible’
12 January 2010 by Shanta BarleyFat chance then. Even with all the green power we muster, preventing dangerous climate change by the end of the century is “barely feasible”. So says an analysis of how fast low-carbon energy sources can be introduced.
For a 50:50 chance of keeping a global temperature rise within 2 °C by 2100, we must halve emissions by 2050. This is the message of climate models by Keywan Riahi of the International Institute for Applied Systems Analysis in Laxenburg, Austria, and colleagues. That means 70 per cent of global energy production must be zero-emissions by 2050.
To see if that target was realistic, the team used factors such as the average rate of technology diffusion in the past. Our prospects are poor even if we roll out sources like wind and nuclear power as fast as we can, plus any new ones that become available before 2050.
“We have only a slim chance,” says Mark New at the Tyndall Centre for Climate Change Research in Norwich, UK. “It looks like we’ll have to prepare for warming greater than 2 °C or hope that geoengineering will get us out of trouble.”
Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0903797106 (in press)
