Peter Wadhams in the Arctic in 2007: ‘We may able to raise the Thames barrier in Britain but in Bangladesh, people will be drowned.’
by Robin McKie, The Guardian, August 21, 2016
No. There is a clear trend down to zero for summer cover. However, each year chance events can give a boost to ice cover or take some away. The overall trend is a very strong downward one, however. Most people expect this year will see a record low in the Arctic’s summer sea-ice cover. Next year or the year after that, I think it will be free of ice in summer and by that I mean the central Arctic will be ice-free. You will be able to cross over the North Pole by ship. There will still be about a million square kilometres of ice in the Arctic in summer, but it will be packed into various nooks and crannies along the Northwest Passage and along bits of the Canadian coastline. Ice-free means the central basin of the Arctic will be ice-free, and I think that that is going to happen in summer 2017 or 2018.
People tend to think of an ice-free Arctic in summer in terms of it merely being a symbol of global change. Things happen, they say. In fact, the impact will be profound and will effect the whole planet and its population. One key effect will be albedo feedback. Sea ice reflects about 50% of the solar radiation it receives back into space. By contrast, water reflects less than 10%. So if you replace ice with water, which is darker, much more solar heat will be absorbed by the ocean, and the planet will heat up even more rapidly than it is doing at present.
The air over Greenland will get warmer, and more and more of its ice will melt. It is already losing about 300 cubic kilometres of ice a year. Antarctica is adding to the melt as well. Sea-level rises will accelerate as a result. The most recent prediction of the Intergovernmental Panel on Climate Change (IPCC) is that seas will rise by 60 to 90 centimetres this century. I think a rise of one to two metres is far more likely. Indeed, it is probably the best we can hope for.
No, it is not. We also have the issue of methane. Russian scientists who have investigated waters off their coast have detected more and more plumes of methane bubbling up from the seabed. The reason this is happening is closely connected with the warming of the planet and the shrinking of the Arctic icecaps.
Yes, we can measure methane over large areas using satellites. These have shown that methane levels that had been fairly flat for most of the last century have started to rise and are accelerating, often with little outliers on the graph. There is a scientist called Jason Box who works in Denmark for the Greenland Survey, and he calls these outliers dragon’s breath. They are not some sort of measurement caused by dodgy instruments. They are real pulses of methane coming from offshore flumes.
How intense is methane as a heater of the atmosphere compared with carbon dioxide?
It is 23 times more powerful. However, methane dissipates much more quickly than carbon dioxide. It gets oxidised so that it only lingers in the atmosphere for about 7 or 8 years. By contrast, carbon dioxide hangs around in the climate system for about 100 years before it ends up in the sea and is absorbed by creatures that die and litter the seabed. At least that is what scientists thought. Today, there are quite a number of researchers who think carbon dioxide could last 1,000 years in the atmosphere.
In the end, the only hope we have is to find a way to remove carbon dioxide from the atmosphere once it has got there. Even the IPCC has admitted that we will have to find a way to extract carbon dioxide from the air. The trouble is that they just don’t know how we can do that. The most favoured scheme is known as BECCS: bio-energy with carbon capture and storage. Essentially, you plant trees and bushes over vast swaths of ground. These grow, absorbing carbon dioxide in the process. Then you burn the wood to run power plants while trapping, liquefying and storing the carbon dioxide that is released.
I am a bit suspicious of this technology. BECCS will need so much land to be effective. Calculations suggest it would need 40% to 50% of the arable land of the planet to make it work on the scale we will need and that would not leave enough land to grow crops to feed the world or to provide homes for a viable population of wild animals and plants. Other techniques, such as crushing and spreading olivine rocks, which absorb carbon dioxide, on beaches, will simply not scale up. They won’t work, so we will have to find some other way to remove carbon dioxide from the atmosphere directly.