ANALYSIS: A drowned Maldives, the opening of new shipping lanes – climate change is too fast for evolution
THE ARCTIC ice-cap is melting and there seems to be very little we can do about it. Global warming is, as ever, the assumed cause but what difference will it make to life on this planet?
Probably a great deal. Losing all of the summertime Arctic ice will change the way the earth absorbs or reflects incoming energy from the sun. Energy balances will change, temperature-driven ocean currents, including the Gulf Stream so very central to our own mild climate, are likely to be altered.
There is a whole catalogue of environmental, biological and social changes that would follow the loss, even if only during the summer, of Arctic sea ice.
Cambridge University’s Prof Peter Wadhams, a noted expert on Arctic ocean ice, yesterday released a new prediction that the Arctic Ocean will be completely ice-free during summer months in as few as 20 years.
His contention is not new. Scientists have been predicting the climate-driven loss of Arctic ice for many years, but the older forecasts had this event comfortably far away in 2100 or 2150. Prof Wadhams’s and other recent predictions suggest this scenario in just 20 to 30 years, soon enough for many of us to witness.
There are a variety of implications arising from such a radical and dramatic change over such a large part of the planet. The loss of ice would accelerate processes that we know contribute to global warming.
The Arctic will lose a great deal of its chill if the ice disappears because of something known as albedo. Albedo refers to the amount of light reflected or absorbed by a surface. A perfect white body reflects all light and has an albedo of 100 per cent. A perfect black body absorbs all light and has an albedo of zero.
On average, Arctic sea ice reflects back between 30 and 60 per cent of the solar energy coming from the sun. Open Arctic water, particularly rough water, reflects back only between 10 and 30 per cent of this energy. This means that the Arctic Ocean will itself warm due to solar heating, providing a winter time hot water bottle that will increase average regional temperatures.
The loss of the Arctic ice-cap during summer would make very little contribution to sea level rise, the greatest threat posed by climate change. It is just the same as ice cubes floating in a drink. The glass does not overflow if the ice melts.
It is a different situation for ice sitting on land, including the second-largest single repository of land ice on the plant, Greenland. We are already losing cubic kilometres of ice every year there, due to the existing climatic situation. It must be assumed a warmer Arctic will accelerate this ice loss, dumping vast quantities of fresh water into the oceans.
There would also likely be significant overland warming within the Arctic circle in the vast permafrost regions of Russian and Canada. This would begin to thaw, releasing huge amounts of the climate-warming gas methane into the atmosphere. This could create a positive feedback, with more methane causing more warming causing more methane release. This, in turn, would likely push up temperatures globally, accelerating the melting of snow and ice over land in other regions.
The release of so much water could produce sea level rise on a grand scale, with levels going up by metres rather than the millimetres seen today. Coastal cities around the globe would be swamped and some island nations such as the Maldives would disappear.
Then there is the influence of all this fresh water on the ocean’s circulation systems. Scientists can only speculate on the impact of this, although the historical record gives us very strong clues. What is now Canada and the northern US bore a heavy burden of ice during the last great ice age. Much of this melted quite quickly during a warm interglacial period, pouring millions of tonnes of fresh water into the north Atlantic.
This disturbed the earth’s heat transfer conveyor belt that circulates water in the deep oceans. This thermohaline circulation flows due to heat differences but also salt content. The Gulf Stream is a part of this circulation and, if it were slowed or halted, Ireland would become a very cold place indeed.
These are global, climatic considerations, but there are many others on a more human scale. Even before the ice is gone, countries bordering the Arctic are haggling over the carve up of the Arctic basin’s oil and gas reserves. Up to 30 per cent of the planet’s undiscovered gas and 13 per cent of its oil may be locked up there so where the national sea-bed boundaries fall is no small consideration. The US, Russia, Canada, Norway and Denmark have already made claims, Russia making a symbolic gesture in 2007 by planting a flag on the sea-bed at the North Pole. Disputes will be hard to resolve.
Oil development would bring drilling rigs and ships into a relatively pollution-free region, but this will certainly change even without the oil. Without ice, new shipping lanes would open, with vessels cutting thousands of miles off voyages. The potential for spillages and accidents would rocket.
This will undoubtedly create a need for large-scale ports to service this traffic, bringing human populations into regions that before now had none. The existing Inuit presence could be swamped by this influx, and put still more pressure on the local environment.
Clearance of the ice would also open up new fishing grounds, once again with attendant squabbles over who has rights to them. On past performance, it would not be long before heavy catches would deplete supplies.
The influx of humans and the loss of ice will also put particular stress on many species including birds, seals and the “poster child” of Arctic ice-loss, the polar bear. The bears depend on ice to capture seals, ambushing their prey as they come up for air. They will have to adapt or face decline when the ice disappears. Species-loss will undoubtedly occur as the ice goes, but the pace of change will eliminate any help afforded by evolution. Environmental change usually occurs over long periods, allowing species to adjust to the new conditions. Many species will succumb to the rapid pace of change in the Arctic.
All this will give world leaders much to consider when they meet at the UN sponsored Copenhagen climate summit in December. Their deliberations will do little however to prevent the Arctic ice from vanishing if Prof Wadhams’s predictions are accurate.