(NCAR sea ice predictions for 2040)
The above image shows NCAR’s 2006 prediction for potential sea ice losses by 2040, but current rates of sea ice loss could result in such conditions within 1-6 years.
Sea ice melt. It’s something we should all be concerned about. That protective cap of ice over the northern polar region provides a number of beneficial services. Its white, reflective layer cools the Earth, reflecting sun into space. As such it is a haven for Earth’s cold air stores. It also rests above a shallow sea filled with sequestered carbon. The cold cap locks these stores in, keeping them out of the Earth’s atmosphere.
Such a large cap of cold ice also has powerful regional influences. Over the past 10,000 years, it has ensured the health of adjacent land tundra which also sequesters massive volumes of carbon locked in organic material. Sea ice and tundra form an insulator that protects Greenland’s massive ice sheets from melt even as they establish a regional climate system that benefits Earth’s life by providing stability in temperatures and weather patterns.
They also form a first line of defense against runaway global warming.
Yet this system — its cold air, its glaciers, its tundra, and its sea ice — is in increasing jeopardy. Sea ice, which is a primary insulator keeping cold air in the Arctic, has declined about 55% by area and 80% by volume since 1979. This loss of ice reduces reflectivity during summer months and enables greater ocean heat uptake, further hastening melt. It also results in warmer seas during winter time, which helps to keep air temperatures much warmer during the coldest season. This one, two punch has the net effect of pushing melt at ever more rapid paces. Now, yearly volume losses are enough, if sustained, to bring the Arctic Ocean to a nearly ice-free state by 2016 plus or minus three years.
For context, take a look at the above NCAR picture again and then take a look at this picture of end summer sea ice in 2012.
(Image source: Cryosphere Today)
Not too different, are they?
Another single year loss equivalent to 2012 would push sea ice to a state comparable to the NCAR prediction for 2040. And such a loss could happen this year, or next year, or the following. Unless current trends reverse (an unlikely event given an increasing CO2 forcing), then NCAR’s 2040 prediction will almost certainly happen before 2020.
We are losing the northern polar sea ice. And we are losing it far more rapidly than previously anticipated. With it, we are losing all the beneficial services sea ice provides. So as the sea ice recedes more sunlight will be absorbed by the Earth’s northern oceans. As this happens, oceans will warm faster, melting tundra. Together, warmer seas and warmer tundra will release more methane into the atmosphere. Over time, this will produce more warming. All the added heat will push Greenland to melt at an increasing rate. The flushes of fresh, cold water from Greenland together with loss of sea ice will play havoc with northern hemisphere weather as cold and hot air build up and battle in places where they hadn’t before. Europe and portions of North America will see especially severe impacts from this whip-sawing climate. But the impacts of ice melt and polar amplification will be global, creating weather that is likely to make a mess of the world’s growing seasons, resulting in potentially severe impacts to the world’s food security. Lastly, a more rapidly melting Greenland will increase the rate of sea level rise.
This is why sea ice isn’t just an image on a map or a number on a chart. This is why loss of sea ice is much, much more than an opportunity to drill in the Arctic. An ‘opportunity’ that will only serve to make a growing problem worse.
If Earth were a space ship, its captains and crew would consider the sea ice one of its key human life support systems. Its health and stability would be a primary contributor to the safety of passengers and crew members. Loss of sea ice, in this case, would mean a loss of a vital life support and climate stability system. After loss of sea ice, life on space ship Earth becomes more difficult and the risk of harm to its passengers grows.
This is why we should all be concerned about the dramatic sea ice losses we are now witnessing. This is why we should view the cynical Arctic profiteering of the oil companies with dread. And this is why we should do our very best to slow and halt the human-caused changes that are robbing us of that vital, protective layer of ice over our northern oceans.