Arctic "death spiral" leaves climate scientists shocked and worried
Worse than worst case
Multiple feedback loops amplify global warming.
- Albedo flip.
Sea ice reflects sun's rays back into space keeping the planet cooler. As sea ice disappears the uncovered ocean absorbs this energy, making the planet hotter. One estimate says the extra heat gained equals the global warming from an additional 20 years of human CO2 pollution.
- Permamelt. As the Arctic rapidly heats up, the "permanently" frozen soils (permafrost) also have started to melt at any increasingly rapid pace. As permafrost thaws it releases methane and CO2 -- both potent greenhouse gases. A new study by University of Victoria climate scientist Andrew Weaver and others predicts that Canada's melting permafrost will accelerate global warming more than 0.5 C by the end of the century. That is about half the warming we still have left before most climate scientists predict dire impacts on humans.
- Methane hydrates melting. Tremendous amounts of methane are frozen on the bottom of the Arctic Ocean. As water temperatures increase, the threat of large emissions of methane bubbling out of the sea grows. Climate scientist James Hansen of NASA says the melting of methane hydrates in the earth's past has triggered rapid global warming leading to major extinction events.
- Dying forests.
Rapid warming is causing the entire western boreal forest to start dying faster than it is growing back according to recent research. This gigantic swath of landscape has shifted from an absorber of CO2 to an emitter of CO2 in recent years. This is creating a feedback loop where over-heating forests release CO2 that then over-heats the forests even more. Forest fires are also increasing in the boreal and arctic, releasing ever more CO2. Meanwhile, the voracious mountain pine beetle that has been unleashed by warming temperatures has already eaten half the pine trees in BC and across large areas of western North America. These dying pine forests are releasing huge amounts of CO2 into the atmosphere. Experts predict that with unchecked global warming the native pine beetles will expand in a few decades into the boreal forest and eat that forest down from coast to coast.
- More fossil fuels to burn.
The Arctic Ocean has huge quantities of oil and methane that humans have not yet been able to turn into CO2. The sea ice has kept us from extracting and burning them. Now, as the sea ice vanishes, a black gold rush is kicking in. Shell Oil just put the very first drilling rig in. Scrabbling for more carbon to burn in an over-heating Arctic reminds me of people smoking cigarettes through their tracheotomy hole. It might not be illegal, but piling on more of what caused a crisis is likely to end badly.
- Vanishing spring snow cover.
One of the most dramatic but least discussed climate changes on our planet has been the rapid decline in our spring snow cover. Warmer temperatures are melting snow earlier each year. In fact the area of missing snow cover is much greater than thearea of missing sea ice. The snow cover is retreating northward at a rate of 60 km per year. This huge decline in snow cover is driving the same kind of global warming feedback loop as the vanishing sea ice. Instead of snow reflecting sunlight back into space in spring and summer, the snow-free land absorbs it, ratcheting up global temperatures.