Saturday, February 19, 2011

The methane monster under Arctic ice - Northwest Passage


By Bob McDonald, host of the CBC Radio One science programQuirks & Quarks.

A new study out of the National Snow and Ice Data Centre in Boulder, Colorado, shows that melting permafrost in the Arctic is adding even more carbon to the atmosphere than previously thought. It will eventually equal half of all the human-generated emissions since the start of the Industrial Revolution.

This is an example of a positive feedback in nature, where a change in one system triggers a cascade of changes in others - and it all centres around ice.

Permafrost is ground that has been frozen year-round since before the last Ice Age, about 12,000 years ago. Back then, mastodons, woolly mammoth, sabre-toothed cats and a whole host of large mammals, including camels, wandered among the grasslands that once covered what is now the High Arctic. Following a major extinction event in the North, all of that animal and plant material became permanently frozen in the ground, storing a lot of carbon with it.

Today, the Arctic is experiencing greater warming than other regions of the planet and the permafrost is melting, releasing all that organic material from its icy tomb. Like thawing out frozen meat, the animal and plant remains rot, releasing methane, which is another greenhouse gas.

But wait - there's more to come.

Warming in the North is also affecting another form of ice, the permanent ice pack covering the Arctic Ocean. Roughly half of the ice has already disappeared, with predictions that the Arctic water will be free of ice all the way to the North Pole during summer months sooner than the current IPCC prediction of 2050. 

In other words, we are quickly changing the colour of the planet.

 The top of the world is a white landscape that reflects sunlight back into space to keep us cool. When that white ice turns into dark seawater, the Arctic Ocean becomes a huge solar collector that absorbs radiation from the sun, which accelerates the warming, which speeds up the melting of permafrost and releases more methane, which traps more heat in the atmosphere, which triggers more permafrost melt ... well, you get the idea.

The implications of this accelerated warming for Canada are huge. On the one side, all that open water will delight shipping companies looking for a shortcut through the Northwest Passage and those seeking oil in the North. On the other side, those building pipelines, roads or permanent structures will find the land sinking beneath them as the permafrost melts. Buildings will lean, roads will turn to muck and pipelines will bend, possibly break.

That's not to mention the multitude of effects that warming in the North will have on animal and plant populations.

The bottom line is that our targets for lower carbon emissions from human activity will have to be even lower, because we have triggered a natural cascade of events that will feed back on itself.

Considering how much is at stake for Canada, it's odd that our country's efforts to curb emissions are lagging behind those in other parts of the world.

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