Thread: Arctic climate change

A conference paper which typically precede peer-review papers.
It's a short discussion of the observations and some of the implications of climate change in the Arctic and possible but uncertain feed backs as the permafrost gets replaced by scrub and boreal forest.


"The effects of climate change in the Arctic are already here. And the changes are taking place significantly faster than previously thought. This is what emerges from a new research report on the Arctic, presented in Copenhagen this week. Margareta Johansson, from Lund University, is one of the researchers behind the report."
http://www.lunduniversity.lu.se/o.o....news_item=5580

I'll post up figures and graphics as they come available.

But as the permafrost thaws there is a risk that carbon dioxide and methane, a greenhouse gas more than 20 times more powerful than carbon dioxide, will be released, which could increase global warming.
“But it is also possible that the vegetation which will be able to grow when the ground thaws will absorb the carbon dioxide. We still know very little about this. With the knowledge we have today we cannot say for sure whether the thawing tundra will absorb or produce more greenhouse gases in the future”, says Margareta Johansson

It seems likely to me that the thawing will proceed far more rapidly than the revegetation. It takes decades to populate new areas with mature trees, which presumably are necessary to sequester the carbon. Or am I barking up the wrong tree?

No, the Ap reported yesterday that a new authorotative report by the 8 nation Arctic Council says Greenland melting will raise sea levels by up to 5 feet (3 feet median) before the turn of the next century. It is losing ice 4 times faster than in 1995-2000.

That's many time greater than the last IPCC projections in the 2007 report that the naysayers laugh at (7-23").

I've tried to find a link, but AP doesn't give it out for free.

Originally Posted by Bunbury

But as the permafrost thaws there is a risk that carbon dioxide and methane, a greenhouse gas more than 20 times more powerful than carbon dioxide, will be released, which could increase global warming.
“But it is also possible that the vegetation which will be able to grow when the ground thaws will absorb the carbon dioxide. We still know very little about this. With the knowledge we have today we cannot say for sure whether the thawing tundra will absorb or produce more greenhouse gases in the future”, says Margareta Johansson

It seems likely to me that the thawing will proceed far more rapidly than the revegetation. It takes decades to populate new areas with mature trees, which presumably are necessary to sequester the carbon. Or am I barking up the wrong tree?

I believe smaller plants (tundra and scrub) sequester carbon at respectable rates. These plants exist where thawing is occuring and will compete more efficiently as thawing proceeds.

Also, soil microbes can consume considerable amounts of methane. there is a substantial body of work on using soil blankets over landfills to allow methanotrophs to convert methane to CO2 and biomass, for example. Such methantrophs exist in arctic soils. It is worth looking for an article that measures actual methane release from soils during thaws, rather than simply modeling what an x-degree rise in temperature may release. The gulf spill, for example, released very large quantities of methane but this was consumed by a seeming explosion of marine methanotrophs before the gas could be released to the atmosphere.

Originally Posted by free radical

I believe smaller plants (tundra and scrub) sequester carbon at respectable rates. These plants exist where thawing is occuring and will compete more efficiently as thawing proceeds.

Also, soil microbes can consume considerable amounts of methane. there is a substantial body of work on using soil blankets over landfills to allow methanotrophs to convert methane to CO2 and biomass, for example. Such methantrophs exist in arctic soils. It is worth looking for an article that measures actual methane release from soils during thaws, rather than simply modeling what an x-degree rise in temperature may release. The gulf spill, for example, released very large quantities of methane but this was consumed by a seeming explosion of marine methanotrophs before the gas could be released to the atmosphere.

I wonder what actually occurs when the permafrost thaws. Every spring on the North Slope the hard frozen surface turns to mush. There are small hills called pingos that are basically mounds of ice covered in thin soil, and thousands of small round lakes. My thought is that if the permafrost thaws permanently the resulting landscape will be essentially swamp, with little exposed soil. The native plants such as arctic cotton are adapted to existing conditions. Will they adapt to being permanently waterlogged?

The methanotroph surge in the Gulf was fortuitous - someone should study it! But the depth of water in the Gulf is vastly greater than the shallow swamp that might form in Arctic regions. This might mean the methanotroph population would be far smaller relative to the rate of methane production, and could be overwhelmed.

I have read, but don't recall where (perhaps Jared Diamond's "Collapse") that the rate of change of habitat is already exceeding the rate of re-population in general (not particularly in the Arctic) for both flora and fauna.

I have a plan.
Let all those who do not believe in global warming buy beach front property.
The rest of us can live in the hills. (I've already remarked that I'm counting on total meltdown and a 100m rise, which will place the shore fifty yards from me, with a nice little sheltered creek to anchor the fishing boat. The great, great, grand-children will love it.)

Originally Posted by Ophiolite

I have a plan.
Let all those who do not believe in global warming buy beach front property.
The rest of us can live in the hills. (I've already remarked that I'm counting on total meltdown and a 100m rise, which will place the shore fifty yards from me, with a nice little sheltered creek to anchor the fishing boat. The great, great, grand-children will love it.)

Here in the Mile High City I think we should be safe from the rising waters. Our problem will be the loss of snow pack and consequent emptiness of reservoirs.