Wednesday, 20 February 2013
Greenland: Strawberries and global warming
The first thing Dani noted as a newcomer to Greenland in August 2012 was the extraordinary melting of the ice sheet. The local potato harvest was on course to rise from 40 tonnes to 250; and as predicted five years before, there were strawberries!
The melt here and elsewhere is followed by Jason Box PhD. He says that Greenland is currently contributing twice as much to rising sea levels as Antarctica, and one possible reason is the increase in atmospheric particles from land clearance fires and fossil fuel burning, darkening the ice and absorbing solar energy.
He says the sea is taking in some of the extra greenhouse energy, too, increasing its power to erode coastal areas including the western Antarctic ice sheet. Surface sea temperatures around Greenland have risen since 1990:
Apparently we are not yet experiencing the full impact of global warming, because for the last 30 years it has been partially offset by a temporary reduction in solar output, and there may also be (for thousands of years yet) a cooling effect owing to variations in the Earth's orbit (hat-tip to Dr Box for both links).
- so if and when when the heat factors start going in the same direction we - or our remoter descendants - could see the situation change much more rapidly.
The world's climatic system is very complex and variable. In the past, temperatures have been higher and lower than now, and the Greenland ice sheet has been both thicker and thinner:
"In the beginning of the Eemian, 128,000 years ago, the ice sheet in northwest Greenland was 200 meters higher than today, but during the warm Eemian period the ice mass regressed, so 122,000 years before now the surface had sunk to a level of 130 meters below the current level. During the rest of the Eemian the ice sheet remained stable at the same level with an ice thickness of 2,400 meters."
A rise in sea levels could be very disruptive and expensive for millions of people, including those who live in cities like London and New York. And we're not helping ourselves with the way that we develop our land use:
"Along the U.S. Atlantic Coast alone, almost 60 percent of the land that is within a meter of sea level is planned for further development, with inadequate information on the potential rates and amount of sea level rise. Many of the nation's assets related to military readiness, energy, commerce, and ecosystems that support resource-dependent economies are already located at or near the ocean, thus exposing them to risks associated with sea level rise."
As recent events in the UK and USA have shown, flooding is hardly a theoretical matter, and the Environment Agency now has a website to assess the risk where you live:
But scientists are not of one mind on the issue - some say we are facing a mini ice age instead.
Returning to Greenland, climate change may cause difficulties for polar bears, but they haven't been there forever and may have migrated from Ireland. I like to see them on TV and I like even better that they're safely on the other side of the screen.
After all, we hardly want a return of the greater ice ages that made Northern Europe uninhabitable for thousands of years (what is now London was under a three-mile-thick glacier at one point).
If I were a Greenlander, I'd be happy with locally-sourced cod and chips, followed by strawberries and dairy ice cream.
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