In relation to the Science behind my estimates of sea level rise we can now add the information from an article by Sharon Begley at newsweek.com published 24 July 2009. Sharon pulls together some recent views on the state of the ice on and around Greenland. Read the article for the details.
...the sea ice found a more open, ice-free, and thus faster path westward thanks to Arctic melting.
...The loss of Arctic sea ice "is well ahead of" what the Intergovernmental Panel on Climate Change forecast, largely because emissions of carbon dioxide have topped what the panel—which foolishly expected nations to care enough about global warming to do something about it—projected. "The models just aren't keeping up" with the reality of CO2 emissions, says the IPY's David Carlson.
... satellite measurements of Greenland's mass, show that it is losing about 52 cubic miles per year and that the melting is accelerating. So while the IPCC projected that sea level would rise 16 inches this century, "now a more likely figure is one meter [39 inches] at the least," says Carlson. "Chest high instead of knee high, with half to two thirds of that due to Greenland." Hence the "no idea how bad it was."
...estimates of how much carbon is locked into Arctic permafrost were, it turns out, woefully off. "It's about three times as much as was thought, about 1.6 trillion metric tons, which has surprised a lot of people," says Edward Schuur of the University of Florida. "It means the potential for positive feedbacks is greatly increased." That 1.6 trillion tons is about twice the amount now in the atmosphere. And Schuur's measurements of how quickly CO2 can come out of permafrost, reported in May, were also a surprise: 1 billion to 2 billion tons per year. Cars and light trucks in the U.S. emit about 300 million tons per year.
...the G8, led by Europe, has vowed to take steps to keep global warming below 2 degrees Celsius by reducing CO2 emissions. We're now at 0.8 degree. But the amount of CO2 in the atmosphere is already enough to raise the mercury 2 degrees. The only reason it hasn't is that the atmosphere is full of crap (dust and aerosols that contribute to asthma, emphysema, and other diseases) that acts as a global coolant. As that pollution is reduced for health reasons, we're going to blast right through 2 degrees, which is enough to ex-acerbate droughts and storms, wreak havoc on agriculture, and produce a planet warmer than it's been in millions of years.
...The test of whether the nations of the world care enough to act will come in December, when 192 countries meet in Copenhagen to hammer out a climate treaty. Carlson vows that IPY will finish its Arctic assessment in time for the meeting, and one conclusion is already clear. "A consensus has developed during IPY that the Greenland ice sheet will disappear," he says.
Now what happens to Greenland will also be mirrored in the Antartic, where as detailed in previous posts and below, the West Antarctic Ice Sheet is showing signs of distress. The combination serves to push the "Very Likely" sea level rise closer to two metres, and the possible worst case through my estimated five metres.
I insure my house against fire for the possible worst case. I don't know anybody who has had their house burned down, do you? But we all act to protect ourselves and our record collections against the conceivable worst case. Five metres is conceivable, and even more so in terms of these latest discoveries by the International Geophysical Year scientists.
We should act accordingly.
Thus we only have a very short window of time (maybe 20 to 50 years at the most) to rebuild the fabric of our coastal civilisation someplace else before we run out of the energy we need to do that. And since we only have the time and resources to do this once. ONCE. Then we must do it where it will be SAFE from whatever is coming.
The level of the ocean at your place or mine in 2100 is irrelevant - it is just a marker on a journey to the finished level of +80 metres.
Eightly (80) metres of sea level rise is coming. We know this. This is the only number that matters. So we have a duty to only expend our diminishing resources ABOVE that level, or else with good cause our names will go down in infamy with our children and our grandchildren, 'yea unto the n-th generation'.
The simple point is that WE KNOW THIS IS GOING TO HAPPEN sooner or later. To pretend anything else is to deny our children what ever small chance at survival we can give them.
I want to be able to look my grandchildren in their eyes, and say "I knew, and I tried."
In my view, while 2 metres was strongly supported by people like Dr Hansen under 2008 Business as Usual scenarios, this recent information making it likely that we will get 5 degrees Celsius warming by 2100 leads me to recommend that we use the 5 metres by 2100 table and chart here as our basis for sign locations.
5 & 5 by 2100. Gulp!
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