Weatherdem's Weblog

Bridging climate science, citizens, and policy


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Climate Change: Indicators, Report on Abrupt Change, Sea Levels and Glaciers

A group of researchers wrote a climate change op-ed piece in the Denver Post about a month ago.  They wrote about recent data pointing to the effects climate change is already having on our planet.  One of the most important results is rising sea levels:

However, if warming continues to accelerate and polar ice sheets begin to shrink more rapidly, a rise of 3 feet or much more is possible. That would affect 145 million people around the world, at a cost of nearly $1 trillion, according to the United Nations.

Potential rises of much, much more are indeed possible.  145 million affected people is on the low end of the range according to a research paper I read recently (and will go over in more detail in a future post).  If 145 million people affected would cost $1 trillion, the cost of millions more will be truly sobering.  We have the science demonstrating the effects.  We need the willpower to actually do something about it.

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A report on abrupt climate change by the US Climate Change Science Program can be found here.  I’ve read through most of it and came away impressed with the depth and breadth of information it holds.  The report looks at historical climate data and assesses what similar climate extremes would mean today.  It points out that human-forced climate could introduce additional abrupt climate changes beyond what might naturally occur.  It also assesses risk in a generalized way and provides policy solutions to mitigate those threats.  Very worthwhile reading.

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Forcing already in the climate system continues to push sea levels higher, as measured by NASA satellites.  I mention the warming already “in-the-pipeline” as many climatologists refer to it because the graph shows continued sea level rise despite a moderate La Nina the past two years, which only affected global temperatures.  Those temperaturs remain in the top-10 of recorded instrumented history, which likely means more sea level rise in the future.

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Swiss and Bolivian glaciers are melting faster and faster.  If current warming trends continue, melting glaciers are forecasted to raise sea levels by at least 14″.  Unfortunately, the warming trend has accelerated in recent years – there is more warming now than occurred over the time periods studied in the two articles.  We much stop emitting greenhouse gases today.  The Earth in 50 years is likely to look quite different than it does today.  How much different is up to us.

An additional glacier diary shows a disconcerting glacier flow in Greenland.  Among the highlights:

From the 1970s until about 2001, the position of the glacier’s margin changed little. But between 2001 and 2005, the margin retreated landward about 7.5 kilometers (4.7 miles), and its speed increased from 8 to 11 kilometers per year. Between 2001 and 2003, the glacier also thinned by up to 40 meters (about 131 feet). Scientists believe the retreat of the ice margin plays a big role in the glacier’s acceleration. As the margin of the glacier retreats back toward land, the mass of grounded ice that once acted like a brake on the glacier’s speed is released, allowing the glacier to speed up.

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Ancient Arctic Ice Shelves Breaking Away

The most recent in a series of break offs was reported today. The 4,500 year old Markham Ice Shelf which is the size of Manhattan broke off Ellesmere Island within the last month. That’s just the latest: two large sections of ice detached from the Serson Ice Shelf, shrinking that ice feature by 47 square miles, or 60 percent. Unusual cracks have been reported in northern Greenland ice features. Southern Greenland glaciers have undergone record melting this year. And the “permanent” Arctic ice has achieved its second lowest extent in recorded history as it melted away this summer like it did last summer, which holds the record (for now) of the lowest recorded extent.

Record warm temperatures in the Arctic circle are causing the abrupt changes in what should be permanent features. The Arctic has experienced more warming than any other part of the globe to date. Anybody who still things the Arctic won’t be ice-free in the summer at the end of the century (likely sooner!) probably won’t ever be convinced of the effects of human forced climate change.

More bad news from the article:

“The Markham Ice Shelf had half the biomass for the entire Canadian Arctic Ice Shelf ecosystem as a habitat for cold, tolerant microbial life; algae that sit on top of the ice shelf and photosynthesis like plants would. Now that it’s disappeared, we’re looking at ecosystems on the verge of distinction,’ said Muller.

Large ice sheets off western Antarctica broke off earlier this year, following a recent trend of catastrophic collapse of sheets from that continent. Now the same thing is occurring up north. Meanwhile, the Canadian Prime Minister, Stephen Harper, in his infinite wisdom, wants to set up additional oil and gas drilling now that more land is accessible. When will the 20th century approach to burning fuel end? No time soon if Stephen Harper and John McCain have anything to say about it.

On the other hand, most Americans want to end our abuse of fossil fuels and implement a renewable energy-based approach. That’s merely one piece of what we’ll have to do as a species to avoid the worst effects of climate change.

Cross-posted at SquareState.

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JohnnyRook has a very well written diary about this event and the declining health of our frozen water features across the globe.