Tuesday, January 19, 2010

The Glaciers of the Himalayas are still melting -- we just don't know how fast

Today, we've seen several articles saying that "World Misled over Himalayan Glacier Meltdown".  From my first reading of these articles, it appears that the IPCC relied on sketchy sourcing and little evidence for its claim in the 2007 IPCC report that the Himalaya's could be entirely ice-free by 2035. 

The rivers that begin with meltwater from the Himalayas are the source of fresh water for around 2 billion people in Asia.  These rivers are important for transportation, farming, fishing, tourism, and religious worship.  Because they cross heavily militarized borders, my blog and others writing about climate change and security have cited this area as a potential source of conflict.

It is important that everything we do in climate policy be grounded in sound science.  However, it is also important that security planners look beyond the lowest-common-denominator science, as its practiced by the IPCC.  We need to look at worst-case scenarios: if you plan for the worst, you'll be prepared for any eventuality. 

In fact, as I've written previously, the melting of the glaciers isn't even the most important part of the story.  Instead, a reduced snow melt, brought on by a reduced Indian Monsoon, is the biggest danger.  While glacier melt at a somewhat predictible (slow) rate, annual snowmelt is the largest driver of seasonal flooding.  The size of this snowmelt is the largest driver of this flooding, and that is predominantly driven by annual precipitation.  We simply do not know how climate change will affect the monsoon. 

Similarly, this row with the IPCC shows that we simply don't know how climate change will affect the Himalayan glaciers.  We know that many have retreated significantly.  For instance, the famous Khumbu glacier, from which climbers begin their ascent of Mt. Everest, has retreated by over one kilometer in the last 50 years.  In fact, according to the blog From a Glaciers Perspective "Everest Base Camp has actually dropped from 5,320m to 5,280m since Hillary and Tenzing first set up camp for their ascent there more than fifty years ago."  The Guardian had an excellent series of photos earlier this year, showing before and after pictures of retreating glaciers.  (I've used one of their photos above) Photos don't lie: some glaciers, at least, are melting!

The answer here, is that we need better science about how glaciers are acting and will act.  We also need better science about how climate changes will affect precipitation in the region.  What we don't need are the typical voices saying that this small (but significant) problem with the IPCC supposedly invalidates all other pronouncements from them.

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