Monday, 6 October 2014

Walruses, Sea Ice, and Global Warming

This photo of a large herd of walruses on the shore at Point Lay in Alaska seems to be the new poster icon to portray the havoc and devastation wrought upon ourselves by global warming as a result of our extravagant lifestyle and persistent excessive CO2 emissions. Now, I have several bones to pick with this (these) assumptions.

Firstly, let’s start with the walruses. This is not the first time a large herd of walrus has come ashore and parked for a while. This youtube clip of walruses at Point Lay from 2011 was also touted as proof of the impact of global warming. 

If you dig a little deeper, though, you discover that large groups of walruses have been observed coming ashore since the 1870s, and there is no reason to assume they weren’t doing so long before then. What makes this year’s herd remarkable is that it is the largest congregation of walruses (an estimated 35,000) on record. Which may have as much to do with increasing numbers of walruses overall (some estimates suggest a doubling of population in the past half century, to over 200,000 now, although walrus numbers are hard to count) as it does to ice melt. As walruses hunt and feed in shallow areas of the continental shelf—molluscs and crustaceans making up a large portion of their diet—when the summer ice moves offshore at the end of the summer, walruses likely find it more convenient to rest up on land near the feeding grounds rather than on the ice floes further from their food source.

As part of the global warming story, articles attached to this photo invariably point out—shock, horror!--that the arctic ice is at it’s 6th lowest minimum since records began! But records began just 35 years ago in 1979 when they started monitoring ice cap size by satellite. A period of 35 years is about the length of time climatologists generally consider as ONE data point in the long-term scheme of things—shorter time periods count as “weather”, not “climate”. Of those 35 years, the ice cover was smaller in 2007, 2008, 2010, 2011, and 2012, which could—if you really want to look at individual years—suggest a cooling trend over the past two years.

You don’t hear quite so much about man-made global warming these days, partly because even global warming enthusiasts are discouraged by the planet’s lack of actual warming for about 18 years in spite of ever-increasing levels of CO2 in the atmosphere. The hot new term is “climate change”, and that’s easier to defend because it’s not really measurable. The fact we live on a dynamic planet that does, of course, change with time makes this an easier problem to defend. When politics gets involved in the story, and it moves out of the realm of scientific observation and into the realm of the manipulation of public perception, and by way of that taxation, things get really interesting.

I’ve written previously about the carbon tax issue and, if this is of interested to you, then read on here.

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