Why Do The Yaks Hate Us?So instead of writing these massive book reviews, I thought I’d share a few tidbits from a book I’m currently reading. The book When a Billion Chinese Jump: How China Will Save Mankind–Or Destroy It. Yes, more light reading. It’s written by Jonathan Watts, a China-based environmental correspondent for The Guardian in the UK. Based on his years living in China, the book takes a look at the four geographic corners of the country, chronicling the China’s environmental history, the damage that’s been done by rapid industrialization and whether the country can avoid becoming an environmental wasteland.
Reading through a chapter on the Tibetan plateau, Watts conveys in three paragraphs how subtle changes to economic policy can have significant impacts on climate. In this case, the impact is negative, but I think a takeaway is that it can go either way.
The culprit here is yaks. Yes, yaks, or more to the point, regulatory changes made in the 1980s that deregulated herd sizes for both sheep and yaks, the two primary livestock on the Tibetan plateau. Deregulation meant that herders could buy as many animals as they could afford, and a subsequent change to tax policy valued yaks at four times the amount of sheep (which on the face of it makes sense, yaks are pretty big). In addition, the government banned polygamy around the same time. All of this incentivized herders to increase the size of their yak herds, because it was now legal, a better value and a larger yak herd made up for the lost prestige of no longer having multiple wives.
Yaks grazing on the Tibetan plateau
More yaks meant more yaks grazing, and that quickly threw off the equilibrium between livestock and grassland that had been set over thousands of years. The overgrazing caused much of the plateau to rapidly become desert and less able to absorb moisture. This caused more heat to radiate into the atmosphere, and with much of the plateau at an elevation of 14,000 feet or more, this heat radiation had an outsize impact on climate. The result was that the Tibetan mountains have been warmed more than anywhere else in China, even with the massive amounts of pollutants created by industrial production in the country’s east.
Set right against the Himalayas, the adjacent mountains funneled water vapor directly into the stratosphere rather than becoming rain or snow, as it would have at a lower elevation. Water vapor has a greater greenhouse effect than carbon dioxide, increasing climate temperatures even more. Because of its place on the globe–at an incredibly high elevation and next to the world’s highest mountain range–changes to the Tibetan land quickly impact climate on a global scale. As Watts writes:
Changes in the soil here fed back rapidly into the atmosphere, affecting global air circulation just as rising ocean surface temperatures affected storm patterns.
It’s a reminder of the law of unintended consequences. When dealing with the environment, every action has an equal and opposite reaction–but we don’t learn what it is until well after the fact.
http://sesnak.wordpress.com/2011/02/01/ ... s-hate-us/
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