A Gross Miscalculation in Climate Science

On the cover of the book, Carbon Dharma, adorns this photograph that I took in December of 2008. It is the photograph of a fence enclosing the protected common land of the village of Karech in Rajasthan, India. To the left of the fence, livestock is allowed to graze and the land is barren, devoid of vegetation, except for the occasional scraggly tree or bush. To the right of the fence, the protected common land is lush green and has regenerated into a forest.

 Until a few days ago, I didn't realize that this photograph also illustrates a gross miscalculation that has been occurring in Climate Science which continues to this day, except in the scholarly work of two UN scientists, Robert Goodland of the World Bank and Jeff Anhang of the International Finance Corporation (IFC). The gross miscalculation is in the carbon cycle imbalance caused by human activities. The majority of climate models assume that livestock is in static equilibrium with the 45% of the ice-free land area of the planet that is currently being used for livestock production. In other words, they assume that the land to the left and to the right of the fence in that cover photograph sequester the same amount of carbon per unit acre. Goodland and Anhang (2009, 2011) and my own two eyes beg to differ with this assumption. 

Livestock is a major source of the carbon cycle imbalance even with this gross miscalculation. The 2006 UN FAO report, Livestock's Long Shadow (LLS), had calculated that the livestock sector is responsible for 18% of the global greenhouse gas emissions. But LLS had failed to take into account the ongoing conversion of carbon from land used for livestock production into greenhouse gas emissions. That is, in the world view of the LLS scientists, that fence should have made no difference in the carbon sequestered per unit acre in Rajasthan. But once we recognize the reality that livestock are literally sucking up the carbon from the land and emitting it as greenhouse gases such as methane and CO2 while turning lush green land into barren wasteland, Goodland and Anhang's calculations become more relevant. And the contribution of livestock to the total human caused greenhouse gas emissions is at least a whopping 51% each year. 

This means that the human impact on the carbon cycle is much bigger than we thought. But on the flip side, this also means that the carbon sinks of the natural world are much more powerful than we thought. If 20% of the CO2 emissions in the present climate model calculations are being absorbed by tropical forests and other carbon sinks, then it turns out these same carbon sinks are actually absorbing that and the additional carbon emitted by livestock as well. Which gives me some conviction that a mass movement towards veganism will have a much bigger impact than I originally thought.