The Hindu: Cookstoves and the climate
In the last article, we considered the climate impact of India’s love for milk (short summary: not good). This time we will consider another aspect of our food: how we cook it. Most readers of this newspaper will perhaps not have more than the slightest acquaintance with wood-fired stoves. Most of us are still wondering whether or not to voluntarily give up our LPG subsidies (more than 3 lakh of us have).
But millions of Indians cook with stoves fuelled with wood, dung or some other form of biofuel. That’s not a good thing. Why?
For several reasons. We'll deal with three here: the warming impact of the black carbon in the smoke generated from using these stoves; the negative health impacts of the smoke, and third, the negative consequences of the smoke on agricultural yield.
“Biofuel” or wood stoves are quite inefficient: they don’t allow the biofuel (for simplicity, let us call this wood) to burn fully: witness the telltale blackish smoke that emanates from them. The primary constituent of this smoke is what scientists call “black carbon” and it warms the world. Black carbon, or soot, absorbs the sunlight directly in the air and releases the trapped energy as heat, warming the air (I'll pass now on the albedo and cloud formation effects). Many leading scientists believe black carbon to be the most potent warming agent after CO2. While the climate benefits of reducing black carbon are clear, there is some uncertainty on how much benefit we will get. Why? Because the smoke that emanates from a cookstove is a complex cocktail of chemicals, some of the which (like soot) warm the climate while others cool it down. This means that cutting smoke may not slow down warming by as much as some models predict.