Friday, July 05, 2019

Climate Change: Easy decarbonisation

If we are to avoid making the earth uninhabitable, we need to reduce greenhouse gas emissions to practically nothing over the next decade. But that will still leave us with the problem of the carbon we have already emitted, which has already "baked in" over a degree of warming into the global climate, with horrifying results we now see in the news every day. Fortunately, there's an easy solution to this: trees. Lots of trees:

Planting billions of trees across the world is by far the biggest and cheapest way to tackle the climate crisis, according to scientists, who have made the first calculation of how many more trees could be planted without encroaching on crop land or urban areas.

As trees grow, they absorb and store the carbon dioxide emissions that are driving global heating. New research estimates that a worldwide planting programme could remove two-thirds of all the emissions that have been pumped into the atmosphere by human activities, a figure the scientists describe as “mind-blowing”.

The analysis found there are 1.7bn hectares of treeless land on which 1.2tn native tree saplings would naturally grow. That area is about 11% of all land and equivalent to the size of the US and China combined. Tropical areas could have 100% tree cover, while others would be more sparsely covered, meaning that on average about half the area would be under tree canopy.

The scientists specifically excluded all fields used to grow crops and urban areas from their analysis. But they did include grazing land, on which the researchers say a few trees can also benefit sheep and cattle.

Returning this area to forest would dramatically shift the balance of carbon in the atmosphere. And it would so so relatively quickly and cheaply - over decades, not centuries, and for tens of dollars a ton, not the hundreds required for (still non-existent) magic tech like "carbon capture and storage". And it would have other ecological benefits as well, such as provided habitat for threatened species.

Obviously, its a huge job. So's replacing all our fossil fuel infrastructure with renewables. But the planet won't be saved in a day. And the sooner we start it, the better.