Why we should discuss soil as much as we talk about coal

I’m done with cow farts.

I’ve written about them several times over the last six months, and I bring them up in polite conversation more than I should. In my defense, I have a legitimate reason: cow farts are a good example of something that contributes to climate change but isn’t related to generating electricity.

Most discussions about fighting climate change focus on electricity and the need for renewable energy. De-carbonizing the way we generate electricity would be a huge step, but it won’t be enough if we don’t reach zero net emissions from every sector of the economy within 50 years (and make a serious dent in the next ten). That includes the agriculture, forestry, and land use sector, which is responsible for 24 percent of all greenhouse gas emissions—just one percentage point less than electricity.

Gassy cattle are a memorable and significant example of emissions — but it’s not the only major contributor to agriculture, forestry, and land use’s slice of the emissions pie. If you’re looking for a climate change boogeyman, you’re just as well-off picking on soil.

Here’s a mind-blowing fact: there’s more carbon in soil than in the atmosphere and all plant life combined.

Here’s a mind-blowing fact: there’s more carbon in soil than in the atmosphere and all plant life combined. That’s not a big deal when left to its own devices. But when soil gets disturbed — like it does when you convert a forest into cropland — all that stored carbon gets released into the atmosphere as carbon dioxide. That’s one reason why deforestation alone is responsible for 11 percent of all global greenhouse gas emissions. (Another reason is that forests and grasslands are natural carbon sinks. Clearing them reduces the planet’s capacity to remove carbon dioxide from the air.)

The microbes in soil can also create greenhouse gases when they come into contact with fertilizer. Synthetic fertilizers revolutionized how we feed the world, but they release a powerful greenhouse gas called nitrous oxide when broken down by those microbes. Natural fertilizers like manure aren’t any better, because they release greenhouse gases as they decompose.

So how do we fight climate change caused by agriculture? We can’t simply get rid of soil — or stop growing crops, using fertilizer, and raising livestock. There are some changes that societies can make — people in level 3 and 4 countries will eat more meat as they move up the income ladder, so people in level 3 and 4 countries could consume less to compensate, for example — but at the end of the day, people need to eat.

That’s why the goal with agriculture is not to reduce the amount created, but to reduce emissions per product. Because every country and every culture approaches food production differently, there are a lot of different ways to do that (I’m involved with a group called Breakthrough Energy Ventures that is backing a number of creative solutions to tackle the problem).

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Source: Bill Gates | LinkedIn