Question: How can earth worms change global worming?

Mark Hodson answered on 18 Jun 2013:

Hi oiikackx,

When earthworms eat organic matter they release some of the carbon from the organic matter as carbon dioxide which is a greenhouse gas. We do the same when we eat food, we convert it into energy in a process called respiration and carbon dioxide is produced as a waste product. So this could increase global warming.

However some of the rest of the carbon in the organic matter that the earthworms eat is locked up in a form that keeps it in the soil – the organic matter is locked up in a way that stops it from being broken down by bacteria. Earthworms also lock up carbon by forming a mineral called calcite – it contains calcium and carbon – and excreting it in their poo. Both these things stop carbon being released from soil as carbon dioxide and therefore act against global warming.

Another process going on is that the bacteria in the earthworms guts convert nitrogen to nitrous oxide, another greenhouse gas. So this also converts to global warming.

So some of the things that earthworms do would increase global warming and some would prevent it. There’s a lot of debate about which is the biggest effect and we’re doing experiments to try and find out.

One thing is for sure though, human activity is having a far bigger effect on global warming than humans.

Incidently, a bit of global warming is a good thing. The atmosphere is full of water moisture which acts as a greenhouse gas. Without it our planet would be too cold for human life!

cheers

m