HEADSCRATCHERS

Hi, I'm Pete and I love science and the natural world. I work with the Royal Institution (Ri) in London, where you can find exciting, hands-on science events for young people. We've teamed up with The Week Junior Science+Nature to answer your burning science questions.

- Peter Gallivan

How do cows affect Earth's climate? Sarah

Greenhouse gases, such as carbon dioxide and methane, are gases in Earth's atmosphere that trap heat from the Sun. The heat they release keeps the planet warm enough for life to flourish. However, human activities have released too much of these gases, causing global warming and changes to Earth's climate.

Transport, factories and power stations emit most of the harmful gases, but around one seventh are emitted by farm animals, such as cows, when they burp. Because grass is actually quite difficult to digest, cows have huge stomachs that are filled with friendly bacteria that do the job. However, as the vegetation is broken down into smaller sugar molecules, methane is produced, which bubbles out of the bovine's belly as a burp.

Scientists have recently discovered that if they feed cows a side order of seaweed along with their regular food, methane emissions can be reduced by 30 to 80%.