I love a January challenge, so I’m trying to get my head around the carbon emissions of the food I eat using a book called How Bad are Bananas? by Mike Berners-Lee that provides the carbon footprint of everything.

Everyone has a carbon footprint, but it’s only recently that this has been figured out. It’s done using a carbon dioxide equivalent (CO2e) - a number equivalent to all the greenhouse gases caused by an item or activity "in terms of the amount of carbon dioxide (C02) that would have the same impact over a 100-year period.”

Berners-Lee reckons we should be using no more than five tonnes of CO2e per year. It’s quite complicated, so to become carbon footprint literate, you’ll need to read the book.

Being vegan helps: already this year, a record 500,000 people pledged to eat only plant-based meals throughout January. Switching to oat and soya milk are also good ways to cut your carbon because dairy, like beef, is a high-carbon way to get calories.

Anything flown across the world tends to rack up carbon totals, but pleasingly, bananas are not big carbon criminals – an apple grown locally in Olden Community Garden, N5, contains 0.3CO2e per kg; a banana shipped from Latin America has 0.7CO2e.

Lifestyle changes are super important: Berners-Lee reckons that a baby born in 2020 to a family with a UK-typical footprint which respects climate science will use up 210 tonnes CO2e in their lifetime.

If that family ignored the climate science, and kept driving and flying at pre-Covid-19 levels, it would be more like 775 tonnes.

  • Nicola Baird is writer and founder of Islingtonfacesblog.Com