This article by Erasmus zu Ermgassen, University of Cambridge was originally published on The Conversation. In a climate conscious era, we’re forever being asked to “turn the lights off” or “drive less!” or “recycle more!”. These familiar messages put the onus on individuals – that is, you and me – to change our behaviour, reduce our impact, and be greener. But what are the limits to these behavioural tweaks? Do they actually make any difference? While they may help a little, to substantially reduce our carbon emissions or be truly more sustainable, we’ll also need a greater focus on “the system”. The problem is that little actions typically only make a little difference. While there are rare examples of small gestures from individual people leading to big changes – think of Rosa Parks’ decision about where to sit on the bus – unfortunately for the do-gooders out there, many people recycle, but it’s a lot more difficult to spark a recycling revolution. And so, it’s understandable if the Tesco approach to greening the planet (“every little helps!”) doesn’t feel like it’ll achieve the deep cuts in greenhouses gases needed to avoid dangerous climate change – because it probably won’t. If, for example, you eat a Western diet, cutting down on meat can reduce your carbon footprint: vegetarian diets produce about 20-30% fewer greenhouse gases than their meat-eating equivalents. Problem solved? Unfortunately not. For most people living in Europe, your diet makes up say 10% of your carbon footprint, so that 30% greenhouse gas saving sums to about a less impressive 3% cut in your total carbon emissions. While that may be an important and achievable 3% reduction, we’re going to have to do more than that – especially if these changes in our behaviour have unforeseen consequences.