My previous post on whether it was necessary to give up meat and dairy to tackle climate change produced a pretty adverse reaction from some of my vegan and vegetarian friends. It was never my intention to upset anyone, and I apologise unreservedly if I did. I feel that the message has got lost in the discussion, so I hope you will allow me a second go.

My key point was – and is – this: it isn’t safe to assume that giving up meat and dairy is the biggest way to reduce your impact on climate change. There are too many variables. It is very clear that we must dramatically reduce the amount of dairy and meat we eat globally, both to reduce impacts on the environment, and tackle climate change.  That is beyond question. But even if the whole world gave up all animal protein immediately, we would still be left with dangerous levels of climate change. So we need to be looking at all the components of our individual carbon footprint, if we really want to make a positive difference.

What are the claims?

Just to recap, Joseph Poore, the author of some recent research claimed that giving up meat and dairy is the “single biggest way to reduce your impact on Earth“. He also claimed that giving up meat and dairy are more significant than giving up flying or swapping to an electric car. Whilst the research itself is both excellent and timely, these claims do not feature at all in the research findings, nor do figures that could demonstrate this. Similar claims have been found to be misleading previously. The headlines are however all that most people will read, and so deserve scrutiny.

What’s the problem?

Headlines of this sort tend to increase what psychologists call ‘moral licence‘ amongst those who are already doing the thing in question. This in turn often drives behaviour that increases greenhouse gas emissions higher than they would otherwise be. It’s like burning 500 calories in the gym and feeling like you’ve earned that pack of Oreos (630 calories!).

The headline also gives the impression that unless you give up meat and dairy, there’s no point taking other action to curb climate change. This risks helping many people to put the whole thing in the ‘too difficult’ box and forget about it. Finally, people are very likely to mix up their  ‘impact on earth’ with their ‘impact on climate change’. We all want to be doing our bit on climate change, so it’s an understandable, but inaccurate, mix up. None of this is helpful at a time when much greater action is needed on every front to combat climate change.

What is the impact of your diet?

In brief, it depends on your diet now, and what else you do in your life. Let’s look at diet first. The impact of your food on climate change all depends on

  • what you eat,
  • how much you eat,
  • where it comes from, and
  • how much is wasted.

As the Poore et al report (rather strangely) doesn’t cover different diets in this detail, we need to dip into another excellent recent piece of research. This tells us that a high meat-based diet in the UK produces around 3 tonnes of greenhouse gas a year. A low to average meat diet produces two tonnes, and a vegan diet produces 1 tonne.

These figures are averages and all standardised to 2000 calories to make the comparison fair. There are, of course, a load of different scenarios to this that can increase the impact of dietary choices. Not many adults manage on 2,000 calories a day in our western culture, which is partly why we are in the midst of an obesity epidemic. Overeating increases greenhouse gases as well as calories of course, for all diets. Food waste also affects greenhouse gas emissions, with some estimates suggesting that up to half of all food is wasted at some point in the chain from farm to fork.

The Poore research also usefully highlights how different farming practices produce staggering variations in impact, so where your food comes from, and how it is farmed are also clearly very important.

Extreme meat/extreme vegan

This raises some ‘extreme diet’ scenarios. According to the Poore report figures, if someone ate 100g of the most damaging beef each day (around two average beef burgers or a mid-size steak) they could easily be accounting for 7 tonnes of greenhouse gas each year  just for the steak! Add in the 3 tonne footprint of the ‘standardised high meat’ diet, and you have a diet that is producing over 10 tonnes of greenhouse gas per year.

A diet without any meat or dairy will nearly always have a lower carbon footprint, but there are exceptions to this too. An uber-climate-conscious vegan eating a substantial amount of home grown veg will probably be able to get as low as half a tonne. Conversely, a recent case study highlighted vegans who existed entirely on fruit – with a carbon footprint similar to that of an average meat eater.

So diet can account for between 0.5 and 10 tonnes of our carbon footprint a year, with an average difference of two tonnes from high meat to vegan.

Comparisons with other lifestyle choices

Here are a couple of comparisons then:

  • If you drive a pretty efficient mid range diesel car for 8,000 miles a year, that works out at 4 tonnes of greenhouse gas a year.
  • If you drive 8,000 miles in a brand new diesel Range Rover, that’s around 8 tonnes of greenhouse gas a year (12 tonnes for a petrol Rangie).
  • If you drive an electric car for 8,000 miles a year, that is around 1 tonne a year  (using the UK grid average for the electricity and including manufacture of the car)

So if you drive an average diesel car and were to switch to electric, the saving is around 3 tonnes per year. If you switch from a big car, the saving is greater. Of course if you don’t have a car at all, then you are on to a winner from the off, at least in carbon footprint terms!

So in this scenario, comparing with the ‘average’ high meat diet, changing your car has a bigger impact than going from a high meat diet to vegan. You have to go straight from the ‘extreme meat’ diet scenario to vegan in order to make bigger changes.

What about giving up flying?

According to the Atmosfair calculator (my go-to flight emissions calculator), two tonnes of greenhouse gas gets you from the UK to Egypt and back once a year (2,147 kg CO2e), or a couple of trips to sunny Spain (1 tonne per person per return trip).

If you go long haul to New York, that’d be around 2.5 tonnes per round trip. So again, it totally depends on how much you fly, but just taking these examples, you could easily match or better the carbon footprint savings of going from a high meat to vegan diet by reducing or cutting out flying.


Reducing or giving up meat and dairy are undoubtedly of huge benefit in tackling climate change and a host of wider environmental issues too, but it just isn’t possible to assume that dietary change is highest impact actions you can take on climate change. There are simply too many variables.

Tackling climate change effectively requires us to be working towards a two tonne lifestyle. As soon as we start to measure our actual personal impacts on climate change, how we achieve that goal then becomes a matter of personal choice (and financial wellbeing – but that is for another blog!).

Til next time

Mr GreenBeard


If you want to find out how to reduce your carbon footprint, why not take a snapshot, which tells you not only where your carbon footprint comes from, but how much cash you can save in the process of reducing it. The results may surprise you.

Leave a comment

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.


Enjoy the Three by 30 blog? Please spread the word!