On Wednesday, the BBC environment analyst Roger Harrabin summarised a new academic study entitled Climate change: top 10 tips to reduce carbon footprint revealed. His news report demonstrates how easy it is to create popular myths in the name of science.

For context, the study was produced by the Centre for Research into Energy Demand Solutions (CREDS), a team of British academics from fifteen academic institutions across the UK. The study was global in its remit, not GB-specific, something that the BBC news report should have made clear up front.

Myth 1: A vegan diet “doesn’t quite have the impact of other measures”

How do we reconcile this finding with that of Joseph Poore, the Oxford academic who led the largest (hitherto) numerical assessment of food’s impact in a global study of 2018 and concluded “avoiding meat and dairy is the single biggest way to reduce your impact on earth”, as quoted in newspaper reports at the time? Or that of Tim Searchinger and colleagues at the World Resources Institute whose December 2018 study in Nature concluded that the average European could reduce their carbon footprint by 9tCO2e per annum by becoming vegan?

These are clearly very different findings. It would help if news reports could at least acknowledge, and ideally attempt to explain with the authors’ help, such differences. It is likely that the CREDS study does not attempt to analyse land opportunity costs, as Poore/Searchinger did – e.g. the fact that around half of the earth’s land surface is used for livestock in one way or another; and much of this could be freed up for reforestation if our diets were more plant-based. It also seems likely that the CREDS study was looking at the global average, not a meat-heavy Western diet. And that the CREDS study defines the food industry more narrowly than Poore et al.

Myth 2: Following these 10 tips can reduce an average Brit’s carbon footprint by 90%

This is not stated explicitly. But in consecutive sentences, Harrabin’s report states firstly that 9tCO2e per annum can be saved by following these tips; and secondly that the average Brit’s carbon impact is 10tCO2e per annum. So it is a natural inference to draw! The news report fails to point out that the figure of 9tCO2e was given as a maximum for a “high consuming high income” footprint, and in that respect is not directly comparable with the average British per capita footprint.

It is of course nonsense to think that with a small number of simple measures we can bring our carbon footprint down to 1tCO2e per capita per annum. The vegan diet on its own would account for that, before we get into heating, transport, clothing, stuff, electricity, … The CREDS study has nothing to say about clothing or stuff.

Myth 3: Switching to a green electricity tariff saves 1.68tCO2e per capita

This is the annual figure given in the CREDS report. It is a global average level of carbon emissions from electricity generation – not to be confused with an amount that can necessarily be saved – and is broadly consistent with the BP Statistical Review 2019. Globally, coal is the main fossil fuel used for generating electricity.

In GB, coal is hardly used any more, and half of the electricity is generated from renewables and nuclear. Here, the corresponding figure is around 0.3-0.4tCO2e per capita, around one quarter of the global average. Economy-wide we have a large carbon footprint compared with the global average – but not because of our current patterns of electricity generation.

There is also the point that, to date, switching to a green supplier has been largely a matter of attribution, leaving those consumers who aren’t bothered to pick up the brown power, as it were. Over the last couple of decades, GB renewables have been built in line with the national pot of subsidies available, not to any significant extent because of consumer switching.

So it is thoroughly misleading to give the impression that switching to a green electricity tariff is one of the top four measures for reducing our individual carbon footprint. At least in this country.

Conclusion

The CREDS study is, reportedly, based on 7000 other studies – which immediately raises questions about the comparability of all those different studies. Be that as it may; however well researched an academic paper is, poor communications can completely undermine both the public’s understanding of its messages, and faith in experts more generally.