or why climate change reporting simply has to improve

One of the most disconcerting environmental trends in recent months has been the emergence of a raft of surveys that suggest the majority of people remain unconvinced about the certainty of climate change and are confused about how best to limit their environmental impact.

"How could this be?" wailed environmentalists. "Why is no one listening to the science? How could anyone still be confused about the seriousness of the problem and what to do about it?"

Well, those looking for a reason for these apparently counter-intuitive survey results need not look very far. In fact, all they need to do is open a newspaper.

The sheer number of nonsensical and contradictory stories emanating from the press has reached epidemic proportions over the last few months as editors keen to jump on the green bandwagon repeatedly approve stories that draw sweeping conclusions from climate change research that is either staggeringly flimsy or based on extremely specific scenarios.

The latest bizarre environmental story comes courtesy of The Times, which ran a story under the headline "Walking to the shops 'damages planet more than going by car'."

The report was based on research from Chris Goodall, author of How to Live a Low-Carbon Life, which supposedly proved that driving is better for the planet than walking on the grounds that the emissions from a typical car are lower than the emissions equated with producing the amount of beef you'd need to eat to give you the energy to walk the same distance.

"Driving a typical UK car for 3 miles [4.8km] adds about 0.9 kg [2lb] of CO2 to the atmosphere," Goodall is quoted as saying. "If you walked instead, it would use about 180 calories. You'd need about 100g of beef to replace those calories, resulting in 3.6kg of emissions, or four times as much as driving. The troubling fact is that taking a lot of exercise and then eating a bit more food is not good for the global atmosphere. Eating less and driving to save energy would be better."

The story prompted Sunday Times columnist Rod Liddle to claim that the contradictory advice emanating from environmentalists meant that he would forever ignore the green lobby, adding that the latest research was proof that you should "save the planet and buy a car".

But if you read beyond the Times' eye-catching headline you quickly realise quite how many dubious assumptions its sweeping conclusion is based on.

The first and most glaring inconsistency in the research is the fact that it takes no account for the carbon dioxide emissions related to the manufacture of the car and extraction and refinement of the petrol that fuels it. Given that the figures used to calculate the environmental impact of cattle are based on a report in the New Scientist that assessed the entire environmental load or embedded carbon from a portion of beef - including the methane emissions, gases related to the production and transporting of cattle feed and the transportation of the meat itself - then for a fair comparison you have to look at the embedded carbon found in the manufacture and disposal of the car and the extracting, refining and transportation of the fuel that powers it.

It is my guess that once this is taken into account the comparative greenhouse gas effect of walking and driving will look quite different.

Secondly, whether or not anyone eating an all beef diet would be in any fit state to walk anywhere is conveniently ignored by the research. Goodall recognises the fact that no one eats just beef and argues in the Times article that the same problem applies to a large number of different food stuffs, but the research offers no indication of how the emissions related to someone with a balanced diet would compare with a car. A vegan would obviously have less of an environmental impact than a car, but what of someone who only eats beef occasionally, consumes little processed food and tries to source produce locally?

Thirdly, where has the arbitrary three mile distance come from? Who honestly is going to walk three miles to and from the shops with their heavy shopping? A more realistic distance for replacing cars with walking would be around one mile so why has this distance not been used and how would it effect the calculations if it was? It might be worth noting that with more energy used to start a car than drive it the calculations would favour the car less the shorter the distance travelled.

Finally, if we must highlight the emissions associated with walking why not compare them with genuinely green forms of transport, such as busses or the tube, rather than with inherently energy inefficient cars. By suggesting cars are greener than walking all the research has done is provide yet more ammunition for the car lobby. 

So why has Goodall, a seasoned environmental campaigner and Green Party candidate for Oxford West and Abingdon, released research that appears to encourage people to get into their cars?

I rang Goodall with my concerns and he was good enough to explain his position. He accepted that accounting for the embedded carbon of the car and looking at shorter distances and more balanced diets would reduce the gap between the climate change impact of the walker and the driver, but he maintained that the gap was so pronounced that in many cases it would remain better to drive.

"If you replenish the energy you use on a walk with a quarter-pounder from McDonalds then you are almost certainly doing more harm in terms of greenhouse gas emissions than if you had driven instead," he explained.

However, Goodall insisted he was not recommending people drive more, rather that "we think more carefully about the carbon content of the food chain". He added that currently the agricultural sector was facing little scrutiny over the environmental impact of its practices and as a result while car manufacturers have been forced to improve designs to begin to limit car emissions there is no such pressure on the agricultural sector to improve its processes.

But while it is entirely right to raise awareness of this important issue the risk remains that using a comparison with car emissions to make the point does little to make people think "I should stop eating beef" and instead invites the conclusion made by Liddle and implied by the Times headline that "we might as well keep driving then".

Climate change science is a hugely complex field and it is critical that scientists and researchers continue to challenge assumptions. But reporters working on these stories need to realise that failing to properly analyse climate change research and simplifying conclusions in order to generate eye-catching headlines only serves to confuse people and businesses who want to limit their environmental footprint and invites the cynicism of professional contrarians such as Liddle.