One of the problems with being a PR guy for an environmentally minded billionaire is that you sometimes find yourself having to utter complete drivel in public fora. There has been a lovely example of this in recent weeks, when, in a letter to the FT, Lord Stern claimed that 7 million deaths each year were caused by pollution derived from fossil fuels. This was disputed by Matt Ridley, who pointed out in another letter that most of these deaths were actually caused by burning wood and dung.

According to the World Health Organisation, the majority of these estimated deaths (4.3m) are from indoor air pollution, and the vast majority of them are caused by cooking and heating with wood and dung.

However, having stuck his neck out, Stern felt he couldn't back down, and therefore decided to adopt a policy of "make some more stuff up and hope nobody notices". So he wrote to the FT again, exhibiting his customary lack of integrity, this time insinuating that Matt had claimed that no deaths were caused by fossil-fuel-related pollution, claiming that he...

...fails to acknowledge that the World Health Organisation noted that coal, as well as wood and biomass, burnt for cooking and heating, is a major source of the indoor air pollution linked to the deaths of 4.3m people each year.

I'm sure that readers can see from the previous quote just how egregious Stern's misrepresentation was.

Then, as if to underline just how badly wrong he had gone, Stern retreated to a claim of "it's hard":

Precision is not possible here but it does seem reasonable to conclude, as I did in my letter of November 12, that “7m people worldwide die each year due to indoor and outdoor pollution, mostly caused by the burning of fossil fuels”.

The mess into which Stern has got himself has now been firmly laid bare by Bjorn Lomborg, whose letter to the FT today sets out the figures in gory detail:

Nicholas Stern (Letters, November 12 and 19) is simply wrong to persist in claiming that the majority of 7m deaths from indoor and outdoor air pollution is caused by fossil fuels. His feeble defence that “precision is not possible here but it does seem reasonable” underlines his lack of evidence. The facts of the matter, as established by the World Health Organisation, are that the majority of air pollution deaths comes from indoor pollution, and about 85 per cent of these deaths are caused by biomass burning. This translates to 3.2m of the 7m deaths caused by indoor biomass burning. Moreover, a large part of the outdoor air pollution stems from non-fossil fuels. The most recent Global Burden of Disease estimates that 12 per cent of all outdoor air pollution comes from indoor air pollution, causing an extra 373,000 premature deaths. The most recent study from Nature estimates that just the indoor air pollution from households in China and India spilling into the open air causes 760,000 outdoor air pollution deaths. The Nature study shows that 600,000 outdoor air pollution deaths are caused by natural sources (mostly airborne desert dust). Another 660,000 deaths are caused by agriculture, mostly from release of ammonia, forming ammonium sulphate and nitrate. Finally, almost 200,000 additional deaths come from large biomass burning (forest burning such as we recently saw in Indonesia). Power generation, traffic and industry, which are mostly fossil fuel-driven and likely what Lord Stern was thinking about, in total cause 854,000 air pollution deaths. Added to the 560,000 deaths from indoor air pollution caused by coal, this constitutes only 20 per cent of total air pollution deaths, and hence is a far cry from Lord Stern’s claim of a majority. This matters for two reasons. First, it is disingenuous to link the world’s biggest environmental problem of air pollution to fossil fuels and indirectly climate. It is a question of poverty (most indoor air pollution) and technology (scrubbing pollution from smokestacks and catalytic converters) — not about global warming and CO2. Second, costs and benefits matter. Tackling indoor air pollution turns out to be very cheap and effective, whereas tackling outdoor air pollution is more expensive and less effective. Lord Stern’s favourite policy of cutting CO2 is of course even more costly and has a tiny effect even in 100 years.

Lord Stern's behaviour is quite extraordinary. It's amazing that any newspaper is willing to publish a word that he writes.