When one government department asks another department to quantify the harm that comes from exhaust emissions, it is reasonable to assume that they are hoping for something that will persuade the public that the drastic and costly policies they propose are essential and so win over their support. A bland report that said " we are unable to quantify the harm caused" would not be at all helpful. Even if they said "we have come up with a figure, but we are very uncertain of it" would be regarded as not much good.
There is a statistic – 40,000 – 50,000 premature deaths caused by exhaust gases per year in the UK. The figure was apparently put out by the UK government’s Department for the Environment Food and Rural Affairs (DEFRA). I came across a letter sent by the UK Statistics Authority to DEFRA in February 2017, asking them to justify the figure and to explain how it was reached and to give an indication of its accuracy.
I decided to write and ask if any answer had been given. DEFRA has replied to me, referring me to a report from the Committee on the Medical Effects of Air Pollutants (COMEAP). They also said they would send me a more complete answer in due course.
The COMEAP report is about 130 pages, much of it in statistical language, but I thought it might give up some information that could be understood by a layman, so I started to read it. It soon became clear that the COMEAP committee, consisting of a least twenty highly qualified experts, was not unanimous in its findings. Indeed it was not certain at all, giving caveats that would leave room for much doubt.
Even though they must have been under pressure to reach a scary scenario a minority of the learned experts had the courage to state: "We regard the evidence for a causal effect of exposure to long-term average ambient concentrations of NO2 on the risk of death as too weak and imprecise to be used as a basis for a calculation of the burden imposed on public health in the UK by long-term average ambient concentrations of NO2"
Now we see that DEFRA has put these figures up even higher to 44,750 – 52,500 deaths per year and added a whole new raft of hypothetical costs based on reams of statistics. So why the new increase in figures? That is a mystery that I am still looking into.
via climate science
September 1, 2018 at 02:19AM