Rather bizarrely and contrary to all the best scientific advice Councillor Brian H Hopkinson seems to be saying that we should all fly more, yes more, in order to help reduce climate change ('Global Warming', Bristol Evening Post, July 25)! What an incredible reply this is to my letter (see blog entry of July 9th) correcting earlier writers climate science errors. Clearly he is wrong and has not looked into the idea of global dimming he refers to that much.
It just reinforces the point in my letter (July 9th blog) that people contributing to the climate debate need to get all the facts of this complex matter straight. This is especially important for elected representatives, like Councillor Hopkinson, because they are presumeably more active in debate and their views may have more influence on public opinion.
Brian said '...if we stop all flights, which some so called eco-friendly experts propose, we may well accelerate our demise even quicker.'. By this logic flying is good for our climate!
Some climate scientists feel that aeroplane vapor trails are implicated in global dimming, but the constant flow of air traffic previously meant that this could not be tested. Near-complete shutdown of flying for three days following the Sept 11 terrorist attacks gave an opportunity to observe the climate of the USA absent from the effect of vapour trails. During this period, an increase in daily temperature variation of over 1 °C was observed in some parts of the USA, that is, aircraft vapour trails may have been raising nighttime temperatures and/or lowering daytime temperatures by much more than previously thought. Note that both temperature raising and lowering effects are happening here.
Brian clearly thinks the dimming phenomenon is in opposition to global warming. He is wrong about this. He is guilty of the mistake of not looking at the whole picture, as other letter writers have been. It's a lot more complex than either a warming or dimming issue. Global warming and dimming are not mutually exclusive or contradictory. In fact they are both clear indications of human ability to impact our climate systems!
Global warming and global dimming in fact occur at the same time. Global dimming interacts with warming, blocking sunlight that would otherwise cause evaporation and the particulates bind to water droplets. Water vapor is one of the greenhouse gases. On the other hand, global dimming is affected by evaporation and rain. Rain has the effect of clearing out polluted skies. You can see how the two, warming and dimming, are all part of the climate change picture.
Climatologists are very keen to stress that the roots of both global dimming causing pollutants and global warming causing greenhouse gases have to be dealt with together and soon. Misuse of the science by people like Councillor Hopkinson risks confusing some of the public. This results in people on this letters page wrongly writing that trees around airports will suck up all the pollution, melting ice does not raise sea levels (July 9th blog) and now, flying helps to reduce climate change. Its highly damaging exactly at the point when we need well informed clarity from the people we elect.