I have been reading several new books about climate science, “climategate” and the IPCC. The first is The Climate Files by Fred Pearce who is a widely respected science journalist with New Scientist and the Guardian. The next is a new book “Climate – the counter consensus” by Robert Carter who is an Australian professor and long standing so-called “skeptic”. I also read the Hockey Stick Illusion by AK Montford and re-read John Houghton’s excellent briefing on Global warming. What is beginning to emerge in my mind is:
A group of privileged scientists who helped initiate and sustain the IPCC process, then consequently benefited from it through the ensuing flood of research funding and would then appear then to have excluded other scientists with different viewpoints. On the other hand a growing group of critics have been attacking them sometimes justifiably and sometimes totally unjustifiably. This unfortunately caused a siege mentality of secrecy and elitism to develop among these climate scientists, who blocked openness in the science, with attempts even to suppress publication of alternative interpretations. The CRU (Climate Research Unit) has had one of the crucial roles in measuring whether there has in fact as predicted been any warming over the last 100 years or so. It is essential that these measurements are trustworthy and completely transparent, as otherwise this debate stops being scientific. The raw data and algorithms used to derive global temperatures should open to all to replicate because that is the way science works. Otherwise climate science will allways remain a bit like kitchen sink alchemy because there are a huge number of variable parameters, and there are still many “unknown unknowns”. Climate Models are huge computer programs modelling complex differential equations, with some built in assumptions, and endless knobs to twiddle. In the end it can only be measurements and experiments that control the science behind these models.
The basic physics of the greenhouse effect is well established and pretty much accepted by everyone. Surprisingly though, its direct effects are really not that bad, despite all the hype of impending disaster, rising sea levels and melting glaciers. Mankind burning of fossil fuels has caused a 30% increase in CO2 concentration in the atmosphere since 1750. Absorption of infrared radiation from the earth’s surface in narrow wavelength bands by CO2 and re-emitted by CO2 results in trapping some extra heat within the earth /atmosphere system. Adding more CO2 to the atmosphere has a progressively smaller and smaller (logarithmic) effect because the absorption in these bands was already saturated at pre-industrial levels. So if no action is taken and man were to continue burning fossil fuels to peak at a doubling of CO2 levels in the atmosphere by the end of this century, then global temperatures could rise by about 1 degree. Far larger natural variations than this have occured over the last 100,000 years. The transition from an Ice age to a warmer interglacial period causes a rise of about 9 degrees globally. This anthropogenic rise of about 1 degree by 2100 is what the basic physics of a doubling of CO2 in the atmosphere predicts.
All the scientific controversy is actually about feedback effects which have been predicted. This is the crux of the argument and in reality no-one currently really knows what will happen. These are the examples feedbacks given:
- If ice caps recede from the poles then more solar energy will be absorbed due to a reduced albedo leading to enhanced warming.
- Warmer oceans lead to more evaporation and more water vapour in the atmosphere. Water vapour is the main greenhouse gas by far on Earth contributing at least 5 times as much as CO2.
- More water vapour however leads to increased cloud cover which on average cools the Earth. Models show that an increase in cloud cover of just 3% would be enough to offset all the enhanced greenhouse effect caused by a doubling of CO2. Some estimate also that more rain will reduce water vapour from the atmosphere and thereby reduce the greenhouse effect.
- Ocean circulation. The oceans have an enormous heat capacity and transport energy across the world through currents like the north atlantic drift which warns Europe. Any changes in these currents would have large changes regionally but probably not globally.
The IPCC estimate a net positive feedback effect giving their prediction of a much higher higher 2-5 degree rise in global temperatures. Despite all the money flowing into research and all the conferences these figures haven’t really changed much over the last 20 years. The science itself also hasn’t changed that much – it is just a question of how it is interpreted. If Milkowski turns out to be right then nothing will happen because he argues the greenhouse effect is already maximised. That is why direct experimental measurements are so important.
The climate change debate has now become far more about politics than about science. If you are green, possibly left wing, favor state intervention to rampant capitalism, oppose globalisation and unfettered growth, then climate change is real, very dangerous and the West is to blame. If on the other hand you are maybe right wing and believe in low taxes, free enterprise, growth, individual rights and oppose state interference, then climate change is myth and hype to bring discredit to enterprise capitalism etc. etc.
The CRU temperature data show a rise in temperature of around 0.5 degrees C over the last 150 years, but it is not a clear linear rise and there have been cooling periods as well such as during the 1940s – 1960s, and the temperature has stopped rising for more than a decade since in 1998. This means that natural variations must also be present and an unambiguous human effect is still not confirmed. Critics argue that these data are also effected by a different human effect namely the large expansion of urban areas leading to local heating through urbanisation – concrete, tarmac and heat from cars and buildings. Many weather stations were naturally close to cities and therefore may need correcting for this effect. The IPCC claim no correction is needed based on a paper by Jones et al studying chinese weather stations in different locations, whose results are now being questioned because these locations now turn out to be uncertain. This paper claimed there was no such urban heating effect, however I know from personal experience that central Milan is always a couple of degrees hotter than where I live in the countryside. Surely the only way to arrive at the truth is to make available the raw station data, their locations and to allow others to carry out independent analysis.
The drive to a low carbon economy may be anyway a good thing for innovation and for the environment in advanced countries. However it will not help developing countries in Africa, where most transport still depends on 10-20 year old trucks, buses and cars shipped there from Europe and Asia, which emit choking black smoke.