It’s amazing what a few months can do. I’ve been watching the activity on the net since Climategate quite closely. Before that, I held the view that the earth was warming and that CO2 was probably a major contributor, but I was already sceptical that CO2 was the whole story because there were other plausible theories based on solar activity that affects cloud formation and they seemed to have a good foundation in historical evidence going back millennia. But like everyone else, I had no real idea how the climate worked. So, Climategate came for me in the middle of a learning period, where I decided that climate would figure much more in futures work, so needed to get a handle on it. I’ve now been studying climate science for about 9 months, so I still only qualify as a novice, and won’t be giving up my day job any time soon.
But Climategate was an eye-opener. I hadn’t realised just how flimsy the evidence for AGW (human-induced global warming) was until then, or how biased some of the climate scientists were, how they had done some bad science themselves, and then managed to block alternative theories, by withholding data, bullying journals into blocking publication, effectively seizing control of the IPCC and so on. I had assumed that the temperature data was sound, but it isn’t. I had assumed that the climate models took full account of solar activity, but they don’t. I assumed they looked at cloud formation mechanism in great detail, but they don’t. I assumed they looked at the data impartially instead of having a predetermined outcome and steering the models in that direction, but it turns out the models were designed to show warming and the inputs and equations selected and distorted to achieve that goal. Since many other researchers based their theories on that same data, their outputs were similarly corrupted. So it turns out that much of climate science has been corrupted and is badly in need of repair. Given that some of the data has been destroyed or altered, there is a lot of mess and damage to be cleared up.
But all is not lost. There is a lot of good science out there, and before climate science was politicised in the early 90s, some of the thinking and analysis was quite good quality. There have been several key studies recently that provide valuable insights, and several more well on the way. I have no doubt that science will recover slowly and we will end up with a good understanding how the Earth’s climate actually works, and will be able to figure out where it is going, and even some ideas how we might control it in some degree.
To give some idea how complex the field is, here are some of the things we know about the climate, and some that we know we don’t know.
There is historically a very strong correlation between cosmic radiation levels and climate. The galactic cosmic radiation (GCR) entering the solar system varies significantly, and the variations correlate well with temperature. The total amount of radiation we get from the sun varies only a small amount, and even the spectrum only varies by a little, but sunspot activity has a big effect on climate. It appears to do so via the enormous magnetic storms associated with sunspots, and the result is that cosmic rays are deflected and fewer enter the earth’s atmosphere. Thanks to some excellent work by Jasper Kirby and his colleagues at CERN, we know that cosmic rays entering the atmosphere produce a shower of other particles, and these can act as nucleation centres for water droplets to form from water vapour present in the atmosphere. These droplets can form clouds, and clouds can change reflect radiation back into space, and can also act as insulation. The exact mechanisms are not yet understood, but CERN is studying them now and expect to report in the next couple of years. As they do, we can start to include cloud formation related to sunspot activity and GCR variation into climate models.
Other studies by NASA on cloud formation will also help. Atmospheric behaviour is very complex, but the more we understand it, the better we can model it. In particular, NASA Goddard Space Research Centre has recently shown that aerosols in the atmosphere have a big effect on temperature. In particular, they discovered that black carbon from diesel exhausts has a huge effect on radiation absorption, and could account for much (50% or more) of the glacier melting that has been observed. Of course, it would be much easier to reduce black carbon than CO2. Other studies at the University of Waterloo suggest mechanism by which CFCs, released in the past by aerosol sprays and refrigerants, but now banned in many countries and phasing out in others, can interact with cosmic rays to break down ozone. Ozone absorbs solar radiation in the higher atmosphere, so reducing ozone results in more radiation being absorbed in the lower atmosphere, so increases warming. CFCs are a powerful greenhouse gas in their own right too. The reduction of CFCs in the atmosphere since 2000 correlates well with the levelling off of temperature, just as the rise over the previous decades correlates with the rise in temperature. As the ozone hole closes, temperature would tend to cool. Deforestation and change of land use is also very important. As trees are burnt, and as land turns to desert, or as fields are ploughed, dust enters the atmosphere. Small particles can stay there for days and affect cloud formation. And we may find that air travel contributes more to warming via contrails than by the CO2 emitted by the engines. Air traffic in most of the world flies too low to be so significant, but across the poles, the same altitude reaches a different region of the atmosphere where different reactions apply. The lower temperature at the poles results in a lower stratosphere, and some flights emit water vapour there. In a nutshell, it hangs around longer and causes more warming via cloud formation interactions with the lower atmosphere. This may be one of the major factors why the north pole is melting far faster than expected, while the south isn’t, having much less air traffic of course. But we need the science to be done, then we can model it properly.
So, with black carbon, dust, CFCs, ozone depletion, galactic cosmic ray flux variation, and a variable shield from solar magnetic activity, it already looks like CO2 is just one of a series of contributors to global warming. The CFCs may well turn out to be the bigger human influence. But as yet, these factors cannot all be properly compared, because we don’t understand the science behind the various interactions well enough. But we will be much better placed to do so in the next couple of years.
Scientists also know that oceans are responsible for much of the climatic variation. Oceans act as a huge thermal store as well as acting as a store of various gases. Movement of water between the depths and surface layers is a very slow process, so acts as both a long term damper and delay. Surface currents that transport heat around the world are also highly significant. And yet our understanding of the many factors is still in its infancy. El nino and la nina are still fairly new terms to most of us, and they still cannot be predicted well. Huge server farms are required just to model behaviour of small areas of ocean, so computer power is still one of the major bottlenecks. Getting good input data is another. It will be several years at least before we can accurately model ocean currents and properly predict their contributions to climate.
One of the most worrying factors is that the historical record indicated that we are in a period similar to the midieval warm period as far as solar activity and galactic radiation are concerned. The MWP was followed by a mini ice age, and there is informed speculation that we may well now be heading into another. It is overdue, and the patterns of warming and levelling off are just right. But the other factors of CFCs, CO2, desert dust, air travel and so on make it a very complex situation indeed.
The danger we are in as a result is that the climate could arguable go either way now. If it turns out that CO2 really is as bad as is made out, then temperature will increase and we are in danger of crossing some critical points where methane clathrates start to vapourise, giving runaway greenhouse warming. If on the other hand, and which is looking more likely by the day, CO2 is only a small player and the bigger effects are either natural or related to CFCs and black carbon, then we will see a few more years of turbulent weather followed by decades of cooling. Technology progress will reduce fossil fuel use anyway, so there will be less CO2 in the atmosphere to offset cooling. If we try to reduce CO2 in such a case, and also clear up other pollutants such as CFCs and black carbon, then we will suffer even more.
So we are like a guy standing on the edge of a cliff, wearing a blindfold. Lots of people are screaming at us, telling us to do something because we are in grave danger. But if we move before we can see the direction of the drop, we are as likely to die as to survive. By far the best course of action is to remove the blindfold before we do anything else.
So, we should spend much less money on wind farms, and put a lot more into research, making sure it goes to people who are more interested in doing good science than in proselytising a particular viewpoint.