Copenhagen, an engineer's view.

I have tried for several years to get to grips with climate science but still only understand a tiny bit now. The environment is an amazingly complex system, and it will take many more years of research before we understand it well. We have made many mistakes in the past when we have interfered with nature without enough understanding. I am worried now because with Copenhagen coming up, it does seem to me that we are again rushing into action before we understand the problem well enough to know what to do about it. The trouble is, as is now obvious to all, that there are too many vested interests on both sides of the debate, and what good science there is out there is diluted by a large measure of nonsense and propaganda, from both sides. And as we've just learned, some science has even been blocked from journals because it disagrees with the views of more powerful scientists. I personally am appalled by the corruption exposed in the UEA's CRU. Claims that the data has not been cherry-picked and distorted and the models fixed to produce the desired results run completely against the words in the culprits own emails. But as has been pointed out often since, the UEA is not the only lab saying we are seeing significant climate change. Some other labs may have been influenced and some may be fixing their results too, but we don't know, and I doubt if they all are.

But I have been an engineer for the 28 years since I got my physics and maths degree, have a decent grounding in the scientific method, and have a good understanding of computer modelling, having been in that field for over a decade. I was also a judge a few years back on the Computerworld awards for contributions to mankind by various computer systems and models in the environmental science field, so I have a fair idea of what they can do, and what they can't. So I think my environmental bullshit detector is reasonably well tuned by now, and I look at the announcements from environmentalists and the opposition and make my own choices of what sounds credible and what doesn't. I'm neither a 'climate change denier' nor a 'true believer', but like many people, somewhere in the middle, trying to filter the truth from the crap. So, here is what I believe:

The earth is experiencing climate change, but I don't know yet how much of it is natural and how much is man made. I am happy to accept that some of it is man-made, but don't have any idea what the right figure is.

Europe has experienced warm periods before, and these seem to have been one of the targets of the cover-up by the UEA CRU as well as the decline over the last decade.

The average temperature was increasing up to 1998 but has since declined slightly. This might mean it is all over, and warming is finished, or it might just be a temporary lapse in a longer term warming trend that will soon resume.

A number of effects in nature seem to have a tipping point, and we are quite close to the point where ocean based methane clathrates (aka methane hydrates, abundant in deposits on the sea floor) and melting pemafrost will start releasing very large quantities of methane into the atmosphere, potentially causing runaway warming.

We don't understand nature fully, by a long way. We see in the evidence that CO2 correlates well with temperature change, but according to some scientists, it appears to lag warming by hundreds of years. If so, something else must be causing the warming, and increasing CO2 only significantly contributes to it later.

However, the dangers are independent of whether any warming is natural or man-made, so even if they are natural, we will still have to try to avoid catastrophes that might result.

We know that CO2 is a greenhouse gas, along with methane, water vapour and several other gases. The bulk of the attention is on CO2 but that might well be inappropriate. Some scientists say it would be much more cost effective to concentrate on methane in the short term. Or perhaps we should look more at cloud formation and see if we can mitigate that better.

The sun has been going through an unusually 'interesting' period, with an unusually prolonged sunspot cycle after a long period of high activity. There does appear to be a strong correlation between solar activity and climate, going back millions of years. Sunspot levels affect the quantity and make-up of the radiation hitting the earth, not so much from the sun directly, which only varies a little, but by affecting the flux of incoming cosmic radiation, which also correlates well with climate as the earth passes through different regions of the galaxy. Cosmic radiation can probably assist in cloud formation, and the possible mechanisms are being investigated by CERN now. Because the physics mechanisms are not understood, it is being ignored by climate models and climate scientists seem keen to play down its impact, though I am far from clear why.

Mars has also experienced warming, so at least some of the effect is variation in solar activity. NASA Goddard claims it is about 25% of what we've measured, and that may well be true, but I think we need more study on that. The Earth has lots of water in its atmosphere of course, and Mars doesn't. If as CERN believes, cosmic radiation causes ionisation, and helps in both initial formation of water droplets and their growth, i.e. clouds, then this is an important factor. These clouds then affect both reflection of incoming solar radiation, and the amount of heat that can escape from the earth into space, so are obviously critical to warming effects. Monitoring the press over the last few years, it looks to me that climate scientists appear to  dismiss its effects too lightly, so avoid giving this mechanism the weight of research I think it deserves.

In particular, some recent science suggests that condensation trails from aircraft might be much more important than previously thought. Emissions in the stratosphere can lead via very complex interactions to much more persistent cloud and heat retention than at lower levels. Increased solar activity may of course contribute to such a cloud formation mechanism. In the Arctic, aircraft sometimes fly in the stratosphere, which is lower down. The apparent fact that the antarctic is cooling while the arctic is warming gives extra weight to this theory, since there are very few flights over the antarctic, but many over the arctic. On the other hand, antarctic cooling could be partially explained by the ozone hole, so this needs more study. We should look carefully at the increase in air traffic over the last few decades, and the solar activity over that time, to see if that can explain a significant proportion of the apparent increase in arctic ice melting. If it does, we should factor in such mechanisms over the whole planet, especially with regard to policies on aircraft routing, flying height etc. It may be for example that aircraft should fly lower in the arctic, emitting more CO2 but contributing less overall to warming because the water vapour is emitted lower in the atmosphere.

The ozone hole over the antarctic will close around 2050. This is expected by some to increase warming there. The ozone hole was created in large part by the emissions of CFS, now banned. So banning CFCs has helped fix the ozone hole at the expense of worsening warming.

It is obvious here that the environment is very complex, and fixing one problem can worsen another. A related problem that is becoming apparent now is that China is building lots of coal powered stations, but the coal is dirty and produces pollutants such as sulphur dioxide, one of the causes of acid rain. In order to prevent acidification of oceans and damaged forests, there will be pressure to clean up the outputs from these power stations. However, sulphur dioxide is a coolant and its presence almost completely offsets the warming effect of the CO2 emitted by the stations according to the NASA Goddard research centre. So in China's case, perhaps we should delay the cleaning up until anti-warming measure are further developed. Perhaps as a short term measure, we should also reconsider the merits of low sulphur petrol and sulphur removal from other power stations.

CO2 levels affect plant growth, which obviously must feed water vapour into the atmosphere. As the atmosphere warms, it can hold more water vapour.  Water vapour is a greenhouse gas of course. Most of this is already accounted for in models as a factor in the warming efficacy of CO2, but I remain unconvinced that the impacts on CO2 and water vapour from deforestation, biofuel production and farming practices are fully accounted for. In particular, I think we need more study of the relative benefits of the use of residual plant material for biofuel versus ploughing it into the ground. Ditto waste such as plastic - recycling v other uses that end up as carbon sinks.

Sea level rise comes from melting of land-ice (not sea ice) and thermal expansion of the water itself, but the latter is most important so far. Land would also rise slightly as ice melts, having a small reducing effect on the rise. Melting ice also affects salinity which has other effects on the ocean ecosystem that will then also feed into climate.

Current environmental models are very far from complete. Large supercomputers can just about cope with modelling ocean currents in a small region. There is no such thing yet as a whole earth simulator that looks at all environmental effects and interactions.

Computer models are highly simplified, they have to be to run at a reasonable speed. Many effects are left out, many very crudely approximated, and accurate input data is sparse and only covers recent periods. And of course, we don't yet know all the basic science that feeds them.

Policies already implemented such as use of biofuels and carbon trading appear to have encouraged significant deforestation and peat bog drainage in Indonesia, contributing significantly to CO2 output and destruction of forest ecosystems. The socio-economic reasons for this seem obvious but they were apparently not anticipated by those who recommended the policies.

To summarise, even with the recent climategate, there is a lot of environmental science out there that looks reasonable to me as an engineer, but I still see lots of holes remaining in the science, and lots of areas that need more study before we can be reasonably sure about what is happening and what if anything we can do about it. In the absence of this knowledge, we risk implementing policies that might make problems worse.

So what do we do? It does look like we are quite close to a tipping point on methane emissions, just a couple of degrees away. Whether warming is natural or man-made, we still need to work out solutions to that, and we need much better monitoring of the environment to keep an eye on it. We must not reach that tipping point. It seems to me that we need more science, better science, and more accurate data.

If we have been barking up the wrong tree to some degree, as is very possible, then it is possible that efforts to reduce warming by limiting CO2 will fail and we may pass the tipping point. It is therefore dangerous to pursue CO2 as the only factor. We may be ignoring environmental interactions that are actually more important than just CO2. It is imperative that we improve the science quickly.

Targeting CO2 might help reduce warming, but in the short term, targeting methane should be the priority - it is simply the 'low hanging fruit' of warming.

We should reduce waste in any case. Whether or not energy production produces CO2, waste reduction still has benefits. There are no obvious negative environmental mechanisms from waste reduction so it is safe to do so.

Other than that, we should stop panicking. We will see very different technology being used in a decade or two even without environmental campaigns. Energy is likely to use solar and nuclear. Transport is likely to become electric. IT will become much more energy efficient. Insulation and building practices will be more energy efficient. So whatever happens, the future will see far less CO2 being produced. If it is the problem, then it will diminish as time goes on. If it isn't then we have to look elsewhere and do more science to find the real problem anyway. So either way, panicking and making polices based on immature science is the wrong thing to do.

The right answer: for at least a few years till we understand it better, spend far more on science and far less on solutions.