I’m definitely not a ‘catastrophist’ in the sense that it is normally understood. One problem lies with defining what counts as ‘dangerous’ climate change – a problem brought in the Hadley report (COP10?) a couple of years ago. The media want ‘dangerous’ to mean the same as ‘disastrous’, or ‘catastrophic, e.g., causing a big, picturesque and pitiable human disaster on a grand scale, like the 2004 tsunami. Politicians seem to want to play on our common misunderstanding of the idea of ‘dangerous’ to play on our fears, thus justifying the changes they are bringing in now. But for climate scientists, ‘dangerous’ can mean something different to either of these.

With the state of our understanding of climate as it is, with some things well understood but others still not well-modelled, not well explained, and responding to unknown causal agencies, there is a genuine concern that, at some given point in the future (which ‘point’ could be a decade or two long), the climate will have been committed to warming by the increase of CO2, to such an extent that the feedback effects become both increasingly unclear and increasingly risky, as well as being unstoppable. This is why there is research in the ice sheets, the arctic, the ocean circulation and heat content, etc.

First, it is clear that these areas need to be better understood and better modelled in the climate simulations under certain forcings, so as to reduce the uncertainty involved. Second, it is clear that, if the assumption that CO2 is the dominant forcing at the moment is correct, the longer it takes to actively reduce the increases in emissions, the more likely it is that we wiil reach a point beyond which the climate is ‘committed’ to some more permanent changes, for example, increased drought in some regions, the loss of the Amazon rain forest, the loss of Summer Arctic sea ice cover, the unstoppable decline of the Greenland Ice Sheet, a collapse of the WAIS…

As to whether such changes, most of which are likely to have impacts decades or further away, are ‘dangerous’; that depends on what counts as ‘danger’. If you live in a marginal society in subsistence conditions, any change which reduces the already perilous state of agriculture and water supply is likely to be rapid and fatal. If you live in marginal coastal areas where flood risk already exists, that risk increases persistently, until a point is reached when it is no longer sensible to preserve the hard-won property you own. If you live in the UK, ‘danger’ is more like to come from secondary effects rather than primary ones, for example, economic recession or hyper-inflation.

The assumption also exists that, where resources and climate are unstable, so political and lawful structures become vulnerable; the greater the hardship, the greater the change of destabilisation.

How do I see things panning out over the next decade? The USA will do nothing until Bush is replaced. Depending on the make-up of the two houses in Washington, it will take at least two years beyond that time before a policy becomes likely, and a further ten years beyond that for the effects of the policy to kick in (allowing businesses to adapt, where needed, to the changes). So, active US emissions reductions are unlikely before 2012 at the earliest, and meaningful reductions, probably not before 2018-20.

China will continue to expand its engergy producing capability, based on coal, for the next ten years, whilst paying lip-service to changes, and making some high-profile but ultimately ineffectual ‘compromises’ to its emissions. India will do likewise, but seems more likely to respond to the challenge of sustainable energy, for a variety of reasons.

Because the balance of world trade and power still resides in oil (and to a lesser extent, gas) production, distribution and consumption, and the power of the various leaders is more or less dependent on this, it seems likely that oil will continue to be extracted, processsed and used until it becomes no longer viable, which will be in 40 years at the least. Therefore, whilst some CO2 output may well be slowed, the amount of CO2 in the atmosphere by 2050 is very likely to equal or exceed 550ppm. How much it goes up beyond that in the following 50 years is harder to tell.

Biofuels will continue to be developed, but it is clear that, as they stand, they will never be able to replace fossil fuels; there isn’t anough land available in the world to grow enough biofuel crops and enough food for 6-9 billion people. For biofuels to become a viable major energy source, there will need to be a breakthrough in this field. Of course, the assumption that biofuels are necessary at all is based on the idea that, in the absence of fossil fuels, we will need something like fossil fuels to replace them (an assumption based on far to many other assumptions to be considered correct).

Nuclear power would seem to be a possible longer-term solution to energy needs, but as Iran shows, there is enough difficulty in working out who controls the worlds nuclear output to make this solution politically challenging. I suspect there may be some ground made in this area in the next decade, but there is still too much politicial self-interest involved in the process to be comfortable with the notion that this will be easy. Once you move away from a mutual dependence on oil-trade to autonomy based on nuclear capability, the entire balance of power between states changes. This is not a comfortable state of affairs for those who currently hold that balance of power.

There is a good chance that there will be a breakthrough in hydrogen-based vehicle fuel technology. Whilst this will reduce demand, eventually, for petrol, it will not prevent the burning of fossil fuels, as these resources will be diverted to other uses.

That’s probably enough of my opinion for the time being.