Planning in a climate of uncertainty
Updated on 18 June 2009
The UK Climate Impact Projections report, published today will offer a range of predictions for an uncertain meteorological future. So how, asks Tom Clarke, should the UK respond to such worrying scenarios?
If, like me, you've been wondering for quite a while now just how worried you should be about climate change, help may be at hand. Today the government publishes the 2009 UK Climate Projections (UKCP09). And the projection is that we should be very worried indeed – probably.
For these projections are what the climate scientists who created them call probabilistic. That means they can only reflect the likelihood of a range of different climate scenarios occurring. What they can't tell you, is actually what WILL happen.
I have been given a sneak preview some of the analysis. Unfortunately I am forbidden to tell you what it contains until around lunchtime due to what Defra are calling parliamentary privilege. Hilary Benn, the secretary of state for the environment, wants to tell MPs what the situation is first and then come back to us later.
Suffice to say, the analysis resembles the existing warnings of what Britain's weather may be doing in future. It's going to get hotter; winters will be warmer and wetter; summers will be warmer, with heatwaves more common and periods of drought interspersed with intense rainfall. Sea levels will continue to rise.
However, it suggests that unless we curb our emissions of greenhouse gases really quite sharply and quite soon, the effect could be very unpleasant (electric blankets really will become a thing of the past). Moreover, the analysis finds what a lot of climate scientists have been warning for a long time: it's going to get quite a bit warmer, even if we vanish from the planet tomorrow. We've simply put too much carbon into the atmosphere already.
Even though these new numbers will only represent a range of probable future temperatures or flood risks, they are likely to be very useful. It focuses solely on the UK, but this is the world's most detailed ever study of future climate.
UKCP09 is the product of seven years of work by a huge number of academics and institutions, led by the Met Office's Hadley Centre for Climate Prediction. It was supposed to be completed last year, but new climate data emerged and a new way of analysing it had to be cooked up, holding things back.
It will attempt to give the probability of likely temperature, rainfall and sea level rises occurring across Britain on a scale of 25 km squares between now and 2080. And while we like certainty, as one of the UKCP authors explained to me, probability can be the next best thing. If you're worried about a tree falling on your head, being told it may or may not hit you if you stand in one particular spot is not very useful. But being told it will definitely hit you if you stand in a range of particular spots can be very useful indeed.
But UKCP09 wasn't designed just to give us climate worriers something in our local area to fret about. It's supposed to be the guidebook for engineers, planners and politicians whose job it will be to help Britain adapt to our uncertain future. Just how high will flood defences have to be? What melting temperature will tarmac have to have so cars don't get stuck in summer? How many new reservoirs will Britain need? Shall we plough up the apples and plant nectarines?
The numbers will be certainly be useful, but what is difficult to see right now is how well we'll actually be able to use them. I was in Hull earlier this week – it's a town faced by many climate change related threats, particularly sea level rise and flooding. But these threats will increase only gradually between now and the end of the century, and the costly strategies to adapt to them (sea defences, engineering drainage) will only need to prove themselves occasionally – like when it floods.
How do local authorities plan to deliver the absence of something like a flood when the investment needed to deliver that absence could be very great indeed? Or if the estimates for sea level rise suggest some neighbourhoods, or even valuable pieces of heritage, are extremely costly to save, what value do you put on people's homes and town's history. When do you decide to let it go
