SPARE a thought for climate scientists. On our backs rode the heroes of the
1992 Earth Summit and the 1997 Kyoto Protocol, which set international targets
for cutting back greenhouse gas emissions. This month, governments will meet
again, this time in The Hague, to finalise details of how the Kyoto Protocol
will work. Many of the delegates gathering there will tell you that the climate
scientists have completed their tasks. It鈥檚 time, they鈥檒l say, for us to turn
off our supercomputers, put away our temperature charts and go back to
measuring the weather.
If only it was that simple.
Kyoto left climate scientists wiser to the ways of politics and international
diplomacy. But the traffic all seems to have been one way. Politicians didn鈥檛
come away with a reciprocal awareness of what climate science can still do for
them as they turn their attention to setting policies to deal with global
warming.
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One of the issues high on the agenda at The Hague will be emissions trading.
This is the idea that rich countries that emit more than their allowed quota of
carbon dioxide or methane can buy the entitlement to do so from countries that
emit less. But delegates will discuss this without actually knowing how much
carbon or methane in the atmosphere poses real dangers.
Similarly, the US and some other countries would quite like to be allowed to
plant forests in place of cutting greenhouse gas emissions. The idea here is
that the trees will suck carbon from the atmosphere. But as any climate
scientist will tell you, predicting trees鈥� carbon uptake is a very imprecise
science.
The Kyoto Protocol is built on the assumption that something, anything, must
be done, and done quickly. It is an application of the precautionary principle:
we may not have all the evidence to know precisely how climate change is harming
the planet, but the risks associated with doing nothing outweigh the risks
associated with taking action. But I think we can do better than this. In this
important area of environmental policy, science really can deliver鈥攁nd
here鈥檚 how.
There are three questions that lie at the heart of how we should respond to
our changing climate. First: how can we tell what rate of climate change poses
appreciable dangers to human health and to the environment? Second: can we
control climate in a way that avoids such dangers? Third: if the answer to the
second question is no, then can we shape our future world to accommodate the
expected climate change? These are questions that scientists from a range of
disciplines, from engineering to economics, can help to answer
Many researchers believe that we need to limit global warming to no more than
2 掳C, and that it is dangerous for CO2 concentrations to rise above
550 parts per million by volume, or twice the level before the Industrial
Revolution. But not everyone agrees on this target, not least because it doesn鈥檛
allow for the radically different effects that warming will have on different
nations and regions of the world. A certain degree of warming could be
catastrophic in some places while barely inconveniencing others.
So what exactly do we mean when we say a particular degree of warming is
dangerous? Danger implies unacceptable risk. And to assess risk we need to know
both the probabilities of particular outcomes and the consequences of those
outcomes. The reality is that at the moment we don鈥檛 know what these risks are.
For example, is the collapse of the West Antarctic Ice Sheet (a low-probability,
high-impact event) a greater risk to society than a 1 掳C warming (a
high-probability, low-impact event)? 快猫短视频s can help to quantify these
risks. Societies then need to arrive at a consensus on which risks they are
willing to accept. Evaluating risk requires input from social scientists, as
well as from climate scientists, physicists, and biologists engaging with
society at large. Only then can we say with any confidence how big a temperature
rise is too dangerous to tolerate.
That brings us to the second question: can we control climate sufficiently to
prevent warming reaching this 鈥渄angerous鈥� level? It is the question that lies at
the heart of the debate raging around the emissions targets set at Kyoto. These
require the richer countries to reduce their greenhouse gas emissions by about 5
per cent before 2012.
But can this target, or any other, be reached? We don鈥檛 know. We do know that
ordinary people and businesses will have to change the way they live and make
money. To find out whether they will do so needs research into the dynamics of
technological change and research into the psychology of consumer behaviour. We
need to answer questions such as why are Western societies so reluctant to
consider nuclear power as an alternative to fossil fuels? And why are we so
opposed to taxes on fuel, even when we know that some of the money will be spent
on energy efficiency improvements? We need evidence-based policy.
More climate research is also critical for the third question: what happens
if we cannot reduce the rate of climate change enough to avoid unacceptable
risk? Can we adapt our institutions, our regulations, our behaviour to somehow
accommodate more rapid climate change? Such questions have hardly been raised
within the UN Climate Convention. Even talking about them is seen as defeatism,
or at best as a diversion from the central issue of slowing down climate
change.
In fact, identifying what 鈥渋nsurance policies鈥� we may need to manage climate
change is an entirely rational response to the problem. Here again, a broad
range of scientific expertise can help put the necessary debate on a sound
footing.
To shape a global community that can evolve with a changing climate, we need
to strengthen links between knowledge producers and the UN Climate Convention.
The real challenge for climate change science in the end is not to be able to
predict future climate; rather, it is to give society the options to choose its
own climate future.