By F. W. Taylor
There are few more important issues at the present time than that of climate change – whether it is real, what we can expect to happen, when and what if anything we can do to prevent or at least ameliorate it. Climate is a ‘crossover’ topic: the facts are mostly in the domain of the scientist, and need special training before they can be understood. However, everyone faces the consequences, perhaps especially people in poor, relatively illiterate counties who already survive on the ragged edge of sustainable agriculture. Finally, if the scientists are to be believed, the politicians must act, and not just by fiddling around the edges of the problem: the changes required are almost unbelievably extensive, expensive, and disruptive. George W. Bush came across as a climate skeptic not because he didn’t believe the science (he wasn’t sure, one way or the other) but mainly because he didn’t want to stifle his nation’s competitiveness by curbing its carbon emissions on the draconian scale the green activists were calling for.
So where are we? In a hole, is the answer, with the news full of reports on expensive, acrimonious and inconclusive meetings on what each nation needs to do to avoid disaster on a global scale through sea level rises, desertification, food and water shortages, and the rest. The broad conclusion is emerging that it is not possible to revert to the levels of carbon production that are needed to “save the planet,” or rather humankind’s present level of occupation of the planet, without sacrifices that are politically (and perhaps also practically) unachievable on the timescale required. That is, if things are as bad, and getting worse as fast, as the scientists say.
The devil is in that last phrase – who are the scientists, and what do they say? Why? How likely are they to be wrong? If there is only a 50% chance that “business as usual” will flood London by the end of the century then we might even feel that is a risk worth taking when we look at the appallingly large number of windmills, tidal barrages, and nuclear plants we have to build to hold back the predicted sea level rise. Some will argue that we could build these things at crippling cost and then find the climate forecasts were wrong. The really cynical – but still not necessarily wrong – could say we may be worse off, through the laws of unintended consequences that seem to apply to most large political projects. Certainly we would have to divert huge sums of money away from other causes and focus on dwindling resources; the resulting tensions could lead to war.
So, the scientists had better be right. The accepted focus of scientific opinion is the Intergovernmental Panel on Climate Change (IPCC) set up by the United Nations and the World Meteorological Organisation to coordinate the best climate research and advise the world’s policymakers. They have been much criticised lately for making mistakes and being blinkered, but still there is no doubt this is the best analysis of the problem that we have. So can we just take their (prolific) output and run with it? No.
Why not? Because the groups that report to IPCC use physics that they know they do not fully understand, and use it as the basis for computer models that include assumptions and approximations. It’s the best we have, but it isn’t perfect. So how can we decide what to do?
We need more research, and not just bigger and better models but even more crucially, more and new kinds of measurements. We are fortunate that the climate problem has loomed just as we have developed the capability to study what is happening from space using instruments on large and sophisticated satellites. There are instruments currently orbiting other planets where the climate physics is the same, but plays out differently due to factors like distance from the Sun. Venus, it turns out, is hotter than expected because of greenhouse warming caused primarily by CO2, water, sulfate aerosols and clouds – the same players that are driving climate change here. And Mars is like a dying Earth, clearly once graced with rain, rivers and warm, possibly even fertile plains, now all arid and frozen. Again, we recognise the causal mechanisms as those we must wrestle with at home, but in this case they went in the other direction, from balmy to frigid.
New understanding of the Earth and its siblings will not only inform current researchers and then everyone else, but also provide the environment in which the next generation of better scientists will grow, and education in which non-scientists also gain insight into the threats they face and must tackle. Meanwhile, we have to assume the worst – that is, accept the median forecast of the IPCC or risk awful consequences. It is not the most dire of predictions by any means, but serious enough. Those who think it is all a big con will get their answers, too. It would be nice if they were right, but don’t count on it.
Fredric W. Taylor is Halley Professor of Physics and Fellow of Jesus College, University of Oxford. He is the author of Planetary Atmospheres (2010), Radiation and Climate (2007), and Elementary Climate Physics (2005), among others. He has been principal or co-investigator on a number of experimental missions into space, and has been awarded numerous honours. He is a Fellow of the Royal Meteorological Society (Vice-President 2005-8), and of the Royal Astronomical Society, and a member of the American Astronomical Society, Division of Planetary Sciences, and the International Astronomical Union.