It is very common these days for uninformed people to write articles denying climate change, or claiming there's some kind of conspiracy behind it, whether from lightbulb manufacturers or red infiltrators from Eastern Europe subverting the environmental movement. Sometimes there are claims of megalomaniac government institutions bent on taking away freedom, or more prosaically imposing punitive taxation.
In amongst all the noise though, is the science. Barry Pittock is one of the world's leading authorities on climate change, having led the Climate Impact Group in CSIRO, and is a lead author on all four reports of the Intergovernmental Panel on Climate Change. Not only has he done the research, but he has subjected it to open scrutiny, assessed the level of uncertainty, measured the risks, evaluated policy options and economic impact and investigated the accuracy of climate models. His book, Climate Change: The Science, Impacts and Solutions, presents the whole complex business with remarkable clarity and honesty.
He starts with a detailed presentation of the indisputable facts of climate change and why it is of critical importance to us. Whether it is the loss of polar ice, or the acidification of the oceans, or the rise in sea temperature, or the increase in sea level, or the level of carbon dioxide in the atmosphere, or even the changing patterns of the Gulf Stream, the Jet Stream and the El Niño-La Niña complex, Pittock presents the evidence. Not only does he present the evidence but he quantifies the uncertainties in the measurements.
For example, many people talk about the rise in sea level during the twentieth century of around 17 cm, but Pittock presents it more accurately as 17 ± 5 cm. In other words, somewhere between 12cm and 22cm but most likely around 17 cm. Throughout the entire book, Pittock takes pains to explain the level of uncertainty. But, as he names one of his chapters "Uncertainty Is Inevitable, But Risk Is Certain," that's why we should take notice.
He reviews our climate past and explains the changes in terms of the known geophysics, explaining what data is available, its significance and limitations, and the difference between direct measurements such as temperature and sea level, compared with proxy data such as ice cores.
In passing, he dispenses with the rather inane objections of the deniers, such as the hockey stick graph of Mann, the medieval cold period, the claims of the significance of solar activity, and a host of others, providing clear scientific explanations of quite how misguided the refuseniks really are. As he points out, even granting all of their objections (and he grants none of them), there is still overwhelming evidence of global warming.
In an excellent chapter on projecting the future, he explains the principles on which climate models are based, the use of external constraints and intrinsic factors, and the use of scenarios, and he spells out the assumptions of the four main scenarios used in the IPCC reports.
The IPCC in its 2007 report elaborated the details of three of the scenarios published in the Special Report on Emissions Scenarios (SRES) but dropped the most extreme — A1F1 — which is based on a continued high level of carbon dioxide emissions. Ostensibly the selection was made to limit the number of simulations, but it had the effect of ignoring the one with the greatest climate change impact, and the one that most closely models our current situation.
The consequence was a much more politically palatable report which understates significantly the level of climate threat. Nevertheless, Pittock takes all of the scenarios equally seriously and spells out the consequences.
He talks about tipping points. Climate is not perfectly elastic and will not automatically return to a stable state when the pressure is removed. There are some changes which cause feedback loops that can run out of control. There are points at which irreversible damage is done. Some scientists argue that we have already reached some of those points, and Pittock provides and evaluates their evidence.
Nevertheless, the book is optimistic. It looks at the two approaches available, adaptation and mitigation. Adaptation is where we modify how and where we live, moving the higher ground, changing the building materials we use to withstand fierce winds, growing different crops, etc. This is an option for some advanced countries but not for poorer developing economies. Mitigation is where we take steps to reduce global warming itself.
Mitigation includes using alternative sources of power such as wind and solar, weening ourselves of oil and other hydrocarbons, producing biomass energy, using geothermal energy, fuel cells, nuclear power providing we can clean it up. Pittock looks at how far we are undershooting the necessary actions and how much impact constructive policies can have from now on. However, the politics of competitive advantage and refusal to change, condemn us to a bleak future.
When the politicians in Copenhagen agreed to discuss some time later, a rise in temperature of two degrees, they were committing everyone to the need to undertake future sequestration, the actual removal of carbon dioxide from the atmosphere. By allowing our actions to overshoot the tipping points, the only remaining way to reduce global warming would be to undertake sequestration of carbon dioxide.
So it's a case of let the damage happen, then some future generation can pick up the tab. Of course, they didn't put it quite like that, but you can't negotiate with the climate.
In two excellent chapters on the politics of climate compromise in an atmosphere of economic competition and suspicion, Pittock surveys the consequences for major areas of the globe. Even one fact should concentrate the mind: more than half of the US population now lives in the 17% of the land that comprises the coastal zone and many US cities will be in a similar situation to New Orleans. Forget about insurance.
This is a highly readable and informative book in which the science is presented with a hard-nosed look at the economic implications as well. Anyone who wants to be well-informed about climate change, and especially anyone who has been led to think that climate change is some kind of scam or conspiracy, should read this book. It is an invaluable source which explains the complex issues with clarity, accuracy, and honesty.