The UN’s International Panel on Climate Change, (IPCC) made the news in September 2013 when it issued a report stating it is “extremely likely” that the globe is warming and human activity is the main cause. John Broome is author of Working Group III on the IPCC, the leading international body on this issue. A Professor at the University of Oxford, Broome is one of the world’s experts on climate change.
His book briefly reviews the science, which includes uncertainty about precisely how and when the climate will change. He also discusses how to cope with that uncertainty, considers how justice is involved, and compares harms and benefits that are widely separated in time, (since the costs of alternate energy are borne now to produce benefits in the distant future).
This review will not repeat most of the familiar science, but some facts aren’t denied. One is that the melting of the Arctic ice cap is proceeding rapidly. In 2007 and 2011, summer ice floating on the Arctic Ocean covered little more than half the area it covered in 1979, when satellite observations began. The volume has diminished even faster than its area, because the ice is thinning: Volume is estimated to be about one-quarter of what it was in 1979. “A time is likely to come within only a few years when there is no ice at the North Pole.”
It matters whether ice melts because ice reflects sunlight energy back into space, but water absorbs most of it, which amplifies global warming. In addition, a lot of methane is locked up in permafrost around and under the Arctic Ocean, and its release will accelerate global warming, since methane is a very powerful greenhouse gas. Losing one of our polar ice caps, writes Broome, will conspicuously signal the climate’s warming. It may also provide a sufficiently dramatic event to teach us how large the unforeseen consequences of our acts can be.
The world recognizes that humanity must reduce our emissions of greenhouse gasses, but we’ve made little progress in that regard. One reason for inaction, Broome explains, is the harm from climate change is slow and insidious, while the costs of alternate forms of energy are conspicuous. “Predicting the effects of greenhouse gas is extremely difficult because the causal system involved in climate change constitutes the entire surface layer of the Earth.” Unless and until we can better predict the costs of inaction, then inaction will seem cheaper than action.
Since uncertainty permeates predictions for the future climate, uncertainty also permeates the ethics of climate change. Some people, writes Broome, use uncertainty as an excuse for inaction, which was the Bush administration’s choice. Most people, however, buy insurance due to uncertainty instead of waiting indefinitely for certainty. We don’t know if our house will catch fire, but that’s not a good reason to delay buying a fire extinguisher. It’s not advisable to act on the basis of what is likely to happen, since our house is unlikely to catch on fire. But the unlikely possibility, when it occurs, would be extremely bad.
We all assess the probabilities of predictions. The IPCC assigns probabilities to various predictions, giving a two-thirds probability of temperature increases over the next century of between 1.4 and 3.8 degrees. There is a five percent chance that temperatures will rise as much as 6 degrees or more, which would cause drastic climate changes.
During the last ice age, global temperatures were about 5 degrees lower than they are now. Six degrees of warming would give us drastic changes in the other direction from the ice age. Ten degrees of warming would be a great catastrophe, causing dreadful destruction and suffering. A terrible result multiplied by a low possibility leads us to take precautions, much like buying a fire extinguisher for our home.
JUSTICE & FAIRNESS
Broome contends that emissions of greenhouse gasses are normally unjust. Our emissions are unjust since they are the result of our actions that benefit ourselves, while imposing harm upon others whom we do not compensate. Among the people harmed are those who live in low-lying Pacific islands that must be abandoned due to rising sea levels. The harm is serious; the gasses we release now will stay in the atmosphere for centuries, and the harm they cause to people will multiply in the future.
We do an injustice when we know our actions have caused significant harm, but fail to compensate the victims of our harm. The harm is not reciprocal, since rich people inflict more harm than poor people who use a fraction of the energy the world’s wealthy do. Rich people have alternatives to easily reduce their emissions, while the very poor have fewer choices. While our emissions harm people currently living, the suffering will be borne primarily by future generations.
It’s easy to decry the lack of action by governments, Broome writes, but private individuals have duties as well. Our individual decisions about how we live have consequences when it comes to emitting greenhouse gasses.
An average person from a rich country born in 1950 will emit about 800 tons of CO2 in a lifetime, which it is estimated will cost more than six months of healthy human life. Even if we’ve already passed the point of no return with climate change, our individual emissions either accelerate or delay catastrophe. On the other hand, individually reducing our carbon footprints won’t solve the problem since everyone would have to do it; the solution requires government action.
One approach is offsetting emissions. That means for every unit of greenhouse gas we cause to be added to the atmosphere, we also cause a unit to be subtracted from it. The goal, Broome writes, is to on balance add nothing to the concentration of greenhouse gasses, and therefore to commit no injustice on others. One way to subtract gas from the atmosphere is to grow trees, since trees remove carbon in order to grow. When the trees die, however, the carbon is released. What’s needed is a mechanism to ensure our trees are replanted perpetually, again and again.
Offsetting works for individuals, but significant progress on reducing emissions is going to have to come from governments, just as it did with reducing CFCs. Reducing our individual emissions to zero, however, does fulfill our individual duty to do no harm.
How should we value future events compared with present ones? People prefer their own well being over that of their descendents they will never know. There’s an argument that the government should be a trustee for unborn generations as well as for present citizens, defending exhaustible resources of the country from rash and reckless spoliation.
How should we value human lives that will be lost due to climate change? Dick Cheney is known for his one percent doctrine: He argued that terrorism is so bad, if there is a one percent likelihood of having a terrorist attack, we must do everything in our power to reduce that one percent - even if certain aspects of our freedoms are compromised; it was a matter of saving lives. It’s obvious that the Bush administration was highly selective in applying the one percent principle.
Global warming is already taking lives via more extreme weather. Our challenge is to calculate how much it is worth spending to save how many lives. A rise in temperatures of 8-10 degrees would put most of the world’s farmland under water, and make it difficult to grow on the remaining land, leading to a drastic drop in population, even to extinction.
The only means we have at present for dealing with uncertainty is democratic public debate, to which this book is an admirable contribution. ###