Climate change: are you willing to take the risk?

Debate about the character of knowledge and uncertainty will continue to be a formative discussion of the 21st century.

What exactly is knowledge?

In today’s complex world, is it possible to know everything about even a relatively small problem? And if complete knowledge eludes us, is partial knowledge still better than ignorance? And what if knowledge is not only partial but also accompanied by uncertainty, as is often the case in science? Does uncertain partial knowledge trump ignorance?

How do we navigate an uncertain world in which most knowledge is partial?

Fortunately, it turns out that we can act on our knowledge with considerable confidence even if it is partial and even if it is accompanied by uncertainty.

The value of partial knowledge is readily illustrated with an example: Suppose your doctor presented you with the choice between laser surgery and likely blindness, would you have surgery to re-attach your retina? I bet you would.

You would opt for the laser surgery because you know that it can prevent blindness, even though most of us personally don’t understand the details of how a laser does its magic. But it’s not just you and me who don’t understand how lasers work; physicists don’t understand all aspects of the quantum mechanics that underlie laser technology. Their knowledge of lasers is partial.

And we nonetheless all use lasers every day, from laser pointers to laser printers to laser surgery.

Lest you think that this is an isolated example, consider the most basic of scientific facts: gravity. You may be surprised to hear that our scientific understanding of gravity is only partial. Contemporary theories of gravity predict the existence of gravity waves, analogous to the electromagnetic waves that drive your TV; however, my colleagues in physics tell me that those gravity waves have yet to be observed directly. Scientific knowledge of gravity is only partial.

And we nonetheless don’t jump out of airplanes or off bridges without a parachute and we nonetheless know that apples will fall to the ground when dislodged from a tree.

The message is clear: All scientific knowledge is partial, but that doesn’t mean we are ignorant.

Far from it; our partial scientific knowledge is vastly preferable to ignorance because even with partial knowledge of retroviruses we can control AIDS, and with partial knowledge of nanotechnology we can develop cheaper solar cells to deliver more clean energy at an affordable price. Partial knowledge of gravity is governing our daily lives, and partial knowledge of quantum mechanics is sufficient for surgeons to re-attach retinas to preserve a patient’s eyesight.

Much the same applies to the uncertainty that accompanies some - but not all - scientific knowledge.

To illustrate, consider the following two statements:

Apples fall down.

Driving your car into a brick wall at 80 km per hour is a bad idea.

Most of us would accept both statements as factual - and this despite the fact that the latter statement has some uncertainty attached to it. After all, when you hit a brick wall at 80 km per hour you might - just might! - get away with a few bruises and a concussion. Of course, it is far more likely that you would break a leg or worse.

No-one in their right mind would drive into a brick wall because the outcome is “uncertain”. And no-one in their right mind would deny that apples fall from trees, just because gravity waves have yet to be observed directly.

It is helpful to bear this in mind when considering important scientific issues that confront society, such as the public health effects of tobacco smoke and the - potentially even greater - impact on public health posed by climate change. Those issues, and many others, are characterised by some degree of uncertainty: After all, no scientist can predict exactly whether or not you will develop lung cancer if you continue to smoke eight packs a day for the next 30 years. The particular outcome is uncertain - but it is nonetheless certain that smoking causes lung cancer, and it is certain that it is a good idea to quit now in order to avoid adverse health consequences later. Likewise, no climate scientist can predict the exact temperature rise during the next decade to two decimal places - but there is virtual certainty that temperatures will continue to rise, and it is certain that it is a good idea to cut greenhouse gas emissions now in order to avoid adverse planetary consequences later.

It is therefore intriguing, and only at first glance surprising, that the history of tobacco reads so much like the history of climate change: In both instances, partial scientific knowledge accompanied by uncertainties was available for decades before meaningful action was taken - in the case of tobacco - or will be taken - in the case of climate change. In both cases, real debate about the fundamentals ceased in the scientific community long before those fundamentals became firmly embedded in the public’s knowledge.

Why the delay? Why did so many more people have to die needlessly from lung cancer for so long after the medical community had clearly identified the risk?

The answer is illustrated with devastating clarity in a recent book by Professor Oreskes, a historian of science at the University of California, who revealed in painstaking detail how a handful of ideologues, aided by shadowy but well-funded “think tanks” were able to manufacture doubt in the public’s mind about the link between smoking and lung cancer. Oreskes and co-author Professor Conway show how those few people, by creating pseudo-scientific “institutes” with pseudo-scientific “conferences”, created the appearance of a scientific debate when there was none. And human nature being what it is, the appearance of debate, and the presence of scientific uncertainty, was sufficient to delay life-saving interventions and public-health campaigns against smoking.

Precisely the same pseudo-scientific “institutes,” using the same pseudo-scientific jargon and the same pseudo-scientific “conferences” are now seeking to create the appearance of a “debate” about the fundamentals of climate science. Indeed, the very same people - yes, the same individuals - who were involved in manufacturing doubt about the link between smoking and cancer are now also involved in manufacturing doubt about climate science.

Anyone who wonders why smoking and climate science should attract the attention of the same clique of manufacturers of doubt can attend one of Professor Oreskes’ lectures later this month: She will be touring Australia in November, with lecture stops at universities in Sydney, Melbourne, Brisbane, Adelaide, and Perth.

Putting aside the manufacturing of doubt by ideologues, how do we best deal with the uncertainty inherent in climate science? In particular, what are we to make of the IPCC’s latest assessment report, published in 2007, which some have labelled “alarmist” despite the fact that it painstakingly circumscribed the scientific uncertainties?

Sadly, the IPCC report was not alarmist but was probably overly conservative.

My fellow cognitive scientist Professor Budescu, from the University of Illinois, recently showed that people’s perception of uncertainty deviates from that intended by the IPCC; in particular, most people underestimate the certainty and confidence that the IPCC assigned to “likely” and “very likely” events. Thus, events that are 90 per cent or more certain to occur - such as the increased frequency of extreme weather events - people perceive as being only 75 per cent probable, simply because the popular understanding of phrases such as “very likely” is more conservative than intended.

Thus, far from being alarmist, the carefully chosen phraseology of the IPCC fails to communicate the urgency of the situation.

The IPCC’s conservatism is not confined to people’s perceptions but extends to the physical climate as well. The planet’s climate is changing more rapidly than anticipated by the IPCC: According to a recent peer-reviewed analysis by Professors Freudenburgs and Muselli of the University of California, nearly 90 per cent of all reports about new scientific findings since the IPCC’s 2007 assessment reveal global climate disruption to be worse, and progressing more rapidly, than expected.

This, then, is the crux of the matter that is too often overlooked or ignored: Uncertainty cuts both ways. Uncertainty means things could be worse, or indeed far worse, than the generally conservative assessment of the state of the climate provided by the IPCC and other bodies, such as the recent document published by the UK’s Royal Society.

Uncertainty doesn’t mean we needn’t worry - because uncertainty also means that things could be worse than anticipated.

Anyone who argues that we need not act on climate change because of uncertainty is really inviting you come along for a ride into a brick wall at 80 km/h because it might hurt only a little.

Are you feeling lucky?

http://www.abc.net.au/unleashed/40652.html