Pilate: “What is truth?”; Lewis Carroll: “What I tell you three times is true”.
Last time, I wrote about something which is scientifically uncertain, the role of human activities in the Queensland floods. This raises the question of truth — scientific truth — for example, whether it can be truthfully said that our activities are changing the climate of the Earth.
Nowadays, many have a sceptical view of what scientists say, such as on the consensus among climate scientists that emissions of carbon dioxide and other “greenhouse” gases are resulting in global warming.
So what do scientists say about scientific truth? The best ones are surprisingly modest. Physicist Richard Feynman once said “We never are definitely right: we can only be sure we are wrong.”
The best of science is done according to Mertonian norms, abbreviated by Robert K Merton to CUDOS: Communalism (research findings belong to the whole scientific community); Universalism (all scientists can contribute, regardless of race, nationality, culture, or gender); Disinterestedness (findings should not get tangled with one’s beliefs or activities); Organised Scepticism (claims must be subject to critical scrutiny).
Scientists are always therefore giving their assessment of what the research currently says, in the form of a model consistent with fact and with predictive power (otherwise it’s not much use!).
Models should be as simple as possible, making a minimum of new assumptions, according to Ockham’s razor (“entia non sunt multiplicanda praeter necessitatem”). This corresponds with the view that scientific theories should be “beautiful”. Einstein felt that his theory of gravity, unlike Newton’s which it corrected and replaced, was beautiful.
But, as Feynman said, “It doesn't matter how beautiful your theory is… If it doesn't agree with experiment, it's wrong.” In fact, according to Karl Popper, if it isn’t possible in principle to refute it, it isn’t a theory at all but an article of faith.
Inevitably, scientists, being human, may depart from Mertonian norms and be influenced by career needs, prestige, laziness, or even money. However, this also holds true for sceptics of science, such as those who describe the work of the IPCC1 as a conspiracy, or as environmentalist fundamentalism.
Theories of climate are imprecise and not, in general, beautiful; they reflect our imperfect knowledge of the world. However, the models are getting better all the time. Writing in New Scientist 2, Anil Ananthaswamy points out that, since there is only one Earth, scientists must rely on computer simulations to predict how the Earth will respond to human actions.
The various models have to make approximations because of incomplete data and finite computing power.
They look at changes in land, oceans, atmosphere, and cold regions. They also look at the interactions between these; they divide the Earth’s surface into units, called grid cells, and look at the effects of changes, say, in vegetation. Grid cell size has been reduced fourfold to 110 km across in the IPCC’s 4th report in 2007, allowing more precise predictions.
Factors such as the effect of water vapour in the atmosphere are difficult to assess but newer models are attempting to do this. Briefly, water vapour is a greenhouse gas and more evaporation of oceans in a hotter climate might lead to positive feedback with an increasing rate of temperature rise. But more vapour would lead to more cloud cover, which can have a warming or cooling effect according to circumstances. Computer models will be more able to take clouds into account by the next IPCC report in 2014.
It is striking that all models give similar predictions for the temperature rise if the CO2 levels double — from 2 to 4.5 ºC. It is also not true, as various climate change deniers charge, that factors such as sunspots and cosmic rays have been ignored. Nevertheless, it is difficult to get across in a headline that a rising trend in temperature is compatible with temporary decreases.
Deniers have also seized on errors and apparent underhand methods revealed in hacked emails. When these were shown not to invalidate the overall predictions, this got less publicity. As a result, public confidence in climate scientists is at an all-time low.
As Evelyn Fox Keller, emeritus professor of the history and philosophy of science at MIT, pointed out in New Scientist3, there has been a long campaign to discredit them, initially funded by business and libertarian-conservative interests in the US. An “army of sceptics” was recruited, some opposed to government regulation, some rejecting of intellectual authority and some believing that everyone has a right to an opinion. “The upshot is,” says Keller, “that internet sites, radio and TV channels now transmit ‘contrarian’ attacks on climate scientists” daily. And, in the interests of “balance”, even responsible media may give the impression that scientists are divided 50:50, rather than 95:5.
Our “own” contrarians, the former writers for Living Marxism magazine who now write for sp!ked, regularly attack climate change science. Ben Pile4 accuses climate scientists of pursuing their theories in order to give themselves a purpose in life. Paul Nurse, president of the Royal Society, says “Trust no-one: trust only what the experiments and data tell you.” Pile cheekily says “But isn’t this also the message from climate sceptics, who accuse institutional, official science of corruption and political motivation?” No, it isn’t.
sp!ked journalists should listen to the economist Murray Rothbard who might have said “It is no crime to be ignorant of [climate science], which is, after all, a specialized discipline … But it is totally irresponsible to have a loud and vociferous opinion on [climate science] while remaining in this state of ignorance.”
Is the theory of global warming a scientific theory? Yes. It can be refuted, not quickly but in time — certainly well within the lifetime of most readers.
1. IPCC = Intergovernmental Panel on Climate Change http://www.ipcc.ch
2. “Behind the predictions”, New Scientist, 15 January 2011
3 .“Stick to your guns”, New Scientist, 8 January 2011
4.”Scepticism is not an ‘attack on science’”. www.spiked-online.com/