Sarah Leach

Environmental pessimists and optimists accuse the other of practicsing unsound science.

Connected to this point is that both sides at times doubt that their opponents have the necessary academic qualification to have anything relevant to say. Because Julian Simon is a business economist rather than a biologist or environmental scientist, Ehrlich and Ehrlich maintain that he does not know what he is talking about as regards species extinction. More generally, the Ehrlich's regularly suggest that the environmental optimists are the equivalent of flat-earthers, astrologers and believers in perpetual-motion-machines. On the other hand, when a critic suggested that he ignores the basic physical realities of entropy, Simon attempted to dismiss this criticism in pointing out ironically that "a sociologist instructs us that the physics of cosmology as embodied in that old chestnut entropy, makes nonsense of what I write about population economics".

Moreover, both sides accuse their opponents of holding their - supposedly unscientific - views for, in part at least, ethically dubious reasons. Beckerman suspects that many climatologists together with other scientists working in the field of global warming pop up their findings into an "alarmist story" in order to reap more money for their research budgets. Worse still, "other organisations and individuals parade the global warming scare for less worthy reasons--political popularity, personal ego-trips, parading their moral sensibilities, or financing pseudo-scientific activities". Ehrlich and Ehrlich, on the other hand, suggest that some of the promoters of the 'brownlash', as they call environmental optimism, "have links to right-wing ideology and political groups" and that the "most extreme--and most dangerous--elements are those who, while claiming to represent a scientific viewpoint, misstate scientific findings to support their view that the U.S. government has gone overboard with regulation, especially (but not exclusively) for environmental protection."

	Pessimist
	Donella Meadows (1941-2001) Professor of Environmental Studies at Dartmouth University, US, who researched into and campaigned for the environment and sustainable living. Her 1972 classic The Limits to Growth described the environmental consequences of the growth of populations and economies. Meadows and her colleagues had been commissioned to study a series of questions about the environment by a group of leading businessmen, statesmen and scientists called the Club of Rome.

Interestingly, both sides accuse their opponents of refusing 'to put their money where their mouths are' and take this very seriously. The row over this aspect of the debate can be traced back to 1980 when Paul Ehrlich together with then Berkeley physicists John Harte and John Holdren engaged in a by now legendary bet with Julian Simon. Simon had challenged the environmental pessimists repeatedly with the offer to bet against him on natural resource prices as an indicator of resource scarcity. Ehrlich and his colleagues chose five metals (chromium, copper, nickel, tin, and tungsten) and the period of 1980 to 1990. At the time of the bet they said that they would "accept Simon's astonishing offer before other greedy people jump in" as the "lure of easy money can be irresistible". However, at the end of the time span they had unambiguously lost the bet as the real price, i.e. after adjusting for inflation, of all metals was lower than in 1980. After their loss, the embarrassment for Ehrlich and his colleagues was great. They tried to explain the outcome with unlucky circumstances, a worldwide recession, the doubling of oil prices and so on. Alternatively, the relevance of the loss was put into doubt by Ehrlich and Ehrlich in saying that resource prices do not matter much. They also allege that Paul Ehrlich and his fellow scientists always knew that real resource prices were not a critical indicator and said so at the time of the bet. Other environmental pessimists came to their help with similar arguments, for example, Abernethy and Myers.

Having won the first bet, Simon kept on inviting environmentalists for another wager. The environmental optimists this time refused to engage in the same bet for a new period of their choice, which puts into doubt their explanation that they lost the first bet merely due to unlucky circumstances. Simon offered a similar bet based on some indicator for his forecast that "the material conditions of life will continue to get better for most people, in most countries, most of the time, indefinitely". The environmental optimists countered with offering a different bet pertaining to 15 indicators over the period 1994 to 2004 ranging from emissions of pollutants to fish catch, agricultural harvest and to deaths caused by AIDS. From their perspective, all indicators related to "material human welfare", as demanded by Simon. This time, it was Simon's turn to decline the offer, saying that he did not want to bet on particular physical conditions of the environment, but only on the consequences of environmental change on human welfare: "...life expectancy rather than AIDS, skin cancers (or even better, lifetime healthy days) rather than a hole in the ozone layer (if that is indeed a problem), and agriculture rather than global warming". The environmental pessimists did not want to change their offered bet, so no new wager was undertaken. As a result both sides saw their case confirmed and their opponents' supposed unwillingness to 'put their money where their mouths are' unmasked. Ehrlich and Ehrlich conclude that "Simon blusters and asserts but won't back up his own rhetoric when seriously challenged", whereas Simon concludes in the same vein that "the doomsayers{A133}refuse to put either their cash or their names on the line to back what they say".