The Rational Optimist_ How Prosperity Evolves - Matt Ridley [142]
Clean air
In 1970, Life magazine promised its readers that scientists had ‘solid experimental and theoretical evidence’ that ‘within a decade, urban dwellers will have to wear gas masks to survive air pollution ... by 1985 air pollution will have reduced the amount of sunlight reaching earth by one half.’ Urban smog and other forms of air pollution refused to follow the script, as technology and regulation rapidly improved air quality. So by the 1980s the script switched to acid rain. It is worth exploring the history of this episode because it was a dress rehearsal for global warming: atmospheric, international and with fossil fuels as the villains. The conventional story you will read in your children’s textbooks is as follows: sulphuric and nitric acid, made mainly from smoke belched from coal-fired power stations, fell on lakes and forests in Canada, Germany and Sweden and devastated them. In the nick of time laws were passed limiting emissions and ecosystems slowly recovered.
Certainly, in the mid-1980s, a combination of scientists scenting grants and environmentalists scenting donations, led to some apocalyptic predictions. In 1984 the German magazine Stern reported that a third of Germany’s forests were already dead or dying, that experts believed all its conifers would be gone by 1990 and that the Federal Ministry of the Interior predicted all forests would be gone by 2002. All! Professor Bernd Ulrich said it was already too late for Germany’s forests: ‘They cannot be saved.’ Across the Atlantic, similar predictions of doom were made. Trees were said to be dying at an unnatural rate in 100 per cent of the forests on the eastern seaboard. ‘The tops of the Blue Ridge Mountains are becoming tree graveyards,’ said a plant pathology professor. Half of all lakes were becoming dangerously acidified. The New York Times declared ‘a scientific consensus’: it was time for action, not further research.
What actually happened? History shows that the biomass of European forests actually increased during the 1980s, during the time when unconstrained acid rain was supposed to be killing them and before any laws were passed to limit emissions. It continued to increase in the 1990s. Sweden’s government eventually admitted that nitric acid – a fertiliser – had increased the overall growth rate of its trees. European forests not only did not die; they thrived. As for North America, the official, ten-year, half-a-billion-dollar, 700-scientist, government-sponsored study did a great rash of experiments and found that: ‘there is no evidence of a general or unusual decline of forests in the United States or Canada due to acid rain’ and ‘there is no case of forest decline in which acidic deposition is known to be a predominant cause.’ When asked if he had been pressured to be optimistic, one of the authors said the reverse was true. ‘Yes, there were political pressures ... Acid rain had to be an environmental catastrophe, no matter what the facts revealed. Since we could not support this claim ... the [Environmental Protection Agency] worked to keep us from providing Congress with our findings.’ The truth is that there were small pockets of damage to forests in the 1980s some of which were caused by pests, others by natural senescence or competition and a few by local pollution. There was no great forest die-off due to acid rain. At all.
It would be wrong to conclude that the anti-acid rain legislation did no good at all. The acidification of mountain lakes by distant power-station emissions was a real (though relatively rare) phenomenon, and this was indeed reversed by the legislation. But even this harm was vastly exaggerated during the debate: far from 50 per cent of lakes being affected, it was 4 per cent, said the official study. Some of these continue to be acid even after the clean-up, because of the chemistry of the surrounding rocks. The fact is, if you read the history of the episode carefully, acid rain was a minor and local nuisance that