Today is the fortieth Earth Day, so it is an appropriate time to consider what the environmental movement has achieved globally over the last four decades. On the first Earth Day, April 22 1970, more than 20 million Americans took part in demonstrations. It has now become a global movement and, this year, organisers say that they hope about 1.5 billion people will take part, in 190 countries.
In the 1970s, climate change was not a well known issue, even though Svante Arrhenius had outlined the dangers of increased concentrations of greenhouse gases in 1896. Focus was instead on acid rain – the destruction of forests and wildlife by rain acidified by sulphur dioxide (SO2) and nitrogen oxides pollution, which comes from the burning of fossil fuels – and air quality, particularly in towns and cities. In 1975, it became mandatory in the US for all new cars to have a catalytic converter, which substantially reduces pollution. In 1980, the US Congress passed the Acid Deposition Act. This was a start, but not much more than that, as it simply established and funded a ten-year research programme. Then, in 1990, Congress amended the Clean Air Act, to set up a cap and trade system to control emissions of SO2 and nitrogen oxides. Since then, SO2 emissions have dropped 40%. US acid rain levels have dropped 65% since 1976. Europe was much slower. Catalytic converters became mandatory on new cars only in the 1990s. It also controlled pollution from power stations, in the 2001 Large Combustion Plants Directive. However, the EU approach has been more effective than the US one – SO2 levels have fallen by over 70% since 1990.
During the 1980s, the depletion of the ozone layer also became a major issue. In 1970, Paul Crutzen argued that emissions of nitrous oxide were sufficiently long-lasting to reach the stratosphere where, following chemical reaction, they would destroy ozone. In 1974, Frank Rowland and Mario Molina argued that long-lived halogen compounds such as CFCs might have a similar effect. Most people did not regard the ozone layer as something to worry about – even though it is essential in protecting humanity from skin cancer – until the discovery of the Antarctic “ozone hole” by the British Antarctic Survey in May 1985. Then, politicians moved with almost unprecedented speed. Later in 1985, the Vienna Convention for the Protection of the Ozone Layer was signed and, in 1987, came the Montreal Protocol, to implement the Vienna Convention. Montreal included commitments to phase out production and consumption of compounds that deplete ozone in the stratosphere, and has been very successful. In 2006, a report using NASA and US National Oceanic and Atmospheric Administration data found that the ozone layer above the Polar Regions stopped thinning around 1997, having declined steadily from 1979 to 1997. The abundance of ozone-destroying gases such as CFCs peaked in the stratosphere in 1997. The researchers conclude that the ozone layer will be fully recovered by around the middle of this century (see America.gov: Data from U.S. Agencies Show Ozone Layer Is Recovering).
The success of Montreal has led some to argue that it, rather than the Kyoto approach, should be used as the framework for climate protection. A good example is Scott Barrett:
“Montreal has several important features that are not shared by Kyoto. First, it not only limits production (like Kyoto); it also limits consumption (defined as production plus imports minus exports). Second, it not only requires industrialized countries to limit their emissions (like Kyoto), it requires developing countries to reduce their emissions, too. Third, while Kyoto’s limits apply for just five years, Montreal’s cuts are permanent. Fourth, under Montreal, industrialized countries finance compliance by developing countries.”
It is certainly tempting to use an approach that has worked. It took only two years to turn the Vienna Convention into the Montreal Protocol, whereas it took 15 years to turn the UN Framework Convention on Climate Change into the Kyoto Protocol. However, Kyoto’s lack of success is not primarily due to the framework. It is due to the politics. Phasing out CFCs and other ozone-depleters was not a major economic transformation, and the producing companies realised relatively quickly that they could not defend the destruction of the ozone layer, and could anyway make money making other chemicals. Phasing out fossil fuels is an altogether more radical challenge, though equally essential.