The Kyoto protocol came into force on 16 February 2005, heralding the advent of a more mature attitude. Mankind, we were told, had finally woken up to the increasing pressure that it is exerting on the environment. Unfortunately a closer look shows that such claims have more to do with wishful thinking than actual fact.

Forecasts of global warming have become more alarmist in recent years. The 2001 report by the Intergovernmental Panel on Climate Change (IPCC) confirmed that the greenhouse effect had significantly increased since the 19th century. Carbon dioxide (CO2) emissions contributed to a worldwide temperature increase of 0.8°C between 1860 and 2000. The same report predicted that temperatures would rise fast-­er, increasing by 1.4°C to 5.8°C between 2000 and 2100. Given that during the last ice age, 15,000 years ago, the planet as a whole was only about 5°C colder, this would be a considerable increase.

A study published by Oxford University in 2005, based on the results of 2,578 computer simulations, forecast an even higher temperature rise: between 1.9°C and 11.5°C, most of the results ranging from 2°C to 8°C. The greatest source of concern is the notion of the point of no-return. Due to climatic inertia, even if drastic measures were taken now, the impacts of the current disturbance would persist for years. They might even be irrevers­ible. A consensus has emerged that the critical threshold could correspond to an overall temperature rise of 2°C. To prevent this, the CO2 concentration should not exceed 550 parts per million (ppm), or perhaps even 400 ppm. But in fact it rose from 270 ppm around 1850 to 380 ppm in 2004, an unpreced­ented increase in the 420,000 years of climate history that scientists have been able to reconstitute. Over that period the CO2 concentration varied between 180 ppm and 280 ppm. The current annual rate of increase stands at 2 ppm, which means a critical thresh­old could be reached within 10 to 30 years. It also means we need a fourfold cut in CO2 emissions by industrialised countries by 2050.

The weight of evidence

Admittedly we are dealing with forecasts, not absolute certainties. But the importance of the risks and the growing consensus among scientists should encourage us to apply the precautionary principle and take effective measures. What, then, would the Kyoto protocol achieve if it was fully implemented, in other words if the United States ratified it and Europe met its commitments? It would only reduce global warming forecast for the end of the century by 0.06°C (or 2% to 3%). Furthermore the protocol does not set any limits on emissions in developing countries, which understandably want to catch up with industrialised countries. The failure, at the end of 2004, of the negotiations at the Buenos Aires conference, which was supposed to prepare a follow-up to Kyto, is an indication of the present deadlock.

Yet, although the forecasts are still uncertain, the signs of an imminent upset are accumulating. The last decade (1995-2004) was the hottest since the start of regular records in the 19th century. It saw an increase in the number of extreme events: the frequency and intensity of El Nino increased; the heat wave that affected Europe in 2003 could become a recurrent feature; in 2004 the US and Asia suffered an unprecedented number of typhoons. It is perhaps too soon to say they are all connected, but the available evidence increasingly points that way.

Several structural phenomena have been confirmed, even if it is still difficult to predict their consequences accurately. In addition to warming in the polar regions (see section on pages 8-9), the increase in the temperature of the oceans is damaging coral reefs, a habitat essential to marine wildlife. The sea level could rise by between 25 centimetres and 1 metre due to dilatation of water as it warms up. Nor does that allow for melting of the ice caps. Some studies are predicting 150 million climate refugees by 2050. Changes in rainfall patterns could affect farming and the areas in which diseases propagate. The consequences for biodiversity are also likely to be particularly serious, with many species struggling to adapt to such rapid changes. Even without climate change human beings have already caused the sixth largest wave of biological extinction the Earth has ever known, simply on account of the destruction and pollution we habitually wreak.

On the web

?United Nations Framework Convention on Climate Change (UNFCCC): www.unfccc.int
>?Intergovernmental Panel on Climate Change (IPCC): www.ipcc.ch
>?Worldwatch Institute: www.worldwatch.org
>?Global Resource Information Database (GRID-Arendal): www.grida.no/climate