Sir

Some loose ends appear in your report of the Worldwatch Institute's estimates of global carbon emissions from fossil fuel use in 1998 (Nature 400, 494; 1999). The industry report cited estimated that global emissions had fallen by 0.47% from 1997 levels, based on a US reduction of 0.2%. The US Environmental Protection Agency later estimated that 1998 US emissions had increased by 0.4%. This indicates that global emissions declined by 0.3%. The Worldwatch Institute claimed a 0.5% global reduction, despite acknowledging the +0.4% US figure.

In fact, the global reduction seems to have been more than 1%. This is owing to a reduction of more than 3% in the Asia-Pacific region and of more than 2% in the economies in transition in Eastern Europe and the former Soviet Union. Developing countries overall saw a decline exceeding 3% (though still up 33% on 1990 levels) because the decline in Asia more than offset small increases elsewhere. By contrast, emissions rose 1% in the European Union.

Reductions around the world were mainly the result of presumably temporary economic difficulties. In many cases they occurred in countries that are neither industrialized nor transitional economies listed in annex I of the climate convention and annex B of the Kyoto Protocol.

The Worldwatch Institute's belief that the 1998 figures are “a sign that it may be less difficult to slow global warming under the Kyoto Protocol” than has been widely assumed, and the suggestion by others that voluntary reductions by industry will suffice, seem seriously complacent.