During the 12-day United Nations Earth Summit in June last year 117 presidents and prime ministers made speeches on the need for partnership between rich and poor nations, and signed vague, non-binding agreements on promoting sustainable development and protecting the global environment. Optimists spoke of the 'spirit of Rio', but over the past year all the trends the summit fretted about continued or worsened: explosive population growth, ozone holes, rising levels of 'greenhouse gases' and extinction of species. In a blow to global solidarity, several wealthy donor nations announced large cuts in their Third World aid budgets soon after the summit.
The spirit of Rio was further flattened when donor nations failed to increase their commitments to the World Bank's International Development Association arm. IDA provides 'soft' loans on extremely easy terms to the world's poorest nations. There had been much talk at the summit of an 'earth increment' - extra money to help make development projects environment friendly - but this did not happen when the time came for donors to make pledges last autumn.
President Fernando Collor had hoped he and Brazil would win enormous prestige by hosting the summit. But the President was mired in a corruption scandal as it began and within a few months he was swept from power. Maurice Strong, the Canadian diplomat and tycoon who spent two years leading preparations for the summit and then chairing it, is back in business as the chairman of Hydro Ontario, a large electricity company. His country is among those that have since made big cuts in foreign aid. From Toronto he said the summit's gravest setback had been the failure of the US to show leadership: 'President Bush failed and no other country or bloc stepped in to fill the gap.'
The single most hopeful development since Rio has been the change in the White House, which may turn the US from laggard to leader. Senator Al Gore wrote Earth in the Balance, the most readable, visionary book about environmental and development issues by any mainstream politician. Vice-President Gore has since had to do a lot of compromising. None the less, President Clinton has proposed a slight increase in aid to poorer countries this year. And he has promised to sign the UN's biodiversity treaty, which his predecessor had refused to do in Rio.
World leaders signed two treaties at the Earth Summit: on conserving biodiversity - the planet's wealth of plant and animal species - and on man-made climate change caused by atmospheric pollution. But signing is only an opening gesture. The treaties have to be ratified by more than 30 countries to come into force. To date only 18 nations have ratified the climate change treaty, 14 the biodiversity accord.
In fact when, or if, the treaties do enter into force they will make little impact. These legal documents recognise environmental threats, call on countries to be formally aware of them and set up mechanisms with which rich nations can help poor ones to start tackling the problems. But they do not oblige any nation to do anything concrete to counter them. That will have to wait for further protocols, which will not be negotiated until the global environmental threats are more immediate.
The climate change treaty goes furthest in requesting developed countries to do their best to stabilise rising emissions of global warming gases at current levels by the year 2000. The language is weak because the previous US administration would not agree to anything firmer. But Mr Clinton has since shown more commitment to the year 2000 target.
Last week there was also a hopeful post-Rio development in Peking. Donor nations agreed in principle to give a World Bank fund called the Global Environmental Facility (GEF) dollars 2.8- dollars 4.2bn ( pounds 1.7- pounds 2.6bn) for the period 1994 to 1997, representing a long-term commitment to the GEF, which began as an experiment in 1991 with dollars 1.3bn to cover its first three years. The GEF is used for 'green' development projects in the Third World.