The United Nation's Biodiversity Convention, which calls on countries to protect their richness and diversity of plant and animal species, came into force yesterday. There are thought to be at least 5 million species. But most developed countries have not yet ratified the treaty so it does not apply to them.
Britain has serious doubts about the treaty - believing it gives developing countries, the majority, too much power in deciding how, and how much, money will be spent.
The convention says the rich minority of nations will have to act as financial donors in implementing the treaty within developing countries. They harbour most of the world's wildlife in their forests, savannahs, coral reefs and deserts.
It speaks of the Western world providing 'new and additional financial resources to enable developing countries' to meet the costs of implementing the treaty, such as recording species, setting up reserves and protection schemes.
So grave were Britain's doubts that it almost declined to sign the treaty, but after much lobbying and unfavourable publicity, John Major eventually did so.
However, Britain and several other wealthy nations made a declaration at the time setting out their own interpretations of how financial decisions would be made by the treaty nations. President George Bush refused to sign the treaty for the United States, a decision reversed by Bill Clinton.
The convention became international law yesterday, exactly 90 days after 36 countries had taken the next step from signing and ratified it. Since that 36th ratification - by Mongolia - Spain, Denmark, Portugal and Germany have ratified, bringing the number of developed countries on board to nine.
Groups such as Friends of the Earth and the World Wide Fund for Nature say that without the support of a solid majority of Western nations, the treaty has no chance of slowing the wave of extinctions caused by man. As the human population continues its rapid expansion, up to 100 different plants and animals a day may be becoming extinct - the greatest planetary loss in tens of millions of years.
The Department of the Environment says there is no need to ratify the treaty for months. The first important meeting of treaty nations, the 'conference of parties', will not take place until late November, and if Britain wants to attend, negotiate and vote it will not have to do so until three months beforehand.
Departmental sources say ministers are considering whether Britain should ratify while presenting a further 'interpretive statement' to ensure that developing countries cannot use the treaty as a blank cheque.
In any case, the treaty sets only a loose framework for preserving biodiversity which enables nations to avoid making binding commitments. The qualifying phrase 'as far as possible and as appropriate' appears frequently. Much will depend on gradually altering the treaty by consensus.