Leaders in politics and business know all about the threat of global warming. But across most of the world they seem unable or unwilling to address it.

In 1988, they set up the Intergovernmental Panel on Climate Change (the IPCC) to report on the pace and scope of the likely changes, how people could adapt to them and what strategies could reduce the rate of change. The IPCC finished its first very long set of reports in 1990. The next step was to negotiate a climate protection treaty. That was concluded by May 1992, in time for the Earth Summit in Rio de Janeiro. Presidents and prime ministers from 180 nations who had gathered in Brazil signed the UN Framework Convention on Climate Change.

But while this treaty provides a fine legal basis for tackling the problem, it bound not one single country to reduce its output of global warming gases. Globally these emissions are rising by about 2 per cent a year as populations grow and developing countries industrialise.

The 36 most developed industrialised countries, including Britain, did make a non-binding commitment to stabilise their emissions at the 1990 level by the year 2000. The point of this was to lead by example. It is now certain that many of them, including important players such as the US and Canada, will fail to meet this commitment. Britain is one of the few developed nations that will have lowered its emissions through the 1990s.

A year ago, in Berlin, the first "Conference of the Parties" to this treaty took place. This ended with the developed countries promising that by late 1997 they would negotiate further limits on their emissions beyond the turn of the century. Whether this means that they will commit themselves to cuts, rather than slowing growth, is not clear. Britain and Germany advocate reductions. There are no controls on rising Third World emissions.

Scientists say emissions need to be a cut by about 70 per cent to stabilise the concentration of heat-trapping gases in the atmosphere and halt warming.

As people become wealthier and more mobile across the world their economies need more energy, and the bulk of it comes from coal, oil and gas. The politicians find it extremely difficult to tax or regulate industry, commerce and households into using less.

Sir Crispin Tickell is an ex-diplomat and mandarin who alerted Margaret Thatcher to global warming. An advanced student of climatology, he still retains some influence on Government. ``We're all a bit schizophrenic about this,'' he says. ``On the one hand, you can't fail to see that governments need to do an enormous amount more. On the other, you have to appreciate that the changes can only be slow and incremental. The only thing that will make people change their minds is a catastrophe.''

We are not sure yet whether this is where we are heading, but it cannot be ruled out.