IN 600 pages, Sir Nicholas Stern spells out a bleak vision of a future gripped by violent storms, rising sea-levels, crippling droughts and economic chaos unless urgent action is taken to tackle global warming.

His heavyweight review - which is broken down into six parts containing 27 separate chapters - stresses that any delay will leave the world in "dangerous territory''.

Climate changethe evidence

There is now "overwhelming'' evidence that shows "climate change is a serious and urgent issue'' and has been created by man's actions. It now "threatens the basic elements of life for people around the world - access to water, food production, health and use of land and the environment''.

Temperatures are expected to rise by between 2 C and 5 C - an increase on the same scale as the last Ice Age - though the increase could be as high as 10 C by 2100 if greenhouse gas emissions continue at current levels.

The changes will see the area affected by "extreme drought'' soar from one per cent of the world's land mass to around 30 per cent. In other areas, there will be widespread flooding and more intense storms. "The risk of abrupt and large-scale changes in the climate system will rise.'' Sea levels could rise by up to 12 metres over the next few centuries.

The severity of the impact requires "strong and urgent global action to reduce greenhouse-gas emissions''. There will also need to be "major action to adapt to the consequences that now cannot be avoided''.

Impact on growth

and development

By 2100, an extra 250,000 children a year will die in the poorest countries as a result of climate change, while up to 220 million more people could fall below the $2 a day poverty line. A temperature rise of just 1 C to 2 C could lead to the extinction of between 15 and 40 per cent of all species.

Rising sea levels will threaten countries like Bangladesh but also some of the biggest cities, including London, New York, Tokyo and Shanghai.

Ocean acidification could destroy fish stocks, crop failure will leave hundreds of millions at risk of starvation and up to 200 million people will be displaced by rising sea levels, floods and drought. It is already too late to avoid many of the problems facing people in the Third World.

"Strong and early migration is the only way to avoid some of the more severe impacts,'' the report warns.

The world's richest countries will suffer with more hurricanes and floods. Climate change could cost between five and 20 per cent of global GDP.

The cost of stabilising

greenhouse gas levels

Greenhouse gas levels have increased steadily since the Industrial Revolution from 280 parts per million CO to 430 ppm but the process has accelerated in recent years. "Very strong reductions in carbon emissions'' are needed to ensure they are cut by 25 per cent by 2050 and "ultimately to less than one fifth of today's levels.''

The goal is to stabilise levels at 550 ppm, though existing fossil fuel stocks could take CO levels beyond 750 ppm, "with very dangerous consequences''.

Early action is vital to stabilise greenhouse gas levels.

This will require moves to ensure the price of goods and services reflect their "full costs'' to the environment, as well as the greater use of new low-carbon technologies.

Policies to

reduce emissions

Carbon pricing must be at the core of any policy. Governments must put an "appropriate price on carbon, through taxes, trading or regulation'' - and encourage people to buy low-carbon goods and services. There must also be an expansion of carbon trading schemes to give industry and business financial incentives to reduce emissions.

At the same time, governments and the private sector need to step up investment in new technology to reduce greenhouse gas emissions. The report calls for a five-fold increase in incentives for "low emission technologies''.

This will involve alternative ways to produce electricity, new forms or transport and other low-carbon energy sources.

Policies to cope with

existing climate change

Increases in greenhouse gases mean countries must adapt to cope with the "unavoidable impacts of climate change to which the world is already committed''.

This could include, for example, farmers switching to more climate-resistant crops. However, this type of adaptation will only have a limited effect and "mute the impacts'' of global warming. It must exist alongside strong and ambitious policies to reduce emissions.

It is also expensive. It could cost the world's richest countries up to $150 billion a year - around pounds 80 billion or 0.5 per cent of global GDP - to construct new buildings and infrastructure that can cope with climate change.

Governments can help by investing in more accurate climate forecasting; regulations to encourage better use of land and higher quality buildings; more coastal protection; and help for the poorest families who cannot afford insurance.

International action

The report wants stronger, more co-ordinated'' international action on climate change.

Such a strategy will require a "broadly similar price for carbon'' across the globe and close involvement of the private sector. More must be done to encourage developing countries to opt for low-carbon technology.

Charles Clover and Ruth Lea: Page 24 Editorial Comment and Letters: Page 25