By Environment Correspondent Alex Kirby

A US report says the world could be taken by surprise by unexpected environmental problems during the twenty-first century.

The report, State of the World 2000, is the latest in an annual series from the Worldwatch Institute, based in Washington DC.

One of the authors, Chris Bright, says: "Environmental decline is often seen as gradual and predictable, but if we assume this we are sleepwalking through history".

Intensifying the damage

"As pressures on the Earth's natural systems build, there may be some disconcerting surprises as trends interact, reinforcing each other and triggering abrupt changes."

One example he cites is hurricane Mitch, which killed 10,000 people in central America in October 1998 and destroyed 95% of the crops in Honduras. Global warming may explain Mitch's ferocity, Mr Bright argues, but the destruction was compounded by the deforestation that had already taken place.

Another example of reinforcing trends is in the Amazon, where logging is thinning out the forests. This means the remaining forest dries out, and so becomes more susceptible to fire.

The senior author of the report, Dr Lester Brown, the institute's president, says that while the burgeoning information economy is affecting every facet of people's lives, it is still what happens to the environment that will shape the century.

"Caught up in the growth of the internet, we seem to have lost sight of the Earth's deteriorating health. It would be a mistake to confuse the vibrancy of the virtual world with the increasingly troubled state of the real world."

Education for women

Dr Brown says that population increase and climate change are the most urgent problems to be tackled.

"The two big challenges in this new century are to stabilise climate and population. If we cannot stabilise both, there is not an ecosystem on Earth that we can save. Everything will change."

Getting population under control, he argues, means every couple settling for two surviving children - "an achievable goal". The key requirements for this are universal access to family planning services and education for girls and women.

"Stabilising climate means replacing fossil fuels with wind, solar cells, and other renewables.

"Three US states - North Dakota, South Dakota and Texas - have enough harnessable wind energy to supply national electricity needs. China could double its current generation of electricity using only wind."

The report lists some of the natural world's pressure points:

• 11% of all bird species, 25% of mammals and 34% of fish are now in danger of extinction
• soil erosion has forced Kazakhstan to abandon half its cropland since 1980
• in the US, the Chesapeake Bay oyster beds yielded over 70 million kilograms annually a century ago, but less than 2 million kilograms in 1998
• the temperature on the Antarctic peninsula has risen by about 2.5 degrees Celsius since 1940
• Aids has driven down life expectancy in Zimbabwe from 65 years to 44, and by 2010 it is projected to be just 39 years.

"The scale and urgency of the challenges facing us in this century are unprecedented", says Dr Brown. "And nature has no reset button."