WASHINGTON: Even without factoring in the impact of climate change, the World Bank and the United Nations said Thursday annual global losses from natural disasters could triple to $185 billion by the end of the century.

The report said the negative impact of climate change could by then add $28 billion to $68 billion a year more in damage from tropical cyclones alone.

The 250-page report, ''Natural Hazards, Unnatural Disasters: the Economics of Prevention,'' was released Thursday in Washington.

It warns that the number of people exposed to storms and earthquakes in large cities could double to 1.5 billion by 2050.

The report suggests a number of measures to prevent death and destruction from natural hazards such as earthquakes, hurricanes and flooding that have ravaged several countries this year from Haiti to Pakistan. Undertaking these measures does not necessarily require governments to spend more, the report says, but to spend better.

For example, governments could make information about hazards and risks easily accessible. Schools could serve as cyclone shelters as in Bangladesh and roads could double up as drains as in Malaysia.

The report says undertaking preventive a measure does not necessarily require governments to spend more but to spend better.

''This report presents necessary evidence and a compelling case for our client countries to reduce their vulnerability to natural hazards,'' said Robert Zoellick, the bank's president. ''We and our (UN) partners stand ready to scale up efforts to assist disaster-prone developing countries.''

The report is the product of a two-year effort by 70 experts from various disciplines and institutions, primarily economists but also climate scientists, geographers, political scientists and psychologists.

One area where the report recommends more spending is on early warning systems, particularly in weather forecasting.

There have been many advances in predicting weather, with three-day accuracy now at more than 85 percent and more than half the seven-day forecasts correct.

The report said, however, that few countries have taken advantage of the progress since many governments inadequately finance their weather forecasting services.