And it is likely to get worse.

In a review published in The Lancet medical journal, the scientists said there was now a near-unanimous scientific consensus that rising levels of greenhouse gases would cause global warming and other climate changes.

"The advent of changes in global climate signals that we are now living beyond the Earth's capacity to absorb a major waste product," said Anthony McMichael of the Australian National University in Canberra and his colleagues, referring to greenhouse gases.

The scientists' review of dozens of scientific papers over the last five years said health risks were likely to get worse over time as climate change and other environmental and social changes deepened.

"The resultant risks to health ... are anticipated to compound over time as climate change along with other large scale environmental and social changes continues," they wrote.

The review said climate change would bring changes in temperature, sea levels, rainfall, humidity and winds.

This would lead to an increase in death rates from heatwaves, infectious diseases, allergies, cholera as well as starvation due to failing crops.

They said climate change may already have led to lower production of food in some regions due to changes in temperature, rainfall, soil moisture, pests and diseases.

"In food insecure populations this alteration may already be contributing to malnutrition," it said.

The scientists said sea levels had risen in recent decades, and people had already started moving from some low-lying Pacific islands. Such population movements often increased nutritional and physical problems and disease, they said.

"The number of people adversely affected by El Nino-related weather events over three decades, worldwide, appears to have increased greatly," it said, referring to the weather pattern caused by warming of the Pacific Ocean off South America.

The review called for research to identify groups vulnerable to climate change and said health concerns should be included in international policy debates about global warming.

"Recognition of widespread health risks should widen these debates beyond the already important considerations of economic disruption," they said.

Copyright © 2006 Reuters

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