LONDON - A weak response to climate change could be catastrophic for international health, leading doctors said in two British medical journals Wednesday.

Experts have previously warned that global warming could mean a spike in diseases including malaria and dengue fever, and that higher temperatures would result in food shortages, sanitation problems and extreme weather events like hurricanes and floods.

In a letter jointly published in The Lancet and BMJ, presidents from 18 medical organizations worldwide called on doctors to pressure politicians meeting in Copenhagen in December to take decisive action on global warming.

"There is a real danger that politicians will be indecisive," wrote the doctors, who included the presidents of the American College of Physicians, Hong Kong's Academy of Medicine and Britain's Royal College of Physicians. "We call on doctors to demand that their politicians listen to the clear facts that have been identified in relation to climate change and act now."

In an accompanying editorial, Lord Michael Jay of the medical charity Merlin and Michael Marmot of University College London wrote that "a successful outcome at Copenhagen is vital for our future as a species and for our civilization."

In December, the United Nations will host a conference to draw up a new climate change treaty to replace the Kyoto protocol. Getting all 193 member countries to agree could be tricky, as officials reported in August that only "selective progress" has been made on getting consensus on the 200-page draft treaty.