Climate change is already beginning to alter the Chesapeake Bay, slowly warming and raising its waters in a way that threatens to damage ecosystems and erode islands and coastlines, according to a report released today by the nonprofit Chesapeake Bay Foundation.

Citing previous scientific research, the environmentalist group's report says that the effects of climate change are already obvious to those studying the Chesapeake. The foundation's president, William C. Baker, said that further warming will only exacerbate some of the bay's existing problems, including the loss of wetlands and the growth of low-oxygen "dead zones."

"We know that the bay is in trouble today, and we know that climate change will make the bay worse in the future," Baker said at a news conference in downtown Annapolis. The location was chosen, he said, because the area was flooded during Hurricane Isabel in 2003 -- and could be in danger of repeated floods if water levels in the Chesapeake continue to rise.

Among the worrisome trends cited in the report:

-- Water temperatures in the bay now sometime rise past 76 degrees, which is as warm as the Chesapeake's rockfish normally tolerate. But Baker said the fish often can't retreat to cooler, deeper waters, because these are often deprived of oxygen because of the Chesapeake's existing pollution problems.

-- The bay's water level has risen about a foot in the last 100 years, a rate that outstrips the global average because land in this area is slowly sinking. If this trend continues, the report warned that remaining Chesapeake islands, like the watermens' outposts on Smith and Tangier, could be permanently inundated.

-- Eelgrass, a species of underwater plant, died off across large sections of the southern bay in 2005, when water temperatures became too hot for the plant to tolerate. If this happens repeatedly, the foundation warned, it could be trouble for blue crabs that rely on the grass for shelter.

The report urged state and federal governments to provide more funding for anti-pollution measures, like the planting of "forest buffers" that filter runoff before it reaches bay tributaries. It cited a study from Yale University graduate students that showed that such measures could reduce both water pollution in the bay, as well as the carbon-dioxide emissions blamed for climate change.