Earlier snowmelts, longer summer droughts and bigger Western wildfires on federal lands are being caused more by "climatic conditions than land management techniques," government investigators conclude.

They fault the Bush administration for not providing managers of national parks, wildlife preserves and marine sanctuaries with better guidance on how to address the effects of global warming.

A report Thursday by the Government Accountability Office found the Interior Department has "not made climate change a high priority," despite a 2001 order to include climate change in land management planning.

That order more than six years ago was issued by then-Interior Secretary Bruce Babbitt on the last full day of the Clinton administration.

"Without such guidance, their ability to address climate change and effectively manage resources is constrained," the report says.

Sens. John Kerry, D-Mass., and John McCain, R-Ariz., requested the GAO's 184-page report on March 8, 2004, when both were running for the presidential nomination in their respective parties.

GAO investigators also found:

— Since 1850, the glaciers in Glacier National Park have declined from 150 to 26, and both summer and winter temperatures are increasing in the park. Some projections say the park's glaciers will be gone within 25 to 30 years.

— As much as 1.4 million acres of forests in Alaska, in the Chugach and the Kenai Peninsula, are dying off at higher rates than usual because of an infestation of spruce bark beetles attributed to climate-related insect outbreaks.

From oceans to deserts, more effects were apparent.

Low-lying areas in the Florida Keys have been hit by rising sea levels already, bringing more saltwater onto the land. Along with more hurricane activity, that is overwhelming fresh waters and areas that supported the region's plants and animals such as the Lower Key marsh rabbit.

The threat extends "not only to wildlife, but also to humans who live on the islands," the report says.

Bleaching of coral reefs in the Florida Keys, too, is being caused by the stress of warmer water — which causes the corals to eject microscopic algae that live within their tissues. That could harm the fishing and tourism industries, because they are needed by fish and other marine species and are popular with snorkelers and scuba divers.

In the Mojave Desert, invasive grasses and drought are increasing the severity and frequency of wildfires: "If a fire starts, it burns much hotter due to the invasive grasses."