U.S. scientists will soon lose much of their ability in space to monitor for global warming, a confidential report to the White House warns.

As President Bush heads to a summit of industrial nations in Germany with a new initiative to reduce the greenhouse gases blamed for climate change, his administration is cutting back on efforts to measure the impact of the warming trend.

The problem is a costly and problem-plagued satellite system. Because of technology glitches and a near-doubling of its original $6.5 billion cost, the Defense Department has decided to downsize and launch four satellites paired into two orbits, instead of six satellites and three orbits.

The satellites were intended to gather weather and climate data and replace existing satellites as they come to the end of their useful lifetimes, beginning in 2010. The reduced system of four satellites will now focus on weather forecasting. Most of the climate instruments needed to collect more precise data over long periods are being eliminated.

Instead, the Pentagon and its two partners — the National Oceanic and Atmospheric Administration and NASA — will rely on European satellites for most of the climate data. U.S. scientists worry they won't provide the data needed.

"Unfortunately, the recent loss of climate sensors ... places the overall climate program in serious jeopardy," NOAA and NASA scientists told the White House in a confidential Dec. 11 report obtained by The Associated Press.

They said they will face major gaps in data collectible only from satellites about ice caps and sheets, surface levels of seas and lakes, sizes of glaciers, surface radiation, water vapor, snow cover and even atmospheric carbon dioxide.