Saturday, August 13, 2005

Last Scientific Doubt About Global Warming: Gone


Satellite and weather-balloon research released Friday removes a last bastion of scientific doubt about global warming, researchers say.

Surface temperatures have shown small but steady increases since the 1970s, but the tropics had shown little atmospheric heating - and even some cooling. Now, after sleuthing reported in three papers released by the journal Science, revisions have been made to that atmospheric data.

Climate expert Ben Santer of Lawrence Livermore National Laboratory in California, lead author of one of the papers, says that those fairly steady measurements in the tropics have been a key argument "among people asking, 'Why should I believe this global warming hocus-pocus?' "

After examining the satellite data, collected since 1979 by National Oceanic and Atmospheric Administration weather satellites, Carl Mears and Frank Wentz of Remote Sensing Systems in Santa Rosa, Calif., found that the satellites had drifted in orbit, throwing off the timing of temperature measures. Essentially, the satellites were increasingly reporting nighttime temperatures as daytime ones, leading to a false cooling trend. The team also found a math error in the calculations.

"Our hats are off to (them). They found a real source of error," says atmospheric scientist John Christy of the University of Alabama at Huntsville, whose team produced the lower temperature estimates.

When examining the balloon data, Yale University researchers found that heating from tropical sunlight was skewing the temperatures reported by sensors, making nights look as warm as days.

Once corrected, the satellite and balloon temperatures align with other surface and upper-atmosphere measures, as well as climate change models, Santer says.

Global warming's pace over the past 30 years has actually been quite slow, a total increase of about 1 degree Fahrenheit. It is predicted to accelerate in this century.

Mark Herlong of the George C. Marshall Institute declined to comment. The group, financed by the petroleum industry, has used the data disparities to dispute the views of global-warming activists. In recent years, however, the institute has softened its public statements, acknowledging that the planet is indeed getting warmer but still maintaining that the change is happening so slowly that the impact is minimal.

Posted by crimnos @ 10:04 AM