Climate Observing Systems Inadequate

Climate Observing Systems Inadequate

Copyright 1999 ASSOCIATED PRESS
February 5, 1999
"Research Panel Critical of Climate-observing System '
By Randolph Schmid

WASHINGTON The current systems for observing the planet's climate change are inadequate and raise questions about the accuracy of some findings, a government advisory panel has concluded.

The National Research Council study found that "deficiencies in the accuracy, quality and continuity of the records ... place serious limitations on the confidence" of the research results.

"This may be a shock to many people who assume that we do know adequately what's going on with the climate, but we don't," said Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colo., who independently reviewed the report.

What scientists primarily have is a system to observe weather changes, "and the big swings in weather from day to day are easy to catch," Trenberth said. "But for climate, we are interested in more subtle changes from year to year, especially trends."

Climate change has become a hot topic in recent years, with the growing fear that rising levels of certain chemicals in the atmosphere could trap additional heat from the sun and cause Earth's temperature to rise.

The problem of collecting accurate data was illustrated just last month: Scientists at the National Aeronautics and Space Administration and at the National Oceanic and Atmospheric Administration announced that last year was the hottest on record.

But the two groups came up with different numbers. Data provided by NASA researchers indicated an average 1998 worldwide temperature of about 58.5 degrees Fahrenheit, topping 1995 as the record year.

But NOAA said 1998's global average was 58.1 degrees, topping 1997, which it calculated as the previous record year.

Climate studies are based on information collected for daytoday weather reporting and forecasting, a system not always adequate for longterm analysis, the new report warns.

Unlike other sciences where strict laboratory controls are the rule, climate scientists have to rely on observations collected in different countries and using different instruments, said Thomas R. Karl, chairman of the committee that prepared the report.

Adequate weather and climate records go back just over a century in the United States and not much longer elsewhere.

During that period, instruments for measuring temperature, humidity and wind have changed constantly. While each new generation of tools is hailed as an improvement, readings may not be consistent with the items they replace. Problems even occur with the most modern observing machines, satellites, Trenberth said.

For example, the NOAA11 satellite collected temperature data for more than five years, but during that time its orbit shifted slightly. The result was that at the beginning NOAA11 passed over a certain area at 1 p.m., for example, but by the end was looking at that spot at 5 p.m., local time. Temperature readings thus would not be consistent.

While the problem is international, the research council, an arm of the independent National Academy of Sciences, which advises the government, faults the U.S. government for not coordinating climate studies nor having one agency organize the data and make sure information is consistent for this country.

Mostly, changes would mean being more careful in collecting information and making sure that when instrument changes are made, both systems are used together for a time to measure differences in their readings.