WEST LAFAYETTE, Ind. - The world may have won the battle against ozone depletion, but that was just a "tempest in a teapot" when it comes to the issue of global warming. That's a struggle that may last for centuries.

That's the perspective of David Fahey, research scientist at the Aeronomy Laboratory of the National Oceanic and Atmospheric Administration, as presented Monday to some 500 researchers, scientists, and engineers during a plenary session at the combined International Compressor Engineering Conference and International Refrigeration and Air Conditioning Conference at Purdue University.

Fahey did not assign specific blame for the global warming problem. Rather he said it involves such factors as "population, economy, environment, technology, and globalization." But many in the audience were aware that HFC refrigerants were part of the global warming issue and have come in for calls of phaseout in some sectors of Europe.

Fahey said more research is needed to get a definitive handle on the topic. "That could provide us some options we don't even envision today."

He did say the ozone depletion concern has been resolved thanks to adherence to the Montreal Protocol, but he said there needs to be continuous investment in ozone control. "We have to maintain diligence and not reverse our position."

But, he said, "Climate change is a totally different issue. An increasing body of observation gives a collective picture. Emissions of greenhouse gases and aerosols continue to alter the atmosphere."

One issue is population growth, he said. "Human influence will continue to change the atmospheric composition throughout the 21st century. When we emit CO2, it is like emitting into a box."

He asked the question, "What do we have to do to stabilize CO2 emissions?"

Some of the global warming issues relate to rising temperatures and sea levels. He said it is important to expand climate observations and to improve model simulations.

He did not address the European calls for phaseout of HFCs, but did say that "any climate response will likely take many centuries" to see resolution.

Publication date: 07/12/2004