The cold facts about global warming

I was sitting at our kitchen table this weekend, watching a rare December blizzard here in the nation's capital, when I started to think about global warming. Don't ask me why. Probably because of the huge international climate change meeting in Copenhagen last week.  What struck me was that rarely has there been a scientific issue that has elicited such spirited response from both sides of the spectrum. And the debate certainly has not been limited to scientists.

So it was with amazement that I read in a story in Chemical & Engineering News (C&EN), the ACS' weekly newsmagazine, that there actually are three major areas in which most agree. C&EN's Dec. 21, 8,900-word cover story notes that global warming believers and skeptics actually agree on a cluster of core points:

● Earth's atmospheric load of carbon dioxide - the main greenhouse gas - has increased since the Industrial Revolution began in the late 1700s.

● Carbon dioxide bloat results largely from burning of coal and other fossil fuels.

● Average global temperatures have risen since 1850, with most of the warming occurring since 1970.

"But here is where the cordial agreements stop," writes Stephen K. Ritter, a senior correspondent for C&EN. "At the heart of the global warming debate is whether warming is directly the result of increasing anthropogenic CO₂ levels, or if it is simply part of Earth's natural climatic variation."

Ritter presents a sweeping panorama of global climate change science from the point of view of those who support both scenarios. The story notes that the debate is growing ever more contentious in light of the recent disclosure of e-mail messages suggesting that some scientists supporting the human activities scenario tried to suppress publication of opposing viewpoints.

Most climate scientists maintain that man-made global warming is happening, the article states. This majority opinion has been disseminated in peer-reviewed reports over the past 20 years by the Intergovernmental Panel on Climate Change (IPCC), an entity established by the United Nations and the World Meteorological Organization.

Climatologist Michael Hulme of the University of East Anglia, in England, told Ritter that the scientific evidence backing the basic idea of human activity changing the global climate system is now overwhelming, even if scientific predictions for future climate change are still shrouded in uncertainty.

"It's fitting that the simplest measurement of the climate debate -- temperature -- is fraught with controversy," Ritter writes. "There isn't one giant thermometer that is consulted to obtain global average temperature." And this is just the tip of the iceberg in the debate. To read Ritter's fascinating analysis of the climate change issue, contact me at  m_bernstein@acs.org.

Image courtesy of the American Chemical Society