Over the past year or so, Berkeley linguist George Lakoff has received a lot of attention because of his writing on the framing of political issues and their significance for shaping debate and discourse. (We discussed Lakoff here.) I’ve thought of framing as I’ve noticed the apparent increased use by scientists of the unique term “harbinger” to characterize the relationship of contemporary climate events and expected future climate changes. Consider the following examples:

17 Feb 2005 – “Scott L. Schliebe, head of the Fish and Wildlife Service’s Polar Bear Project in Anchorage… said “We are seeing harbingers of change which are dictated by climate… It doesn’t take a rocket scientist to see that [the changes] could affect polar bears…”

3 Feb 2005 – “Steve Schneider from Stanford University, California, said there was clear proof that species were reacting to the 0.7 degrees centigrade warming of the atmosphere that had already taken place over the past century. “This is a harbinger — nature is already responding,”"

7 Nov 2004 – “Four hurricanes in a five-week period could be a harbinger of things to come,” said Dr. Paul Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School.”

21 Oct 2004 – “[Kevin] Trenberth said, “But the evidence strongly
suggests more intense storms and [the] risk of greater flooding events, so that the North Atlantic hurricane season of 2004 may well be a harbinger of the future.””

23 Sept 2004 – “University of Colorado at Boulder researcher Ted Scambos said… “As temperatures crossed the threshold of melting in the summer months, ice shelves in the area rapidly disintegrated… While the consequences of this area are small compared to other parts of the Antarctic, it is a harbinger of what will happen when the large ice sheets begin to warm”"

30 Jan 2003 – “The 1998-2002 drought affected much of the United States as well as southern Europe and southwest Asia. And while they can’t be certain, National Oceanic and Atmospheric Administration climate scientists Martin Hoerling and Arun Kumar say it may be a harbinger of droughts to come.”

And as chance would have it, the term “harbinger” has been proposed by the Union of Concerned Scientists as part of a strategy to advocate support for greenhouse gas reductions to combat climate change. UCS says on its WWW page, “Frustrated because a friend or colleague says global warming is the future’s problem? Compelling new evidence demonstrates that global warming is already under way with consequences that must be faced today as well as tomorrow. The evidence is of two kinds:

* Fingerprints of global warming are indicators of the global, long-term warming trend observed in the historical record. They include heat waves, sea-level rise, melting glaciers and warming of the poles.

* Harbingers are events that foreshadow the impacts likely to become more frequent and widespread with continued warming. They include spreading disease, earlier spring arrival, plant and animal range shifts, coral reef bleaching, downpours, and droughts and fires.

UCS is taking steps to bring this evidence to the public’s attention, with the goal of building support for action to reduce the heat-trapping gas emissions that cause global warming.”

Of course an important role for UCS and other advocacy groups is to work to shape the dialogue on issues. But scientists who use the term “harbinger” in this manner risk playing fast and loose with the science of climate change. It allows a scientist to imply that contemporary events are directly related to CO2-caused climate change but at the very same time it also provides the scientist with a plausible deniability that an explicit connection was implied. It is doublespeak. As Von Storch and Stehr recently wrote,

“… more and more often [scientists] connect current extreme weather events with anthropogenic climate change. To be sure, this is usually carefully formulated; interviews sound something like this: “Is the flooding of the Elbe, the hurricane in Florida, this year’s mild winter evidence for the climate catastrophe?” Answer: “That’s scientifically unproven. But many people see it that way.” Neither of these statements is false. In combination, however, they suggest the conclusion: Of course these weather events are evidence. Only no one ares to say this explicitly either.”

Climate science and policy will be better served by scientists who speak directly to the issue of attribution of contemporary events to CO2-caused climate change and not to rely on cute and clever rhetoric.