That day you shoveled snow or the report of a scientific agency. Which do you believe in the global warming debate?

Perhaps my favorite weekly feature in the news media is “Earthweek: A Diary of the Planet,” which I read on page two of the Saturday Pittsburgh Post-Gazette.  Earthweek is a compendium of five or six small stories about weather or geology related events that occurred in the prior week, for example, monsoons, tornadoes, plagues, discoveries of new species or earthquakes. Each story has a little circular icon by it, which is also placed on a map of the world which comes with the feature. 

This past weekend, Earthweek’s lead story was about the latest analysis by the National Oceanic and Atmospheric Administration  (NOAA) that found that so far, 2010 is the hottest year in the record books, which started in the late 1800’s.  And believe it or not, the extent of snow cover in North America was the smallest since those records have been kept in 1967.

I’d like to go beyond the obvious question of why this NOAA release of data was so little publicized in the mainstream media.  I think it’s clear by now that high on the agenda of virtually all the news media is keeping the controversy about the validity of global warming alive, despite the overwhelming evidence and acceptance by the scientific community that global warming is occurring. 

Instead, I want to use this analysis of the first four months of the year to talk about the power of anecdotal evidence.  When I first read about the NOAA data, I immediately thought of all those right-wing lie-mongers like Glen Beck and Rush Limbaugh scoffing at global warming in the dead of winter with 30 inches of snow on the ground.  They expected that their audience would place more credence in what they are feeling at the moment than on the mountain of studies about warmest years on record and retreating snow lines that has accumulated over the past two decades.

That’s the emotional power of the anecdote.  Each cold day is an anecdote of weather, just as Willie Horton and Reagan’s imagined welfare queens were anecdotes of grave threats to civil society;  just as the weak and powerless people that presidents since Reagan have taken to parading before the nation during State of the Union speeches are anecdotes of inspiration.

Anecdotal evidence is always based on a story, whether it’s the time you saw a dark-faced youth rob someone on the subway to the slow growing throb of cold pain in your hands when you’re into the second hour of shoveling out your car.

Anecdotal evidence works best when the anecdote symbolizes the message of the speaker, and it seems to be most powerful when it runs counter to facts but with the flow of belief.  For that reason, anecdotal thinking thrives wherever there is a clash between faith and science, with the side of faith more prone to making the anecdotal argument.

I believe that the best argument is one that is based on the facts but uses anecdotes to serve as examples of those facts.  In this way, you appeal to both the head with facts and the heart with stories that bring the facts to life.  But beware anybody who tells you the story, but doesn’t give you the facts. 

By the way, in the vast scheme of things, four months is also anecdotal, in that the warmest four months in recorded history could occur as an aberration during an extended cold spell.  But in fact, as NOAA and other statistics have proven, the earth has been rapidly warming over the past two centuries to the point that it is changing environments and weather patterns.