Do people care about polar bears when the economy contracts? Is it easy to worry about climate change if you rely heavily on coal? There’s some circumstantial evidence that the answer to both is “No”.

Worries about climate change have declined worldwide since the 2009 Copenhagen summit failed to come up with a binding deal to fight global warming. But how can policymakers revive public interest, and who needs to be targeted?

In countries where the economy is heavily dependent on coal – emitting most greenhouse gases of the major fossil fuels — people seem to worry less about climate change than those living in nations that are relying more on sources such as gas, nuclear, hydro, solar, or wind power.

Of course the coal-dependent countries shouldn’t be unconcerned, because they have more work to transform their economies. Or is it like the American writer Upton Sinclair (quoted by former U.S. vice President Al Gore) used to joke: “It is difficult to get a man to understand something if his salary depends on his not understanding it.”

Here is a graph showing the rate of people (blue) in various nations who consider climate change a “very serious” problem, topped by Brazil with 85 percent in 2010 and with Poland at the other end on 37 percent — the rates of electricity generated from coal (red) generally rise in an inverse relationship with these worries. Brazil gets 2 percent of its electricity from coal, Poland about 95 percent.

(Source: coal statistics 2005: International Energy Agency report on Energy Efficiency Indicators for Public Electricity Production from Fossil Fuels; “Is Climate Change a serious problem?”, 2010 survey by the  PewResearchCenter

The United States is among the nations most sceptical about climate change, and gets about 50 percent of its electricity from coal — high for a developed nation.

So more education about coal may be a policy goal.

Dozens of environmental activists (some of them in the photo at the top) wore polar bear suits to urge action at U.N. climate talks in Bali, Indonesia, in 2007  — incongruously sweating on the equator as they paraded thousands of miles from the bears’ icy habitat. Since that meeting, environmental groups agree that the number of polar bear suits worn at U.N. negotiations has tumbled: why?

Are people bored of the bears and the theme of climate change in general, after the U.N. summit in Copenhagen in 2009 failed to come up with a treaty? Is it that Arctic summer sea ice reached its lowest extent on record in 2007 and so was most newsworthy that year?

Or is it harder to be concerned about an iconic species – one that very few people will ever see – when the economy is in recession and people have more immediate worries about jobs? Mobilising efforts to “save nature” as an abstract idea may be easier to sell when the economy is strong.

It’s hard to know the answer, but here’s a graph tracking the number of mentions of polar bears (red) in leading U.S.  newspapers year by year against changes in annual U.S. Gross Domestic Product (blue):

(Sources: U.S. official government statistics for GDP; Factiva searches of general news mentions of polar bears in the New York Times, Los Angeles Times, Washington Post, Boston Globe, San Francisco Chronicle)

It looks like the polar bear series roughly follows trends in the blue, GDP series, with a couple of years’ delay. The number of mentions of polar bears rises steadily from 2001 to a peak in 2007-08 and then declines sharply. The U.S. economy grew robustly until about 2006 when growth slowed, it entered a recession in 2008, which deepened in 2009 before a rebound in 2010.

So if there is a link – obviously it’s impossible to say just from a correlation –the message for policy makers is: if you want to push major environmental reforms, do it when the economy is picking up, or has good chances of staying strong for several years. (…of course, that may require a well-functioning crystal ball)