Less than half of Americans – 47 percent – believe human activity is the primary cause of climate change, according to new poll results. The results came last week as one Republican presidential candidate referred to man-made global warming as liberal “junk science.”

The poll, conducted annually by researchers from Yale and George Mason universities, suggests that slightly less than two-thirds of Americans – 64 percent – acknowledge the planet’s average temperature is rising.

That figure is about three percent higher than last year, indicating that public attitudes about climate change have not changed significantly.

The poll also suggests that only 52 percent of Americans are “very worried” or “somewhat worried” about the effects of global warming, despite repeated warnings by scientists that rising temperatures could imperil everything from world food supplies to major coastal cities.

Those results perhaps can be partly explained by the Tea Party-influenced Republican surge in last November’s midterm elections.

Indeed, a recent Los Angeles Times profile on GOP congressman Fred Upton details how the former environmental moderate has now scaled back some of his positions, even removing language about climate change from his website.

“Overall we’re very pleased with what he has done so far,” Gene Clem, president of the Southwest Michigan Tea Party Patriots in Kalamazoo, Michigan, told the Times.

And Republican presidential hopeful Rick Santorum recently had this to say about global warming:

“The idea that man, through the production of [carbon dioxide]...is somehow responsible for climate change is, I think, just patently absurd," according to a New York Daily News report.

Delegates from roughly 180 countries are currently meeting in Bonn, Germany, to discuss solutions for a rapidly warming planet.

The two-week talks were given a greater sense of urgency last week when the International Energy Agency released a report showing global greenhouse gas emissions are the highest they’ve ever been, despite 20 years of efforts to control them.

Canada so far has faced criticism from several countries at the talks, partly in relation to the high carbon footprint of Alberta's oil sands, and its apparent reluctance to regulate the industry.

One of the world's top United Nations climate scientists told the Tyee last week that further development of the oil sands is a "fundamental mistake."

Geoff Dembicki reports for the Tyee.