This Thursday is Earth Day.Entering UVM, I had a lot of preconceived notions about what that might entail in a city like Burlington. I figured that on April 22, thousands of environmentalists would converge on the city like medieval pilgrims and then ritually slaughter a Hummer on the campus green.Needless to say, I was disappointed. As everyone learns, most campus environmentalists are — contrary to some crude caricatures — soft-spoken and articulate. In fact, many self-described tree huggers pack as much empirical ammunition as anyone out there. That being said, this Earth Day I’d like to offer some tips to my environmentally conscious friends. I’ve been particularly frustrated recently. Polls show that a lot of support for dealing with global warming has evaporated. But climate change is as real as ever, and we political science-types may be able to get us back on the offensive.For example, the most common way to fight “denialism” is with some of the abundant data on climate change.Of course, that often proves to be frustratingly ineffective.  Political scientists Jason Reifler and Brendan Nyman recently performed an experiment on how people react to facts that don’t congeal with their existing beliefs. As it turns out, people tend to cling to their prejudices even more strongly after they’ve been factually shut down. To quote Nyman in a op-ed for The New York Times, people “argue so vehemently against the corrective information that they end up strengthening the misperception in their own minds.” A better approach, I think, is to fight them on their own territory. For example, accept that there’s a degree of uncertainty to climate science. However, you’ve then opened the door to the obvious rejoinder — uncertainty can cut both ways. Maybe the climate models overstate the potential warming, and maybe in a hundred years the world will be a swampy, primordial mess. The uncertainty argument crumbles the minute you engage it.Here’s the best thing you can do though: Challenge the idea that fighting climate change will be an economic catastrophe. Paul Krugman’s been fighting the good fight for a while, and it’s time to add some voices to the chorus. As Krugman pointed out, the Congressional Budget Office predicts that strong action on climate change would leave the 2050 economy only between 1.1 and 3.4 percent poorer. That tidbit won’t help you turn the corner with more committed deniers, but for people on the margins this could be key. While it won’t run opponents out of town, torpedoing their non sequiturs and untrue conclusions can definitely help on the edges.All the facts are on our side, now we just need to take advantage of the other side’s weak spots.