Photographer James Balog, whose film "Chasing Ice" documents the rapidly melting glaciers, says "Climate change is based on evidence. Lots and lots of it. ...This is a real and present danger that will degrade our kids' futures" ("Chilling beauty," Dec. 4).

He's seen firsthand the consequences of rising global temperatures, as have we all in the extreme droughts, floods and storms of the past few years. What's it going to take before we start addressing this issue? How much more evidence do we need that we can't keep pouring CO2 into the atmosphere without disastrous consequences?

We need to wean ourselves off of fossil fuels. Environmental writer Bill McKibben spoke to a sold-out crowd on Nov. 30 at the University of Minnesota on this very topic. Check out his organization's website, for steps you can take to help steer the future in a direction we and our children can live with.