Sis has a lovely head full of dreadlocks, a stud in her nose, and a hemp T-shirt that reads, "Meat is Murder." Nobody's fool, she can also be a touch strident. You may think you're an environmentalist, but Sis thinks you're a sell-out.

Sis says: Look at those @#$%-ing Christmas lights. What a waste! I'm sure glad we're stoking up the power plants for the sake everyone's holiday cheer.

So you say:
Easy now, Sis. In the hierarchy of environmental sins, holiday lights seem pretty minor. I mean, think of it this way: if people just took a few simple energy-saving measures year-round, like installing compact fluorescent light bulbs and using energy efficient appliances, it would more than make up for the energy spent on a few strings of holiday lights. Come to think of it, that might make a good present. Did you ever think about giving compact fluorescents as gifts? How about rechargeable batteries?

Sis says: Oh, give me a break! The next thing you know, you'll be making excuses for SUVs.

So you say:
Actually, you're right about that. Believe it or not, a couple of years ago, the Sierra Club helped Ford market a new hybrid SUV, and this year Ford's bringing out an updated version. It's an SUV so, yeah, it still might be the kind of car that you and I don't like and that people don't really need. But you can preach till you're blue in the face, and people will keep buying SUVs. So why not encourage them to buy one that gets 30 miles per gallon? That's better mileage than most cars on the road today.

Sis says: Are you nuts? Encouraging people to buy SUVs? From Ford? So what if it's a hybrid. It's just greenwashing.

So you say:
So we're supposed to be always against things? Environmentalists pushed Ford for years to make an SUV that gets better mileage and they went and did it. What, we should beat them up for doing what we've asked?

Sis says: Oh, don't get me started on cars. We should be doing what they do in Europe. Keeping cars off the streets of the downtowns and opening it up to pedestrians and bikes. We environmentalists should be visionaries, not realists.

So you say:
Can't we be both? Sure, let's all work toward the day when everyone's practicing permaculture in the backyard and biking to the store and eating organic, union-picked, soybean-hemp-low-fat patties with homegrown tomatoes on top. But like this book title says, "The Impossible Will Take a While." In the meantime, let's work to elect people who will make cars get more miles per gallon, clean up power plants, enforce our environmental laws instead of undermining them? Believe me, I share your frustration, but taking down our Christmas lights isn't going to get us anywhere.

Sis says: Don't give me that -- people need to wake up and smell the coffee! The fair trade, shade grown organic coffee, that is. Global warming is happening! Cars are part of the problem. We can't be encouraging people to buy them. We're only going to make our country's oil addiction worse.

So you say:
You're right, of course, and I'm sure you don't own a car and never will, right. But we don't convince people who are sympathetic by being all doom and gloom. Yeah, global warming is bad news and something we need to address, but let's talk about ways people can work to make it better. Walking and bicycling, of course. And public transit too. What if people who have cars commuted by public transport just once a week? They'd reduce their fuel consumption and greenhouse emissions by nearly 20 percent -- that's no small thing.

Sis says: You sound like a politician. The fact is, we're in trouble if we don't swear off cars, spray cans, fancy stationery, and those @#$%-ing Christmas lights -- and I mean now!

So you say:
If we could only harness your outrage, Sis, we could power the lights of dozens of Christmas trees. But we'll never get anywhere if we cram change down our neighbors' throats. So we set good examples, we walk our talk, we put pressure on about governments and corporations. Before you know it, we'll be getting all the electricity we need to run those Christmas lights from solar panels. Then you'll have to find something else to get angry about.