“Anything else you’re interested in is not going to happen if you can’t breathe the air and drink the water. Don’t sit this one out. Do something.”

– Carl Sagan

Yes, do something. But what?

Before addressing that question, I want to share some information about the persistence of the principal greenhouse gas carbon dioxide in the atmosphere – as a reminder of why this could be your last opportunity to do something meaningful.

It takes a decade for the first 40 percent of any given day’s CO2 emissions to disappear from the atmosphere. Most of that is absorbed by the oceans, increasing acidity and wreaking havoc with marine ecosystems. Removal of the remaining CO2 is very slow – after a century about one third of the original emissions remain, and some CO2 can persist for 1,000 years or more.

So the vast majority of excess anthropogenic (human-emitted) CO2 that’s warming the planet today was not released yesterday or last week, but over the past half century. And the CO2 that you and the rest of your fellow humans release today, tomorrow and next month will be added to that accumulated stockpile and contribute to global warming for decades and centuries to come. Every day we don’t do something, we’re adding to the problem – permanently.

But what can we do – what can you do – on a planet where the rate of CO2 emissions is increasing, not decreasing as we desperately need it to?

Of course, you should do everything you can to conserve energy, water and other resources. But it’s too late for those measures, in and of themselves, to confront a problem of such magnitude. If you’re concerned, you also will need to engage publicly on some level – inform yourself, then spread the word and help build a consensus to curb carbon emissions.

To do so, you’ll have to find your own voice (if you haven’t already). Some people might be challenged by simply explaining and justifying to a skeptical neighbor or relative their purchase of a more expensive but also more energy-efficient and cheaper-to-operate Energy Star appliance. But for others, there are many creative opportunities for communication.

For example, my sister, who lives in a small farming community in Minnesota – hardly a bastion of climate-change radicalism – surprised me recently with this email:

“... about three years ago, I found something meaningful (for) me to do over Lent – the ecumenical carbon fast. It’s an attempt to highlight ways that we can all lighten our carbon footprint on this planet we call home. After registering at www.macucc.org/carbonfast, I get a daily email with an idea for making a change in how I live (everything from light bulbs to vampire voltage) that will make a positive difference to my carbon consumption. Over the years I’ve enjoyed the challenge; some things we were already doing, others required a change.

“I’m up for another year of trying to make a difference in my little corner of the world. Hope you will consider checking it out.”

But my sister, who is spreading the word, and the United Church of Christ, which started this particular carbon-reduction campaign four years ago, are doing more than affecting a little corner of the world. The church’s deceptively simple action has started a global interdenominational movement. From its website:

“Initiated by the UCC and endorsed by other denominations and faith groups, people of every Christian perspective – and people who are not Christians – have benefited from this opportunity to become more conscious and conscientious in their daily lives.

“This invitation (to participate) is being emailed to pastors all over the country by UCC Conference Ministers and by our ‘bishop’ counterparts in numerous denominations. Our experience is that Christians the world over – from every denomination – will participate in this carbon fast.”

Please understand that I’m not citing the UCC’s action as an endorsement, but as an example of how to get multiple yields from a single investment of time and energy. Christians, Muslims, Jews, secular humanists – everybody can and must get in on the act of building a consensus to drastically curb CO2 emissions on God’s green Earth. But you just might find that there is no need to reinvent the wheel, and that the UCC’s template works well at your ecological house.

Philip S. Wenz, who grew up in Durango and Boulder, now lives in Corvallis, Ore., where he teaches and writes about environmental issues. Reach him by email through his website, www.your-ecological-house.com.