Whether I’m talking with a donor, my child’s class or giving a speech to a university or organization, I’m often asked what’s the greatest environmental threat to our planet and what can we do about it. You don’t need to look far to see the effects of climate change: Mountains are getting more rain than snow, coral reefs are dying and storm surges are leaving many communities vulnerable.

It’s time for action. Participants at December’s UN climate change meeting in Bali left with a clear roadmap that will guide the world to a new climate treaty over the next two years, taking up where the Kyoto treaty leaves off. WWF will be part of that process, making sure key countries around the world agree to deep emission cuts and that they leverage new funding and support for technology transfer, finance and adaptation.

Climate scientists are projecting CO2 emissions to be exponentially higher in the coming decades. It’s our job to change the slope of those curves, which means using our brand of membership, our expertise and partnerships to cut greenhouse gas emissions and substantially increase energy efficiency in the United States.

Our work with Google, Coca-Cola, Intel, the city of Chicago, and many other institutions, will be part of that solution. At the same time, we must also address deforestation and land degradation, which accounts for 20 percent of global emissions. As the organization with the largest forest conservation projects in the world, WWF has the unique responsibility to make that happen.

But as Richard Moss—our new climate change director and a leader on the Nobel Prize winning Intergovernmental Panel on Climate Change—puts it, while we can argue about ultimate goals and timetables, it’s imperative that we change our carbon footprint now.

So what am I doing? At home, we’ve replaced our lights with compact fluorescent bulbs, we’re using a hybrid car or bicycle to commute to work and we’re reinsulating our house to use energy more efficiently. At the office, I plan to fly less often and engage colleagues in other cities by videoconference more frequently.

And at 8 p.m. on March 29, I hope you’ll join me in taking a symbolic action on climate change by participating in Earth Hour (see page 4). We’re uniting with our technology partner HP and the leaders of Atlanta, Chicago, Phoenix and San Francisco, who are darkening their iconic buildings and national landmarks in a sign of commitment to finding solutions to climate change. Every action you take to lower your emissions helps. Make your own energy resolutions— and then put them into action. If we’re going to make a difference in the world, we need to make changes in our lives.

So let me ask you a question: What on Earth are you doing?