"I've been a professional volleyball player for about six years, and I spend time every day outside on the beach. Because of global warming, sea levels are predicted to rise about half a meter by 2100, and we may lose our beaches if we don't make some changes.

"My goal is to raise awareness, so I've come up with a temporary tattoo of menacing waves crashing that I put on a half meter up my body. I'm six feet six inches, so it ends up near my knee. I'm wearing it during the professional beach volleyball season this summer.

"Educating volleyball fans is huge. This is where I have leverage. I'm giving people a reusable shopping bag with a compact fluorescent lightbulb and a tip sheet with 20 easy, fun ways to go green. I'm also starting Colleen's Green Team: To join my team, people have to agree to make one change to green their lives. I'll post their ideas on my blog.

"I'm focusing on the positive things people can do to change their lives, like having less stress from sitting in traffic because you ride your bike or reducing your electricity use and enjoying a lower power bill. I want to motivate people to make small changes in their lives that will make a big difference for all of us."