Most of us have seen the monarch butterfly at some point, since they spend at least part of their lives in every state in the lower 48. Global warming, however, poses a serious threat to this migratory species, and soon glimpses of their tiger-striped wings may be a thing of the past. Let us know your favorite monarch sightings by commenting below!

The American pika is an adorable little furball that hikers in the Mountain West know and love. Unfortunately, this rabbit-like animal can't stand high temperatures for very long and as a result, global warming has put the pika in serious danger. If you've ever come across one of these cute little creatures, comment below!

The leatherback sea turtle has been endangered for decades, due to human activity ranging from accidental trapping to actual hunting. They've survived all this, but global warming might just be the clincher that pushes this massive, powerful animal over the edge to extinction – and they're not alone. Other sea turtles are struggling because of global warming, too. If you've ever seen a sea turtle, please share your story with us below!

The "clown of the sea" is being seriously threatened by global warming, and this intriguing creature may not be around much longer. Please, share your puffin story with us by commenting below!

You've learned the danger the sugar maple is in – and of course, the economic danger that also poses in New England. Share your favorite fall foliage story, or let us know – are you ready for naked pancakes?

You've read about the problems the polar bear is facing – and the implications its disappearance will have on the Arctic ecosystem. Now, tell us what you think: Can we save the polar bear?

As EDF's National Climate Campaign Director Steve Cochran points out, last week's passage of the Waxman-Markey American Clean Energy and Security Act was a huge victory and sets the stage for action in the full House and Senate this year.

The United States transportation system is at a fundamental crossroads. While car travel is in an unprecedented decline, transit ridership has increased dramatically, even remaining strong as gas prices dropped back down. But diminishing tax revenues are forcing transit systems to make cuts and layoffs.

The U.S. is now poised for a large-scale investment in its transportation infrastructure, but questions remain about how those funds should be spent. We need state and local officials to think creatively about new forms of transportation that match the increasing demand for transit while also addressing national priorities on energy, the economy, and – most importantly – the environment.

EDF created our transit report to help guide this transition. Follow this link to watch a video summary of the report and view case studies that exemplify what the future of transit should be. See if your state made the list! If we missed an innovative project near you let us know by commenting below and/or emailing us at transit@edf.org.  Then, check out our transit blog to learn more.  For instance, could innovative transit help boost real estate development?

As we gear up for an intense month of global warming action in Washington, we pause to honor Earth Day with this special video message, featuring several of our online activists wearing their favorite "Cap Carbon" hats.

Happy Earth Day, everyone!

Today, EDF has released our Innovations Review 2009 report highlighting innovative businesses that are making green by going green.

Check out our report, and let us know what you think by commenting below.