The more people learn about the proposed Keystone XL tar sands pipeline, the worse it looks.

Young people are already leading on climate action. I see it at rallies to reject the Keystone XL dirty tar sands pipeline. I see it in the push to demand justice for communities being run over by fracking operations.

Tar sands oil is the dirtiest fuel on Earth. Because producing it consumes so much energy, a gallon of tar sands crude generates 17 percent more carbon pollution than conventional crude oil.

I have visited people whose health has been endangered by tar sands oil. I have watched neighbors struggle to recover from Superstorm Sandy. I have seen solar panels and wind turbines become an increasingly familiar part of the landscape.

The Keystone XL pipeline is a threat to our nation. It would increase pollution and intensify climate change for generations to come. We must raise our voices and demand our leaders reject this dirty scheme.

Declaring the San Gabriel Mountains a national monument will make this natural wonder more accessible. It will welcome people from all walks of life and maintain the mountains' wild character at the same time.