For weeks, activists have been touting the Sept. 21 People’s Climate March, in New York City, as the largest rally ever demanding that government take action on climate change.

If you’d like to join the tens of thousands expected to march, two local groups have organized a bus trip from Pittsburgh.

The Sierra Club Allegheny Group and the Thomas Merton Center have chartered a pair of buses to leave from Edgewood Town Center way early that day — 3 a.m. — to arrive in time for the 11:30 a.m. march kicking off from Columbus Circle. (The return trip is set to arrive back in Pittsburgh at midnight that same day.)

The three-mile march — expected to include representatives from more than 1,000 environmental, social-justice, union and faith-based groups, including the likes of 350.org — coincides with the Global Day of Action, timed to precede the Sept. 23 U.N. Climate Summit.

Scientists tell us that climate change’s effects are becoming more obvious by the day, from rising oceans to drought, floods and other extreme weather — not to mention other health effects. Activists are calling for big reductions in carbon emissions — bigger even than those recently proposed by the EPA.

And climate activists say that while the time to act was yesterday, the sooner we start cutting back on greenhouse gasses, the less the trauma future generations will face.

“My [individual] actions don’t pressure our political leaders to find a solution [to climate change] on the collective level,” says Warwick Powell, a leader of the Pittsburgh bus trip, in a statement. “What will is The People’s Climate March …, which is an invitation to all of us to change everything.”

Activists feel the movement to confront climate change is growing, and the Sept. 21 march will be a big step.

The round-trip from Pittsburgh to the march costs $68. You can register here.