How can we urge our leaders to act on climate change? Ahead of next week’s Climate Summit, we are joining people worldwide in calling for immediate action to protect our planet.

In countries across the globe people are taking to the streets this Sunday to demand that leaders take action to form an agreement that will create “a world safe from the ravages of climate change.” The Elders will be at the march and at the summit, doing their part to mobilise the delegates who meet in New York for one day’s deliberation on Tuesday 23 September.

But will one day be enough?

Will government, business and civil society leaders from around the world agree on how to address climate change?

Gathered for the Climate Summit, they must galvanise political will to form a robust agreement ahead of the December 2015 deadline.

Will you lend your voice to the call to action? Join the conversation on Twitter and tell leaders to act #NowNotTomorrow.