"Governments have no excuse not to act on climate." Our CEO Lesley-Anne Knight explains why The Elders have written to all heads of state calling for bold, concerted action ahead of a major climate summit in December 2015.

At the start of this year, The Elders called for ‘extraordinary leadership’ on climate change. We are now well aware that failing to act will be catastrophic – not only for future generations, but for the communities already vulnerable to changing weather patterns, natural disasters, and poverty.

Momentum is building. A few months ago, In Paris, we held a fantastic discussion with young people – students, activists, entrepreneurs – who had already begun mobilising ahead of the big climate conferences later this year. The Elders are committed to supporting these efforts. The climate summit in New York this September and the COP20 in Lima this December are crucial milestones towards the December 2015 COP in Paris: our deadline to agree an ambitious, fair, universal and legally-binding climate deal.

To this end, The Elders have written to heads of state urging each of them to demonstrate the ‘extraordinary leadership’ required. These letters call on governments to work together between now and December 2015 to ensure that any new climate deal sets the world on course to stay under a 2°C rise in global temperatures.

This means making bold national commitments to climate action; setting a goal of carbon neutrality by 2050 (for further information on this, see our guest blog by climate policy expert Farhana Yamin); and adopting an internationally harmonised price on carbon.

It is also crucial, as The Elders have reminded leaders, that the new climate agreement recognises the disproportionate impact of climate change on the poor – and includes measures to help them not only adapt, but to reap their fair share of the benefits of transition to a carbon-neutral world.

I am thrilled that Mary Robinson has just been appointed the UN Special Envoy for Climate Change. Building on her work on climate justice, she will continue to engage governments in order to mobilise political will and action, and raise ambition in advance of the upcoming climate conferences.

President Carter and Mary Robinson wrote earlier this year, “As former heads of state ourselves, we’ve experienced global crises from within the corridors of power. Some may take the world by surprise, but sometimes the warning signals are such that there is no excuse not to act.”

Governments have no excuse not to act on climate. Our job – as The Elders, as civil society, as communities affected by climate change – is to keep reminding them of this.