So the moment is here, and a record has been shattered.

But this isn’t the kind of record you wish to remember and tell your grandchildren about. This is no tale of great sporting achievement like Usain Bolt smashing his way into the Olympic record books. No, this is something entirely more sombre. I’m in the Arctic as part of a Greenpeace crew to bear witness to this year’s ‘sea ice minimum’ – the moment of the year when the extent of Arctic sea ice is at its lowest. And today, we have a new record, breaking the one set in 2007 – the lowest ever sea ice minimum.

This means that the Arctic – which research suggests has not been ice free for many thousands of years – is likely to see ice free summers within the next decade. The melting is happening much faster than previously predicted by the UN’s Intergovernmental Panel on Climate Change, whose models estimate ice free summers by the end of the century.

Why does this matter? Well, just as some people say that distant rainforests are the lungs of the planet, regulating the air that we breathe; the Arctic is the heart of the planet, a vital organ which keeps our atmosphere cool by reflecting the rays of the sun back into space, regulating our weather systems. The changes we are seeing in the Arctic have already resulted in coastal erosion, and the migration of fisheries. We don’t yet know the full impacts of the future, but we do know that it will cause global warming to increase rapidly, as the dark waters beneath the ice absorb even more heat, and as the methane stored beneath the permafrost is potentially released – leaking huge quantities of greenhouse gas into the atmosphere.

We don’t need to visit the Arctic to see climate change, it is all around us – the cracked and barren soil of farms in the US; the dank smell of waters rising over crops in Pakistan; even in the UK where I live, this year we lost spring to months of rain and there are barely any ripe berries or apples on the trees.

And while the planet heats up, causing Arctic melting; what do our leaders do to curb the extraction and burning of the fossil fuels which are causing global warming? The US government has just given Shell permission to begin drilling for oil in Alaska, while in the Russian Arctic Gazprom is making final preparations to its drilling rig.

We arrived at the edge of the ice a few days ago, in Greenpeace’s ship, the Arctic Sunrise. Standing on deck, watching the sun rise over the floes of ice, some so thin melt pools had formed on the surface, others so deep that the ocean below was the clearest cold blue; we saw paw prints in the snow and then a lone polar bear appear in the distance - a cream blur against the sea of white. It felt unimaginable that the breath-taking beauty we saw before us could be threatened by a handful of rich companies who care more about their quarterly figures than the future of this stunning region.

So here is the moment we must act, to stop the reckless and greedy oil companies, and the political leaders who allow them to continue. A new global movement has formed – 1.7 million people and counting – to save the Arctic and declare the uninhabited area around the North Pole a global sanctuary for all on this planet. Wherever big companies break the Arctic silence with their oil drills, this movement will be ready to stop them. Later this month the United Nations general assembly will meet in New York, and we will be there to convince the leaders of the world to tackle the Polar emergency, by massively scaling up their efforts to reduce greenhouse gas emissions, and creating a global sanctuary in the uninhabited area around the North Pole.

We want to help build the biggest movement ever – and that would be a record I’ll proudly tell my grandchildren about. That in 2012, we noticed, we did something, we came together across the planet and saved the Arctic – heart of the world.