So I was thinking about polar bears the other day. They're not my normal topic for musing while dodging London traffic on my bicycle, but I was thinking about them because a friend told me something I just couldn't believe. She said that polar bears could be the first mammals to lose their entire habitat to climate change. I was shocked. Polar bears have no natural predators. They're on the top of the food chain. They're perfectly adapted to the inhospitable Arctic environment, but now their icy home is disappearing beneath their paws because of our carbon polluting lifestyles.

If we don't act now, we could lose the polar bear in our lifetime. And this just isn't acceptable. We need to do something to see it doesn't happen. And I think the UN Climate Summit in Copenhagen this December is our chance. We need to demand that our world leaders pull back from behaviour that is rapidly heating the earth and take action to curb climate change. And in these last weeks before the climate summit we really need your help more than ever.

We have to seize this moment before it's too late to salvage the polar icecaps. We must secure a future for thousands of species, like the polar bear, and millions of people threatened by the effects of climate change.

The next few weeks are critical and could influence the future of our planet for generations to come. Here at Greenpeace we're piling on the pressure in the lead up to Copenhagen. We're investigating the impacts of climate change, exposing those responsible and lobbying governments worldwide to tackle the greatest sources of emissions. We're fighting for a global treaty to stop climate change now and keep the world on track for the desperately needed decline in global emissions by 2015. But to do all this, we need your help.

Please join us. Please donate today. Copenhagen could be the turning point that our planet so badly needs. It has to be, if we want to preserve the Arctic habitat and save the polar bears.