The UN climate change negotiators have been descending on the Polish town of Poznan this week for their annual conference. No big conclusions are expected until next year when they meet in Copenhagen, but it would be useful if they acknowledged the need to examine emerging science.
Up until very recently, it was thought that greenhouse gases could rise until 2050, before they must start to come down, and that a 2 degrees Celsius rise in the global mean temperature would still be relatively safe. New evidence shows otherwise. Greenhouse gas levels need to be coming down before 2030 if we are going to have a world we recognise.
The new science comes from studying the Earth's climate history. We may be about to step out of a civilisation 'sweet spot', in climate terms, into conditions that dramatically alter the Earth. This will be dangerous for humans. The planet will continue to exist, but we - and especially our descendents - may not survive the transformed conditions.
Negotiators are not yet listening to the latest science and weighing up the consequences of the risks because, presumably, of a belief that there is still plenty of time. If they could only hear the voice of the planet, they would know this is not so.
The fact is there has already been a significant loss of biodiversity, Arctic ice sheets and glaciers on mountain tops are thinning, and the sea is becoming more acidic as it absorbs more carbon dioxide.
These are three of the most obvious pieces of evidence. Once a tipping point has been reached, we may have reached a point of no return and ecosystems could begin to change. For example, vast tracts of the oceans may become dead zones, sea levels may rise faster than previously predicted, and the extinction of species could lead to the loss of many 'free' ecosystem services, such reduced pollination capacities and the loss of forests, which absorb carbon dioxide.
If the oceans and forests are no longer huge 'carbon sinks', the Earth will be less able to deal with further warming, thus exacerbating the situation.