The plenary speech today was a summary of the science in the IPCC’s fourth assessment – a somewhat more sobering counterpart to the light-hearted talk by Larry Page on Friday. It would amaze me somewhat if there was anyone in this room who didn’t already know the conclusions – that the world is committed already to a certain degree of warming, that this warming is very likely due to human-generated emissions of greenhouse gases, and that the impacts of this will include more extreme weather and sea level rise of an unknown but frightening amount. It is, I hope, a case of preaching to the converted. But it’s a message that can’t be hammered home too hard – it only gets better the more it is bashed into peoples’ heads. And it is particularly nice to hear it being done in America.

The AAAS only just this year released its first consensus statement on climate change, saying “global climate change caused by human activities is occurring now, and it is a growing threat to society”. It is amazing how long it takes for such things to happen. Perhaps the only thing slower than the planet’s response to climate forcings is mankind’s psychological response: convincing a planet full of people to do something before it’s too late seems to be about as hard as turning a giant ship at sea before it whacks into an iceberg. It will be rather unfortunate if our policy response runs on the kinds of geological time scales that will see Greenland melt and the Antarctic start to turn green.

People have been thinking of adaptation to climate for a very, very long time. As we’re told today in the plenary, Thomas Jefferson observed: “The changes between heat and cold in America, are greater and more frequent, and the extremes comprehend a greater scale on the thermometer in America than in Europe. Habit, however, prevents these from affecting us more than the smaller changes of Europe affect the European. But he is greatly affected by ours.” The lesson – that those un-used to changes in climate are ill equipped to deal with them – is one that we are still learning today, and will learn with some force in the near future.

The plenary speech today was a summary of the science in the IPCC’s fourth assessment – a somewhat more sobering counterpart to the light-hearted talk by Larry Page on Friday. It would amaze me somewhat if there was anyone in this room who didn’t already know the conclusions – that the world is committed already to a certain degree of warming, that this warming is very likely due to human-generated emissions of greenhouse gases, and that the impacts of this will include more extreme weather and sea level rise of an unknown but frightening amount. It is, I hope, a case of preaching to the converted. But it’s a message that can’t be hammered home too hard – it only gets better the more it is bashed into peoples’ heads. And it is particularly nice to hear it being done in America.

The AAAS only just this year released its first consensus statement on climate change, saying “global climate change caused by human activities is occurring now, and it is a growing threat to society”. It is amazing how long it takes for such things to happen. Perhaps the only thing slower than the planet’s response to climate forcings is mankind’s psychological response: convincing a planet full of people to do something before it’s too late seems to be about as hard as turning a giant ship at sea before it whacks into an iceberg. It will be rather unfortunate if our policy response runs on the kinds of geological time scales that will see Greenland melt and the Antarctic start to turn green.

People have been thinking of adaptation to climate for a very, very long time. As we’re told today in the plenary, Thomas Jefferson observed: “The changes between heat and cold in America, are greater and more frequent, and the extremes comprehend a greater scale on the thermometer in America than in Europe. Habit, however, prevents these from affecting us more than the smaller changes of Europe affect the European. But he is greatly affected by ours.” The lesson – that those un-used to changes in climate are ill equipped to deal with them – is one that we are still learning today, and will learn with some force in the near future.