 C-ice is the frozen sea surface. It's just a few metres thick, but it covers up to 20 million square kilometres of the polar seas during winter. That's about double the size of Europe. On the other hand, the glaciers and the ice sheets that cover large land areas of the earth's surface are up to kilometres in thickness. Glaciers are a few hundred metres thick. The great ice sheets of Antarctica and Greenland are up to three and five kilometres thick respectively. If all that ice on land were to melt, global sea level would rise by about 60 metres or perhaps even a little more. What is the climate context in which the icy world sits? Temperatures have been rising over the past century and they've been accelerating in that rise since 1980. Global temperatures have risen at least half a degree since the 1960 to 90 period. Both CO2 and other greenhouse gases together with volcanism and natural effects are generating this change. Sensitivity is high in the Arctic because reflective sea ice is being replaced by open water and there's a self-reinforcing process there, which means that the energy balance is changing and therefore less sea ice produces more warming of the water and therefore less sea ice the next year. We see this in this image here where in the 40 years of which satellites have accumulated data, the amount of sea ice present during summer has dropped by almost a third. That's about half the size of Australia is now open water instead of very reflective ice and that makes a big difference to the energy balance. Freezing sea water also generates the densest water anywhere on the globe. That water sinks and flows south with depth. The return flow is the Gulf Stream. If we produce less sea ice in the Arctic in particular then the global circulation will change with implications for all of us. In the Arctic that means that shipping routes and the like will be much more open over the coming decades. All global models, all 20 or so of them predict that there will be less sea ice and almost no sea ice in the Arctic during summer. Some predict that in a decade, some predict that in the next three decades either way change will be taking place. My first question therefore is how do we deal with the changing Arctic? You can see the white polar bear in the water here swimming for its life in an environment where there is no sea ice now. Shipping, mining, hydrocarbons will all be opened up. How do we deal with that and the sovereignty issues also that are involved? Turning to glaciers and ice sheets, this splendid painting almost 100 years ago since it was done and the modern comparison on the left shows very clearly that glaciers and ice sheets in this part of Spitsburg have both receded and thinned over that period. The same is true over most of the icy world and if we look out of the window of 747 and I recommend you do this next time you go to the west coast rather than looking at the film you will see the thinning and the retreat of ice and this is a characteristic almost everywhere in the icy world. Those glaciers that you see there in Baffin Island in Canada will be gone in 40 or 50 years time. The Greenland ice sheet is also suffering from very much increased melting since about the year 2000. A number of its fast flowing outlet glaciers have doubled in speed over the last 10 years decanting much more ice through the carving of icebergs into the ocean and therefore having an effect on sea level. The same is true of most of the mountain glaciers of the world. Turning to Antarctica, the huge east Antarctic ice sheet is the least affected part of the icy world at present. Indeed precipitation change may mean that east Antarctica is growing slightly which would have an effect of a suppressing sea level rise. There are three controls on global sea level. The first is melting of glaciers and ice sheets. The second is the thermal expansion of the ocean. If you warm a water body it will expand and it's doing so. The third is changing storage of water on the earth surface whether it be in rice fields, large reservoirs and the like. Those are the three controls on global sea level. Global sea level rose during the 20th century by a bit less than two millimetres per year. Today it's rising just over three millimetres a year and with the predicted global warming of between one and four degrees centigrade over the coming century it's likely that sea level will rise by between 0.2 of a metre and almost a metre by the end of the 21st century. My second question is therefore how do we deal with sea level rise? How do we deal with it in the great port cities of the world on the one hand? How do we deal with it on the other in the deltaic areas of the Asian Far East? There are clearly going to be major differences in our ability to deal with sea level change in those places. Thank you.