Professor Peter Stott:

I thank the members for the questions. It is a great list of questions. I will go through them in order.

Yes, we need to move on and the scientific community is ready to respond to the new challenge we have in the scientific community. The fifth assessment report, AR5, in which I was involved was a very important staging post. Human influence on the climate system is clear. It was a very clear statement. What the scientific community is ready to do - and I provided an example from Maynooth University - is provide our science in order to understand exactly what the risks are, understand them on a more granular level and help citizens to respond. Climate change is now part of everyday conservation in light of some of the recent events in the UK and Ireland, such as the floods, the heatwave and the drought. The scientific community is ready to engage in that discussion and to help citizens and governments respond in the most appropriate way to this challenge. It is a really important challenge for the scientific community because it requires us to provide further refinement into our levels of prediction. For example, we need to have an even greater understanding of exactly how particular localities would be affected by climate change.

Let me stress again the clear point that the basic physics mean there is an increasing frequency of many of these types of extreme weather events. We have seen these events play out and they are giving us a lot of confidence that the climate model projects are reliable and that we can use them to provide an extra level of detail.

We had a question on the implications of business-as-usual scenario, with the member pointing to the graph that shows a rise in temperature of 4o Celsius or 5o Celsius relative to pre-industrial levels. Earlier, I related that to the climate of the most recent ice age. There is no doubt that emissions continuing to grow and a business-as-usual mindset remaining in place for the rest of the century will lead to levels of warming weather and significant risks. I refer, for example, to rising sea levels resulting from the melting of the west Antarctic ice sheet and the melting of ice in Greenland. There are significant challenges associated with food security. In circumstances where there is 4o Celsius or 5o Celsius of warming, there is a significantly enhanced risk of the sort of drought that would mean, potentially, that the world would really struggle its population. One can see already that there is not total food security in certain parts of the world. With levels of climate change such as those to which I refer, feeding the world's population will become extremely challenging. There are significant risks associated with rising sea levels and concomitant flooding. As the item on the infographic relating to the water stress hows, there will be a challenge in the context of ensuring that people will have access to water. Given that there are concomitant risks, climate change is also a threat multiplier as well. There are already particular levels of threat in existence even without climate change. However, the latter is then adding to those stresses in terms of, for example, migration.

To be honest, scientifically, it is difficult to paint a picture of the type of world I am describing. This is where we need to look very much in a risk-based context. We can paint pictures of what could happen. I could talk at length about the west Antarctic ice sheet and the fact that there is this massive body of ice that is what we term "dynamically unstable" because seawater is warming and melting the ice from beneath. The latter process poses the risk of the entire mass of ice being dislodged. If the scientific community or I were asked to give a precise probability of that to which I refer happening, we would both potentially struggle to do so. What I can tell members, however, is that there is a risk of it happening and that the impact would be considerable.

We need to think about food security and other issues in the same sort of way, particularly as they have such major impacts. As a scientist, I can say that there is plenty of evidence to support the supposition that we really do not want to discover what a world such as that which I am describing would look like in reality.