Professor Ray Bates:

Ireland has a big agriculture output and it could be even greater.

On the question of model projections, the larger the scale one is predicting for, the more reliable projections are likely to be. The grid sizes of the current climate models, or the ones on which the 2007 IPCC report were based, are based on a resolution in the order of 100 sq. km. In other words, there is 100 sq. km in which the climate variables have been predicted. Ireland falls within approximately one grid box of these models. Therefore, when one is predicting for an area the size of Ireland, it is very difficult to obtain detail from the model. There are various techniques of interpolation, either dynamical or based on statistical downscaling, to get from the scale of the global models to the scale for Ireland. It is quite problematic to predict on a county or provincial level in Ireland based on a global model with a resolution of 100 sq. km. When one goes to a larger scale, such as the continental or global scale, one has very detailed coverage with models with a resolution of 100 sq. km. The confidence that can be placed on the model projections is greater for the larger scales. To answer the Deputy's question, the projections for the larger scales, such as the continental scale, are projections in which we can have more confidence than the projections for larger scales that are smaller than the grid scales of the global models. That is why I suggest greater confidence could be had in the larger-scale projections.

We know that, for Ireland, there are projections for very dry summers or drought in the south east. While the projections are for decades ahead, the evidence we have seen so far is that in the south east recently there have been many summers with rainfall 200% or more of the norm. There are no indications so far that the model projections on the Irish scale are turning out to be valid. I realise that the projections are for a longer timescale but we have already reached an increase in carbon dioxide of 40% above pre-industrial levels. In terms of the radiative forcing associated with that, we are now more than halfway towards a carbon dioxide doubling. The forcing goes up exponentially. A 40% increase in concentration amounts to an increase in radiative forcing of more than half because of the nature of the change based on concentration.

Given that we are more than halfway, the projections for a doubling that we see at the small scales at present are not been borne out. Perhaps in decades to come, we will see them borne out. As I said, on the larger scale, we can have more confidence in the projections. Therefore, the argument is valid that the committee should point out to the Government that the projections for Mediterranean countries point to a very severely changed climate towards the end of the century and that the Irish climate will be a resource for Europe in terms of food security.