THE worst scenarios port rayed are little short of terrifying. Large areas of Dublin, Cork and Belfast, we are told, could suffer frequent, if not permanent, inundation as the seas rise inexorably around our coastline.

The long droughts of our Saharan summers would be interrupted by catastrophic flash floods as the occasional thundery deluge descends upon arid terrain unable to cope with such an onslaught.

And the extra rainfall during our wet, wet winters could turn the central plains of Ireland into one vast untropical lagoon, with the former dwellings of the unfortunate inhabitants protruding above a liquid landscape like so many grim palazzi in a bleak Orwellian caricature of Venice.

Is this vision of post greenhouse Ireland, (with the population laid low by virulent malaria epidemics) realistic, or will we survive the dreaded global warming more or less unscathed?

On a global scale the verdict has been leaked. The oracle in these matters is the team of several hundred world class scientists who comprise the IPCC the Intergovernmental Panel on Climate Change.

They produced a lengthy and authoritative report on global warming in 1990, and for the past 8 months or so have been reviewing their conclusions in the light of later evidence. Most of their findings have been widely reported in the media.

The latest conclusions of the IPCC appear to differ only in detail from those they reached six years ago. They say that if greenhouse gases such as carbon dioxide and methane continue to accumulate in the atmosphere at current rates, the average temperature of the globe is likely to increase somewhere between 0.150 and 0.30C per decade over the next 100 years or so a cumulative increase of, say, 2.50C.

Their best guess as regards sea level is a rise of somewhere between 30 centimetres and 1 metre by the end of the next century.

These figures in themselves may not seem startling, but if they were to materialise they would represent a greater change of global climate in a century than the world has seen take place gradually over the past 10,000 years.

And their plausibility must surely have been enhanced by the tact that, coincidence or not, 1995 has been, by all accounts, the warmest year on record.

Leaving aside the uncertainties inherent in the predictions themselves, supposing Ireland followed the global average exactly, how would we fare?

The news is not all bad. In agriculture, for example, the higher average temperatures would mean that many crops would provide a significantly greater yield. Summer droughts might be a problem, and unfamiliar pests and weeds might require more attention than at present, but grass growth might be 20 per cent greater than it is now.

A wider variety of fruits could be cultivated successfully in Ireland, and it is even possible that vine growing might become viable in Wexford and adjoining counties.

But there would be casualties, too, Peatlands, for example, would suffer serious damage in our greenhouse world, And the fear of floods is not entirely groundless. Ireland's "saucer shaped" topography means that much of the centre of the country is flood prone anyway in its natural state, owing to the relatively poor carrying capacities of many of its rivers.

The enhanced winter rainfall in a greenhouse world would bring serious flooding more frequently than at present to places that are already vulnerable in this respect, and many regions currently flood free might experience flooding on an occasional basis.

Fears about the effect of the rise in sea level, too, are not without foundation, Given the predicted figures, a small number of very vulnerable coastal locations might well succumb to permanent inundation and some of these would be adjacent to highly populated areas.

Most of the impact, however, would be associated with severe storms which some authorities believe might well be more frequent in a greenhouse world.

Even a slight rise in sea level would increase the statistical recurrence of the coastal flooding currently associated with strong winds and high tides, so that an event which now might be expected to occur once every 100 years might be expected every five years by the middle of the next century.

The major coastal cities, like Cork, Waterford and Dublin, could expect more frequent regular flooding of water front zones.

Others say it will not be like this for us in the brave new greenhouse world. Although there is now a broad convergence of opinion on likely global trends, no one denies that there is great uncertainty concerning possible regional variations.

The averages, it is feared, may mask even more dramatic warming in some regions, to be balanced by other places that may flip, dramatically and paradoxically, to a much colder and more harsh regime.

Indeed the more cautious experts, with precisely this in mind, are careful to refer to "climate change" rather than to "global warming" when discussing future trends.

ONE nightmare scenario, from an Irish perspective, is that which predicts that the fresh water being added to the northern waters of the North Atlantic by the melting polar ice in a greenhouse world could affect the buoyancy of the water in sub arctic regions.

This, they theorise, could disrupt the natural tendency of the ocean waters in these regions to sink, thus making way for the northward drift of warm surface waters from the south.

In effect, they argue, it could divert the Gulf Stream from our western shores, and deprived of its benign influence Ireland might develop a summer climate similar to Iceland's, and experience winters of the kind we now associate with the less hospitable regions of the Baltic.

Many of us might prefer not to have to wait around for that to happen.