The future shape of Dublin and its hinterland will be set for decades to come by what happens in the next 10 years. That much is clear, whether or not Brian Hughes, lecturer in urban economics at the Dublin Institute of Technology, is correct in forecasting that it could have a population of 1.93 million by 2011.

But what is Dublin? As Dr Hughes sees it, the capital necessarily includes not only the historic city and county, but also Meath, Kildare and Wicklow. Together, they constitute what has become known as the Greater Dublin Area even though nobody in, say, Oldcastle, Co Meath, would see it that way.

So it is not the case, as one newspaper report this week portrayed it, that Dublin - as a city - or even as a metropolitan area might have a population of nearly two million at the end of the next decade. What is true is that the eastern region, which already has a disproportionately large share of the Republic's population, will become more dominant.

According to Dr Hughes, who delivered a paper on the issue to the Society of Chartered Surveyors this week, the greater Dublin area is now emerging as "Ireland's city-state of the 21st century". Furthermore, he argues that any attempt to constrain its growth by interfering with the market-led demand would mean that "all of Ireland will be the loser".

This is hardly a view that the Council for the West, for example, would endorse. Like many others over the years, it has been campaigning for balanced regional development, to bring jobs and hope to depressed areas along the Atlantic seaboard, instead of allowing Dublin, willy-nilly, to become a bottomless pit for inward investment.

The National Development Plan, due to be published shortly, will be crucial in charting the right course. Whether it comes down in favour of designating alternative growth centres, as the Buchanan Report recommended 30 years ago, or continues with the present laissez faire policy towards Dublin's growth is in the lap of the gods.

Dr Hughes's projection of 1.93 million for the greater Dublin area, the GDA, in 2011 is based on a business-as-usual planning scenario in terms of regional development and also on the continuation of burgeoning economic growth. On the latter, he can take comfort from this week's ESRI report which predicted an average annual growth rate of 5 per cent to 2005.

His forecast is substantially in excess of the 1.65 million figure given in the current Strategic Planning Guidelines for the GDA. However, it is curiously similar to the 1.85 million projected by ERDO, the Eastern Regional Development Organisation, in a controversial settlement strategy published two years before it was wound up in 1987.

In the depressed mid-1980s, with the rate of population growth falling rapidly, ERDO's figure was regarded as wildly over-the-top. The fact that its strategy also wrote off the entire inner city, saying that it did not have the capacity to house even an extra 10,000 people, and focused instead on blanket surburban development, did not help either.

No more than any economist at the time, ERDO did not hear the distant roar of the Celtic Tiger and, with it, the advent of unprecedented levels of immigration, not only by returning Irish emigrants but also by foreign nationals. That influx is largely responsible for boosting the Republic's population by 1,000 per week.

Two-thirds of this growth is happening in the GDA, adding to the pressures brought about by our new-found prosperity. The results are evident in historically high house prices, maddening traffic congestion and an "infrastructural deficit" that has deprived Dublin of an adequate supply of housing and a functioning transport system.

If Dr Hughes is right, we would need to provide a staggering 31,000 housing units per annum, more than double the figure envisaged under the Strategic Planning Guidelines. Failure to do so and to deal with other deficits would imply "a continuing nightmare scenario of under-providing for housing, transportation and infrastructure".

THE crunch issue is where all the new housing is to be built. As the ESRI said this week, Dublin and other Irish cities will be cast in concrete by 2011 because that's when the rate of population growth is expected to level off; it will be too late then to undo mistakes made over the next decade or to mitigate the errors already made during the past 30 years.

If policies favouring higher residential densities are not properly implemented, the relentless sprawl of Dublin will continue - not only at the periphery of the existing built-up area, but also popping up around provincial towns within a 50-mile radius of the city, such as Drogheda, Navan, Mullingar, Tullamore, Portlaoise and Carlow.

Two other DIT academics, Brendan Williams and Patrick Shiels, have noted that this phenomenon of leap-frogging beyond traditional dormitory towns like Bray or Maynooth has created a housing boom in the more distant towns, as they are drawn into the extended commuter belt; Drogheda's annual output, for example, is up by 269 per cent.

In a paper, 21st Century Dublin - the Edge City and Commuterland, they also drew attention to the continuing trend of major multinationals such as Amdahl, Dell, Intel, IBM and Hewlett Packard locating in a ring around the outskirts of Dublin, in an incipient American-style edge city that also includes shopping malls and business parks.

Similar edge city development to the north, south and west of Chicago has consumed no less than 420 square miles of farmland since 1970, covering it with car-dependent sprawl, including a 31-storey skyscraper located 25 miles from a city centre littered with derelict sites - it is the classic doughnut effect that characterises most US urban areas.

DUBLIN was going the same way until urban renewal saved the day, and there is now every reason to believe that the gains made over the past 10 years in reversing inner city decline will be consolidated during the next decade. But it is still an open question as to whether middle-class people are ready to bring up families in areas like the Docklands.

What's needed, in the words of the British government's Urban Task Force, is "a well-designed, more compact and connected" city that would support a diverse range of uses to allow people "to live, work and enjoy themselves at close quarters within a sustainable urban environment which is well-integrated with public transport".

There is an increasing appreciation here, in the higher echelons of Government, that Dublin desperately needs a proper, functioning public transport system. The fact that a metro is being seriously considered, at least for the city centre, is particularly welcome as it would link up with every other public transport service, both existing and planned.

The city manager, John Fitzgerald, told The Irish Times that he would favour the establishment of a company involving CIE, Dublin Corporation and private sector interests to procure the underground circle line now being proposed to link Spencer Dock with Heuston Station, with a rail spur serving Dublin Airport. That would be one way of delivering such a major project as fast as the French.

As Mr Fitzgerald complained recently, much-needed infrastructure in Dublin is often held up by an endless round of public consultations. In some cases, indeed, the long-established NIMBY (not in my back yard) syndrome has been replaced by what Dr Hughes termed the BANANA (build absolutely nothing anywhere near anything) factor.

If the DIT lecturer's population forecast is right, a lot of feathers are bound to be ruffled by plans for high density housing, large pieces of infrastructure and the various other facilities required by an exploding city-region. We will also have to adjust to living in an increasingly multicultural metropolis, quite unlike Dublin in the "rare oul' times". Much depends on the performance of the economy. After the next set of national and regional population estimates are available, Dr Hughes suggested that the Minister for the Environment, Mr Dempsey, order a formal review of the Strategic Planning Guidelines and the various development plans of the GDA's seven local authorities.

Though the city manager insisted that the indicative population target of 1.65 million in the current guidelines was the prudent one to aim for, he said the monitoring system now in place was flexible enough to respond to changes in circumstances. "There's no reason why we couldn't plan for a higher figure, if required," he said.

John Henry, director of the Dublin Transportation Office, agreed. The DTO is also working to the 1.65 million figure. If it was likely to be almost 300,000 higher, "it just means that we would have to do things quicker". The only thing certain about different population projections is that they will probably all be wrong, he said.