Ghadira may disappear within 50 years

Low-lying beaches like Ghadira could be entirely wiped out in under 50 years unless some form of remedial measures are taken, climate change experts have warned.

Malta should start contemplating building flood defences as it braces itself for a possible maximum one-metre increase in sea levels within a century, they said.

Alfred Micallef and Adrian Mallia, members of Malta's Climate ChangeInitiative under the UN Framework Convention on Climate Change, said decisions couldn't be postponed.

"As a small state, Malta is more susceptible to the consequences of climate change," Dr Micallef warned.

Rising sea levels are among the anticipated effects of global warming, amid predictions of a possible increase in temperatures of 3°C in the yearly average temperature by the end of the century and a gradual decrease of rainfall on a yearly basis.

The recently-published Stern review warns of a possible rise of under one metre before 2100 mainly from the thermal expansion of the oceans and the melting of glaciers, increasing to over a metre by 2100 - within the lifetime of many children being born nowadays - and an astonishing 12 metres over a longer period if, as seems likely, the Greenland and West Antarctic ice sheets begin to melt.

Incidentally, a study released by leading climate scientists yesterday says the Arctic could lose virtually all its summer sea ice by the year 2040 - 40 years earlier than previously thought.

Just a one-metre rise would make low-lying countries such as the Maldives uninhabitable, for example, and dislocate some 13 million in Bangladesh alone.

But what kind of impact will the anticipated rise in sea levels have on a small island like Malta?

Quite realistic, according to Dr Micallef from the university's Department of Physics, because a few centimetres increase in sea level could translate into water moving metres inland.

In fact, one of the reports drawn up about climate change show that the areas prone to inundation include Mellieha, the Ahrax peninsula, Xemxija, Salina, Ramla l-Hamra, Marsalforn, Dwejra, Marsascala, St Thomas Bay and areas around Marsaxlokk harbour.

The popular beach of Ghadira could well be gone because of the proximity of the high rising adjacent road, which means the sand has nowhere to retreat, Mr Mallia explained.

Ironically, localities like St George's Bay, Balluta, Xlendi and many areas around Grand Harbour would also have been subject to flooding had they been left in their pristine state.

However, infrastructure works undertaken over the past 40-50 years have so radically changed the coastline or its approaches that as long as the change in sea level is as predicted, little or no flooding would occur.

The report says that the authorities should take action against those building illegal structures, which are found to negatively affect adjacent shorelines or the wave dynamics in the area.

Coastal zone management plans are essential and beach nourishment and relocation of the infrastructure may be necessary.

Dr Micallef underlined the importance of the planning and environment authorities to work hand in hand to minimise the impact.

If possible, water catchment areas need to be developed further inland to reduce the flow of storm water in water-prone areas. Such defences involve the development of new coastal strips to protect vulnerable inward areas, like Msida.

In these cases, storm water generated upstream would need to be collected upstream for later use or channelled to the sea via pumps or bypass culverts, thereby avoiding flooding of the low-lying area.

Low-cost and versatile inflatable dams may provide an interim solution and protective solid structures can be built in coastal areas of great vulnerability and importance, the report suggests.

"We cannot keep postponing decisions and we really need to start thinking about it now. We have to see what kind of technologies make sense," Mr Mallia said.

Sea level change is difficult to measure. While the monitoring of sea levels in Malta started being carried out in 2001, Aldo Drago, from the university's Physical Oceanography Unit, said the unit would need some 25 years of data to carefully assess the changes, especially with a change in the mean sea levels of 20 cm a year.

"If the sea level rises so much, it's still not easy to come out with affordable structures that actually work," Dr Drago said. "What we really need to do is to indicate the consequences to really drive the message of global warming home."

Since 1979 the extent of sea ice in the Northern Hemisphere has decreased by an average of more than eight per cent per decade during September, when the ice is at its minimum extent. Any changes in sea ice extent in the Southern Hemisphere are not statistically significant. In both cases, the green lines indicate uncertainty.

Ice responds with a delay to a warming climate. The global warming that took place between the 1960s and 1970s is just now being registered by the melting sea ice and retreating glaciers. The accelerated warming since the 1970s will bring about even higher rates of ice loss in the near future.