Breaking the waves

Coastal cities are more than a match for rising sea levels.

Peter Sammonds

Topics Science & Tech

The UK government’s chief scientific adviser Sir David King is taking the issue of sea-level rise resulting from climate change seriously. After recently returning from Moscow, where he argued for Russia to ratify the Kyoto Protocol on limiting global carbon dioxide emissions, he briefed journalists on the threat of rising water levels to cities such as London, New York and New Orleans (1).

This story was reported by the press as a Hollywood-style eco-disaster scenario, with headlines such as ‘Melting ice: the threat to London’s future’, and ‘Melting ice could swamp cities’. This is a shame, because King does have a serious point to make.

Sea levels are rising. The predicted sea-level rise for this century by the world’s experts on climate change, the Inter-Governmental Panel on Climate Change (IPCC), is between 0.1 and 1 metre. Sea level will rise with climate change because of the thermal expansion of water in the oceans. The reason for the large range of sea-level rise predicted by the IPCC is that the responses of the large Greenland and Antarctic ice sheets to global warming are not known. Polar research is still in its infancy, and one of the key satellites needed to make measurements on the size of these ice sheets, the European Cryosat, has still to be launched.

The key question is what is happening to the total mass of ice on the planet. In terms of sea level rise it doesn’t matter if, on the one hand, we are currently melting ice, when on the other hand increased precipitation (which you would expect with global warming) is causing the Antarctic ice sheet to expand. (Another more surprising unknown is how much sub-surface groundwater there is stored in the continents.)

Even if there is presently a net melting of ice, is King right to paint this in a doomsday scenario by saying that London is in danger? Response times of the vast ice sheets are measured in thousands of years (2) – the Greenland ice sheet is still responding to climate change that occurred during Roman times.

By contrast, cities can be transformed in decades. Liverpool grew from nothing into one of the great world cities, and then shrunk back, all within a couple of hundred years. Old Goa in India is even more remarkable: as you wander around the huge cathedrals set in open fields, it is impossible to imagine that this was once one of the most populous cities in the world.

Dynamic cities can deal with the challenges posed by their environment. Today Tokyo is not retreating from the rising sea levels, but expanding into Tokyo Bay in a hugely ambitious land reclamation and urban expansion project. Challenging assumptions about cities of the future, the world-renowned architects Foster and Partners have proposed a new Millennium Tower Tokyo, rising out of Tokyo Bay, two kilometres offshore, and linked to the mainland by road and rail (3). At 170 storeys high it would be the world’s tallest projected building, capable of housing a community of 50,000 people, generating its own energy, processing its own waste, and with its own transportation system.

The UK government and research funders have helped to put the UK at the forefront not only of climate change research, including funding polar science such as the Centre for Polar Observation and Modelling at University College London, but also of the impacts of climate change through the Tyndall Centre at the University of East Anglia and the Foresight initiative on flood and coastal defence.

However, the government’s scientific boldness isn’t backed by political boldness and foresight. Rather than studying the rising waters, and working out how to manage them, too often the suggestion is that we should shrink back and take cover.

Peter Sammonds is professor of geophysics at University College London.

Read on:

spiked-issue: Global warming

(1) Melting ice: the threat to London’s future, Guardian, 14 July 2004

(2) The Physics of Glaciers, WSB Paterson, Pergamon, Oxford, 1994

(3) Sustaining Architecture in the Anti-Machine Age, I Abley and J Heartfield (eds.), Wiley-Academy, 2001

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Topics Science & Tech


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