Two weeks after the latest International Panel on Climate Change report, contributing author David Vaughan talks at the Natural History Museum about the effects of sea level rise on the UK.
Matt Brown
The ice man cometh
The Antarctic ice sheets are disappearing. We don’t know why, and we can’t predict what this will do to global sea level. That’s the key message from David Vaughan of the British Antarctic Survey, who tonight delivers the Natural History Museum’s Annual Science Lecture. Vaughan is a world authority on glacial retreat, a veteran of eight seasons in the south polar regions, and a coordinating author of the latest IPCC report.
“Antarctica is a crucial piece in the global warming jigsaw,” he says. “Understanding how its ice sheets respond to climate change is one of the biggest uncertainties in predicting sea-level rise.” Tonight, Vaughan will spell out these uncertainties, and predict what a rise in sea level might mean for the UK, where 17 million people live in coastal areas.
Antarctica’s ice sheets are losing mass more quickly than can be replaced by snow fall; not through melting, but because ice is flowing into the ocean. Satellite data only go back 15 years, and geological information is poorly preserved, making ice sheets a slippery study in more ways than one. The deficit could be down to higher sea or air temperatures, or some process at the base of the ice sheet. Vaughan’s team are trying to understand this process, to inform models of climate change and predict effects on sea level.
Threats to London
In London, significant investments may be needed to keep the water out. “There are three effects here,” says Vaughan. “Sea levels will rise, climate change will bring an increase in storms, and the South East of England is slowly subsiding.” Protecting London from the combined effects will probably require more ambitious flood protections than the Thames Barrier. However, Vaughan is quick to note that sea rise will always be a gradual phenomena, so we have time to meet the threat.
The Environment Agency, which estimates that tidal levels are rising by about 60 cm per century, is formulating plans to do just that, through its Thames Estuary 100 consultation.
“There is now a good dialogue between the scientists on the ground and the people making policy,” says Vaughan. He believes the issue is being taken seriously, and effective defences can be built “with the proviso that we’re talking about extreme events here. If the greatest storm surge in a thousand years enters the Thames, there’s nothing we can realistically do about it.”
Other parts of the UK might not be so lucky. “We may have to make decisions about each and every part of the coastline," warns Vaughan. "In some cases—Glasgow, Liverpool and other large cities—it will of course be worth investing in defences. In more rural areas, we may have to consider retreating from the coast.”
Flood Warning? The Global Impact of the Melting Ice Sheets is on at the Natural History Museum tonight from 19.30-21.00