The Thames barrier built in response to the 1953 floods is a 520 metre, £500 million flood defence designed to protect London from Tidal surges and the threats from increasing levels of rainfall. Commissioned in 1982, the Thames Barrier has seen and prevented the flooding of London on over 182 occasions. The constant threat of climate change however is leading to an ever-increasing river level rise, leading to uncertainty over the future stability of the barrier.
Recent research undertaken by the IPCC (Intergovernmental Panel on Climate Change) warns of a 3-4°C global temperature increase by 2100 leading to a rise in sea levels of 59cm. This would lead to increased tidal surges with the increased quantity of rainfall putting pressure on the River Thames Barrier.
Experts are warning of the necessity of immediate prevention action. However, the risk of tidal surges and increased rainfall appear to be underestimated by the government. The possibility of a shock event, such as the floods of 1954 leading to the deaths of over 300 people, looms in the near distant future. The estimated cost of damage lies at £200 billion disclosing the economic productivity and industry costs.
It seems a mystery as to why the proposed plan of a second £17 billion Thames Barrier near the Dartford crossing is not in later stages of development with over £200 billion worth of assets being protected by the barrier. The current barrier is not defenceless, however, and was built to withstand an 8mm water level rise up to 2030. The Thames has only been rising on average 3.1mm per year delaying the necessary redevelopment for a new barrier by a considerable amount. Despite the new estimates of a 2070 replacement date, the lack of thought for the future safety of London is disconcerting.
With the emphasis clearly not lying on a replacement barrier the government is focusing its attention on reducing London’s greenhouse emissions and developing alternative cheaper schemes to increase the length at which the barrier can survive. For example, the £5 billion super sewer set to be completed in 2023 reduces the 4 million litres of sewage that enters the Thames every day. This will lower the pressure on the Barrier in future years as well as decreasing the impact of our constantly changing climatic conditions. In addition to this, the mayor’s office has initiated carbon emission reducing measures such as the congestion zone and London’s hybrid bus fleet to limit the local effects of climate change. This, in theory, will reduce the threat of the increasing water levels of the Thames lessening the future pressure on the Thames barrier. However, the effectiveness of these initiatives is yet to be seen. Could it be too little too late?
“The barrier is yet to exceed 50% capacity” Dick Tappin stated. The constant threat of rising global temperature resulting in the rising water levels of rivers is leading to an increased pressure on the barrier. Measures have been taken such as London’s new super sewer built to release this pressure, but the barrier must still cope with the imminent upsurge in sea levels and rising water levels in rivers due to the expected increase in rainfall. These will both add immense pressure to the barrier, pressure which cannot be counteracted by the measures adopted to prolong its survival. The risk of a shock event, such as a flood within the Thames basin, is needed to force change in the government’s attitude and to protect the £200 billion worth of assets that currently remain under the ever-diminishing protection of the Thames Barrier.