38 THE CLIMATE CHALLENGE
Flooding & water shortages
F
looding is one of the most pressing issues regarding climate change for most people in the UK. In England, for example, one in six homes are currently at risk of flooding; annual flood damages cost around £1.1bn; and, according to one rescue equipment manufacturer, you are more likely to get flooded than burgled.
On the extreme end of things – while it may be a long way off yet – the ice caps will melt if temperatures increase by three degrees. Ocean chemist David Archer calls this the “long thaw,” and believes that ultimately, the sea will rise by at least fifty metres (the U.S. Geological Survey puts it at 80 metres). If this were to come to pass, most of London would be covered by the sea.
More immediately however, according to the CCC report approximately 1.8 million people are already in areas of significant flood risk. It reports that the impacts of flooding and coastal changes in the UK right now are significant, and that this will worsen as the climate warms. “Improving protection for some commu- nities will be possible through community scale defences, but others will face signifi- cantly increased risks,” the report reads. “If unmanaged, these risks will affect property values, business revenues, and in extreme cases the viability of communi- ties.” It adds that warming of 4 degrees
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celsius or more immediately implies “inevitable increases in flood risk across all UK regions, even in the most ambitious adaptation scenarios.”
It is often assumed – while they certainly will be at risk – that it is coastal towns that will feel the brunt of this in the form of rising sea levels and coastal erosion. London, for example, is well protected from predictable sources of flooding due to the Thames Barrier, and around 400 smaller barriers and moveable flood gates, plus over 300 km of river walls and embankments stretching into Essex and Kent. Unfortunately however, there are many sources of unpredictable flooding which even heavily protected areas like our capital may not be able to cope with. Somewhat counter-intuitively, scientists expect that global warming will lead to more extreme rainfall. The IPCC has predicted that the UK and Europe are “very likely” to see more heavy rainfall throughout the century, and the Met office reported last year that nine of the UK’s 17 record breaking rainfall periods since 1910 have taken place since 2000. The Met Office’s chief scientist Julia
Slingo commented: “all the evidence suggests there is a link to climate change.” Though she makes it clear it is extremely difficult to determine a “definitive answer” as to what causes certain extreme weather, she said: “There is no evidence to counter the basic premise that a warmer world will lead to more intense daily and hourly rain events.” As global warming causes this ever- heavier rainfall, and sea level rises lead to bigger storm surges, flood risk will grow dramatically. Unpredictable flash floods and freak weather occurrences will endanger even our most protected habitats and settlements.
CONSTRUCTION RESPONSE The industry has already taken steps to alleviate the pressure of such flood risks. The CCC report said that investment in flood alleviation schemes have increased since 2015, and between April 2015 and April 2017, 97,000 homes in England benefitted from new or replacement flood defences.
The UK Green Building Council
(UKGBC) reported that 83 per cent of BREEAM new construction projects completed in 2016 used flood resilient design measures, 10 per cent of all paving sales in 2013 were permeable, and 80 per cent of social housing is “relatively safe” from flooding. However, it is becoming clear that our
current system of collecting surface water from homes using pipes and then releas- ing it into local waterways is no longer proving adequate. Sustainable urban drainage systems (SuDS) are a rising trend to supplement and/or replace these. They form a more effective water management system, and help to mitigate the effect that human development has had on the natural water cycle, making it more resilient against storm surge overflows and other forms of flooding. Some examples of SuDS include swales,
SOMEWHERE OUT ALONG THE TIMELINE IS THE ‘JAWS OF DEATH’ – THE POINT AT WHICH, UNLESS WE TAKE ACTION, WE WILL NOT HAVE ENOUGH WATER TO SUPPLY OUR NEEDS
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