Last reviewed 8 August 2016

Be very worried! Every five years, the Government is obliged under the Climate Change Act 2008 to plan how the UK will adapt to current and future climate change risks. The next assessment, and what we must and can do about it, is due in January 2017. As Jon Herbert discovers, floods, wrecked transport, power, gas and IT links, plus general mayhem, are predicted.

The UK is not prepared for the weather-driven domino effect that will hit it in the next 35 years, new ministers taking their Whitehall desks are being warned. Greg Clarke, the new Head of Business, Energy and Industrial Strategy, Chris Grayling at transport and Andrea Leadsom at environment are likely to find the unwelcome news in their in-trays.

Preparing the next Climate Change Risk Assessment (CCRA) is a huge piece of work taking several years. However, its implications of how the UK should plan for the future affect everybody. It determines how floods, droughts, water supply, soaring temperatures and freezing cold could impact us — and what we can do before this happens. There is also a direct cost on our wallets.

Specifically, the findings now being released predict flooded rivers washing away bridges, power cables, gas mains, IT connections and transport arteries. At the same time, heat-related deaths among elderly people are expected to triple to 7000 annually by 2050.

In parallel, Britain’s best but over-worked East Anglian soils are losing their fertility, leading to more expensive shopping trollies. London summer temperatures could, in theory, occasionally top 48°C. Wildlife will also take a bashing. Flooded power stations alone could trigger a long domino effect through the environment and society.

The assessment also shows that half a million UK homes could be at risk by 2050, a figure that might conceivably double in the worst case if global temperature rises are not kept below 2°C.

The UK gets off lightly compared to other countries, although new commercial opportunities in engineering, insurance and adaptation-related goods and services are small compensations.

Government advisors

Responsibility for CCRA delivery falls on the Adaptation Sub-Committee (ASC) of the Government’s environmental advisors, the Committee on Climate Change, which has been working with a wide range of experts to review published data. Its aim is to publish an independent evidence report of risks and opportunities that modern Britons must learn to live with and turn to their advantage as the impacts of global climate change grow.

The ASC’s report will be delivered to the Government at the end of July 2016 and could affect business planners and development managers in companies, large and small, across the UK.

The logic is that the UK economy, society and environment are all affected significantly by climate variability and extremes — a statement that recent winter storms would seem to confirm. Extreme events can cause the Government, community and economic disruption unless mitigating steps are taken. They have costs as well as benefits. So knowing in advance is crucial.

Knowledge has value

Being more positive, the UK is a leader in cutting-edge climate science and has a growing understanding of risks. Knowledge is a prerequisite for better strategic planning, building resilience and measuring future costs, and expensive social dislocation.

Going further, being aware of opportunities will help the UK to identify investment and marketing advantages that could be useful in forging new international trade links.

The ASC’s role falls into two parts. It must provide independent expert advice on climate threats and opportunities — its advisory role. At the same time, it has a duty to report to Parliament on how well the UK is adapting to the inevitable impacts of global warming and climate change — its scrutiny role.

From hundreds of risks and opportunities identified, and external evidence and research work across 11 sectors, it is expected to pinpoint any policy barriers to adaptation, while showing where adaptation programmes will be needed most urgently between 2017 and 2022.

It must also show how climate change interacts with socio-economic risk factors — people and businesses — and how adaptation actually affects risk levels. The report must identify how distant climate change impacts overseas could affect the UK.

The final outcome will be an accurate list of priorities for the UK’s next National Adaptation Programme (and devolved adaptation programmes for Scotland, Wales and Northern Ireland) to limit our vulnerability and make the most of bad weather.

Broader reach

Specific research projects carried out with Natural Environment Research Council (NERC) funding have looked at flood risks for all four UK nations, updated water availability projections — droughts are as large a problem as floods — climate change impacts on UK national assets, high-end extreme scenarios and biodiversity.

The first CCRA in 2012 highlighted a raft of threats, including changes in the frequency and size of floods, health impacts of hot days, pests and disease outbreaks, and natural environment damage. Fewer winter deaths, lower winter heating bills and longer growing seasons were also pinpointed.

However, it did not take full account of how policy and trends could affect impacts, such as the paving over of gardens. The possibility of not limiting temperature rises this century to 2°C has also been factored in since. How urgently action needs to be taken in the coming five years will also be taken into account so that policy makers are fully aware of both the magnitude of events and the need to act quickly.

This is a classic risk/impact analysis. Some risks may be significant but mitigation is not so urgent. Flooding is an example where a major new and replacement flood and coastal defence programme in England is taking place over six years, but swifter action may be needed to protect individual vulnerable communities.

International impacts taken into account include effects on global food markets, migration, and the need for humanitarian assistance overseas.

The work is supported by more than 60 contributing authors, 25 peer reviewers and more than 100 other interested parties who have helped to review drafts. Meanwhile, the results of four in-depth research projects have been considered in detail.

Wet and dry weather

Floods and droughts can occur back-to-back, as happened early in 2012. A study has found that by mid-century almost half a million UK homes are likely to be at significant flooding risk. However, if global temperatures rise by 4˚C rather than 2°C in the 2080s, coupled with high population growth, more than a million UK homes could be at risk.

While sustainable drainage systems (SUDS) could help to offset risks under a 2°C temperature rise projection, even this could not cope with a 4°C increase.

In addition, a 0.5m to 1.0m sea-level rise considered possible by the end of this century could render some 200km of coastal defences vulnerable to failure — 20% of the UK’s total. As a result, 200,000 hectares of land and 400,000 properties could face a 1-in-200 year tidal surge.

Water supply availability

A second study commissioned by the ASC has updated water availability projections. It finds that at present the UK has a 10% surplus of 2000 million litres per day, with only some small local deficiencies. This picture changes as temperatures and the population size rise so that by 2050 water demand could exceed supply by some 800 to 3200 million litres per day, a 5%–16% shortfall.

Further water demands by agriculture, energy generation and industry would call for water abstraction from rivers, lakes and groundwater that would have to be balanced against the needs of the natural environment.

One conclusion is that not considering floods and droughts in isolation could lead to better solutions.

Extremes

A phenomenon of the future could be more extremes of weather outside average prediction ranges.

The effects of extra high and low climate changes, collectively known as H++ scenarios, have been studied. They are unlikely to occur, but if they do their impacts could be intense. H++ scenarios are useful in testing the voracity of adaptation plans and are helping with the understanding of what could face us if extreme scenarios do begin to unfold.

As such, a series of H++ scenarios for high and low river flows, droughts and wind storms have been developed which take into account historic and geological results, global climate models, Met Office evidence and other climate research centre information.

The Thames Estuary 2100 Plan is one example of H++ possibilities that has already influenced planners who have been able to test the robustness of long-term plans to protect London. It may not be essential to fully implement expensive mitigation measures as yet so much as be aware of additional costs and the appetite for risk in the future.

For the Thames, a series of trigger point markers have been set that once reached could lead to later defence upgrades.

One extremely high emission scenario foresees daily summer time temperatures in England and Wales as high as 30°C to 34°C, with a maximum of 48°C not ruled out. Passive cooling measures for existing housing would be necessary. However, again, it is important to stress that these are extreme predictions.

Conversely, an abrupt slowdown in the Atlantic Meridional Overturning Circulation (AMOC) and reduced solar activity could result in significantly colder winters with average temperatures falling from the current 3°C to –5°C and even –14°C. This would be in line with “The Little Ice Age” seen between 1450 and 1850 when the Thames froze over in winter.

Such scenarios come with important assumptions and caveats.

Wildlife

UK wildlife and natural systems are very sensitive to change. Average temperature rises already seen have led to new species arriving in southern Britain from Europe and native species moving northwards.

A full study models the effects of temperature changes, water availability and seasonality on more than 4700 native British species and finds that spiders, ants, moths and wasps should see its climate space expand significantly. Birds, plants, butterflies and dragonflies will see little change.

Although a warm climate could, in theory, enhance wildlife diversity, this will be dependent on enough habitats in the right place in good ecological condition. Degraded rivers, waterways, estuaries, woodlands, grasslands and heathlands will make it harder for species to adapt and could accelerate species loss.

Important habitats, such as peat bogs and fens, are known to be in poor condition, including 70% of deep peats in England because of drainage, overgrazing and rotational burning. This matters because 13% of the world’s blanket bog habitat is in the UK.

Mossy habitats capture and store carbon dioxide from the atmosphere as peat — an estimated 3.2 billion tonnes of carbon in the UK. A further estimate predicts that a 5% loss of UK peatland carbon storage capacity would be equal to a whole year of current UK greenhouse gas (GHG) emissions.

Upland river and reservoir dissolved carbon levels have doubled over 30 years, suggesting that soil carbon is leaving peatlands. When drinking water with a high carbon content is disinfected during treatment, carcinogenic by-products are produced. The alternative for water companies is expensive and energy-intensive processes, with higher customer bills.

It is, therefore, economically as well as environmentally vital to restore peatlands.