Last reviewed 25 February 2014

Both the UK and the wider world are facing increasing pressures on land available for housing and food production, placing more pressure on limited resources such as biodiversity. More people, the movement of populations into urban areas and worsening impacts from climate change are also playing a role in the growing problem. Rob Bell reports.

The Town and Country Planning Association (TCPA) has published a report (The Lie of the Land: England in the 21st Century) warning of a “looming environmental catastrophe in parts of eastern England, with climate change and rising sea levels threatening communities and food production”. In addition, a report by the Institution of Mechanical Engineers (IMechE) on the global picture warns that the world population shift to urban areas is increasing the risk of natural disasters because: a) people are moving to earthquake-, storm- and flood-prone areas and city slums; and b) natural defences are being removed.

A research paper from the Computation Institute's Centre for Robust Decision Making on Climate and Energy Policy (RDCEP) at the US Argonne National Laboratory has found that a warmer world is expected to have “severe consequences for global agriculture and food supply, reducing yields of major crops even as population and demand increases”.

Its analysis, which combined climate, agricultural and hydrological models, found shortages of freshwater for irrigation could double the detrimental effects of climate change on agriculture. The RDCEP said: “Given the present trajectory of greenhouse gas emissions, agricultural models estimate climate change will directly reduce food production from maize, soybeans, wheat and rice by as much as 43% by the end of the 21st century. But hydrological models looking at the effect of warming climate on freshwater supplies project further agricultural losses, due to the reversion of 20 to 60 million hectares of currently irrigated fields back to rainfed crops.”

The TCPA report goes on to warn the concentration of economic, political and cultural activity around London and the greater south east makes England “one of the most polarised of the advanced nations”, requiring the Government to address the condition of England at a “national and strategic scale”.

TCPA Chief Executive Kate Henderson says: “The report throws up a series of questions that urgently need addressing — principally the capacity of the Government, as currently organised, to cope with the environmental, economic and social challenges facing the country.

“It is a matter of concern that England — unlike Scotland and Wales — has no Government Department or Agency charged with addressing acute strategic or spatial problems across the country. For instance, the threat of climate change is one of the greatest challenges facing England and has major implications for food production, with the greatest proportion of top grade agriculture land located in the south and east of the country.”

Environmental Consultancy Ricardo-AEA’s Resource Efficiency and Waste Management Practice Director Adam Read says: “Land area is finite, and scarce in some respects, with multiple demands on the resource.

“For food and other agricultural goods, land quality is important. Productive land is often in most demand for other competing uses (such as housing development, which often occurs in areas where food could be grown), so productive land is scarcer than less productive land.

Key impacts

According to the TCPA report: “Climate change is, by a considerable order of magnitude, the biggest threat to the nation’s future in the 21st century. Key impacts, such as extreme weather, heat and sea level rise, make it imperative to consider the nation’s vulnerabilities, notably in the East of England.

“We argue there is now a renewed and urgent need to re-examine future population distribution in the light of these critical vulnerabilities and to decide on the future of those communities most at risk.

“This also means urgently addressing the medium- to longer-term consequences of water availability for households and for business in those areas of the South East already under water stress.”

The TCPA’s findings relating to the UK dovetail with the wider global picture presented by IMechE. Its report says: “The unprecedented influx of people to urban areas across the developing world is leading to a large increase in people living in locations susceptible to natural disasters, and the situation is exacerbated by the explosive expansion of informal settlements or slums. About 180,000 people move to urban areas every day, with 18% of all urban housing being non-permanent or slums, which are particularly vulnerable to the impact of extreme natural events.

“In addition, many of the world’s largest cities are located in earthquake-, storm- and flood-prone areas (three-quarters of the world’s largest cities are located on a coast), and urban land development is leading to the degradation or even total destruction of natural barriers like swamps, wetlands and mangroves. Globally, changes to ecosystems have contributed to a significant rise in the number of floods and major wildfires on all continents since the 1940s.”

Resilience and preparedness

IMechE Head of Energy and Environment Dr Tim Fox, Lead Author of the report, says: “Extreme natural events like earthquakes, storms and floods are not in and of themselves disasters. Given adequate levels of preparedness and resilience many disasters could be avoided and lives and communities saved.

“The shift towards urban living means more people are locating on coasts, more of the land that historically protected communities from floods like wetlands and swamps has been removed thanks to inappropriate development, and there has been a substantial rise in the number of people living in informal settlements or city slums. This means more people are exposed to the risk of being involved in a natural disaster.

“It is clear that much more needs to be done to focus international development funding on resilience and preparedness. There is also the need for engineers to be more involved in the short-term response to natural disasters that have occurred, to help ensure effective decisions are made for the longer term.

Fox tells Croner: “The total amount of land surface on the planet is approximately 14.8 giga-hectares (Gha), of which 10Gha is capable of supporting biomass (is not desert, tundra, mountains etc); some 50% of the latter is currently utilised for food production. The amount of land used for human habitation, in the form of towns and cities, is relatively small at 0.03Gha. Thus only around 50% of the available suitable land is already appropriated.

“Although this might suggest there is plenty of room for the expansion of human activity in food production and urban growth, it needs to be recognised that the balance of unused land currently supports the world’s remaining natural ecosystems. Considerable tensions are likely to emerge in the coming decades as competition develops for use of available land between the need for food production, demands for preservation of ecosystems and the desire to produce biomass as a source of renewable energy.”

Both the TCPA and IMechE agree governments need to consider future land use more carefully.

The TCPA report also says: “With the revocation of regional planning and the abolition of Regional Development Agencies, England no longer has an effective regional framework to deal with the pressing issues of housing and climate change.”

Biofuels and land use

According to Read, the UK (and other) governments do recognise the issue of pressure on finite land resources, but he says: “Governments have competing pressures and policies often reflect this. For example, impacts from land use change (direct and indirect) are considered by governments when making policy decisions about biofuels, and this is related to land availability.”

Fox also raises biofuels as an important issue in the land use debate. He says: “Governments around the world are becoming increasingly aware of the need to mitigate land use tensions through appropriate holistic decision-making, particularly in regard to the unforeseen tensions that emerged in the past decade from initiatives that encouraged greater production of biomass for biofuels at the expense of food production.

“The 2003 EU Directive on renewable fuels for transport was a significant landmark in this regard. It established the goal of reaching a 5.75% share of renewable energy in the transport sector by 2010 and as such led to a dramatic increase in biomass production for biofuels across the world, with unforeseen impacts on stocks of grain, food prices and food security. As a consequence it is now widely recognised by governments that in formulating renewable energy policies care must be taken to understand potential global land use tensions that may result, and to design initiatives that mitigate against such outcomes.

Rising sea levels and flooding

But while governments can influence how land is used, rising sea levels are another matter altogether. While the TCPA points to the East of England as particularly vulnerable to the growing impacts of climate change, the IMechE report shows nations worldwide face a growing threat.

Fox says: “Throughout the 20th century and into the 21st, there has been a continuous demographic shift, characterised by a mass human migration to cities and urban landscapes, many of which are located on sites vulnerable to the impacts of extreme weather events, climate change and sea level rise.

“These include settlements susceptible to flooding from adjacent rivers, estuaries and lakes, or on coastlines exposed to storms, tsunamis and extreme tides. Of particular concern are the effects of global warming induced sea level rises on coastal cities. Three quarters of the world’s large cities are on the coast and some of the biggest are based on deltaic plains (such as Dhaka, Bangkok and Shanghai), where land subsidence will exacerbate water level rises.

“In the United States alone, 39% of the population live in areas directly on the shoreline, and this is projected to grow from 122 million people today to 134 million in the second decade of this century. With rising sea levels and an increase in extreme weather events as a result of climate change, many of these residents will be at risk from the impact of storm surges and flooding.

“Given that river and coastal-based cities account for about 80% of global GDP, and 380 million people are already at risk of flooding today, as sea levels rise and climate change occurs the impact on living space will become tangible and in some cases extreme. Urgent action is therefore needed to implement adaptation measures, develop preparedness programmes and build resilience in infrastructure and communities if cities like New York, Mumbai, Boston, Sydney and Shanghai are to thrive as living spaces into the future.”

Flooding has also proved a major issue in the UK in recent years, and according to the TCPA report: “Redistributing our population to avoid flood risk areas or water shortages is an increasingly urgent imperative and requires policy-makers to think about England at a national and strategic scale.”

It continues: “Decisions to flood-defend the east coast of England — where the nation’s best agricultural land is concentrated — must be made now, and such defences will have to be built to much higher standards than had been anticipated.”

Despite the flooding events of recent years, including those that have occurred at the beginning of 2013, housing in the UK continues to be built in risk areas.

Read says: “Before 2010, development was controlled by Planning Policy Statements. PPS 25 prescriptively sought that developments should have a flood risk assessment. There was emphasis that developments should not be built in flood plains.

“Then the recession hit and the change in Government replaced Planning Policy Statements with the National Planning Policy Framework. The result is that development in flood plains continues to go ahead where there are other overriding interests.

“The main way forward is to encourage new developments to be sustainable by building out flood risk.”

While UK policy seems to be backtracking, Fox says that, internationally, recognition of the part played by natural barriers in natural disaster mitigation is leading to a growing interest in the conservation and restoration of these types of structure.

Other actions could be taken to help mitigate against the increasing scarcity of land resource. For example, Read says: “Productivity can be increased to produce more on a finite area, reducing pressure on land that is providing other services. And better planning of land use at national level would help ensure other uses such as commercial and residential developments minimise competition for land with high value for production of food and other ecosystem services.

“Finally, policy measures to encourage sustainable consumption could be introduced. Land can feed more people if people do not over-consume and if the types of food consumed are appropriate.”