Environmentally sustainable populations: why the statistics matter Royal Statistical Society, 19 April 2007 Martin Desvaux Rosamund McDougall Optimum Population Trust Discussant: Professor David Coleman, Oxford University Chair: Philip Turnbull, RSS

World population growth: 2.5 billion more humans by 2050? Optimum Population Trust

The world is getting hotter Map: Geophysical Fluid Dynamics Laboratory, Princeton University IPCC temperature trends scenario Surface air warming in the 21st century: Best estimate for low scenario: 1.9º - 2.9ºC Best estimate for high scenario: 2.4º - 6.4ºC Likely warming in next two decades: 0.4º Fourth Assessment Report, Working Group 1, IPCC, February 2007

Less water for more people GEO 2000, United Nations Environment Programme, Earthscan

More people, more urbanisation, more consumption, more waste 1950: 2 megacities with populations of more than 10 million: Tokyo and New York. 2005: 20 megacities: Tokyo conurbation 35 million. Half of world’s 6.5 billion people live in urban settlements. 2030: 60 per cent of world population will be urban dwellers: 4.9 billion people. World Urbanization Prospects: The 2005 Revision, UN, 2006

A future population crash or environmentally sustainable population policies now? Optimum Population Trust Climate change is happening The world cannot support another 2.5 billion or more people The world, nations and individuals need to mitigate and adjust to climate change The world - and each nation - needs to have an environmentally sustainable population policy. Globally, full access to family planning services is needed for the 350 million couples who do not have it The UK has failed to curb population growth - 10 million more people are expected in the next six decades

Slower world population growth: only 1.1 billion more humans by 2050? Optimum Population Trust

The UK - environmentally stressed and shrinking Sea level rises Department of Geomatic Engineering, Benfield Hazard Research Centre Sea level rose by about 20cm in the 20th century, and the UK Met Office estimates a further 41cm rise by 2080, without taking into account catastrophic melting of ice sheets. Melting of either the Greenland or West Antarctic ice sheets would raise sea level by about 7 metres. If both these ice sheets melted, sea level rise would rise by about 13 metres. With additional melting of the East Antarctic ice sheet, sea level could rise by 84 metres. 7m13m84m

UK population - growing by more than 300,000 a year Optimum Population Trust

Housing need with population growth of 0.5% a year: England Optimum Population Trust

Housing need with population decrease of 0.25% a year: England  Optimum Population Trust

Traffic growth and population growth UK Optimum Population Trust

Traffic growth and population decrease UK Optimum Population Trust

Climate change and population growth UK Optimum Population Trust

Climate change and population decrease UK Optimum Population Trust

Why are these statistical relationships ignored? Governments, policymakers, and the media think short-term: lack of historic data and long-term projections and scenarios. Government departments, academic researchers and others think in diminishing boxes: increasing specialisation, Government statistics have been presented under tight political control. Population issues have been, until recently, distorted by highly emotive debate. This has stifled rational discussion about population and environment issues and delayed essential policy making. The longer the delay, the more painful the solutions are likely to be. Optimum Population Trust

Climate change is making people think differently Potentially catastrophic Impacts of small but cumulative changes over the long- term require long-term information and analysis. Population growth is being recognised as one of the main drivers of climate change and environmental deterioration. There is recognition of the need for joined-up international and national policies to mitigate and adapt to climate change It is becoming easier to hold a rational debate about population issues, and about the migration component. Each extra Briton will generate about 740 tonnes of CO2 during their lifetime. Ten million more people by 2074 means cutting emissions by 15% just to stand still. UK policymakers are beginning to understand the environmental impacts of continuous population growth. Optimum Population Trust

Action needed in the UK England is the fourth most-densely populated country in the world. The UK is the seventeenth, and more densely populated than China. Using the latest ecological footprint estimates, the UK’s environmentally sustainable population could be as low as 17 million. Rapid population decrease is neither feasible nor advisable. OPT recommends a UK policy of gradual decrease of at least 0.25% a year, to be achieved by preventing more unwanted pregnancies, especially among teenagers, by encouraging smaller family size and by zero net migration. Decrease of 0.25% leads to a UK of 54m in 2050 (51.8m if started in 2000). GAD based Natural Change Only projection leads to 57.7 m in The ONS is being given greater independence and methods of collecting population data will improve. This will help future governments to formulate a new and environmentally sustainable population policy. Optimum Population Trust