Adapting to the impacts of climate change will be a painful process for people around the world. Adapting our homes and habits to the floods, droughts, storms, rising sea levels and hotter summers it heralds will mean giving up things we care about and the places we love. Reports of the United Nations Intergovernmental Panel on Climate Change (IPCC) in 2007 show that rising global temperatures will alter the geography of where we live, whether it is in cities, flood plains or the coast. How and where the next generation will move is a major issue for international governments, even if they don't know it yet.

Take two places where people are contemplating this very different future. In the English villages of coastal Norfolk, erosion and sea-level rise is already affecting local residents' livelihoods and their plans for the future. At Happisburgh and elsewhere, the sea has already eroded the soft cliffs and claimed a number of homes and other properties.

Residents are concerned about the uncertain future for their families and villages. Current projections for the rise in sea levels by 2100 are between 15 centimetres and 60 centimetres. Where will people live, where will their children go to school, and what is the future of their communities?

Dr Sophie Nicholson-Cole, of the United Kingdom’s Tyndall Centre for Climate Change Research, says: "The local council is funding a few more years of coastal protection while looking creatively at how to help villages adapt to the already changing coastline. It may not be long before long-term residents and businesses decide to throw in the towel."

Rising sea levels already have reached the doorstep of the people of Tuvalu, a nation of small islands in the Pacific midway between Hawaii and Australia. There the 11,000 citizens are similarly contemplating their future. The islands' low-lying terrain means that Tuvaluans are likely to become the world's first climate-change refugees and that global warming may mean wholesale relocation elsewhere. New Zealand immigration policy currently has a quota of 75 migrants from Tuvalu per year

The climate change risks are with us now, and the prospect of migration looms large for some. But no one wants to move. Dr Saleemul Huq from the International Institute for Environment and Development (IIED) in London is calling for massive international funding to allow the poorest countries to adapt in situ because people have a right to security and safety where they live.

A British child born in 2007 will be 50 in 2057. What will life be like for our 50-year-old citizen? Here is a plausible scenario:

Summer top temperatures will be around 38C (100F), winters will be shorter and floods more frequent. To combat the latter, the government already will have controlled, through the planning process, where people live. Houses, businesses and land already in risky areas will have lost value because insurance companies will have withdrawn protection. People will simply choose not to live in risky areas. But, as now, climate change will retain the ability to spring unforeseen weather surprises.

Climate change will have brought about significant population shifts, primarily relocating the world's poor. Mediterranean Europe, North Africa, California and the southwest United States in 2057 has become severely water-stressed. In the northern hemisphere, there are frequent severe storms with concurrent summer droughts. The UN climate reports’ predictions in 2007 were right: up to 500 million people in south Asia and Africa live with incomes that put them at risk from hunger. This has exacerbated political instability in the worst-affected regions, including in the Horn of Africa and west and southern Africa.

Despite the problems of planning risk, the rush to the coast, begun in the 20th century, continued: 350 million people had moved to the coastal cities of China by 2027. These cities by the sea invested heavily to protect their new infrastructure from rising sea levels, flooding and limited fresh water. Adaptation is easier done with new building than in the ancient European capitals. All continents lose agricultural productivity. The rural poor stay poor.

Public health agencies in 2057 are stretched by new diseases and the resurgence of malaria, diarrhoea and dengue fever -- diseases transmitted through pests and in water. The three decades from 1970 to 2000 saw 30 emerging infectious diseases, including HIV, Ebola, Lyme disease and toxic E. coli, and the trend continues. In rural Africa, health-care needs overwhelm national health agencies. Ill health acts as a significant constraint on Africa's economic productivity.

A major issue for the UN is the fair allocation of migration-compensation quotas. This proposal is for polluting countries to allocate emigration quotas to affected countries on the basis of historical responsibility for the pollution and subsequent extreme weather that led to displacement. The proposal is fiercely resisted by the major pollution of the G8+4, who seek limited immigration by skilled workers, rather than taking on environmental refugees.

Given what we know about climate change in 2007 and where it will have the most impact, future migration, in effect, will be a failure of adaptation to climate risks. The decision to adapt or move leads to tough choices now and in the future for the people of Tuvalu, Happisburgh and other vulnerable regions across the world.

Neil Adger, a professor at the University of East Anglia, leads the Tyndall Centre's research into adaptation to climate change. He was a convening author of this year's United Nations report on vulnerability to climate change and adaptation to its impacts.

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