The global population is moving to coastal zones, according to United Nations reports. Nearly half of the world's population lives within 200km of coastline, and that number is likely to double by 2025 (Creel Population Reference Bureau, 2003). Although some of these are large inland lakes, such as the Great Lakes, much of the concentration is near the ocean. Sea-level rise will impact directly upon these areas as well as interior floodplains.
Highly developed countries, such as the UK and The Netherlands, have invested heavily in engineering solutions to protect urban areas from flooding. In the UK, the Thames Barrier is a massive engineering structure designed to reduce tidal river flow during storms. From 1990 to 2002, the system has operated, on average, four times per year. In 2003, however, it was put into operation 14 times, with two-thirds of all closures taking place since 2000 (Environment Agency, 2009). When designed, it was estimated that it would protect London from serious flooding through the 21st century - a forecast that seems overly optimistic today.
Much of The Netherlands was reclaimed from the sea and the small land area has been protected for centuries by systems of dikes and canals that were significantly strengthened after World War II. More recently, given sea-level rise forecasts, The Netherlands is exploring floating housing systems and other alternatives to adapt to the changing sea level as their engineers have determined that raising the dikes is no longer practical (Kolbert, 2006).
A sea-level rise of 1m jeopardizes nearly every coastal city - its economy, inhabitants and infrastructure. If the US response to the devastation of New Orleans by Hurricane Katrina in August 2005 is a guide, even developed countries may not be fully prepared to deal with climate impacts of this magnitude. If the forecasts are right, we will need to deal with similar events on a more frequent basis as the planet warms. To maintain urban stability and security in this environment, new strategies are needed to assess the risk of catastrophic flooding, new emergency plans are needed to move people and equipment in and out of danger zones, and new leadership is required to sustain support for a response capacity that is a quintessential public good. We may also have to abandon some areas and create new urban centres; but few policy-makers are yet considering how climate impacts may cause relocation, demand major new infrastructure investments or force a change from 'business-as-usual' patterns of behaviour.
The UK and The Netherlands have invested financial and technological resources to protect their coastal regions from the consequences of sea-level rise - and even these countries now recognize there will be a measure of flooding that they will have to accept. Few developing countries, however, have the capacity to undertake expensive engineered solutions.
In 2004, the Maldives were overwhelmed by an Indian Ocean tsunami that damaged critical infrastructure on 60 of the inhabited islands, and more than 20 of the smaller uninhabited islands disappeared. More than 1000 islands comprise the archipelago, and the average elevation is less than 3m above sea level. Engineering solutions are not an option for the Maldives or many other small low-lying island states that may well be inundated. The threats posed by climate change have encouraged this group to organize politically within the United Nations as the Alliance of Small Island States (AOSIS) and to promote early action and support for adaptation. With the most recent IPCC report, the international community can expect more urgent demands for action.
Bangladesh poses an even more complex challenge. The country is a floodplain with seven major rivers flowing into the low-lying area from the Himalayas. A sea-level rise of 1m will eliminate a significant portion of the country, displacing millions - a worst case scenario estimate suggests 55 million people could be displaced (Hulme, 2001). Today, the movement of 500,000 refugees has political, economic and social consequences; but a shift of 55 million would exceed the capacity of Bangladesh or its neighbouring states to manage and absorb. And if it occurred rapidly, in a decade - instead of a century - the population shift would severely pressure neighbouring states, leading to possible conflict.
A measure of the impacts of such human displacement exists in two recent mass migrations prompted by resource competition and long-term drought -the Rwandan genocide and the displacement of farmer communities in Darfur Province of Sudan. In the spring of 2004 more than 2 million people moved into refugee camps in the border area of Rwanda and the Democratic Republic of Congo as the genocide unfolded and more than 1 million Rwandans were internally displaced. The movement took less than 90 days as whole villages fled the rampaging Rwandan military. Yet the international response took weeks to mobilize and was barely adequate - although many more would have died without it. Rwanda illustrates the potential scope of human security challenges should massive migration result from climate-related change.
The Darfur conflict in eastern Sudan appears directly related to climate change (Faris, 2007). Rainfall patterns declined during the early 1990s, creating severe competition between nomadic herders and farmers. The Sudanese government openly sided with the nomads and their janjaweed militias, permitting them to force farmers off their lands. Since 2002, humanitarian experts estimate that more than 1 million people have been displaced and approximately 200,000 have died (International Crisis Group, 2007). To address the crisis, the international community has sought to establish peacekeeping operations, provide humanitarian assistance and impose sanctions on Sudan. This imperfect response has provided some protection for the refugees; but the conflict continues to simmer. International attention has been focused, justifiably, on stopping the killing; but unless the rainfall returns and the competition between herders and farmers is reduced, a sustainable solution to the crisis appears unlikely.
These conflicts - and the human consequences that ensue - offer a window on situations that could occur with greater frequency as climate change progresses. Such events further underscore the extreme vulnerability of people everywhere, but particularly in developing countries, to climate patterns that compromise traditional livelihoods. Yet, on a smaller scale, environmental migration is already under way. Hurricane Mitch in 1996 displaced entire communities in Honduras, Guatemala and El Salvador with a resultant surge in illegal and legal migration to the US (Glantz and Jamieson, 2000). Similarly, African migrants from the drought-prone Sahel continue to move into Europe. Climate change may well amplify these trends and their consequent social tensions (United Nations Foundation and Sigma XI, 2007).
Was this article helpful?