In addition to the estimates given above, even the size of the population in areas that will be particularly affected by climate change can provide a useful reference as to the number of people who will be facing special climatic challenges in future and who may possibly regard migration as an alternative.
The United Nations standing committee responsible for determining internationally recognised terminology (Inter-Agency Standing Committee, IASC)
Hydro-meteorological extreme hazard events
Environmental degradation and/or slow onset extreme hazard events
Significant permanent losses in state territory
Armed conflict/violence over shrinking natural resources
Endangered states are deemed in general to be the poorly developed island states (Small Island Developing States, or SIDS), the sub-Saharan states, Asian coastal states, the Polar region, African developing states (Less Developed Countries, or LDC), the least developed countries worldwide (Least Developed Countries, or LLDC), the Near and Middle East, and Central Asia.
Areas affected by significant, permanent losses in state territory
This phenomenon comes as a result of rising sea levels and will most probably affect the South Pacific island states in particular (Carteret Islands, Kiribati, the Maldives, the Marshall Islands, Palau, the Solomon Islands, Tokelau, Tuvalu and Vanuatu), which have come to be known as "Sinking Islands", but also low-lying coastal regions in Alaska and the Bay of Bengal. As a result of land losses and the salinisation of coastal regions, some states have already started to permanently relocate inhabitants of their island states, while other countries are not ruling out the possibility of the permanent relocation of all or large parts of their populations.
The rise in sea levels in particular, as well as its hydro-meteorological consequences (increase in periodic floods, tropical storms, coastal erosion, salinisation of coastal waters), represents an important possible inducement for mass-migration. This would affect coastal regions. in addition to small island nations,. According to the Stern Review, by 2080 between 10 and 300 million people will have been affected by the rise in sea level alone, assuming a temperature rise of between 2°C and 4°C. The IOM estimates that an one-metre rise in sea level would affect 360 000 kilometres of coastline worldwide. Roughly two thirds of the world´s population live no further than 100 km from the coast, and areas that lie a maximum of ten metres above sea level alone, the so-called Low Elevation Coastal Zone (LECZ), are home to 634 million people – nearly a tenth of the world´s current population. Of these, 360 million live in large towns near the coast (in other words, 13% of the global population living in towns). Most of the people in the zone that is affected by rising sea levels live in Asia, Africa and Europe. A current study on the rate of urbanisation in the LECZ recently showed that, alongside the small island states, the densely settled and heavily urbanised deltas and coastal areas in Asia and Africa are particularly exposed to an increased risk of flooding.
|Most strongly affected states with coastal areas up to a maximum of 10 m above sea level (LECZ)|
|States ranked according to population in LECZ||States ranked according to population percentage in LECZ|
|State||Population||In Percent||State||Population||In Percent|
|2. India||63.341.208||6||2. Suriname||317.683||76|
|6. Japan||30.477.106||24||6. Bangla-|
|7. Egypt||25.655.481||38||7. Belize||91.268||40|
|8. USA||22.859.359||8||8. Djibouti||248.394||39|
|Source: Balk (2008).|
The listed countries have a minimum population of 100,000 people and a minimum area of 1,000 km². This therefore omits, for example, the Maldives, whose total population according to the study carried out by the Potsdam Institute for Climate Impact Research is resident within the LECZ. In addition, there are 15 small island states with a total population of 423,000 where more than 39% of the population is living in low-lying coastal regions. These are also not included here.
Not everyone in the LECZ will have to leave their homes, but rising sea levels could place those in low-lying areas and areas near the coast in acute danger. According to a study carried out by the Potsdam Institute for Climate Impact Research, there are already about 200 million people living in coastal areas that lie less than a metre above sea level. Thirty of the world´s 50 biggest cities lie directly on a seacoast. In the event of a rise of just one metre, according to the study, Egypt´s Nile Delta and close to a fifth of Bangladesh (with 35 million inhabitants) would be especially affected, as too would large areas of Suriname, Guyana, French Guiana, the Bahamas, Benin, Mauritania, Tunisia, the United Arab Emirates, Pakistan, India, Vietnam and China.
In Europe, an estimated 13 million people would be threatened by a one-metre rise in sea level (especially in the Netherlands and Denmark), including about 3.2 million in the German flood plains.
Numerous other areas will in future have to contend with a shortage of drinking water due to climate change. The authors of several UN Millennium Ecosystem Assessment studies established that droughts, desertification and the associated decline in agricultural yields are among the strongest factors that will cause people from arid areas to migrate to other regions. The reason for this lies in the far-reaching impact of water shortage, which will bring with it difficulties in supplying drinking water, loss of harvest and health and hygiene problems.
Already today there are more than 1.2 billion people living in regions where there is a shortage of fresh water, i.e. where natural fresh water resources are insufficient to cover the needs of the people living there.
Regions vulnerable to conflict over natural resources
In addition to emigration movements, the impact of climate change may also lead to conflict over resources. An external WBGU report concludes that, where possible climate-related conflict is concerned, the core regions are in Africa, Asia and Latin America. The climate-induced decrease in cultivable land and water resources affects a population with a growing percentage of youth who already today are likely to migrate into the cities. This could promote religious, ethnic and civil conflict.
No matter which trigger for possible environmental migration we examine more closely, those most severely affected will be the small island states as well as the LDCs and LLDCs of Africa and Asia. But not all of the people living there will migrate for environmental reasons. Infrastructure measures to shore up the coasts, water management plans and new technologies might suffice in a large number of countries and regions to lessen the impact of climate change. Yet, even if only a few percent of the people affected by climate change become environmental migrants, their numbers may reach the scale of the currently estimated refugees and internally displaced people (IDPs) (as at the end of 2008: approx. 42 million).