Debatt: klimatrelaterad havshöjning: ett problem för Sverige?

Large changes are planned and implemented to meet the negative effects of the global warming forecasted by IPCC (Intergovernmental Panel on Climate Change). For example, some municipalities in Sweden have plans for protection walls against future rising sea levels and decisions have also in some cases been taken to build walls. All these measures and changes of the society will have and have already resulted in large economic consequences. The sea level has been measured at ports etc. in many countries for a long time. The level has so far been rising at a constant rate and the rate has not increased even though the atmospheric concentration of carbon dioxide has increased. There is, however, a great deal of uncertainty about how fast and how much sea level will rise in the future and model calculations presented by IPCC give very different results depending on assumed future concentrations of greenhouse gases. It is also difficult to give a specific “global” sea level rise since the rise velocity varies from one geographic place to another. In Sweden, the land is rising because of melting of the land ice covering the country some 10 000 years ago, resulting in a lowering of the sea level compared to the land level. In the south of Sweden, however, the land is rising much less resulting in almost no or a small increase in sea level compared to land. Thus, building walls for protection against sea level rise does not make sense because no or very small sea level rise has been observed in Sweden. Also, a possible future sea level rise will be gradual and slow, which will give time to act if needed. Protection against flooding at extreme weather situations can, however, be needed where buildings etc. are situated at low-lying areas close to the sea.