Climate change

The climate has always varied, with warmer periods being interspersed with cooler periods. However, the real problem now is that the changes are happening so quickly that the environment, plants and animals are unable to adapt.

One obvious effect of climate change is that the sea is growing warmer. The effects will be clearest towards the poles. By 2100, the average temperature of the Baltic Sea region is expected to rise by 3-5°C.

The majority of this warming will occur in the northern and eastern parts during the winter months, and in the southern parts during the summer. This would extend the growing season by 20-50 days in the Northern Baltic and by 30-90 days in the southern parts by the end of the century.

This climate change is due to mankind emitting large quantities of greenhouse gases, particularly carbon dioxide. The emissions come from us burning fossil fuels. In a hundred years’ time, the planet’s average temperature may have risen by between 1°C and 6°C. The effects of climate change can already be seen, not least in the sea, which is also being acidified by carbon dioxide.

The main cause of carbon dioxide emissions is burning oil, coal and gas. Over the last century, the sea has absorbed around 40% of these emissions. Carbon dioxide levels in the sea increase when carbon dioxide is dissolved in sea water. Carbonic acid levels rise, lowering the pH value. Many marine creatures and plants form calcium skeletons, which is more difficult in a more acidic sea. This includes corals, mussels, molluscs, crustaceans, sea urchins and certain species of phytoplankton. Other animals and plants are also affected by acidification, affecting the entire marine food web.

These pages include factual information from - a site run by Stockholm University, Umeå University, the University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) within the collaborative framework of the Swedish Institute for the Marine Environment, and in cooperation with the web agency Azote.

Baltic Sea Science Center