Oceans and lakes

Sea levels are likely to rise for a very long time in the future. Even water levels in lakes may change in a future climate.

The Intergovernmental Panel on Climate Change (IPCC) represents the most widespread scientific assessment of climate trends and future global sea level change. In January 2007, IPCC’s fourth assessment report was presented, which was based on the available climate science at that time.

Since then, several new scientific articles have been published highlighting the risk that global sea level could rise faster than what IPCC indicated in 2007. This concern has also been pointed out in several international synthesis reports produced to support adaptation to climate change in coastal areas.

Usually calculations of sea level by 2100 are reported, but sea levels are very likely to continue to rise for a long time after that. Adaptation to climate change also requires taking local conditions into account such as land rise and winds. Heavy storms provide the most extreme water levels.

Adaptation actions require both a dialogue with those responsible for the consequences, and that other factors are considered such as; acceptable risk, what values are at stake, the planned object's lifespan and future possibilities to adapt to new conditions.

Conditions in lakes

Water levels in lakes depend mainly on how large inflows and outflows are and how the lakes are regulated. Control strategies are likely to change as the climate changes. It is not possible to give a general picture of how the water level in the lakes is expected to change in future climate. This varies between lakes, but also between seasons. Some lakes are expected to have increased water levels during certain parts of the year, while others may have low water levels, mostly during the summer.

Climate scenarios indicate an increase in air temperature, which in turn affects the ice on the lakes. According to previous studies ice formation is expected to occur later and ice break-up earlier in a future climate.