Key fact

Almost every new scientific study predicts a faster sea level rise than the preceding ones!


Global warming, believed to mainly be caused by increasing levels of the greenhouse gas carbon dioxide in the atmosphere, is the main cause of global sea level rise. The sea level rise consists of two main components. One is the increase of volume of existing sea water caused by the warming of it, which may have been the major contributing component during the 20th century. The other is the addition to the seas from melting ice sheets on land, which is believed to be the major component during the 21st century. The reason for the change is mainly that the melting of ice sheets on land has increased during the 20th and 21st century.


Approximately 17,000 BCE (= 17,000 BC), the ice sheets formed during the Weichselian ice age started melting away, and up until approximately 5,000 BCE, they had contributed to a sea level rise of approximately 120 m in 12,000 years, i.e. 1 m/century or 10 mm/year. After this, the speed of sea level rise decreased, and in the next 5,000 years, up until 0 BCE, sea level rise was approximately 4 m, i.e. 0.08 m/century or 0.8 mm/year. In the next 1,800 years, until 1800 CE (= AD 1800), the sea level rise was only approximately 0.120 m, i.e. 0.007 m/century or 0.07 mm/year. Between 1800 CE and 1900 CE, the sea level rise was approximately 0.06 m/century or 0.6 mm/year, between 1900 CE and 2000 CE, the sea level rise was approximately 0.18 m/century or 1.8 mm/year, and at present, 2017 CE, the sea level rise is approximately 0.34 m/century or 3.4 mm/year. Sea level rise estimates can vary depending on statistics on actual measurements.

Meltwater pulses

The melting of the ice sheets between 17,000 BCE and 5,000 BCE was no smooth process, but periods of rather slow sea level rise were interrupted by catastrophic episodes, where sea level could rise many meters in just a few centuries. At least one such episode is known, Meltwater pulse 1A approximately 11,800 BCE, when the sea level rise was 16-25 m in 400-500 years, i.e. 3.2-6.3 m/century or 32-63 mm/year. Two more are possible, Meltwater pulse 1B approximately 9,300 BCE, when the sea level rise was 6-13 m in 300 years, i.e. 2.0-4.3 m/century or 20-43 mm/year, and Meltwater pulse 1C approximately 6,000 BCE, when the sea level rise was approximately 6.5 m in 140 years, i.e. 4.6 m/century or 46 mm/year.

New meltwater pulses

Many scientists believe that the catastrophic episodes above were caused by rapid collapses of major ice sheets. Today, there are observations indicating that the same can be happening to the West Antarctic ice sheet, possibly causing a 3-4.8 m sea level rise in just 60-100 years, i.e. 3.0-8.0 m/century or 30-80 mm/year, and to the Greenland ice sheet, possibly causing a 3-7.2 m sea level rise in 100-300 years, i.e. 1.0-7.2 m/century or 10-72 mm/year. In the past 10 years, the belief that sea level rise, even in the near future, can be predicted by extrapolating the current average rate of sea level rise, has been challenged by new observations and models, indicating that sea level rise can accelerate much faster than what was the general belief just a few years ago. In fact, almost every new scientific study, based on more data and better understanding of mechanisms, predicts a substantially faster ice sheet melting and sea level rise than the preceding ones.

Previous history

During the last interglacial (Eemian), 130,000-115,000 year ago, when the temperature was 1-2 centigrades above the present, global sea level is estimated to have been 5.5-10 m above the present, mainly owing to increased melting of Greenland and Antarctic ice sheets. The last time the atmospheric carbon dioxide level was at 400 ppm, the same level as at present, during Pliocene, 5.3-2.6 million years ago, global sea level is estimated to have been peaking at 88 m above present 5.3 million years ago, 55 m above present 3.8 million years ago, and 16 m above present 3.0 million years ago. The reason we don't see the same effects at present is an inertia making warming lag behind carbon dixoxide levels and melting of ice sheets lag behind warming.

Total melting

So, looking back to before the last few ice ages, the present ice sheets on and around Greenland and Antarctica are not given, but may be seen as remains from the last ice age, yet to melt. If those, and other remaining ice sheets, e.g. the glaciers in the Arctic archipelago and in major mountain ranges, would melt, they would add in total approximately 65 m to the sea level, on top of the 120-130 m added by other already melted ice sheets. Even if such a melting, if it occured, according to present models would take thousands of years, rather than centuries, like for Greenland, or decades, like for West Antarctica, it has been taken into account when presenting the effects of sea level rise in these pages. Here is a global overview of effects of sea level rise.

Post-glacial rebound

Sweden is still undergoing a post-glacial rebound after the Weichselian ice age, excluding the sea level rise, varying between at most 1.05 m/century or 10.5 mm/year just north of Skellefteå in northern Sweden, to at least 0.08 m/century or 0.8 mm/year at Trelleborg in the southernmost part of Sweden. In Stockholm, it is 0.53 m/century or 5.3 mm/year, in Göteborg 0.31 m/century or 3.1 mm/year, and in Malmö it is 0.10 m/century or 1.0 mm/year. This means the effects of the global sea level rise is somewhat mitigated in big parts of Sweden, the most in the north and the least in the south. At the present global sea level rise of 0.34 m/century or 3.4 mm/year, the net effect is zero in a belt stretching across Fårösund (northern Gotland), Figeholm (between Oskarshamn and Västervik), Hultsfred, Vetlanda, Vaggeryd, Borås, Göteborg and Porsgrunn (in Norway). Maps and videos in these pages show the effects of the net sea level rise, i.e. global sea level rise minus local post-glacial rebound. Other local conditions may also affect the sea level rise, but have not been taken into account here.