This indicator shows trends in the area of Arctic sea ice in March (annual ice maximum) and September (annual ice minimum). Satellite observations cover the period from 1979 until now. Projections until 2100 are based on an ensemble of climate models from the CMIP6 exercise, which informs the Intergovernmental Panel on Climate Change Sixth Assessment Report. Note that earlier versions of this indicator have shown the extent rather than the area of Artic sea ice, which is closely related, but can lead to somewhat different numbers.
The indicator also shows observations of maximum annual ice extent in the Baltic sea, reaching back to 1719.
Methodology for indicator calculation
Observations of Arctic sea ice were available from the EUMETSAT OSI SAF reanalysis project, in which a consistent time series of daily, gridded data for sea ice concentration is made from the passive microwave sensors SMMR and SSM/I data. Monthly aggregated sea ice products are provided by theEUMETSAT OSI SAF. Projections for Arctic sea ice area were derived from the CMIP6 ensemble experiment.
The annual maximum ice extent in the Baltic Sea was estimated based on three sources. Ice extent for the winters of 1720-1940 is based on a construction from various sources, including observations at lighthouses, old newspapers, records of travel on ice, scientific articles, and air temperature data from Stockholm and Helsinki. Data for 1945-1995 stems from the Finnish operational ice service. Data since 1995 are based on satellite observations.
The graphs show the data as delivered; linear trend lines and moving averages were added.
Methodology for gap filling
Not applicable.
Methodology references
No methodology references available.
Observed changes in the extent of sea ice provide evidence of global warming. Reduced Arctic sea ice will accelerate global warming through the ice-albedo feedback. Several studies have also suggested causal links between Arctic sea ice decline and summer precipitation in Europe and the Mediterranean. Reduced Arctic ice cover may also lead to increases in heavy snowfall in Europe during early winter.
The projected loss of sea ice may offer new economic opportunities for oil and gas exploration, shipping, tourism and some types of fisheries in the Arctic. Most of these activities would increase the pressure on, and the risks to, the Arctic environment.
Targets
No targets have been specified.
Related policy documents
No related policy documents have been specified.
Methodology uncertainty
Not applicable.
Data sets uncertainty
No uncertainty has been specified.
Rationale uncertainty
No uncertainty has been specified.