Arctic sea ice forecasts

It is widely accepted that the volume of Arctic sea ice has on average been declining over the last thirty years. However, the extent of the sea ice cover in the Arctic remains variable as synoptic weather conditions play a role in determining the growth and melt of sea ice and its movement within the Arctic basin. Arctic sea ice reaches its minimum extent in September and we are currently participating in the Sea Ice Prediction Network international effort to provide a community-wide summary of the expected September mean Arctic sea ice.

International sea ice outlook

The sea ice outlook includes estimates of September mean sea ice extent from dynamical, statistical and heuristic methods which are combined to provide the median of the estimates. Since 2010, the Met Office has provided an estimate based on our seasonal forecast system. The estimated sea ice extent (for the forecast started in June, unless otherwise specified) from the  sea ice outlook for 2010 onwards is shown in the table:

         Year

Outlook median (× 106 km2)

Outlook range (× 106 km2)

Observed (× 106 km2)

Met Office contribution (× 106 km2)

Outlook document

2020

(June)

2020

(July)

2020

(August)

4.3

 

4.4

 

4.3

4.1-4.6

 

4.1-4.6

 

4.1-4.5

 

4.6 ± 0.6

 

4.7 ± 0.7

 

4.4 ± 0.5

2020 SIPN report

2020 SIPN July report

 

2020 August SIPN report

2019

(June)

2019

(July)

4.4

 

4.3

 

4.2-4.8

(quartiles)

4.0-4.6

4.32

5.2 ± 0.6

 

5.2 ± 0.7

2019 SIPN report

 

2019 SIPN July report

2018

(June)

2018

(August)

4.6

 

4.6

3.4-5.9

 

3.4-5.2

 

4.7

 

4.9 ± 0.6

 

4.9 ± 0.4

2018 SIPN report

2018 August SIPN report

2017

(June)

4.4

3.4-6.0

4.8

3.6 ± 1.0

2017 SIPN report

2016

(June)

4.3

4.1-4.6

4.7

4.4 ± 0.9

2016 SIPN report

2015 (June)

 

2015 (August)

5.0

 

 

4.8

3.3-5.7

 

 

2.7-5.6

 

 

4.6

 

4.4 ± 0.9

 

 

3.7 ± 0.7

 

2015 SIPN report

2014 (June)

2014 (August)

4.7

 

5.0

3.2-6.3

 

4.0-5.6

5.3

4.1 ± 1.0

 

5.3 ± 0.6

2014 SIPN report

2013

4.1 3.4-6.0 5.4 3.4 ± 1.5

2013 SEARCH report

2012 4.4 4.1-4.9 3.6 4.4 ± 0.9

2012 SEARCH report

2011 4.7 4.0-5.6 4.6 4.0 ± 1.2

2011 SEARCH report

2010 5.0 1.0-5.7 4.9

5.5

 

2010 SEARCH report

Met Office contribution to the outlook

Given current capabilities for seasonal forecasting of sea ice, we consider our contribution to the outlook as an experimental forecast. A prediction of regional-scale ice coverage is beyond the capabilities of current long-range forecasting. Therefore our estimates are restricted to the extent of the Arctic sea ice. This is defined as the area of the Arctic Ocean with at least 15% ice coverage. In the long-term average, this area varies from 14.4-16.5 million km2 in March to 3.6-8.0 million km2 in September (based on data for 1979-2017). The minimum extent for September since 1979 (the satellite period) was 3.6 million km2 in 2012, almost 20% below the next lowest ice extent of 4.3 million km2 in 2007.  March 2017 represented the lowest March maximum during the satellite period, with a maximum extent of 14.4 million km2.

The August outlook for September 2020 sea ice extent, based on the ensemble mean of 42 forecasts, is 4.5 milion km2 with an uncertainty of 0.5 million  km2. Shown below are our forecast ice extents (blue circles) compared to the observed ice extents during the 1993-2016 period (black squares) with the most recent forecast shown as a red diamond.

Regional predictions of ice cover are still very experimental.  In a collaborative effort to improve these regional predictions, the Met Office provides maps of sea ice probability - the probability that ice fraction is over 15% in a given grid cell - as part of a SIPN multi-model ensemble.  The forecast from August of sea ice probability in September 2020 as provided by the Met Office is shown in the figure below.

 

Related pages

  • Arctic sea ice briefs: An archive of Arctic sea ice briefing documents.
  • Sea ice in the climate system: Arctic sea ice is a sensitive indicator of climate change and changes to the sea ice cover can have potential implications for the Arctic region and beyond.
  • Sea ice - an introduction: Sea ice is a critical component of the Earth's climate system and has a wide-reaching impact beyond the polar regions.