{"id":9214,"date":"2026-05-28T12:11:57","date_gmt":"2026-05-28T10:11:57","guid":{"rendered":"https:\/\/nersc.no\/?p=9214"},"modified":"2026-05-28T12:14:44","modified_gmt":"2026-05-28T10:14:44","slug":"marine-heatwaves-are-becoming-more-frequent-and-longer-lasting-around-svalbard","status":"publish","type":"post","link":"https:\/\/nersc.no\/en\/features\/marine-heatwaves-are-becoming-more-frequent-and-longer-lasting-around-svalbard\/","title":{"rendered":"Marine heatwaves are becoming more frequent and longer-lasting around Svalbard"},"content":{"rendered":"

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Marine heatwaves are becoming more frequent and longer-lasting around Svalbard<\/h1><\/div>[vc_column_text css=””]Marine heatwaves, periods when ocean temperatures stay unusually high for days or weeks, are becoming more common in Arctic waters. A new study shows that around the Svalbard Archipelago; these events now occur more often and last longer than they did just a decade ago.<\/strong><\/p>\n

Marine heatwaves are known to affect marine ecosystems worldwide, but detailed studies in the Arctic are still limited. This is particularly true for heatwaves below the ocean surface. The waters around Svalbard are of special interest, as they lie at the boundary between warm Atlantic currents and colder Arctic waters.<\/p>\n

More frequent and longer-lasting events
\n<\/strong>By analysing ocean temperatures from 1991 to 2022, the researchers found a clear increase in both the frequency and duration of marine heatwaves around the Svalbard Archipelago during the last decade. In some areas, events now occur several times each year.
\nThe strongest changes in duration were detected west of Svalbard. Since around 2011, long-lasting summer marine heatwaves have become more common in this region, with some events lasting close to a month. Several of these heatwaves covered wider areas, including large parts of the Barents Sea.
\nWhile the peak temperatures during individual events have changed little, longer duration means that the ocean remains unusually warm for extended periods of time.<\/p>\n

Heatwaves are not just at the surface
\n<\/strong>A key contribution of the study is that it also investigates what happens below the ocean surface. Several of the long-lasting summer marine heatwaves extended deep into the water column, in some cases reaching several hundred metres below the surface.
\nSubsurface marine heatwaves are still poorly studied in the Arctic. By showing how both surface and subsurface events can be identified and analysed, the study provides new insight into how heatwaves develop and persist in this region.<\/p>\n

Ocean currents are the main driver
\n<\/strong>To understand what causes marine heatwaves around Svalbard, the researchers examined both atmospheric heating and heat transported by ocean currents. Their results show that for most prolonged events west of Svalbard, heat carried by ocean currents plays a greater role than heat input from the atmosphere.
\nWarm Atlantic water flowing northwards brings large amounts of heat into the region, helping to trigger and maintain marine heatwaves. Atmospheric conditions still contribute, particularly at the onset of events, but ocean heat transport is the dominant driver for most of the long-lasting heatwaves identified in the study.<\/p>\n

Why this matters
\n<\/strong>The waters around Svalbard support productive ecosystems and important fishing grounds, and commercial fishing takes place throughout much of the region. Knowing where marine heatwaves occur, how deep they reach, and how widespread they are can provide useful information for fisheries and ecosystem management.
\nThe results are also relevant for policy makers. Svalbard is included in one of Norway\u2019s Ocean Management Plan areas, and improved knowledge of marine heatwaves can support long-term planning in a rapidly warming Arctic ocean.<\/p>\n

As climate change continues to affect the Arctic, marine heatwaves are expected to become more common. This study provides new insight into how these events are developing around Svalbard, and into the processes that drive them.<\/p>\n

Key researchers:<\/strong> Marianne Williams-Kerslake<\/span><\/a>, Helene R. Langehaug<\/span><\/a>, Annette Samuelsen<\/span><\/a>, Noel Keenlyside<\/span><\/a>[\/vc_column_text][\/vc_column][vc_column width=”1\/3″ css=”.vc_custom_1695033709348{padding-right: 0px !important;}”]

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Publication<\/strong><\/h3>\n

“Characterising marine heatwaves in the Svalbard Archipelago and surrounding seas”<\/span><\/a>, published in Ocean Science<\/em><\/p><\/div>

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What is a marine heatwave?<\/strong><\/h3>\n

Marine heatwaves are periods when ocean temperatures are much higher than normal for the time of year and persist for several days or longer.
\nThey are identified by comparing daily ocean temperatures to long-term conditions. If temperatures exceed a high threshold (the 90th<\/sup> percentile) for at least five consecutive days, the period is classified as a marine heatwave.
\nMarine heatwaves can occur at the surface or below the surface and may be local or cover large areas of the ocean.<\/p><\/div>

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How the study was done<\/strong><\/h3>\n

The study analysed ocean temperatures around Svalbard from 1991 to 2022.
\nResearchers used TOPAZ, a relatively high-resolution ocean reanalysis for the North Atlantic and Arctic. Marine heatwaves were identified at the surface and tracked below the surface.
\nThe analysis focused particularly on waters west of Svalbard, where changes in duration were strongest. The study compared the role of atmospheric heating and heat transported by ocean currents.<\/p><\/div>[\/vc_column][\/vc_row]<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

[vc_row][vc_column][\/vc_column][\/vc_row][vc_row][vc_column width=”2\/3″ css=”.vc_custom_1693479579188{background-color: #ffffff !important;}”][vc_column_text css=””]Marine heatwaves, periods when ocean temperatures stay unusually high for days or weeks, are becoming more common in Arctic waters. A new study shows that around the Svalbard Archipelago; these events now occur more often and last longer than they did just a decade ago. Marine heatwaves are known to […]<\/p>\n","protected":false},"author":4,"featured_media":9216,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"","_relevanssi_noindex_reason":"","footnotes":""},"categories":[80],"tags":[],"class_list":["post-9214","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-features"],"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-06-05 01:51:28","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/posts\/9214","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/comments?post=9214"}],"version-history":[{"count":2,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/posts\/9214\/revisions"}],"predecessor-version":[{"id":9220,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/posts\/9214\/revisions\/9220"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/media\/9216"}],"wp:attachment":[{"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/media?parent=9214"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/categories?post=9214"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nersc.no\/en\/wp-json\/wp\/v2\/tags?post=9214"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}