Climate change hotspot

The High Arctic Svalbard Archipelago is an Arctic climate change spot – warming and loosing sea ice faster than anywhere else in the region, and therefore well-suited to study links between changes in climate and storminess. Yet despite this potential, few researchers have focused on this topic, which has also hindered a deeper understanding of the drivers of coastal development on Svalbard. Because across the archipelago, one can find extensive beach ridge sequences – formed by the interaction between sea level change, sea ice variability, sediment input from deglaciating hinterlands, and storminess. As all of these processes will shape the future, we need more knowledge to prepare for the changes to come.   

Rigor and resolution

To – for the first time – unravel the history of storminess on Svalbard throughout the current Holocene interglacial, we targeted Lake Steinbruvatnet. Facing the Easterly and Westerly winds, and sitting on a stable rocky shoreline, sediments that were wind-blown into this basin during the past 10 000 years allow us to assess storminess through time against a stable baseline. 

To do so with rigor, we relied on multiple methods that provide independent lines of evidence for wind-blown input in the core taken from Lake Steinbruvatnet. This toolbox combined the precision of traditional methods like granulometry with the resolution of more recent approaches such as X-Ray Fluorescence (XRF) and Computed Tomography (CT) scanning. Combined in a statistical framework, these methods helped characterize dense minerogenic wind-blown sediment input.

Warmer not stormier

Our results lift the veil on the long-term links between climate change and storminess in the Arctic. The 10 000-year long context provided by our sediment record offered a major surprise, by suggesting that winds might have been more powerful during colder rather than warmer past periods. In other words, the opposite of what scant observations and simulations suggest.

There are some important caveats to bear in mind though. First and foremost, because wind-blown material is locked in place by snow and ice that also shields lakes during the rest of the year, our sediments capture a summer season signal. This is important, because climate models suggest that the signature of future Arctic (wind) climate varies greatly between seasons. In addition, our findings derive from one small lake in a vast region – we hope other researchers will investigate more sites to assess the representativeness of our data. Time will tell.

Also, while stormier phases coincide with colder periods, they follow a 1500-year cycle that has been observed in other paleoclimate reconstructions. And although we still don’t fully understand this heartbeat of the regional climate system, it does suggest that natural variability can either amplify or dampen future human-driven changes in (wind) climate. And while on the topic of periodicity, our storminess data also suggest that there was more year-to-year variability when climate was warmer than now. So although (summer) winds were generally weaker during such periods, extreme storms might have been bigger. This is relevant for the future.

Unknown not unloved

We hope that our results, and the method toolbox used to acquire them, will encourage more colleagues to look into past storminess. In the Arctic, we provide a first building block for a regional stack of records – the more the merrier. Winds can wreak havoc and provide energy these days, so a robust long-perspective on their interaction with a changing climate is sorely needed.