Those who called Longyearbyen’s infamous 111-month streak of above-average temperatures during most of the 2010s a lot statistically outdated hot air are proving to be prophetic, as an update to the official 30-year average at Svalbard Airport show the mean annual temperature is now -3.9C, compared to the average of -6.7C used for the past three decades.
The new averages largely affirm studies from the past few years showing Svalbard is about 4C warmer than 50 years ago and may warm another 5C to 10C by 2100, with the most pronounced changes during the winter months and northernmost parts of the archipelago. Practically speaking, they also show Longyearbyen has lost two months of “winter” weather during the past 50 years and may lose another two months by 2100.
But lest one think this might be the final hard proof of man-made climate change that sways the 0-2 percent of scientists (and considerably larger percentage of the general population) not yet convinced, there are still some caveats in Svalbard’s new averages, said Steinar Midtskogen, a longtime weather and climate observer in Oslo.
“One observation is that these three past normals, by coincidence, have aligned with a climate oscillation so that they don’t really reflect normality,” he said. “(The period) 1991-2020 was unusually warm, 1961-1990 was unusually cold, 1931-1960 was unusually warm, and we also know that there was a very cold period before that. The next decades will be interesting. Will there be a big freeze in the 2030s or will global warming trends cancel that?”
The biggest and oddest change in change in Longyearbyen is February, historically considered the coldest month of the year with an average temperature of -16.2C for the years 1961 and 1990 that was the “normal” used for comparison until this year. But the new average, calculated on the years 1991 to 2020, is 4.6C higher at -11.6C – and February is no longer the town’s coldest month.
Instead, that title belong to March with a new average temperature of -12C, compared to -15.7C degrees previously. That affirms research showing temperatures aren’t just getting warmer, but the entire climate ecosystem is shifting unpredictably, affecting other weather such as precipitation, winds and storm patterns in the process.
Summer changes are less drastic, with July remaining the warmest month at a new average of 7C degrees, with the increase of 1.1C from the previous average of 5.9C being the smallest monthly figure.
New averages at other locations in Svalbard – which do not include the most extreme changes observed in the far north – show factors beyond latitude play an influence. Bjørnøya, the southernmost weather station in Svalbard, experienced an annual increase of 2C (-0.4C, up from -2.4C). Progressing northward, the increase at Hopen was 2.8C (-3.6 vs. -6.4C), Svea 2.2C (-4.9C vs. -7.1C) and Ny-Ålesund 2.1C (-4.2C vs. -6.3C).
As for long-term trends, while temperatures between 1931-60 were warmer compared to the next 30 years, the annual difference at Svalbard Airport is 1.2C – far less than the increase recorded during the past 30 years. Also, while temperature fluctuations exist throughout Svalbard’s history – and are extremely sizeable if one goes far back in time when the archipelago’s land mass was at the equator – recently global patterns of warming that are at least twice as large in the Arctic are nearly universally considered by climate experts to be evidence of human rather than natural change.
Globally temperatures have risen about 1C since 1900, with the pace of warming increasing in recent decades. Precipitation levels are far more variable, with more extreme flooding and droughts – and for more extreme periods of time –generally occurring in temperate and arid zones, respectively. While climate experts have stated preventing a further increase of between 1.5C-2C by 2100 is necessary to avoid catastrophic global impacts, numerous studies suggest warming is likely to exceed that – perhaps by a significant margin – due to lack of commitment by many nations to commit to climate goals and ineffective actions/agreements by those making pledges.
Precipitation also shows significant increases in most – but not all – of the archipelago. Svalbard Airport’s annual average during the past 30 years was 217 millimeters, up from 190mm between 1961-1990. At other locations, Bjørnya’s new average was 447mm, up from 369mm; Hopen’s new average of 308mm a decline from 469mm previously; and Ny-Ålesund’s new average of 467mm up from 385mm earlier.
Looking at the longer-term precipitation trend, a study published in 2011 suggests “total annual precipitation has increased by roughly 14 percent in the Arctic north of 60°N over the past century. The greatest increases were observed in autumn and winter. However, uncertainties in measuring precipitation in the harsh Arctic environment and the sparseness of data in parts of the region limit confidence in these results.”
More recently, two major avalanches in Longyearbyen in 2015 and 2017 resulted in climate and avalanche experts declaring the historic models they based risk on were no longer valid due to new precipitation and wind patterns almost certainly attributable to man-made climate change.
While the vast majority of experts are predicting ever-increase temperatures, precipitation and extreme storms that will ultimately result in Svalbard no longer having an Arctic climate in the coming decades, Midtskogen said he believes Svalbard’s large amount of natural variability raises questions both about the degree of human impacts and what changes here mean elsewhere.
“Obviously, besides global warming, there is quite a bit of natural variability going on in Svalbard,” he said. “For that reason I’ve always been somewhat puzzled that Svalbard has become such a popular place for studying global warming. Usually, if studying a phenomenon you would find the place with the least noise. Going to Svalbard to study one specific climate phenomenon is like going near a waterfall to study the rustling of leaves.”