Arctic Climate Change: Global Early-Warning

from Lloyd’s Report 2012: Arctic Opening – Opportunity and Risk in the High North

From an environmental perspective, there is not one Arctic, but many¹ . Conditions at similar lines of latitude can be starkly different.

On an average day in January, the minimum temperature in Tromsø in northern Norway will be minus 6.7°C (iv). A little to the south and considerably to the east, in Salekhard, capital of Russia’s Yamal-Nenets district and focus of Russia’s Arctic natural gas prospects, it will be minus 29.7°C. In Tiksi, on the east Siberian shoreline, it will be colder still: minus 36.7°C. Across the Bering Strait and far inland, the temperature in Fairbanks, Alaska will be minus 28.1°C. It will not be much different in Iqaluit, capital of Canada’s Nunavut territory. Meanwhile, in Nuuk, capital of Greenland and part of the kingdom of Denmark, it will be relatively warm: around minus ten degrees.

Temperatures in July will be similarly varied: from a maximum temperature on an average day of 8.7°C in Tromsø to 22.4°C in Fairbanks. The range from average daily minimum in January to average daily maximum in July is less than 20 degrees in Tromsø, representing a relatively temperate and stable climate. In Salekhard, Tiksi and Fairbanks, the swings between winter and summer are much greater: nearly 50 degrees.

Temperature is only one indicator, and one determinant, of environmental diversity. This diversity is even greater for other conditions: rates of precipitation, the prevalence of sea ice in coastal areas and the presence of permafrost, forest or tundra. Most of Greenland is covered in year-round ice, amounting to approximately 2.85 million cubic kilometers. Most of the rest of land in the Arctic is not.

What unites the Arctic, however, is the rate at which it is warming and the speed of change this implies for its natural environment as a whole – transforming the Arctic’s geography, ecosystems and how it relates to the rest of the world.

The Arctic is not only warming – it is warming more rapidly than anywhere else on earth (see Figure 2) – acting as an early-warning signal for the globe. In 2011, annual near-surface air temperatures over much of the Arctic Ocean were 1.5°C warmer than the 1981–2010 baseline. Against an earlier baseline² , the differences in temperature, both on land and over water, are greater still. These data points form part of a much longer warming trend³ .

The feedback loops that explain this process are collectively known as ‘Arctic amplification’. Reductions in sea ice and snow cover are one factor: as the Arctic becomes less white it absorbs more heat and reflects less. But there are also factors that relate to cloud and wind patterns, themselves affected by broader climate change, and the enhanced movement of moisture and heat from the equator towards the poles.

To the extent that some global climate change is locked in by current and past greenhouse gas emissions, the Arctic will continue to warm, and warm more quickly than the rest of the world, for the foreseeable future. Success in global climate negotiations under the UNFCCC (v) would not substantially alter that outlook over the next few decades. The Arctic is already undergoing a profound and hard-to reverse environmental state change.

Temperature changes are reflected in other data. In Barrow, Alaska, 30 June 2011 marked the beginning of a record-breaking run of 86 days where the minimum temperature stayed at or above freezing (the previous record was 68 days in 2009)⁴ . All across the Arctic, summers have come earlier and lasted longer. Indigenous peoples who hunt on sea ice have noticed that the ice has become more unpredictable and that the hunting season has become shorter⁵ .

Figure 2: Surface temperature anomalies compared to 1961-1990 baseline

Footnotes: 

(iv) All figures from the World Meteorological Organisation, which in turn depends upon national reporting organisations, which may calculate averages slightly differently. The figures here are described as the mean daily minimum for January and the mean daily maximum for July. Available at: http://worldweather.wmo.int/

(v) United Nations Framework Convention on Climate Change.

Charles Emmerson, Glada Lahn, 2012, Arctic Climate Change: Global Early-Warning, Lloyd’s.©