The future of the Arctic is taking shape. Let's take a look at climate change in action.
Melting ice and future shipping
Sea ice has eroded steadily over the past three decades. The following graphic from the National Snow and Ice Data Center shows Arctic sea ice extent from 1979 to 2012.
Climate models now provide a basis for calculating the probability of shipping routes opening up in the Arctic within 50 years. In the Proceedings of the National Academy of Sciences, Laurence Smith and Scott Stephenson of UCLA examined the probability of peak season (September) navigation of three routes for medium and high emissions scenarios by mid-century (2040-2059). Those three routes are illustrated in this figure. From left to right, the Northwest Passage (NWP) cuts through the Canadian Arctic Archipelago to the Bering Strait, the central route cuts directly across the North Pole, and the North Sea route hugs the Russian coast to reach the Bering Strait.
Optimal September navigation routes for hypothetical ships seeking to cross the Arctic Ocean between the North Atlantic (Rotterdam, The Netherlands and St. John’s, Newfoundland) and Pacific (Bering Strait) during the consecutive years of 2040–2059 as driven by ensemble-averaged general circulation models’ projections of sea ice concentration and thickness assuming a medium-low (+4.5 W/m2) increase in climate forcing. Red lines indicate fastest available trans-Arctic routes for Polar Class 6 (PC6) ships; blue lines indicate fastest available routes for common open-water (OW) ships. Where overlap occurs, line weights indicate the number of successful transits using the same route. Dashed lines reflect currently existing (200 nautical mile) national Exclusive Economic Zone boundaries; white backdrop indicates period-averaged sea ice concentration.
The NWP is predictably navigable today only by ships with moderate ice-breaking capability (Polar Class 6). For standard open-water vessels, the NWP was only technically navigable prior to 2005 about 15% of time during peak season. By mid-century, the probability of navigation by open-water vessels increases to 53% in the medium emissions scenario and 60% in the high emissions scenario.
Even more impressive, Polar Class 6 ships will be able to cut directly across the North Pole. At present, only Polar Class 1 ships (heavy ice-breakers) are currently capable of reliably making the passage. Polar Class 6 ships cannot handle large concentrations of multi-year ice, but these concentrations are likely to be very limited by mid-century.
Peak season travel probability by the North Sea route is expected to rise from 40% to near 100% by open-water vessels by mid-century. Moreover, the passable routes will extend farther from the Russian coast into international waters.
Let the territorial and trade fights begin.
The prospect of OW ships (which comprise the vast majority of the global fleet) entering the Arctic Ocean in late summer, and even its remote central basin by moderately ice-strengthened vessels (like those used today in the Baltic), heighten the urgency for a comprehensive International Maritime Organization (IMO) regulatory framework to ensure adequate environmental protections, vessel safety standards, and search-and-rescue capability in this unique and challenging polar ecosystem (4). Many of the new “Supra-Polar” routes identified here deviate outside of the standard 200 nautical-mile Exclusive Economic Zone of the Russian Federation, thus enhancing potential appeal of the international high seas and Norwegian, Greenlandic, Canadian, and US coastal waters for transits relative to the NSR (the Russian Federation currently charges escort fees for international vessels seeking to traverse the NSR). Finally, two chronic, long-standing debates over the status of international shipping through the NWP (now claimed as a domestic waterway by Canada but international straits by the US and other countries) and US ratification of the United Nations Convention on the Law of the Sea (5) may warrant renewed attention, in light of its nascent navigability and the broader circumpolar changes projected here.
Changing flora
A team of researchers examined patterns of vegetation changes in the Arctic region in a paper just published in Nature Climate Science. Plant growth in the Arctic has rapidly accelerated in the later half of the 20th century. These trends are expected to dramatically green the face of the Arctic by the middle of the 21st century, even under mid-range greenhouse gas emission conditions. The researchers modeled predicted temperature and precipitation levels to assess the viability of different plant types, using current trends to validate the predictions.
We predict that at least half of vegetated areas will shift to a different physiognomic class, and woody cover will increase by as much as 52%.
Those changes are illustrated in the following figure. The left panel shows the current distribution of flora (dominated by tundra) and the right panel shows the likely distribution by 2050 around the Arctic circle.
Caption: This set of images shows the observed distribution of Arctic vegetation (left) in relation to the predicted distribution of vegetation under a climate warming scenario for the 2050s (right). Data used to generate the observed image are from the Circumpolar Arctic Vegetation Map (2003).
All those purples and greens indicate a rapid transition to brush and trees as the permafrost melts. These changes will also initiate many positive feedbacks likely to further accelerate climate change, including diminished albedo as tundra shifts to trees and methane released from permafrost. The authors conclude those feedbacks are likely to be far larger than predicted by current models.
Less ice, more storms
Milder conditions in Arctic may bring climate chaos to the south. Charles Greene describes how the loss of Arctic sea ice is likely to increase the frequency of superstorms like Sandy in Oceanography.
(T)here is increasing evidence that the loss of summertime Arctic sea ice due to greenhouse warming stacks the deck in favor of (1) larger amplitude meanders in the jet stream, (2) more frequent invasions of Arctic air masses into the middle
latitudes, and (3) more frequent blocking events of the kind that steered Sandy
to the west (Francis and Vavrus, 2012; Greene, 2012; Greene and Monger, 2012; Liu et al., 2012). Although a direct causal link has not been established between the atmospheric phenomena observed in late October 2012 and the recordbreaking
sea-ice loss observed during the preceding summer months, all of the observations are consistent with this interpretation.
Greene argues that the loss of Arctic ice disrupts the jet stream in ways that set the table for a tropical storm to develop into an extraordinarily large and powerful storm that blasts into the Atlantic coast. There is growing evidence to support links between Arctic ice cover and increased frequency of the three jet stream components found during Sandy. How often these components will cluster together is an open question, but the data to address it are likely to become available in the coming decades.
Same old stupid
Climate science is moving from predicting temperature changes associated with greenhouse emissions to studying the likely climate consequences of those changes. These three articles give a taste of how fast the climate is changing, particularly in the Arctic region where temperature changes have been the most extreme to date.
Unfortunately, many politicians continue to worship the unholy trinity of oil, gas, and coal. While climate change is likely to make the Arctic downright hospitable in the near future, these stupid political animals cannot seem to grasp that many current population centers are likely to become far less pleasant.
Speaking of stupid, Ted Cruz:
Sen. Ted Cruz strikes again! This time, he asked for wording in a routine Senate resolution to be nixed because of one objectionable word: Climate.
The resolution commemorating International Women’s Day last month, had to be taken back and edited after Cruz took issue with climate in the phrase that, women in developing countries “are disproportionately affected by changes in climate because of their need to secure water, food and fuel for their livelihood,” according to New York Times columnist Gail Collins. Collins said the resolution was nearly identical to the previous year’s resolution.
A Cruz spokesman told the Times the freshman senator felt there was no need to mix a hot-button issue in an otherwise perfectly normal resolution.
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