Navigating the Arctic’s - 7 Cs Vol.1

Long before humans changed the composition of the atmosphere—and with it the climate— WILSON CENTER 19 Polar Institute the evolution of plants dramatically altered the ratios of gases—especially oxygen and carbon dioxide—in the atmosphere, eventually establishing conditions conducive to animal life.11 Oxygen, generated by plant photosynthesis, began increasing in the atmosphere with the rise of la. [...] Only with the adoption of steam- powered vessels in the late 1870s were the whalers able to transit the Beaufort Sea coast of Alaska in its brief open water period to reach the whales’ summer grounds.38 The fleet then overwintered frozen into ice between Herschel Island and the mainland and realized large harvests when the ice broke up and the whales arrived in the subsequent summer. [...] That accumulation of greenhouse gases in the earth’s atmosphere is warming the entire planet, but the rate is accelerated in the Arctic by changes in the cryosphere.45 In recent decades, warming of the atmosphere and oceans has diminished the area of the Arctic covered by sea ice in summer by 50 percent, an environmental change so abrupt as to challenge the abilities of species and society to adap. [...] Over the past three decades, the impact of the self-perpetuating warming in the Arctic was equivalent to 25 percent of the global warming from carbon dioxide accumulated in the atmosphere.46 Warming is further accelerated in the Arctic by the physics of heat transfer at colder temperatures and by the temperature structure above the surface of the Arctic.47 The amplification of warming in the Arcti. [...] The combination of multiple stressors and rapid changes in climate will challenge society’s and ecosystems’ ability to respond.79 The rapid pace of environmental change in the Arctic begs the question, has or will the Arctic system transition to a new state or are the changes in recent decades within the range of previous natural variation of the system? A recent modeling study showed that the dra.