Lecture 11: global change in the Arctic and global warming

Transcription

1 Lecture 11: global change in the Arctic and global warming

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4 Mann et al. 1999

5 The history of global warming Surface Air Temp Delworth+Knutson, Delworth + Science Knutson 2000 Nature 2000 Surface air tem, Upernavik, West Greenland, Imke Durre, pc

6 Large Cod taken in the Godthåbsfjord W Greenland in 1951.

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8 John Walsh

9 Sea ice is shrinking

10 the albedo the whiteness of the Earth s surface has a strong effect on temperature

11 IPCC 2001

12 Sea Ice Area Coverage Central Arctic September Thousand tons Greenland Shrimp Production

13 3 decades of decrease in salinity of the subpolar gyre and Nordic Seas (here, the overflows, gyre and Labrador Sea from ) From Dickson, Yashayaev, Meincke, Turrell, Dye and Holfort, Nature 2002

14 Air temperature is increasing Comiso and Parkinson, Physics Today, Aug. 2004

15 The Greenland ice cap is melting back farther in summer

16 Glaciers are receding and permafrost is warming and softening

17 Permafrost Distribution PERMAFROST J Overland, PMEL Alaska Russia Alaska

18 J. Overland Bering Sea Ecosystem Changes Increased temperature and decreased ice in recent years Warm temperatures favor pollock over Arctic species

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20 Depth averaged temperatures for 15 July to 15 September are warmer by 20C for the mean of compared with the mean of (location chart shown below)....these recent warm ocean temperatures could result in a two-fold or greater difference in zooplankton production as well as direct physiological impacts on upper trophic level species. Overland goes on to describe the biological effects of this warming and change in ice cover. In normal years ice lasts until March, and when it melts there is a strong phytoplankton bloom...an explosive growth of vegetable algae...that uses up the nutrients in the sun-lit upper few ten s of meters of the ocean. If there is no winter ice, the time of the spring bloom is delayed until May or June, when it is affected by the warming of the surface layer by the sun (which produces stratification...layering of buoyant water above denser water). The whole food chain is altered when this happens: it is remarkable how local and how immediate the growth of larger creatures..animals...the cows of the sea, some spherical, depends on the supply of phytoplanktion, the grass of the seas. The vegetation of an early, ice-related phytoplankton bloom tends to fall to the ocean bottom, supporting communities of bottom feeding animals (benthic communities) while a later spring bloom favors a pelagic or open-ocean surface ecosystem.

21 J. Overland

22 Vegetation distribution based on Koppen classification J.Overland Green Tundra Blue Boreal Yellow Frost Red - Temperate Lost Tundra areas from 1950 to 1998: 11% reduction in 5 decades.

23 Land Change Over Alaska Regions Permafrost degradation on the Tanana Flats Jorgenson et al., 2001, Climatic Change Photos from the Ayiyak River (Alaska) show an increase in shrubs. Sturm et al., 2001, Nature

24 Downward Trend in the Coverage of Tundra Group NDVI Area 10 6 [km 2 ] CRU NCEP NDVI Year NCEP Area CRU Area

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26 Arctic Life Threatened by Toxic Chemicals, Groups Say By Sharon Guynup National Geographic Today October 8, 2002 There's something seriously wrong in the Great White North. Polar bears are birthing fewer cubs. Seals that swim in northern seas carry high levels of mercury and cadmium in the body fat that insulates them from the cold and animals from reindeer to whales to sea birds also carry industrial chemicals in their bodies. Some Inuit newborns are born with high blood pressure that persists into elementary school. The reason, according to a new study, is that the Arctic has become a repository for some of the world's most toxic chemicals, and at higher concentrations than previously thought. Although the brilliant white snow and clear blue Arctic seas appear pristine, small concentrations of industrial chemicals are carried here on air, river, and ocean currents from as far away as Asia and gradually build up. This is why "the Arctic is a very important area to take the pulse of the globe," said Lars Otto Reiersen, leader of the Norway-based Arctic Monitoring and Assessment Program (AMAP), who co-produced the new report Arctic Pollution 2002 in collaboration with the World Wildlife Federation (WWF). Nervous System Damage, Weakened Immunity "[These chemicals] come from us," said Samantha Smith, director of the WWF Arctic Program. "They come from people in industrialized countries, from the factories that make our products and the way that we grow our food." The Inuit Circumpolar Conference, an organization representing Inuit people in Alaska, Canada, Greenland, and Russia, expressed concern over the report. The group's chair, Sheila Watt-Cloutier, called for expanded research on threats from toxic industrial chemicals, and asked for international cooperation to protect Arctic indigenous people. The study showed that levels of some heavy metals like mercury, lead, and cadmium; and persistent organic pollutants (POPs) toxins like Polychlorinated Biphenyls (PCBs); the insecticide DDT, and dioxins exceeded previous estimates or hadn't dissipated over time. POPs are chemicals that break down slowly in the environment. They damage the nervous system and interfere with development. They also weaken immunity: fur seals and polar bears with high PCB levels had increased rates of infection. Mercury Rising Mercury has risen to dangerous levels. Among some indigenous people, levels are high enough to affect childhood development, causing nerve and brain damage. It may also be affecting the reproduction of peregrine falcons. "The increase in levels of organic mercury in some parts of the Arctic is primarily due to increased burning of coal for energy production in Southeast Asia, showing once again the tight links between the Arctic as recipient of pollutants and the rest of the world," said Reiersen. Lake sediments in Greenland show mercury concentrations are three times higher than in pre-industrial times. Globally, 5,000 tons of mercury are present in the air at any time. In addition to known pollutants, newly-detected toxins were added to the list. Among those were flame retardants that affect brain development and weaken immunity, and perfluorooctane sulfonate (PFOS), a stain repellant. PFOS, which was recently found in the livers of northern Alaskan bears, is of particular concern because of its "extreme persistence." "It does not seem to break down under any circumstance," the authors said. Many of these chemicals persist longer here than in other regions because of the frigid climate and the lack of soil and vegetation to absorb pollution. Even small amounts of toxins go a long way since northern animals accumulate them over a lifetime in the fat they store to survive the extreme cold. Chemicals in Breast Milk Inuit people are particularly at risk because the staples of their diet include animals that sit high on the food chain, like seal, whale, and fish, that have absorbed large quantities of contaminants. Chemicals have also been found in breast milk. There was some good news. Since the introduction of non-leaded gasoline in North America in the 1970s, lead levels have dropped steadily in Greenland ice core samples. But tests on animals, from moose in the Yukon Territory to Swedish reindeer, show little change in the amount of lead stored in body tissues. Steps are being taken to address the problem. In 2001, the United Nations Environment Programme identified the most dangerous pollutants and initiated global negotiations, a move that created the Stockholm Convention on Persistent Organic Pollutants, an international treaty to ban these chemicals. As of July, Canada, Iceland, Norway and Sweden had ratified the agreement. WWF says that toxic chemicals are slowly poisoning some of Earth's most unique residents, and is urging the United States and Russia to act. "Without a global ban, we can't protect indigenous communities and wildlife in the Arctic," said Smith. "The U.S. and Russia need to stop ignoring the scientific evidence and ratify the Stockholm Convention." Join the world's largest nonprofit scientific and educational organization, and help further our mission to increase and diffuse knowledge of the world and all that is in it. Membership dues are used to fund exploration and educational projects and members also receive 12 annual issues of the Society's official journal, National Geographic.

27 Chemical find spurs toxic fears in Arctic (Xinhua) Source: The China Dailey Updated: :30 Chemicals widely used as flame retardants in homes have been found in polar bears and birds in the Arctic, raising fears that they could pose a health hazard, Norwegian scientists said last week. Norway's government said it would seek a European Union (EU) review of the chemicals, used in everything from computers to clothes, saying their presence in the Arctic showed the need to investigate whether they were damaging for humans and wildlife. "Traces of the compounds were found in studies of polar bears and in glaucous gulls," said Geir Wing Gabrielsen, head of a toxicology research programme at the Norwegian Polar Institute. "This is the first time that this flame retardant has been found in the Arctic," said Gabrielsen, when discussing the research by the Polar Institute and Norwegian Veterinary Institute on the Arctic archipelago of Svalbard in the north Atlantic. Traces of the so-called deca-bde (BromoDiphenyl Ether) flame retardant, also commonly used in car upholstery and TVs, had previously been found in falcons in Sweden and samples of human blood further south.

28 Toxic chemicals a major threat to the Arctic - WWF 01 October 2002 Source: World Wildlife Fund Gland, Switzerland - Arctic wildlife and some Arctic indigenous people, particularly Inuit, are contaminated by industrial pollutants such as polychlorinated biphenyls (PCBs), pesticides and insecticides, according to a report released today by the Arctic Monitoring and Assessment Programme (AMAP), and endorsed by WWF, the conservation organization. The AMAP's new report Arctic Pollution 2002 demonstrates that Inuit in Greenland and Canada have among the world's highest exposures to certain toxic chemicals as a result of long-range transport. The study also reveals that polar bears, Arctic fox, seals, killer whales, harbor porpoises, and birds such as glaucous gulls and peregrine falcons, are among the Arctic species contaminated with the highest levels of persistent organic pollutants (POPs). POPs are known to damage the nervous system, development and reproduction, and are able to travel great distances. In order to combat the threat they pose, WWF is calling on Russia and the US to ratify the Stockholm Convention on Persistent Organic Pollutants, a new international treaty which will phase out and ban some of the most dangerous pollutants. Several other Arctic rim countries, including Canada, Norway, and Sweden, have already ratified this important convention. "Most of these chemicals come from outside the Arctic, including the Southern hemisphere, and are carried to the Arctic by wind and water currents," said Samantha Smith, director of WWF's International Arctic Programme. "Without a global ban, we can't protect indigenous peoples and wildlife in the Arctic. The US and Russia need to stop ignoring the scientific evidence and ratify the Stockholm Convention." According to the report, the arctic species with the highest levels of POPs are already showing adverse effects. For example, researchers have linked POPs levels to reduced immune system function, and increased rates of infection, in polar bears and fur seals. WWF believes that the use of toxic industrial chemicals results in slowly poisoning some of the world's unique species. The Inuit Circumpolar Conference (ICC), which represents Inuit in Alaska, Canada, Greenland, and Russia, is also concerned by the report's finding. "Inuit call on all Arctic states to work together in global meetings to protect the health of Arctic residents, and to renew and expand scientific programmes on contaminant threats to the health and way of life of Inuit and other Arctic indigenous peoples," said Sheila Watt-Cloutier, ICC chair. One of the alarming issues highlighted in the report is the increase in levels of organic mercury found in some parts of the Arctic. The trend is primarily due to increased burning of coal for energy production in South-east Asia, showing once again the tight links between the Arctic - as a recipient of pollutants - and the rest of the world.