The dramatic lack of Arctic sea ice come early july is just among the signs global warming hasn’t stopped, scientists say.
(Image: © Jeremy Potter NOAA/OAR/OER)
NEW YORK — Scientists predict global warming will affect certain areas more significantly than others. The Arctic is among these climate-change hotspots.
Significant changes are happening sooner and more intensely in the cold northern cap over the earth. For instance, recently, Arctic sea ice has already reached unprecedented low annual extents, and making an archive retreat in September.
The signs of change, and the implications for the social people, animals and plants that reside in the Arctic, are numerous.
A panel of researchers from institutions in Canada and america discussed the rapid change in the Arctic from a number of angles — from melting sea ice and tundra, to the consequences on marine mammals and indigenous people on Monday (Nov. 13) at Columbia University.
Listed below are five ways rapid warming could be changing the Arctic:
1. Last sea-ice refuge : The rapid summer retreat of Arctic sea ice each summer has resulted in talk of the prospect of ice-free summers in the Arctic. But a restricted amount of ice will probably linger in summers until late in this century, said Stephanie Pfirman, a climate scientist at Columbia’s Lamont-Doherty Earth Observatory. Computer models simulating ice thickness show the older, thicker ice clinging to the Arctic waters north of Canada and Greenland even while it retreats elsewhere. That older ice is similar to a «snow bank» that takes longer to melt, Pfirman said. Not merely is ice formed in this area, but currents and mainly winds transport it there also. This «last sea-ice refuge» will probably retain summer ice for many years to come, she said.
2. Winners and losers in the ocean : Changes in the Arctic waters, specially the thinning and receding ice, will probably both hurt and benefit year-round and seasonal Arctic animals, said Pierre Richard, a marine biologist with the Department of Oceans and Fisheries Canada. While conclusive evidence that climate change has effects on species is difficult to come across, the increased loss of sea ice is impacting polar bears’ capability to hunt. Meanwhile, sea-ice melt is which makes it problematic for ringed seals, which polar bears hunt on the ocean ice, to shelter their pups in lairs in the ice. Other species might change or expand their ranges. Killer whales, for example, look like spreading farther north in to the Arctic looking for seals and other whales as prey, Richard said. The increased loss of ice and warming water are also prompting earlier blooms of tiny plants, referred to as phytoplankton, that may likely have ripple effects for other organisms in Arctic waters. [Endangered Beauties: Images of Polar Bears]
There are a great number of predictions about the implications for Arctic marine food webs, «but nobody has answers, it really is an elaborate topic,» Richard said.
3. Unlocking the tundra’s carbon stash : On land, frozen ground, called the permafrost below the tundra holds 14 percent of the world’s carbon, an component that plays an essential role in the greenhouse effect. Global warming gets the potential to create itself worse by leading to the release of the carbon. For days gone by 10,000 years, low-growing tundra plants, like other plants everywhere, have already been sucking carbon out from the air because they photosynthesize. This carbon eventually ends up being kept as dead organic matter in the bottom. However in the Arctic permafrost, the cold prevents microbes from decomposing the organic matter, an activity that could release carbon back to the atmosphere. Warming is allowing taller shrubs to invade the reduced tundra landscapes. These shrubs themselves promote more change by trapping more snow above the soil and insulating it, which promotes decomposition, said Kevin Griffin, a plant physiologist at Lamont-Doherty Earth Observatory.
A considerably faster, more dramatic process can be releasing the kept carbon: tundra fires. Due to dry tundra and lightning strikes, that have increased by as much as 300 percent, tundra fires are occurring at a higher frequency, Griffin said.
4. Throwing nature’s timing out of whack : The Arctic is a significant summer destination for most migratory species, including songbirds attracted by the abundant food, insufficient predators and parasites, said Natalie Boelman, an ecologist at Lamont-Doherty Earth Observatory. The songbirds’ migration north is cued by changes in light, therefore the timing of their spring journeys remain constant; however, the changes in the Arctic are affecting the meals at their destination. A far more shrubby tundra landscape can offer more insects, but their emergence times might change. Also, shrubs, which are more technical compared to the low-growing tundra, trap more snow and delay the snowmelt. Thismeans seeds and berries the birds longer eat remain hidden for. The changes in the landscape may also affect birds with particular nesting preferences, Boelman said. [The 10 Most Amazing Animal Migrations]
«We want to see if a mismatch is developing and the type of repercussions it has for different species of songbirds,» Boelman said of her research.
5. Challenges for indigenous communities : Previously 50 years, indigenous communities around the Arctic have already been transformed into modern towns along coasts and rivers, and they are now facing the potentially devastating effects from climate change, Igor Krupnik, an anthropologist at the Smithsonian Institution in Washington, D.C., told the audience. Many of these grouped communities, outfitted with less resilient modern infrastructure now, are unprepared for rising sea levels and increased storm activity; 178 Alaskan native communities have already been determined as at risk for various kinds of erosion, including spring floods from rivers; 12 have previously made a decision to relocate to raised ground, at enormous cost, Krupnik said.
Observations created by native Arctic folks of the change within their environment are powerful resources of knowledge for scientists, he said, noting they view the changes in the Arctic than scientists do differently. «Everywhere we asked people, they discussed increasing uncertainty, they discussed increasing unpredictability,» he said. «They discuss irregular changes in weather and weather patterns, they discussed flooding and storms, they discussed new risks of venturing out on thin ice.»
New research on dynamics adding to the retreating and thinning ice in the Arctic was also discussed. Narrow, linear cracks in the ocean ice, called leads, pump deep, warm ocean water up toward the top, said Bruno Tremblay, an ocean and atmospheric scientist at McGill University. Scientists are actually attempting to better understand the physical forces accountable for the upward movement of warmer water under the leads, Tremblay said.
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