ENV100Y5 Lecture 49: Goodbye Polar Bears - Module 5 Session 53
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ENV100Y5 Full Course Notes
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Document Summary
Methane releases further accelerating arctic warming, with the danger of triggering runaway global warming. Treeline will move north and to higher elevations. Forests will replace a significant fraction of existing tundra. Some southern species are already expanding their ranges. Increases in insect outbreaks and forest fires; invasive species. Implications for biodiversity around the world because migratory species depend on breeding and feeding grounds in the arctic. Persistent organic pollutants: extremely toxic, long-lasting, organic chemicals (pesticides, insecticides, industrial chemicals) Carried to the arctic on wind and water currents where they bioaccumulate and biomagnify in the arctic food chain. Polar ice can trap and release contaminants during melting periods. Breakdown products may be toxic as well. Arctic ecosystems show indications of being much more susceptible to biological damage at low levels of pollutants than higher-energy ecosystems in temperate latitude. Shallow roots of tundra plants means they can"t escape uptake of deposited contaminants.
