Geography - The impacts of global warming

Environmental impacts: 

• Temperatures have risen more than twice the global average (3-4 degrees) 
• Melting ice caps - 2004-2005 NASA reported a 14% loss of Arctic ice - 3x the size of the UK. (2012 - 12x the size of the UK).
• 40% of permafrost is expected to thaw (Siberia) - methane released
• Methane increase from melting permafrost and wetlands will increase global warming (positive feedback mechanism)
• Melting glaciers and Greenland ice sheet - reduction in albedo effect (snow and ice reflect solar energy; when the melt, more energy is absorbed so warming increases = quickly melting. (positive feedback mechanism)
• Eustatic global sea level rise
• Melting ice caps reduced the saliniy of the oceans which could cut off the arctic conveyor belt - would cause massive cooling in the NW Europe due to the loss of the warm Gulf Stream.

Ecological impacts:

• Change in Biomes - Tree line movement northwards - increase in forest vegetations (Boreal Forests) replacing Arctic vegetations (Tundra) affecting local ecosystems
• Freshwater fish e.g. Arctic Char and Trout will decrease as frozen ground beneath them thaws, draining lakes and rivers
• Invasion of Alien species
• Increased forest fired and insect caused tree deaths
• Phytoplankton at the bottom of the food chain will be destroyed as UV radiation increases
• Some land based animal species will shift northwards with the forests e.g. Caribou
• Many land species e.g. Arctic hare, fox and lemming will suffer major decline
• Marine species dependent on sea ice e.g. seals, polar bears and walruses will decline
• Breeding patterns and ecosystems will be affected as many species breed and live in the Arctic.

Social impacts:

• Greenland - 90% of the population are Inuits
• loss of tradition and culture
• harder to hunt as the ice is melting earlier
• clothes rely on being able to hunt (Reindeer coats etc)
• herd animals e.g. Caribou will change migratory patterns (can't hunt them - reliant on them also)
• loss of traditions hunting culture - lack of food for Inuits
• decline in Northern freshwater fisheries (Arctic Char)
• disruption of land based transport (ice road truckers) due to melting permafrost
• vulnerable to exploitation of oil, gas, fish etc (loss of culture)

Any positives?

• Ecological: new species may evolve, increase in Cod in the open water, increase in trees which will absord Carbon Dioxide, longer, warmer growing season which would be a benefit to Arctic agriculture (soils aren't good for agrictulture, which is a limiting factor)
• $1billion deposit of zinc and lead in Greenland - economic growth
• enhanced agrictulture and forestry
• enhanced marine fisheries (Cod and Herring due to warmer water)
• increased access for marine shipping
• immigration may occur as living conditions become more hospitable 
• as glaciers retreat they expose natural resources (oil etc)

(THERE ARE NO REAL BENEFITS FOR THE INUITS - THEY DO NOT WANT CHANGE)

Exam question example: examine the ecological impacts of global warming in Arctic Areas.

Glacial areas (sea ice) 80-90 degrees North

·         Marine foodchain - top predators - polar bears (reducing in numbers) - shorter hunting season 

·         UV rays are absorbed - reducing phytoplankton - severe impact on whole marine ecosystem 

·         One positive: warmer oceans - Cod may migrate into these waters

Periglacial areas 66-80 degrees North

·         Treeline will shift northwards - Boreal forests replaces Tundra

·         land based animals e.g. Caribour will migrate North

·         Arctic fox (camouflaged) may be replaced by woodland fox

·         Forest fires/pests/alien species

·         One positive: potential for agriculture on the land/forestry. 

Use statistics!! e.g. summer sea ice - melting 3 weeks earlier each year