Arctic

Arctic

1. Atmospheric Forcing

   • positive feedback
     • albedo effect
       • light surfaces reflect energy back to space
         • sea ice
         • cools down earth
       • dark surfaces absorb energy
         • sea
         • warms up earth
           • melts ice at a faster rate
   • negative feedback
     • cloud cover
       • more clouds trap heat on earth
         • cools down earth
         • top of clouds white surface so reflect energy back into space
       • warmer

2. Introduction

   • north pole
   • northern hemisphere
   • covered with sea ice
     • above arctic ocean
   • arctic has warmed twice the rate than any other region in the world
   • 80% solar radiation reflected from polar ice caps

3. How is the climate changing?

   • atmospheric forcing
   • glaciers absorb more sunlight
     • increases surface temperature
       • melting on greenland ice sheets
   • hypothesis - in 100 years oceans will warm upto a further 3-5 degrees
   • 50-60% of arctic will be lost by 2100
     • could disappear entirely by 2070

4. evidence of changes

   • link between rising global temperatures and rising C02 levels
     • evidence
       • ice cores from polar ice caps
   • NASA 2006 said permanent sea ice decreased by 14% between 2004-05
     • 2007 warmest year on record at the arctic

5. Socio-economic impacts

   • negative
     • thinner sea ice so collapses easily
       • dangerous for inuit men who go fishing
     • melting of ice leaves inuit village unprotected
       • along coast
       • exposed to more waves and storms
         • destroy villages
         • migrate further inland
         • 24 villages in Alaska threatened by flooding
     • 80% Inuits hunt caribou, fish, marine mammals and other species
       • these species declining in numbers
       • marine stocks decline
         • inuits rely on hunting for caribou for income
           • creates pressure on caribou stocks
         • 70% inuits income rely on hunting or paid employment
   • positive
     • warmer water attracts cod, herring
       • more food for people
       • more fish to sell
     • warmer weathers
       • enhanced forestry
       • enhanced agriculture
     • melting of snow and permafrost
       • expose new land and open sea
         • arctic will become more accessible
         • vulnerable for exploitation of oil and natural gas
           • oil industry
             • create 250,000 to 735,000 jobs
     • tourism
       • opportunities for locals to act as guides
       • warm weather attracts tourists
       • investments from major corporations into local communities
         • improve infrastructure and communitites
     • less energy needed to warm colder areas
     • less deaths from cold weathers / hypothermia
     • northwest pasage accesible for longer time periods
       • tourism
       • Trade

6. environmental impacts

   • large chunks of ice collapse into sea
     • glaciers melting rapidly
     • polar bears struggling to find ice to live on
   • species become endangered extinct
     • traditional part of an indigneous diet
   • timing of melting sea ice in summer spring
     • effects krills
       • start of foodweb for most animals
   • permafrost in some areas rapidly thawing
     • release of methane (GHG)
       • melt greenland ice sheets
       • changes in ocean circulation
     • permafrost supports pipelines and buildings
       • infrastructure more unstable, drunken forests burst bent pipes
     • carbon, methane trapped from millions of years released
       • further global warming
         • reach tipping point
     • positive feedback
   • snow cover decreasing 1-2% a year
     • glaciers shrinking
   • ice melting 3 weeks earlier each year
   • Marine ecosystems
     • species adapted and dependant on sea ice and edge
     • warmer temps increase productivity in marine ecosystem
     • melting of ice sheets
       • polar bears, walrus seals lose their habitat
         • polar bears could become extinct if cant hunt prey
   • Terrestrial ecosystem
     • species not able to adapt quick enough so will be extinct
     • rain late winter
       • collapse polar bears dens before females and cubs have departed
     • tree line
       • push vegetation zones northwards
       • reindeers and muskox might be extinct
   • shipping disaster
     • spilt 11 million gallons of oil on alaskan coast
     • killed 250,000 birds
     • food web effected
       • death of some species
         • starvation