Transcript - Arctic Portal Library

Can we imagine a World without Ice?
Climate change:
Impacts on glaciers
Helgi Björnsson
Institute of Earth Sciences, University of Iceland
What is at stake?
Glaciers in the hydrological cycle
0,001%
0,01%
2,15%
0,63%
97,2%
Global sea level rise
0.2 – 0.5 m ?
Depending on
climate
scenarios
IPCC 2007
Contributions to rising sea level
1993-2003
1961-2003
3.1 +/- 0.7 mm year-1
Varmaútþensla
Antarctica
Greenland
?
Jöklar utan
heimskauta
Sea level equivalent: 61.1 m
SLE: 7.2 m
?
Glaciers
outside polar
regions
SLE 0.5 m
Thermal expansion
IPCC AR4
Glaciers in polar regions
Sea level equivalent: SLE 69 m
Arctic islands of N-Europe
Canadian Arctic islands
(Spitsbergen, Novaya Zemlya)
Greenland
SLE: 7.2 m
Antarctica
SLE: 61.1 m
Arctic glaciological research require international collaboration
Melting of the ice cover on the Arctic Ocean
The most visible expression of global warming
1979
2005
Of global importance for ship-transport of goods and cargo
Muli-national collaboration of Arctic research
Impact of climate change in the Arctic
•
•
Substantial decrease in Arctic Sea Ice, thinning and reduced area
Amplified by reduced albedo
•
Thawing of permafrost, release of methane
•
Extinction of many organisms that are adapted to this habitat, endemic
species.
– What are the walrus going to eat if they have to come ashore in the
summer?
•
Models predict:
– 5 cm sea-level rise from melting in Greenland during the 21st
century.
Greenland may almost completely melt during the next 1,000 years
(starting melting rapidly by 2100).
Mid-latitude glaciers
Sea level equivalent: SLE 0.5 m
Iceland
Norway
Alps
Pyrenees
Alaska
The Third
Pole
Pacific Coastal
Range
Rocky Mountains
Patagonia
New Zealand
Third-pole glaciological research require international collaboration
Glacier changes in The Tibetan Plateau and the Himalaya region have
economical and social impact on more than 1000 million people
Indus
Ganges
Brahhmaputra
Salween
Yellow river
Yangtze
Mekong
Tropical glaciers
Kilimanjaro
Mount Kenya
New Guinea,
Indonesia
Ecuator
Bolivia
Northern
Andes
Impacts of glacier retreat on:
Hydrology
Seasonal runoff changes. Excessive Flooding. Water arrives earlier than needed
Glacial lakes outburst floods (e. g. Nepal, Bhutan)
Sediment transport
Replenishment of reservoirs for drinking supplies, domestic use,
Irrigation, droughts (e. g. Mongolia, western China, Pakistan, Afghanistan,
India, Tajikistan, South America).
Societal matters, regional planning, geoengineering
Development, adaptation
Engineering and transportation, design of roads, bridges, hydropower plants,
Tourism, ski resorts, mountain recreation.
Food production, Reduced Agricultural Output
Public health
Political conflicts
Ecosystems
Animal, Bird, and Fish Habitat Loss. – Plants.
Oceans
Sea level rise, effect on coastal regions worldwide.
Alterations to the ocean currents, thermohaline circulation.
Longer term albedo changes, climate feedback.
The Ocean’s Conveyor Belt
Warm
Cold
Iceland is located at the border of warm and cold ocean and atmospheric
currents
Heavy
precipitation
Mild tempeartures
Global sea level rise
0,8 – 1 m ?
New predictions
Potential dynamic instability of landbased glaciers is not
considered in the present IPCC report
May contribute < 2 m before 2100.