• Current CO2 emissions are near (but not above) upper end of IPCC scenarios
• 4°C global warming (relative to pre-industrial) is possible by the 2090s, especially under high emissions scenario [without considering feedback]
• Many areas could warm by 10°C or more
• The Arctic could warm by 15°C or more
• Annual precipitation could decrease by 20% or more in many areas
• Carbon cycle feedbacks expected to accelerate warming
• With high emissions, best guess is 4°C in 2070s
• Plausible worst case: 4°C by 2060
Note: many areas with higher precipitation are likelier to become drier with temperature increases.
From Nayamuth audio, looking at effect of climate change on sugar cane biofuels in Mauritius, which will decrease between 24 and 62% with a 4°C increase:
Sugarcane industry highly vulnerable to CC
Adaptation impossible because of
• Increased water demand
• High costs of irrigation network
• High costs of water storage
• Less water from reduced rainfall
• 4°C beyond adaptation limit
4°C = GHG emissions = Further GLOBAL WARMING [due to lower availability of biofuels]
Australian bushfires linked to climate change associated with a temperature increase of only 0.8°C in February 2009 killed more than 170 people. This year, consistent with predictions, California, Australia, and Athens experienced large fires.
Climate change doesn’t cause fire, but does change weather conditions (seasonal maximum, humidity, and winds), fuel conditions (dry due to droughts), and the frequency of lightning. While there have been large forest fires earlier, the forest fire danger index is much larger than ever before in places like Australia and southern California.
Climate change impacts on fires
• British Columbia: 30% increase in fire season,
95% increase in fire weather severity in summer
for a +3°C world (Nitschke and Innes, 2008)
• California: 12% to 90% increase in number of large
fires (depending on region) for a +3°C world
(Westerling and Bryant, 2008)
Australia’s fires in February were 50% of anthropogenic greenhouse gas emissions this year were from fires, but for now are considered “natural” and not added to the Australia column.
Which impacts of climate change induce population displacements, and where?
• Droughts and desertification, water stress
In Subsahelian Africa
In Northern Asia
In Central America
• Extreme weather events
In South-East Asia and Asia-Pacific
In the Gulf of Mexico
• Sea-level rise
In coastal and deltaic regions
In small island states
> Most of these regions are very densely populated
Calculations on the impact of climate change on migration will be difficult, because of the existence of and interaction with other problems, including environmental problems. The impact of climate change on a population depends on adaptive capacities. And little is known about population reaction to environmental disruptions.
See Environmental Change and Forced Migration Scenarios for 23 case studies. The poorest and most vulnerable often lack the resources to migrate.
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