December 2002 Section 5a Global Impacts of Climate Change (1)

Ecological systems are sensitive to climate change Biological systems have already been affected by changes in climate at the regional scale The structure and functioning of ecological systems will be altered and the biological diversity will decrease, especially in niche systems, e.g., alpine and arctic Ý Ý forests, especially tropical and boreal forests are vulnerable due to changes in disturbance regimes (pests and fires), likely to change species composition Ý Ý coral reefs are threatened by increases in temperature, more than increases in sea level Ý Ý the current terrestrial uptake of carbon will likely diminish over time and forest systems may even become a source of carbon

There will be large shifts in the eventual distribution of global ecozones 1xCO22xCO2

…causing a major redistribution of global forest types

Vulnerable species will be increasingly threatened by changing habitat and food supply

There are also many reasons for concern about the impacts on humans A place to live –sea level rise –floods Food to eat –crop losses in tropical regions –droughts Health –extreme weather –disease/air quality Economic well-being

Changing ice sheets Receding glaciers Rising ocean temperatures Sea levels will rise

…although the rate of rise will vary from region to region Year metres Eastern Pacific Equatorial Atlantic NW Atlantic Arctic Ocean

Many people will be affected Coastal areas highly vulnerable to a 44 cm Sea-level Rise by the 2080s Assuming 1990s Level of Flood Protection

Some small island states may simply disappear Examples of vulnerable islands: Marshall Islands Tuvalu Kiri bati Maldives

Deltaic countries like Bangladesh would be particularly vulnerable Today 1 M sea level rise 20.7% land loss 14.8 million people affected

Other examples of costs of sea level rise: Impacts –for 0.5 m rise 32% of urban Egypt property flooded, loss of US$ 35 B $20 to 150 billion property loss in the USA –for 1 m rise 17 million people directly affected by flooding in Vietnam US$410 property loss in Germany Protection Costs –for 1 m rise, ~US$30 B for Germany For 1 m rise, ~$200 B for Japan

Inland flood disasters may become more frequent as rains become more intense

El Nino - Southern Oscillation behaviour may change significantly distribution distribution Nino-3 Monthly SST Anomaly (deg. C)Nino-3 SST Monthly Anomaly (deg. C)

…possibly causing both intense El Ninos and La Ninas to become more frequent Neutral La NinaEl Nino Change in Percent of Total Events Nino-3 Monthly SST Anomaly (deg. C) <-1.5C-1.5 to -1.0 to to to to 1.5 >1.5

>80 Wind Speed (m/s) Number of Cases per year (NW Pacific) Control High CO2 The number of intense hurricanes may increase in some areas