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UNIT 1: WHERE DO WE STAND? THE STATE OF THE GLOBAL ENVIRONMENT
A shift in largescale
weather
patterns such
as depression
tracks could
greatly alter the
variability and
the extremes of
weather
patterns.
The greatest concern about global warming is that it is causing climate change.
Computer models predict that the heating of the earth’s atmosphere will alter
atmospheric and oceanic temperatures as well as air circulation and weather
patterns. This could result in:
• ALTERED RAINFALL PATTERNS
Rainfall is expected to increase in the middle and high latitude
continents and decrease in the lower latitudes. This will cause flooding
and erosion in some regions, and drought in others.
Boreal forests and permafrost areas are expected to undergo major
changes. Coastline ecosystems, flatlands and small islands risk
disappearing altogether. Changes in water availability will affect
crop yields and increase the incidence of vector-borne diseases. For
example there has already been a global resurgence of malaria,
dengue fever and cholera.
• SHIFT IN CLIMATE ZONES
Projected changes in rainfall and temperature for the next 50 years
could result in a shift of climate zones by several hundred kilometres
towards the poles. Flora and fauna will lag behind the climate shifts
and find themselves in ‘hostile’ environments. As some species will not
be able to adapt to such rapid changes in habitat, species will become
extinct in greater numbers than before.
• INCREASE IN THE FREQUENCY AND INTENSITY OF STORMS
A shift in large-scale weather patterns such as depression tracks could
greatly alter the variability and the extremes of weather patterns.
For example, intense storms usually only develop around oceans that
are warmer than 26°C. Global warming means larger areas of ocean
will reach such temperatures. This will cause more frequent and more
intense storms all over the world. Already, the worldwide increase in
natural disasters is causing extraordinary losses for property insurers.
Annual insured losses have risen dramatically – from about US$1.8
billion a year in the 1980s to over US$10 billion a year in the 1990s.
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• RISING SEA LEVELS
The UN International Panel on Climate Change (IPCC) predicts that
thermal expansion of the oceans and melting of the glaciers could
cause average sea levels to rise by 6cm a decade. Increased flooding
will displace millions, alter coastlines, contaminate freshwater
supplies, and destroy agricultural land. Islands, lowlands and
coastlines are particularly at risk from devastating flood and storm
damage.