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Climate Change 2001 Assessment

5. How could Climate Change affect us in the future?

  • 5.1 What would be the effects on and vulnerability of the natural systems?
  • 5.2 What would be the effects on and vulnerability of the human systems?
  • 5.3 How does climate change vulnerability vary across regions?

5.1 What would be the effects on and vulnerability of the natural systems?

5.1.1 Hydrology and Water Resources

Most scenarios project increases in annual mean streamflow in high latitudes and southeast Asia, and decreases in central Asia, the area around the Mediterranean, southern Africa, and Australia.

The population living in water-stressed areas is projected to increase. Floods could increase in many regions. However, water management could be applied to adapt to the changes. More...

5.1.2 Agriculture and Food Security

Crop yield responses to climate change vary widely, depending upon many parameters. Increased CO2 concentration can stimulate crop growth and yield, yet that benefit may not always overcome the adverse effects of excessive heat and drought . Crop yields are projected to increase in mid-latitude regions for less than a few degrees C warming, and to decrease in all other cases. More...

5.1.3 Terrestrial and Freshwater Ecosystems

In certain ecosystems or biomes, species composition and dominance would change. Distributions, population sizes, population density, and behavior of wildlife have been, and will continue to be, affected directly by changes in global or regional climate and indirectly through changes in vegetation.

Fish distributions would move towards the poles, along with loss of habitat for cold- and cool-water fish and gain in habitat for warm-water fish. Extinction risks should increase for endangered or vulnerable freshwater fish species.

A small amount of climate change would increase global timber supply in developing countries. More...

5.1.4 Coastal Zones and Marine Ecosystems

Impacts on oceans would include increases in sea surface temperature and mean global sea level, decreases in sea-ice cover, and changes in salinity, wave conditions, and ocean circulation.

Many coastal areas should experience more flooding, accelerated erosion, loss of wetlands and mangroves, and seawater intrusion into freshwater sources. Coastal ecosystems such as coral reefs, atolls and reef islands, salt marshes and mangrove forests would be affected to varying degrees. More...

5.2 What would be the effects on and vulnerability of the human systems?

5.2.1 Human Health

The geographic range would spread for many infectious diseases like malaria and dengue (which currently impinge on 40-50% of the world population).

Heat-wave related deaths and illness episodes are expected to increase, but reduced winter deaths would outnumber increased summer deaths in some temperate countries.

Any increase in flooding would increase the risk of drowning, diarrheal and respiratory diseases, and, in developing countries, hunger and malnutrition.

For each anticipated adverse health effect there is a range of social, institutional, technological, and behavioral adaptation options to lessen that impact. More...

5.2.2 Human Settlements, Energy, and Industry

Human settlements would be affected by climate change in three major ways: economic productivity, infrastructure and population health or migration.

The most widespread direct risk is flooding and landslides. The number of people who would be flooded by coastal storm surges would increase several fold. More...

5.2.3 Insurance and Other Financial Services

The costs of ordinary and extreme weather events have increased rapidly in recent decades. Part of this increase is linked to socioeconomic factors, such as population growth, increased wealth, and urbanization in vulnerable areas, and part is linked to climatic factors such as the observed changes in precipitation and flooding events.

Climate change would place upward pressure on insurance premiums and/or lead to certain risks being reclassified as uninsurable. More...

5.3 How does climate change vulnerability vary across regions?

The vulnerability of human populations and natural systems to climate change differs substantially across regions and across populations within regions.


Click on the different areas of the map to obtain summaries of the adaptive capacity, Vulnerability and Key Concerns for each region
North America Latin America Africa Europe Asia Small Island States Polar Region Polar Region Australia and New Zealand northamerica Small Island States Small Island States Small Island States

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