Impacts of Global Warming

Rising sea level:
At present, global sea level is gradually rising, and is projected to rise at an even greater rate in the future. The two main causes are thermal expansion of sea water at higher global temperature, and the additional water from the melting of land-based ice. The UN Intergovernmental Panel on Climate Change (IPCC) warned that thermal expansion will push sea levels up by 18 cm to 59 cm by 2100. It is enough to wipe out several small island nations.

Coastal areas are home to 20% of global population and the number is still rising. Coastal mega cities normally have their supporting infrastructure of port facilities and oil refineries along the coastlines. Sea-level rise will pose a serious threat to their socio-economy. The East coasts of China and India, the Caribbean region and Central America in particular, will be vulnerable.

Rising sea level:
Shanghai - with an underlying fear: The rising sea level may severely disrupt low-lying mega deltas in Asia

Changing of precipitation pattern:
Global warming not only results in more frequent and more severe droughts,
it also results in more frequent and more severe floods.

More frequent and more severe droughts:
The higher temperature increases the water vapor retention power in the air, resulting in higher intensity when precipitations do finally occur. It thus increases the frequency and severity of droughts, as have happened in many areas. In the Sahelian region of African, warmer and drier conditions have led to a reduced length of growing season with detrimental effects on crops. .

Studies show that drought has become widespread in Africa, and now more common in the tropics and subtropics.

(Photo: More frequent forest fires
due to intense droughts)

Global warming also results in
more frequent and more severe floods.
This may cause large scale population displacement; resulting in socio economic instability and resource insecurity.

(Photo: A villager rows a boat past huts submerged in floodwaters in the northern Indian state of Assam, Reuters)

Increase in tropical storm and hurricane intensity and duration. Thus storms are projected to be more destructive. Specifically, the number of category 4 and 5 hurricanes have increased by 75% by the year 2007.

Ice melting:
There is a shift of temperatures to higher values. It means the Earth experiences higher maximums and higher minimums. Equivalently there are more extremely warm days and nights; thus more incidences of heat waves.
In the colder latitudes, the equivalent change is the longer frost-free winter season and earlier spring with less number of very cold days and nights.

To name them are glacier-melting and sea-ice shrinking in the Arctic; diminished snow cover in the Northern Hemisphere, decreasing permafrost, frozen lakes and rivers. This would result in increasing number of potentially hazardous glacial lakes and enlarge glacial lakes. Settlements in mountain regions are at enhanced risk of glacier lake outburst floods.

Surface melt from the Greenland ice sheet (Photo).

This fresh water river can undermine the stability of the Greenland ice sheet while it makes its way to the sea. Global warming decrease coverage in snow/ice causing stress on fresh water resource.

More precipitation occurs in the form of rain rather than snow, especially in autumn and spring, at the beginning and end of the snow season. It would mean less water resources in summer, when they are most needed.

The warming and melting in the Arctic which is now occurring at an accelerating rate disrupts the region, its ecosystems and its people in many ways. Warming may improve fish stocks (for example cod and herring) but threaten cold water stocks (such as northern shrimp).

Arctic thaw due to global warming is opening up more passages of the Arctic to sea exploration and raising security concerns. Beneath the the frozen region north of the Arctic Circle lies a huge reserve of about 20% of untapped fossil fuels and 33% of untapped natural gas in the world. One of the most significant potential conflicts arises from intensified competition to control these new found Arctic and much needed energy resources, which will continue to create increasing military instability.

Recent studies on the relationship between observed warming and impacts conclude with high confidence that recent regional changes in temperature have had discernible impacts on many physical and biological systems

Ecosystem and biodiversity
Agriculture, forestry, and fisheries are among the most climate-sensitive sectors. Therefore their production processes – whether for food, feed, fiber, beverage, energy or industrial crops, or for livestock, poultry, fish or forest products – will be heavily impacted by climate change. In the next decades, impacts in temperate regions are expected to be positive, and those in tropical regions negative, although there is still considerable uncertainty about how projected changes will play out locally, and projected impacts could also be altered by adoption of risk management measures and adaptation strategies that strengthen preparedness and resilience.

Warming has affected the thermal structure and quality of water in terms of thickness of ice cover, salinity, oxygen level and circulation; and distribution of marine species. Salinity and water quality leading to fresh water scarcity may affect 2 billion people.

There has been a pole ward shift in varieties and abundance of algae, plankton and fish; and earlier fish migration.

Global warming reduces biodiversity and the functioning of most ecosystems are perturbed. It is assessed that about 20% - 30% of the plant and animal species under studies will face risks of extinction with an increase in global temperatures of 1.5 - 2.5^oC (relative to 1990).

The corals and marine shell organisms are in particular, most vulnerable.

Coral bleaching was particularly pronounced during 1997-98 strong El Nino year superimposed with a sea temperature rise that might be linked to global warming.

Studies conducted in East Malaysia in 1970s have shown that up to 65% of all commercial marine fish species spend part of their life in mangroves, estuaries and coral reefs. Global warming will thus affect the multitude of (bird) species that dwell on mangrove marine ecosystems.

(The blue-eared kingfisher, common sight of mangrove swamps)

Crop and livestock production will be increasingly challenged

More frequent and more intense, extreme weather will have adverse immediate impacts on food production, food distribution infrastructure, on livelihood assets and opportunities in both rural and urban areas. Changes in mean temperatures and rainfall, and rising sea levels will affect the suitability of land for different types of crops and pasture, the health and productivity of forests, the incidence of pests and diseases, biodiversity and ecosystems socio economic and resource insecurities. Loss of arable land due to increased aridity, groundwater depletion and sea water inundation will reduce crop and livestock productivity.

Equally worrying is the likelihood of transformation of soils and forests into a net source of carbon, amplifying the rise in temperature, further amplifying effects of climate change.

The overall effect is that climate change will exacerbate existing conflicts over depleting resources of food, land/soil, water and energy.

Climate change will impose health risks

Health impacts of climate change are related to heat stress, waterborne diseases, poor air quality, extreme weather events, and diseases transmitted by insects and rodents.

New studies confirm that Africa is one of the most vulnerable continents to climate change due to multiple stresses and Africa's low adaptive capacity.

Higher warming rate of the troposphere

Higher cooling rate of the stratosphere

References and related news:

Slowdown of Coral Growth Extremely Worrying Guardian.co.uk
An Inconvenient Truth: Staffwww.fullcoll.edu
Many global warming impacts may be irreversible in next 1000 years (01/27/2009)
Food Security: Fao.org
Climate Change Effects: Ecosystems and Biodiversity: EPA

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