Global Warming and the resulting Climate change is a threat to mankind! More frequent and powerful cyclones and hurricanes, more frequent and intense floods and droughts are clear
indications that climate change has already begun. The potential impacts of climate change on
disasters cover all sectors of human society and functions of ecosystems, as explained below:
1. Extreme weather
The Intergovernmental Panel on Climate Change (IPCC)
expects extreme weather and weather-related events to
become more frequent and/or intense, with serious
consequences for human health and well-being. Scientists
expect heat waves, droughts, wildfires, floods, severe
storms, and dust transported between continents to cause
locally severe economic damage and substantial social and
cultural disruption. The IPCC projects an extended fire
season for North America as well as increased threats from
pests and disease (which could significantly enlarge the
area burned in a fire). Rapid temperature changes would
affect the seasons, causing variations in season length.
Changes such as shorter winters could lead to mismatches
between key elements in an ecosystem, such as feeding
periods for young birds and availability of worms or insects for food. Increases in the frequency of droughts and floods would negatively affect local food production, and communities in mountain regions would face an increased risk of floods caused by melting glaciers. In addition, the risk of flood-induced illness and death from diarrheal diseases could rise in South and Southeast Asia. A region's vulnerability to such extreme events depends both on how much the climate changes and whether or not nations develop effective responses to potential threats
3. Impact on Agriculture
The impacts of climate change on crops and vegetation depend on the complex interactions among
increased levels of CO in the atmosphere, rising temperatures, water and nutrient availability. Elevated 2
levels of CO can essentially fertilize plants and crops. This is termed as the “CO fertilization effect”. A 2 2
mild increase in temperature levels usually enhances growth, while a drastic increase in temperature
levels can actually slow down the growth rate of plants. Rising temperatures also increase the
photosynthetic rate as well as the rate at which plants release CO . As the temperatures increase, there is 2
a subsequent increase in the rate of evaporation, thereby drying out soils. As a result of insufficient water
supply, the plant growth is adversely affected.
Climate change will affect agricultural yield directly because of extreme weather conditions (such as high
temperature, heavy rainfall, floods, droughts, etc.) and indirectly through changes in soil quality, pests,
and diseases. As the temperature rises, pest population would increase and so will the pest related
problems.
The IPCC expects food production to decline in low-latitude regions (near the equator), particularly in the
seasonally dry tropics, as even a small temperature increase could decrease crop yields in these areas.
Crop yield in tropical countries (including India) is projected to reduce by at least 30% by 2050, which will
have a devastating impact on the country's food security. Several developing countries in Asia face a
continued very high risk of food shortages from a combination of projected declines in crop production,
rapid population growth, and urbanization.
The IPCC projections show drought-prone areas of Africa to be particularly vulnerable to food shortages
due to a reduction in the land area suitable for agriculture; some rain-fed crop yields could decline as
much as 50 percent by 2020. The likely degradation of African coral reefs and mangroves would have
negative consequences for fisheries. Rising lake temperatures in Africa combined with over fishing may
also decrease fish supplies.
In the higher latitudes, agriculture will benefit with the rise in temperature as the winter season will be
shorter and the growing seasons longer. Under local average temperature increases of 2 to 5°F (1 to 3°C),
regions such as Northern Europe, North America, New Zealand, and parts of Latin America could benefit
from increased growing season length, more precipitation, and/or less frost, depending on the crop.
However, these regions can also expect more flooding, and if local average temperatures rise beyond this
range, crop yields could decline in some of these areas. Note that these higher-latitude regions warm at a
faster rate than the global average.
The populations most vulnerable to climate change-induced food shortages are those that depend on
climate-sensitive food and water supplies and also lack the economic resources and government support
to plan for or recover from extreme events such as floods or prolonged droughts.
4. Glacial retreat
Glaciers are the Earth's largest freshwater reservoirs. They are ancient rivers of compressed snow that
creep through the landscape, shaping the planet's surface. Glaciers have been retreating worldwide since
the end of the Little Ice Age (around 1850), but in recent decades glaciers have begun melting at rates that
cannot be explained by historical trends.
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Simulations project that a 4°C raise in temperature would cause
nearly all of the world's glaciers to melt; a 2-3°C rise in
temperature would cause the meltdown of the Greenland ice
sheets; a 1°C rise in temperature along with an increase in rain
and snow would cause glaciers to lose volume.
Glacier retreat has been observed in all continents. Nearly all
glaciers surveyed in Alaska are melting. Thinning rates in the last
5 to 7 years are more than twice those recorded in previous years.
The northern Andes contain the largest concentration of glaciers
in the tropics, but these glaciers are receding rapidly and losses
have accelerated during the 1990s. Glacier melting has
accelerated in the European Alps. 10-20% of glacier ice in the Alps
has disappeared in less than two decades.
Although only a small fraction of the planet's permanent ice is stored outside of Greenland and Antarctica,
these glaciers are extremely important because they are particularly susceptible to climate change and
their loss directly affects human populations and ecosystems. Continued and widespread melting of
glaciers during this century will lead to floods and water shortages for millions of people. As sea levels
rise, coastal communities and habitats will be destroyed.
There are many regions at risk including -
Ecuador, Peru and Bolivia - shrinking glaciers supply water year-round, and are often the sole source
of water for major cities during dry seasons.
The Himalayas - the danger of catastrophic outburst and flooding, especially of glacial lakes (GLOF)
is severe and glacier-fed rivers supply water to one third of the world's population (in Asia).
Small island nations such as Tuvalu and some of the Solomon Islands - sea level rise is submerging
low-lying land and saltwater is inundating vital groundwater reserves.
Rapidly melting glaciers pose a great risk for nature. For instance, the endangered Royal Bengal tiger will
lose a large portion of their worldwide habitat as the Sundarbans succumb to sea level rise, thereby
threatening their existence. Similarly, many other species such as the Kittlitz's murrelet (rare bird species
which nest on top of ice and hunt in cloudy glacier water) and the coral reefs (unique organisms that can
be starved of energy from the sun when the sea level rises) would be severely affected. The Golden Toad
and the Gastric Brooding Frog, are already presumed to be extinct because of climate related impacts.
Amphibians are especially vulnerably to climate change because of their high level of endemicity,
restricted microhabitats and range and limited food base. Polar bears will face starvation. Many species of
whale depend on the Arctic as their main feeding ground. Currently the Arctic ocean is the most
productive marine ecosystem in the world and home to the highest density of birds in the world. Loss of
sea ice and rising temperatures will reduce food availability for whales, seals, polar bears and sea birds.
5. Sea Level Rise
Melting of glaciers and polar ice sheets and heating up of oceans
due to global warming is expected to reduce the size and extent
of the polar ice caps and raise the average sea level. The
Greenland and West Antarctic ice sheets face substantial melting
if the global average temperature rises more than 2 to 7°F (1 to
4°C) relative to the period 19902000eventually contributing to
an additional sea-level rise of 13 to 20 feet (4 to 6 meters) or
more. This would result in the inundation of low-lying coastal
areas, including parts of many major cities.
Flooding caused by sea-level rise is expected to affect millions of
additional people every year by the end of this century, with small
islands and the crowded delta regions around large Asian rivers (such as the Ganges-Brahmaputra) facing
the highest risk. Sea-level rise exposes coasts to higher risks of flooding and erosion, which would be
exacerbated by growing population, increased human infrastructure within flood-prone areas, and
human activities that increase erosion or local subsidence.
As the sea level rises, more and more land will get submerged. Coastal areas and small islands will be at
maximum risk because of the rise in sea level. This would result in loss of land due to inundation and
erosion, increased flooding, and salt-water intrusion. These would adversely affect coastal agriculture,
freshwater resources, fisheries and aquaculture, human settlements, and health. Mangroves and coastal
wetlands (which are a home to birds, mammals, crustaceans and fishes, as well as valuable breeding
habitat) are very sensitive to sea level rise, as their location is closely linked to the existing sea level. The
World Wide Fund for Nature predicts that among the victims of the flooding of mangroves is the famous
Bengal tiger in the Sundarbans.
Regions especially at risk are low-lying areas of North America, Latin America, Africa, populous coastal
cities of Europe, crowded delta regions of Asia that face flood risks from both large rivers and ocean
storms, and many small islands whose very existence is threatened by rising seas. In North America,
current preparedness for rising seas, more frequent severe weather, and higher storm surges is low.
6. Scarcity of Water Resources
Climate change would also lead to a reduction in the availability
of freshwater. Hundreds of millions of people face water shortage
that will worsen as the global temperatures rise. At maximum risk
are the current drought-affected regions, areas with heavily used
water resources, and areas that get their water from glaciers.
The IPCC expects many Latin American glaciers to disappear
entirely over the next couple of decades, and water resource
competition to increase in western North America when
decreased snow pack in the mountains reduces summer river
flow. Several of the African lakes, such as Victoria, Malawi and
Chad, will experience shrinking lake area and basins, further
exacerbated by over extraction and mismanagement. Many rivers
that derive their water from melting glaciers or snow will have earlier peak runoff in spring and an overall increase in runoff, at least in the short term. Such a temporary increase in water flow would not always be welcome; for example, melting glaciers in the Himalayas would increase flooding and rockslide risks,
while flash flood risks could increase in Northern, Central, and Eastern Europe.
The supply of water is very likely to increase at higher latitudes due to glacial melting while it is likely to
decrease over the mid-latitudes and dry tropics, which are already water-stressed areas. Such shifts in
water availability would drastically affect hydropower generation and industries that require large
quantities of water (e.g paper and pharmaceutical industry).
7. Threats to Human Health
The Climate change will have several direct and indirect impacts
on human health. The IPCC expects heat waves, floods, storms,
fires, and droughts related to global warming to contribute to
increased rates of death, disease, and injuries for millions around
the world. It is anticipated that there will be an increase in the
number of deaths due to greater frequency and severity of heat
waves.
The affect will be more pronounced in urban areas than in the
rural areas owing to the formation of urban 'heat islands' that
develop in cities owing to the presence of concrete structures and
tarred roads. It could also lead to an increase in the incidents of
skin cancer, cataract and other forms of eye disorders. Shrinking
food and water resources, especially in Africa, could also lead to malnutrition related disorders.
Scientists project an increase in the incidence of cardio-respiratory diseases caused by the higher
concentrations of ground-level ozone (smog) that may accompany higher air temperatures. Some
infectious diseases, such as Malaria and other vector borne diseases may also become more common in
regions where those diseases are not currently prevalent.
Developing countries, many of which are already under stress, could experience increases in the
incidence of diarrheal diseases, malnutrition and consequent disorders, affecting child growth and
development. The populations most vulnerable to harsh living conditions in any nation (the elderly,
children, and poor) may be unable to cope with further climate change.
8. Ecosystems and Species in Peril
Climate Change has already sounded the death knell for its first
victims. The golden toad (Bufo periglenes) and the harlequin frog
(Atelopus varius) of Costa Rica have disappeared as a direct result
of global warming. According to IPCC, upto 30 percent of plant
and animal species could face extinction if the global average
temperature rises more than ~3 to ~5°F (1.5 to 2.5°C) relative to
the 19801999 period. Many projections suggest the low end of this
temperature range could be reached by mid-century.
Many species have already shifted their home ranges to higher
latitudes (toward the poles) and higher elevations over the past several decades. Spring has been arriving
earlier during this time, influencing the timing of bird and fish migration, egg laying, leaf unfolding, and
spring planting for agriculture and forestry in the high northern latitudes. Satellite records since the early
1980s confirm that increased temperatures have produced longer growing seasons.
In the Alps, some plant species have been migrating upward by one to four meters per decade, while some
plants previously found only on mountain tops have already disappeared. Butterflies, dragonflies, moths,
beetles, and other insects are now living at higher latitudes and altitudes, where previously it was too cold
to survive. Changes in climate may bring about a shift in the feeding points and disruptions to the flight
patterns of migratory birds.
Scientists expect the magnitude of these changes to increase along with temperatures over this century.
Many species and ecosystems may not be able to adapt as the effects of global warming and its associated
disturbances (including floods, drought, wildfire, and insects) are compounded by other stresses such as
pollution and resource exploitation. Polar and alpine species are especially vulnerable to the effects of
climate change, as their unique habitats could shrink due to warming.
The ecosystems that are most likely to be affected by climate change are the ones in the higher latitudes,
such as the tundra forests. Polar Regions will be severely affected. It is now an established fact that
species are being forced due to climate change to move higher up the latitudes and altitude to find a
suitable habitat, thereby reducing the area in which they can live. If the rate of climate change continues
to accelerate, then the extinction of some mountain plants and animals is certain.
Natural forests are under severe threat from climate change. Particularly vulnerable are forest systems on
remote islands, and fragmented forests surrounded by agricultural or urban development (e.g. Western
Ghats), since the species they support have no opportunity for migration. Himalayan forest systems are
thought to be equally vulnerable to climate change. In a warmer, drier world, forests from the lower
slopes are likely to migrate upwards but forests near the tree line will be squeezed into smaller areas or
even disappear altogether.
Some areas, such as the national parks of Australia and New Zealand and many parts of tropical Latin
America are likely to experience a significant loss of biodiversity. The Great Barrier Reef could experience
such a loss by 2020. By mid-century, tropical forests in the eastern Amazon Basin could be gradually
replaced by less species-rich savanna because of rising temperatures and decreasing soil moisture.
Species Endangered by Global Warming
Scientists predict that global warming could contribute to the mass extinction of wild animals in the near
future. An overheating world is creating a big change in climatic conditions and this can harm the delicate
ecosystems in which species live. Provided below are examples of threatened species from all over the
world:
The Arctic sea ice is melting at a rate of 9% per decade, endangering the Polar Bear's habitat and
existence.
Sea Turtles lay their eggs on Brazilian beaches, many of which are threatened by rising sea levels.
Climate change also threatens the offspring of sea turtles, as nest temperature strongly determines
the sex: the coldest sites produce male offspring, while the warmer sites produce female offspring.
This nest-warming trend is reducing the number of male offspring and seriously threatens turtle
populations.
The North Atlantic Right Whale is one of the most endangered of all large whales, with a long
history of human exploitation. Since warming waters contain less plankton for whales to feed on,
the non-availability of food due to climate fluctuations is also becoming an increasing cause of
mortality.
The Giant Panda's future remains uncertain due to a number of threats. Its forest habitat in the
mountainous areas of south-western China is fragmented; giant panda populations are small and
isolated from each other; bamboo, the panda's staple diet, is a part of a delicate ecosystem that is
being severely affected by global warming; poaching remains an ever-present threat.
Asia's only ape, the Orangutan is in deep trouble. Its last remaining strongholds in the rainforests of
Indonesia are being threatened by a range of pressures, including climate change, putting the
animal at risk of extinction within a few decades. With global warming increasing the duration and
frequency of droughts, bushfires are occurring more often in these heavily logged forests, further
fragmenting the orangutan's living space.
In Africa, Elephants face a range of threats including shrinking living space, which brings them
more frequently into conflict with people. With diminished living space, elephants will be unable to
escape any changes to their natural habitat caused by global warming, including more frequent and
longer dry periods, placing further pressure on their existence.
Climate change is affecting home range, abundance and breeding cycles of many of Australia's
Frog species. Since frogs rely on water to breed, any reduction or change in rainfall could reduce frog
reproduction. Higher temperatures contribute to the drying out of breeding pools, and as a result,
to the deaths of tadpoles and eggs. Drier conditions also cause adult frogs to die, due to increased
rates of internal water loss through their permeable skin.
Some of the largest remaining areas where Tigers occur are the mangrove forests of India. The
projected rise in sea levels could cause these living spaces of the tiger to vanish altogether. Apart
from the loss of their habitat, the depletion of the tiger's natural prey and extensive poaching
together contribute to the shrinking population of these wonderful species.
The Tawny Eagle, is feared to become extinct in its African habitat in the southern Kalahari due to changes in precipitation predicted with climate change.
Warming ocean waters and major shifts in species that support the ocean food web are causing a decline in sandeel population (a crucial prey species for the seabirds). This shortage of prey base leads to breeding failure of seabirds (such as Common Guillemots, Arctic skuas, great skuas, kittiwakes and Arctic terns) and the starving adult birds are seen eating their own young ones.
The Siberian Crane is a critically endangered migratory wetland bird which breeds in Arctic Russia
and Siberia and spends most of the winter in China. This bird's Arctic tundra habitat is forecasted to
decline by 70% due to global warming (it becomes colonized by trees). Decreased precipitation
coupled with more intense rainfall negatively affects the crane in its habitat in China.
Galápagos Penguins are island seabirds that are highly vulnerable to climate change. Endangered
penguin populations have halved since the early 1970s because the adult penguins become
emaciated (sometimes dying) and fail to reproduce during severe El Niño years. Because climate
change is expected to make El Niños more frequent in future, it is expected to further reduce the
populations of Galápagos penguins and threaten them with extinction.
Tufted Puffins are specialist seabirds which are highly vulnerable to climate change. At the world's
largest puffin breeding colony, two decades of unusually warm temperatures associated with
climate change between 1975 and 2002 led to drastically decreased growth rates of tufted puffin
nestlings, with fledging success near zero when waters were warmest. Climate change could
eventually make this puffin colony unsuitable for breeding for tufted puffins.
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The southeastern Australian habitat of the endangered Red-Tailed Black Cockatoo. It is expected
to contract to just 2% of its current extent under climate projections of 3°C of warming with a 10%
decrease in rainfall.
Threats to Marine Life
Coral reefs are extremely important for biodiversity, providing a home to over 25% of all marine life. These
reefs are effectively the rainforests of the seas, with a staggering array of different types of fish and
other marine animals living in and around them. They are also vital for people and business. They provide
nurseries for many species of commercially important fish, protection of coastal areas from storm waves,
and are a significant attraction for the tourism industry.
However, a coral is a living organism, and it is extremely sensitive to changes in temperature. As a result,
the coral reefs can tolerate only a narrow temperature range and are considered to be very fragile and
sensitive ecosystems.
Warming ocean waters represent serious threat to corals; Ocean warming causes coral polyps to expel the
algae that live within their tissues, an action known as 'Coral Bleaching' because it turns the coral white.
Bleaching is also thought to make corals more vulnerable to epidemics. If they are unable to adapt to
projected sea surface temperature increases of 2 to 5°F (1 to 3°C), corals would die due to bleaching.
Scientists expect coral reefs and mangroves in Africa to be degraded to the point that fisheries and
tourism suffer.
A WWF report shows that less than 5% of the Great Barrier Reef will remain by 2050 if the world fails to
reduce carbon dioxide emissions. In the Indian Ocean, 70 per cent of coral reefs, harbouring one-quarter
of all ocean species and at least 65 per cent of marine fish species - appear to have died. If the situation
continues, nearly three-quarters of the ocean's richest biome may disappear in 50 years. In autumn 2005,
in the biggest bleaching event in the Caribbean, corals that were alive even when Columbus shipped
through these waters were all found dead.
Acidification of the oceans due to increasing atmospheric carbon dioxide negatively affects corals,
phytoplanktons and zooplanktons (and also the species dependent on them). Because of acidification of
water and the rising ocean temperatures, the Zooplankton population has been fast receding which in
turn is having a detrimental impact on the fish population and on the number of sea birds that feed on
these organisms. Ocean warming, acidification of the ocean waters, destructive fishing practices,
pollution, coastal development and climate change are all taking their toll on this delicate ecosystem.
Sadly, there are a few other global warming effects also that threaten coral reefs, which include -
But this is not just an environmental tragedy as coral reefs provide enormous quantities of food
for humanity. Around half a billion people - a twelfth of the entire population of the world -
relies on fish from coral reefs as their main source of protein. If the reefs are destroyed, so will
this wonderful larder for the planet.
More frequent tropical storms caused by global warming could wipe off the corals.
Unusually warm water (by up to 5°C) caused by more frequent El Niño (El Niño - Southern
Oscillation) years, would also be an additional stress.
More frequent heavy rains means more flooding, more river runoff, and therefore more sediment
deposit in the seas.
Finally, climate change could also reduce the ability of corals to form their limestone skeletons.
Courtesy : World Wildlife Fund - India |