global warming is a process of
increasing the average temperature of the atmosphere, ocean, and land Earth.Global
average temperature at Earth's surface has increased by 0.74 ° C ± 0:18 (1:33 ±
0:32 ° F) over the last hundred years. Intergovernmental Panel on Climate Change
(IPCC) concluded that, "the majority of the increase in global average
temperatures since the mid-20th century, most likely caused by increased
concentrations of greenhouse gases due to human activities"through the
greenhouse effect. These basic conclusions have been put forward by at least 30
scientific and academic bodies, including all national science academies of the
G8 countries. However, there are still some scientists who do not agree with
some of the conclusions of the IPCC stated.
Climate models referenced by the IPCC project shows global surface temperature
will increase by 1.1 to 6.4 ° C (2.0 to 11.5 ° F) between 1990 and 2100.The
difference in estimates was caused by the use of different scenarios on the
emissions of gas- greenhouse gases in the future, as well as models with
differing climate sensitivity. Although most research has focused on the period
up to 2100, warming and sea level rise is expected to continue for more than a
thousand years even if greenhouse gas emission levels have stabilized.This
reflects the large heat capacity of the oceans.
Increasing global
temperature will cause changes such as rising sea levels, increased intensity
of extreme weather phenomena, as well as changes in the amount and pattern of
precipitation. Consequences
of global warming include its impact on agricultural output, loss of glaciers
and the extinction of various animal species.
Some
things that scientists are still in doubt about the amount of warming expected
to occur in the future, and how warming and changes that occur will vary from
one region to another. Up
to now there is still political and public debate in the world about what, if
any, action should be taken to reduce or reverse the further warming or to
adapt to the consequences there. Most
governments in the world have signed and ratified the Kyoto Protocol, aimed at
reducing emissions of greenhouse gases.
The
cause of global warming
Greenhouse effect
All energy
sources that exist on Earth comes from the sun. Most of the energy in the form
of short-wave radiation, including visible light. When this energy arrives surface
of the Earth, he turned on the light into heat that warms the Earth. Earth's
surface will absorb some of the heat and reflect the rest. Some of this heat tangible
long-wave infrared radiation into space. However, some heat remains trapped in the
Earth's atmosphere due to the accumulated amount of greenhouse gases include water
vapor, carbon dioxide, sulfur dioxide and methane that become traps for this
radiation.
These gases absorb
and reflect radiation emitted by the Earth and consequently the heat stored in the
Earth's surface.
The
greenhouse effect is very much needed by
all living things on earth,
because without it, the planet would
be very cool. With
an average temperature of 15 ° C (59 ° F), the earth has actually hotter 33
° C (59 ° F) from its original temperature, if there is no greenhouse effect the earth's temperature is only -18 ° C so that the ice will cover
the entire Earth's surface. But
on the contrary, if these gases in the atmosphere has been excessive, will
lead to global warming.
·
Feedback effects
Elements of the cause of global warming is also influenced by various feedback
processes that result. An example is the evaporation of water. In the case of
warming caused by greenhouse gases such as CO2, warming will initially cause
greater volumes of water that evaporates into the atmosphere. Because water
vapor is itself a greenhouse gas, warming will continue and increase the amount
of water vapor in the air until it reaches equilibrium with the water vapor
concentration. The resulting greenhouse effect greater than the effect of CO2
alone. (Although this feedback raises the absolute water content in the air,
the relative humidity of air is almost constant or even fall because the air
becomes warm).This feedback affects only slowly because of CO2 have longevity
in the atmosphere.
Feedback effects due to the influence of clouds is the subject of current
research. When viewed from below, clouds will reflect infra-red radiation to
the surface, thereby increasing the warming effect. In contrast when viewed
from above, the clouds will reflect sunlight and infrared radiation into space,
thereby increasing the cooling effect. Whether the net effect produces heating
or cooling depends on some specific details such as the type and height of
these clouds. These details are difficult to represent in climate models,
partly because the clouds are very small compared to the distance between the
boundaries of computational climate models (around 125 to 500 km for models
used in the IPCC Fourth Report of view). However, the cloud feedback is ranked
two when compared to water vapor feedback and considered positive (add heating)
in all models used in the IPCC report into four views.
Another important feedback is the loss of reflectance (albedo) by ice.As global
temperatures rise, ice near the poles melts at an increasing rate. Along with
melting ice, land or water below it will open. Both land and water has the
ability to reflect light much less when compared to ice, and consequently will
absorb more solar radiation. This will add to warming and causing even more ice
to melt, causing a continuous cycle.
Positive feedback due to release of CO2 and CH4 from the softening of frozen
ground (permafrost) are other mechanisms that contribute to warming. In
addition, the ice that melts will also release CH4 which also give rise to
positive feedback.
The ability of the oceans to absorb carbon will also be reduced when he warmed
up, this is caused by the decline in the level of nutrients in the mesopelagic
zone, limiting the growth of phytoplankton diatoms rather than a carbon sink
lower
· Control of global warming
Total consumption of fossil fuels in the world increased by 1 percent per year.
Measures undertaken or are being discussed at this time no one can prevent
global warming in the future. The current challenge is to overcome the effects
that arise while performing steps to prevent increased climate change in the
future.
Severe damage can be overcome in various ways. Coastal areas can be protected
by a wall and a barrier to prevent the ingress of sea water. Alternatively, the
government can help the population in coastal areas to move to higher ground.
Some countries, like the United States, can save plants and animals while
maintaining the corridor (lane) habitat, vacate the land that has not been
built from south to north. Species can slowly move along these corridors
leading to cooler habitats.
There are two main approaches to slow the increasing greenhouse gases. First,
it prevents the carbon dioxide released into the atmosphere by storing the gas
or its carbon component elsewhere. This is called carbon sequestration
(removing carbon). Secondly, reducing the production of greenhouse gases.
·
Removing carbon
The easiest way to reduce carbon dioxide in the air is to preserve trees and
planting more trees. Trees, especially young and fast growing, absorb carbon
dioxide, breaking it down through photosynthesis and store carbon in the wood.
Around the world, the level of encroachment has reached an alarming level. In
many areas, the plants that grow back a little once because the soil loses its
fertility when converted to other uses, such as for agriculture or construction
of residential houses. Steps to resolve this is to reforestation that play a
role in reducing the increasing greenhouse gases.
Carbon dioxide gas can also be removed directly. How to inject (inject) the gas
into oil wells to bring oil to the surface (see Enhanced Oil Recovery).
Injection can also be done to isolate the gas below ground such as in oil
wells, coal seams or aquifers. This has been done in one of the drilling
platform off the coast of Norway, where the carbon dioxide is brought to the
surface along with the natural gas captured and reinjected into the aquifer so
it can not return to the surface
The impact of global
warming
·
Climate started unstable
·
Sea level rise
·
Global temperatures are likely to
increase
·
ecological disturbance
quote “As best as
can be determined, the world is now warmer than it has been at any point in the
last two millennia, and, if current trends continue, by the end of the century
it will likely be hotter than at any point in the last two million years.
JAMES M. INHOFE, speech in U.S. Senate, July 28, 2003
sumber quote:
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