Global Warming - A Global Warning....
today Global warming is Rapidly increasingh it is the need of the hour to control it......
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4. Global
Warming......
What is Global Warming?
Global Warming is the increase of Earth's average surface temperature
due to effect of greenhouse gases, such as carbon dioxide emissions
from burning fossil fuels or from deforestation, which trap heat that
would otherwise escape from Earth. This is a type of greenhouse
effect.
Is global warming, caused by human activity, even remotely
plausible?
Earth's climate is mostly influenced by the first 6 miles or so of the
atmosphere which contains most of the matter making up the
atmosphere. This is really a very thin layer if you think about it. In the
book The End of Nature, author Bill McKibbin tells of walking three
miles to from his cabin in the Adirondack's to buy food. Afterwards, he
realized that on this short journey he had traveled a distance equal to
that of the layer of the atmosphere where almost all the action of our
climate is contained. In fact, if you were to view Earth from space, the
principle part of the atmosphere would only be about as thick as the
skin on an onion! Realizing this makes it more plausible to suppose that
human beings can change the climate. A look at the amount of
greenhouse gases we are spewing into the atmosphere (see below),
makes it even more plausible.
5. MatterOf
Concern....
The rapid rise in greenhouse gases is a problem because it is changing
the climate faster than some living things may be able to adapt. Also,
a new and more unpredictable climate poses unique challenges to all
life.
Now, with concentrations of greenhouse gases rising, Earth’s
remaining ice sheets (such as Greenland and Antarctica) are starting
to melt too.The extra water could potentially raise sea levels
significantly.
As the mercury rises, the climate can change in unexpected ways. In
addition to sea levels rising, weather can become more extreme.
Scientists are already seeing some of these changes occurring more
quickly than they had expected. According to the Intergovernmental
Panel on Climate Change, eleven of the twelve hottest years since
thermometer readings became available occurred between 1995 and
2006.
6.
7. Causes....
What Causes GlobalWarming?
Scientists have spent decades figuring out what is causing global
warming.They’ve looked at the natural cycles and events that are
known to influence climate. But the amount and pattern of
warming that’s been measured can’t be explained by these factors
alone.The only way to explain the pattern is to include the effect
of greenhouse gases (GHGs) emitted by humans.
Different greenhouse gases have very different heat-trapping
abilities. Some of them can even trap more heat than CO2. A
molecule of methane produces more than 20 times the warming
of a molecule of CO2. Nitrous oxide is 300 times more powerful
than CO2. Other gases, such as chlorofluorocarbons (which have
been banned in much of theworld because they also degrade the
ozone layer), have heat-trapping potential thousands of times
greater than CO2. But because their concentrations are much
lower than CO2, none of these gases adds as much warmth to
the atmosphere as CO2 does
8.
9. Greenhouse
Effect....
The “greenhouse effect” is the warming that happens when
certain gases in Earth’s atmosphere trap heat.These gases let in
light but keep heat from escaping, like the glass walls of a
greenhouse.
First, sunlight shines onto the Earth’s surface, where it is absorbed
and then radiates back into the atmosphere as heat. In the
atmosphere, “greenhouse” gases trap some of this heat, and the
rest escapes into space.The more greenhouse gases are in the
atmosphere, the more heat gets trapped.
Scientists often use the term “climate change” instead of global
warming.This is because as the Earth’s average temperature
climbs, winds and ocean currents move heat around the globe in
ways that can cool some areas, warm others, and change the
amount of rain and snow falling.As a result, the climate changes
differently in different areas.
10. Greenhouse
Gases......
What are the Greenhouse Gases?
The most significant greenhouse gas is actually water vapor, not
something produced directly by humankind in significant amounts.
However, even slight increases in atmospheric levels of carbon dioxide
(CO2) can cause a substantial increase in temperature.
Why is this? There are two reasons: First, although the concentrations
of these gases are not nearly as large as that of oxygen and nitrogen
(the main constituents of the atmosphere), neither oxygen or nitrogen
are greenhouse gases. This is because neither has more than two atoms
per molecule (i.e. their molecular forms are O2 and N2, respectively),
and so they lack the internal vibrational modes that molecules
with more than two atoms have. Both water and CO2, for example,
have these "internal vibrational modes", and these vibrational modes
can absorb and reradiate infrared radiation, which causes the
greenhouse effect.
Secondly, CO2 tends to remain in the atmosphere for a very long time
(time scales in the hundreds of years). Water vapor, on the other hand,
can easily condense or evaporate, depending on local conditions.
Water vapor levels therefore tend to adjust quickly to the prevailing
conditions, such that the energy flows from the Sun and re-radiation
from the Earth achieve a balance. CO2 tends to remain fairly constant
and therefore behave as a controlling factor, rather than
a reacting factor. More CO2 means that the balance occurs at higher
temperatures and water vapor levels.
11. Effects.....
Sea levels are expected to rise between 7 and 23 inches (18 and 59
centimeters) by the end of the century, and continued melting at
the poles could add between 4 and 8 inches (10 to 20 centimeters).
Hurricanes and other storms are likely to become stronger.
Polar bear biologist Ian Stirling has found a similar pattern in
Hudson Bay. He fears that if sea ice disappears, the polar bears
will as well.
The decline of the Adélie penguins on Antarctica, where their
numbers have fallen from 32,000 breeding pairs to 11,000 in 30
years.
Sea level rise became faster over the last century.
Ecosystems will change—some species will move farther north or
become more successful; others won’t be able to move and could
become extinct.
12. Etymology....
The term global warming was first used in its modern sense on 8
August 1975 in a science paper byWally Broecker in the journal
Science called "Are we on the brink of a pronounced global
warming?". Broecker's choice of words was new and represented a
significant recognition that the climate was warming; previously the
phrasing used by scientists was "inadvertent climate modification,"
because while it was recognized humans could change the climate, no
one was sure which direction it was going.The National Academy of
Sciences first used global warming in a 1979 paper called the Charney
Report, it said: "if carbon dioxide continues to increase, we find no
reason to doubt that climate changes will result and no reason to
believe that these changes will be negligible."The report made a
distinction between referring to surface temperature changes as
global warming, while referring to other changes caused by increased
CO2 as climate change.
Global warming became more widely popular after 1988 when NASA
climate scientist James Hansen used the term in a testimony to
Congress. He said: "global warming has reached a level such that we
can ascribe with a high degree of confidence a cause and effect
relationship between the greenhouse effect and the observed
warming." His testimony was widely reported and afterward global
warming was commonly used by the press and in public discourse.
14. SolutionsTo
It....
A commonly cited goal is to stabilize GHG concentrations around
450-550 parts per million (ppm), or about twice pre-industrial
levels.This is the point at which many believe the most damaging
impacts of climate change can be avoided. Current concentrations
are about 380 ppm, which means there isn’t much time to lose.
According to the IPCC, we’d have to reduce GHG emissions by 50%
to 80% of what they’re on track to be in the next century to
reach this level.
In addition to reducing the gases we emit to the atmosphere, we
can also increase the amount of gases we take out of the
atmosphere. Plants and trees absorb CO2 as they grow,
“sequestering” carbon naturally. Increasing forestlands and
making changes to the way we farm could increase the amount of
carbon we’re storing.
Some of these technologies have drawbacks, and different
communities will make different decisions about how to power
their lives, but the good news is that there are a variety of options
to put us on a path toward a stable climate.
