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Today news:
Global Warming
By: Raúl Escamilla and Jasmín Gómez
We probably
lost our
home
What does it mean?
Global warming is the
rise in the average
temperature of Earth's
atmosphere and
oceans since the late
19th century.
Future warming and
related changes will
vary from region to
region around the
globe.
Proposed policy
responses to global
warming
include mitigation by
emissions
reduction, adaptation
to its effects, and
possible future
Geoengineering.
Read more about this…
Glaciers are melting, sea levels are rising, cloud forests are drying, and
wildlife is scrambling to keep pace. It's becoming clear that humans
have caused most of the past century's warming by releasing heat-
trapping gases as we power our modern lives. Called greenhouse gases,
their levels are higher now than in the last 650,000 years.
We call the result global warming, but it is causing a set of changes to
the Earth's climate, or long-term weather patterns, that varies from
place to place. As the Earth spins each day, the new heat swirls with it,
picking up moisture over the oceans, rising here, settling there. It's
changing the rhythms of climate that all living things have come to rely
upon.
A change in the temperature, as
you can see
What will we do to slow this warming? How will we cope with the changes we've already set into motion? While we struggle to figure it all out, the face of the Earth as we know it—coasts, forests, farms and snow-capped mountains—hangs in the balance.
The Earth's average surface temperature rose by 0.74±0.18 °C over
the period 1906–2005.
The rate of warming over the last half of that period was almost
double that for the period as a whole (0.13±0.03 °C per decade,
versus 0.07±0.02 °C per decade). The urban heat island effect is very
small, estimated to account for less than 0.002 °C of warming per
decade since 1900. Temperatures in the lower troposphere have
increased between 0.13 and 0.22 °C (0.22 and 0.4 °F) per decade
since 1979, according to satellite temperature measurements.
Climate proxies show the temperature to have been relatively stable
over the one or two thousand years before 1850, with regionally
varying fluctuations such as the Medieval Warm Period and the
Little Ice Age.
Global warming is when the earth heats up (the temperature rises). It
happens when greenhouse gases (carbon dioxide, water vapor, nitrous
oxide, and methane) trap heat and light from the sun in the earth’s
atmosphere, which increases the temperature. This hurts many
people, animals, and plants. Many cannot take the change, so they
die.
The global warming is the rise in the average temperature of Earth’s
atmosphere and oceans since the late 19th century and its projected
continuation.
Global warming has been detected in a number of natural systems.
Some of these changes are described in the section on observed
temperature changes, e.g., sea level rise and widespread decreases in
snow and ice extent. Anthropogenic forcing has likely contributed to
some of the observed changes, including sea level rise, changes in
climate extremes (such as the number of warm and cold days),
declines in Arctic sea ice extent, and to glacier retreat.
In terrestrial ecosystems, the earlier timing of spring events, and pole
ward and upward shifts in plant and animal ranges, have been linked
with high confidence to recent warming.
Future climate change is expected to particularly affect certain
ecosystems, including tundra, mangroves, and coral reefs. It is
expected that most ecosystems will be affected by higher
atmospheric CO2 levels, combined with higher global temperatures.
Overall, it is expected that climate change will result in the
extinction of many species and reduced diversity of ecosystems.
The current cycle of global warming is changing the rhythms of climate
that all living things have come to rely upon.
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.
Naturally occurring amounts of greenhouse gases have a mean warming effect of about 33 °C (59 °F). The major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone (O3), which causes 3–7%. Clouds also affect the radiation balance through cloud forcings similar to greenhouse gases.
Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have increased by 36% and 148% respectively since 1750.
These levels are much higher than at any time during the last 800,000 years, the period for which reliable data has been extracted from ice cores. Less direct geological evidence indicates that CO2 values higher than this were last seen about 20 million years ago. Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. The rest of this increase is caused mostly by changes in land-use, particularly deforestation.
Over the last three decades of the 20th century, gross domestic product per capita and population growth were the main drivers of increases in greenhouse gas emissions. CO2 emissions are continuing to rise due to the burning of fossil fuels and land-use change. Emissions can be attributed to different regions, e.g., see the figure opposite. Attribution of emissions due to land-use change is a controversial issue.
Emissions scenarios, estimates of changes in future emission levels of greenhouse gases, have been projected that depend upon uncertain economic, sociological, technological, and natural developments. In most scenarios, emissions continue to rise over the century, while in a few, emissions are reduced. Fossil fuel reserves are abundant, and will not limit carbon emissions in the 21st century.
Emission scenarios, combined with modeling of the carbon cycle, have been used to produce estimates of how atmospheric concentrations of greenhouse
gases might change in the future. Using the six IPCC SRES "marker" scenarios, models suggest that by the year 2100, the atmospheric concentration of CO2 could range between 541 and 970 ppm. This is an increase of 90–250% above the concentration in the year 1750.
The popular media and the public often confuse global warming with ozone depletion, i.e., the destruction of stratospheric ozone by chlorofluorocarbons. Although there are a few areas of linkage, the relationship between the two is not strong. Reduced stratospheric ozone has had a slight cooling influence on surface temperatures, while increased tropospheric ozone has had a somewhat larger warming effect.
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. In order to understand the effects of all the gases together, scientists tend to talk about all greenhouse gases in terms of the equivalent amount of CO2. Since 1990, yearly emissions have gone up by about 6 billion metric tons of "carbon dioxide equivalent" worldwide, more than a 20 percent increase.
Levels of greenhouse gases (GHGs) have gone up and down over the Earth's history, but
they have been fairly constant for the past few thousand years. Global average
temperatures have stayed fairly constant over that time as well, until recently. Through
the burning of fossil fuels and other GHG emissions, humans are enhancing the greenhouse
effect and warming Earth.
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.
Aren't temperature changes natural?
The average global temperature and concentrations of carbon dioxide (one of the major
greenhouse gases) have fluctuated on a cycle of hundreds of thousands of years as the
Earth's position relative to the sun has varied. As a result, ice ages have come and gone.
However, for thousands of years now, emissions of GHGs to the atmosphere have been
balanced out by GHGs that are naturally absorbed. As a result, GHG concentrations and
temperature have been fairly stable. This stability has allowed human civilization to
develop within a consistent climate.
Occasionally, other factors briefly influence global temperatures. Volcanic eruptions, for
example, emit particles that temporarily cool the Earth's surface. But these have no
lasting effect beyond a few years. Other cycles, such as El Niño, also work on fairly short
and predictable cycles.
Now, humans have
increased the amount
of carbon dioxide in
the atmosphere by
more than a third
since the industrial
revolution.
Changes this large
have historically
taken thousands of
years,
but
are
now
happening
over the
course of
decades.
Why is this 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.
Historically, Earth's climate has regularly shifted back and forth between temperatures
like those we see today and temperatures cold enough that large sheets of ice covered
much of North America and Europe. The difference between average global temperatures
today and during those ice ages is only about 5 degrees Celsius (9 degrees Fahrenheit), and
these swings happen slowly, over hundreds of thousands of years.
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. This means more intense
major storms, more rain followed by longer and drier droughts (a challenge for
growing crops), changes in the ranges in which plants and animals can live, and loss
of water supplies that have historically come from glaciers.
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.
The main cause of global warming
It took more than 20 years to broadly accept
that mankind is causing global warming with
the emission of greenhouse gases. The drastic
increase in the emission of CO2 (carbon
dioxide) within the last 30 years caused by
burning fossil fuels has been identified as the
major reason for the change of temperature in
the atmosphere (click the following link for
a summary and graphs about the cause and
effects of global warming ).
More than 80% of the world-wide energy
demand is currently supplied by the fossil
fuels coal, oil or gas. It will be impossible to
find alternative sources, which could replace
fossil fuels in the short or medium term. The
energy demand is simply too high.
Another issue is the non-renewable characteristic of fossil fuels: It took nature
millions of years to generate these resources, however we will have used them up
within the next decades. Alone the shrinking supply will not make it possible to
continue as usual for a longer time.
The main cause of global warming is our treatment of Nature
Why have warnings about climate change been ignored for more than 20 years?
Why were ever more scientific evidence demanded to find the coherence of man-
made CO2 emissions as cause of global warming? Why wasn't common sense
reason enough to act?
Why can one still today
find people who stick
their head in the sand
and don't want to
understand what's going on in the earth's atmosphere?
Why do most people refuse to change their personal behavior voluntary in order
to reduce CO2 emissions caused by their activities?
The true cause of global warming is our thoughtless attitude
to Nature.
The answer to all these questions is a rather simple one:
In our technology and scientific minded world, we seem to have forgotten
that mankind is only a relatively minor part of Nature. We ignore being
part of a larger whole.
We believe to be able to control Nature instead of trying to arrange ourselves with
Nature. This haughtiness is the true main cause of global warming. As a matter of
fact, some people still believe that technical solutions alone would be sufficient to
fight global warming.
Although we are guests on Earth, we behave as if no further visitors would arrive
after us. It's like having a wild party where we destroy beds, the kitchen as well as
the living room of a hotel without ever thinking about our future staying in the
hotel nor about other guests arriving later.
There is a loss of value behind these attitudes. We got blind for the true reason of
our incarnation on earth:
We live here to train those traits, which will finally lead to perpetual
harmony with ourselves and with our environment as well as to inner calm and
peace.
The ultimate global warming solutions is to behave as part of a larger whole
Many people between 20 and 65 years seem to live for the one and only purpose of
earning as much money as possible in order to be able to buy as many things as
possible. In this light, it is not surprising those discussions about potential
solutions to fight global warming concentrate on technical measures instead of a
fundamental change of our attitude to life in general and to Nature in particular.
The lesson from global warming is to base all decisions on deep respect and
consideration for Nature.
Someone who respects Nature and regards mankind as a part of a larger whole
would never dream about using up non-renewable resources in a short time nor
would this person contaminate the environment with gigantic amounts of pollution.
By contrary, someone who respects Nature and regards mankind as a part of a
larger whole would in all decisions carefully evaluate any effects on Nature. The
preservation of Nature would be given a very high priority. On this base, it
wouldn't have been possible to deny and ignore global warming for more than 20
years!
It's your personal decision whether you want to be the cause of global warming
In this context the question is whether global warming and its effects will
eventually wake up mankind and spark off a change of paradigm. Will we understand
this hint of Nature to follow the true meaning of life or will we continue to let us
manipulate by media and advertisement as sheer and willing consumers in the
economic cycle? Will we continue to strive for power, prestige and possessions
following the concept „the more the better "? Shall economic growth and an ever
increasing personal income continue to be the reason for being here, beyond
everything else?
These questions can and must be answered by everyone. It is not primarily a
decision of politicians or of the government. Everyone has to make a personal
decision.
It is in our very own interest to induce fundamental changes in our attitude and
behavior towards Nature: Modesty and humility, admiration and respect for all life
on Earth instead of arrogance and haughtiness.
Let's emphasize it again: Not the others need to change, we must change
ourselves. There are no international treaties or additional national laws required
to start changing. We can start to change our consciousness immediately. It is
really only about our personal behavior - independent of what others do or don't
do.
It's time for change!
The planet is warming, from North Pole to South Pole, and everywhere in
between. Globally, the mercury is already up more than 1 degree Fahrenheit
(0.8 degree Celsius), and even more in sensitive Polar Regions. And the effects
of rising temperatures aren’t waiting for some far-flung future. They’re
happening right now. Signs are appearing all over, and some of them are
surprising. The heat is not only melting glaciers and sea ice; it’s also shifting
precipitation patterns and setting animals on the move.
Some impacts from increasing temperatures are already happening.
. Ice is melting worldwide, especially at the Earth’s poles. This includes
mountain glaciers, ice sheets covering West Antarctica and Greenland, and
Arctic sea ice.
. Researcher Bill Fraser has tracked 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.
. Some butterflies,
foxes, and alpine
plants have moved
farther north or to
higher, cooler areas.
. Precipitation (rain
and snowfall) has increased across the globe, on average.
. Spruce bark beetles have boomed in Alaska thanks to 20 years of warm
summers. The insects have chewed up 4 million acres of spruce trees.
Other effects could happen later this century, if warming continues.
. 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.
. Species that depend on one another may become out of sync. For example,
plants could bloom earlier than their pollinating insects become active.
. Floods and droughts will become more common. Rainfall in Ethiopia, where
droughts are already common, could decline by 10 percent over the next 50
years.
. Less fresh water will be available. If the Quelccaya ice cap in Peru continues
to melt at its current rate, it will be gone by 2100, leaving thousands of people
who rely on it for drinking water and electricity without a source of either.
. Some diseases
will spread
such as
malaria
carried by
mosquitoes.
. Ecosystems
will change—
some species
will move
farther north
or become
more
successful;
others won’t
be able to
move and could become extinct. Wildlife research scientist Martyn Obbard has
found that since the mid-1980s, with less ice on which to live and fish for
food, polar bears have gotten considerably skinnier. 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.
A Quick Look at the Various Effects on Global Temperature
Most of the studies discussed below looked at the same few influences on
global temperature, because they are the dominant effects.
As we know, human greenhouse gas (GHG) emissions warm the planet by
increasing the abundance of greenhouse gases in the atmosphere, thus
increasing the greenhouse effect.
Solar activity also warms or cools the planet by increasing or decreasing the
amount of radiation reaching the Earth’s atmosphere and surface.
Volcanic activity generally cools the planet over short timeframes by releasing
sulfate aerosols into the atmosphere, which block sunlight and reduce the
amount of solar radiation reaching the surface. However, unlike many
greenhouse gases, aerosols are washed out of the atmosphere quickly, mostly
after just 1-2 years. Thus the main volcanic impact on long-term temperature
changes occur when there is an extended period of particularly high or low
volcanic activity.
Human aerosol emissions (primarily sulfur dioxide [SO2]) also tend to cool the
planet. The main difference is that unlike volcanoes, humans are constantly
pumping large quantities of aerosols in the atmosphere by burning fossil fuels
and biomatter. This allows human aerosol emissions to have a long-term
impact on temperatures, as long as we keep burning these fuels. However,
because aerosols have a number of different effects (including directly by
blocking sunlight, and indirectly by seeding clouds, which both block sunlight
and increase the greenhouse effect), the magnitude of their cooling effect is
one of the biggest remaining uncertainties in climate science.
The El Niño Southern Oscillation (ENSO) is an oceanic cycle which alternates
between El Niño and La Niña phases. El Niño tends to shift heat from the
oceans to the air, causing surface warming (but ocean cooling), whereas La
Niña acts in the opposite manner. As we’ll see, a few studies have begun
examining whether ENSO has had a long-term impact on global surface
temperatures. Because it’s a cycle/oscillation, it tends to have little impact on
long-term temperature changes, with the effects of La Niña cancelling out
those of El Niño.
There are other effects, but GHGs and SO2 are the two largest human
influences, and solar and volcanic activity and ENSO are the dominant natural
influences on global temperature. Now let’s see what the scientific literature
has to say about the relative influences of each effect. here was a period of
warming between 1910 and 1940 which was predominantly caused by
increasing solar activity and an extended period of low volcanic activity, with
some contribution by human effects. However, since mid-century, solar
activity has been flat, there has been moderate volcanic activity, and ENSO has
had little net impact on global temperatures. All the while GHGs kept
increasing, and became the dominant effect on global temperature changes, as
Figures 3 and 4 illustrate. A wide variety of statistical and physical approaches
all arrived at the same conclusion: those humans are the dominant cause of
the global warming over the past century, and particularly over the past 50
years. This robust scientific evidence is why there is a consensus amongst
scientific experts that humans are the dominant cause of global warming.
Just think…
But, wait you can do something…
What if you start now
The evidence that humans are causing global warming is strong, but the question of
what to do about it remains controversial. Economics, sociology, and politics are all
important factors in planning for the future.
Even if we stopped emitting greenhouse gases (GHGs) today, the Earth would still warm
by another degree Fahrenheit or so. But what we do from today forward makes a big
difference. Depending on our choices, scientists predict that the Earth could eventually
warm by as little as 2.5 degrees or as much as 10 degrees Fahrenheit.
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.
Is this possible? Many people and governments are already working hard to cut
greenhouse gases, and everyone can help. Researchers Stephen Pacala and Robert
Socolow at Princeton University have suggested one approach that they call
"stabilization wedges." This means reducing GHG emissions from a variety of sources
with technologies available in the next few decades, rather than relying on an enormous
change in a single area. They suggest 7 wedges that could each reduce emissions, and
all of them together could hold emissions at approximately current levels for the next
50 years, putting us on a potential path to stabilize around 500 ppm. There are many
possible wedges, including improvements to energy efficiency and vehicle fuel economy
(so less energy has to be produced), and increases in wind and solar power, hydrogen
produced from renewable sources, biofuels (produced from crops), natural gas, and
nuclear power. There is also the potential to capture the carbon dioxide emitted from
fossil fuels and store it underground—a process called "carbon sequestration."
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. One of the biggest issues facing us right
now is global warming. Its effects on animals and on agriculture are indeed frightening,
and the effects on the human population are even scarier. The facts about global
warming are often debated in politics and the media, but, unfortunately, even if we
disagree about the causes, global warming effects are real, global, and measurable. The
causes are mainly from us, the human race, and the effects on us will be severe.
So, what do you think? Can
you do it for your home?
Natural World Raúl Escamilla and Jasmín Gómez are supported
by the organization Greenpeace; also they’d
like to thank National Geographic for the
support.
Colegio García Flamenco
April/2013
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