Natural World

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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