Monday, June 6, 2011 0 comments By: Unknown

What is the Difference Between Greenhouse Effect and the Hole in the Ozone Layer?



Greenhouse Effect
Apparently about 99% of climate scientists believe these concepts to be fact.
The terms Greenhouse Effect, global warming, climate change, Ozone Depletion and used almost daily in the media but on questioning children (and many adults for that matter) they use the terms as if they are interchangeable.
Friday, June 3, 2011 1 comments By: Unknown

How Do Humans Contribute to the Greenhouse Effect?


While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.
  • Burning natural gas, coal and oil -including gasoline for automobile engines-raises the level of carbon dioxide in the atmosphere.
  • Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
  • Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and "global warming" that is currently under way.
  • Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.
  • Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.
Thursday, May 19, 2011 0 comments By: Unknown

Briefly About Uses And Defects Of Greenhouse Gases

Greenhouse Effect, the capacity of certain gases in the atmosphere to trap heat emitted from Earth’s surface, thereby insulating and warming the planet. Without the thermal blanketing of the natural greenhouse effect, Earth’s climate would be about 33°C (about 59°F) cooler—too cold for most living organisms to survive.The greenhouse effect has warmed Earth for over 4 billion years. Now scientists are growing increasingly concerned that human activities may be modifying this natural process, with potentially dangerous consequences. Since the advent of the Industrial Revolution in the 1700s, humans have devised many inventions that burn fossil fuels such as coal, oil, and natural gas. Burning these fossil fuels, as well as other activities such as clearing land for agriculture or urban settlements, releases some of the same gases that trap heat in the atmosphere, including carbon dioxide, methane, and nitrous oxide. These atmospheric gases have risen to levels higher than at any time in at least the last 650,000 years. As these gases build up in the atmosphere, they trap more heat near Earth’s surface, causing Earth’s climate to become warmer than it would naturally.
Scientists call this unnatural heating effect global warming and blame it for an increase in Earth’s surface temperature of about 0.6°C (about 1°F) over the last 100 years. Scientists project global temperatures to continue rising during the 21st century. Warmer temperatures could melt parts of polar ice caps and most mountain glaciers, causing a rise in sea level that would flood coastal regions. Global warming could also affect weather patterns causing, among other problems, 
prolonged drought or increased flooding in some of the world’s leading agricultural regions.

Earth’s atmosphere and the way it interacts with the oceans and radiation from the Sun are responsible for the planet’s climate and weather. The atmosphere plays a key role in supporting life. Almost all life on Earth uses atmospheric oxygen for energy in a process known as cellular respiration, which is essential to life. The atmosphere also helps moderate Earth’s climate by trapping radiation from the Sun that is reflected from Earth’s surface. Water vapor, carbon dioxide, methane, and nitrous oxide in the atmosphere act as “greenhouse gases.” Like the glass in a greenhouse, they trap infrared, or heat, radiation from the Sun in the lower atmosphere and thereby help warm Earth’s surface. Without this greenhouse effect, heat radiation would escape into space, and Earth would be too cold to support most forms of life.
Wednesday, May 11, 2011 3 comments By: Unknown

What is Greenhouse Effect?


There are two meanings of the term "greenhouse effect". There is a
"natural" greenhouse effect that keeps the Earth's climate warm and
habitable. There is also the "man-made" greenhouse effect, which
is the enhancement of Earth's natural greenhouse effect by the
addition of greenhouse gases from the burning of fossil fuels (mainly
petroleum, coal, and natural gas).

In order to understand how the greenhouse effect operates, we need
to first understand "infrared radiation". Greenhouse gases trap some
of the infrared radiation that escapes from the Earth, making the Earth
warmer that it would otherwise be. You can think of greenhouse gases
as sort of a "blanket" for infrared radiation-- it keeps the lower layers of
the atmosphere warmer, and the upper layers colder, than if the green-
house gases werenot there.

About 80-90% of the Earth's natural greenhouse effect is due to water-
vapor, a strong greenhouse gas. The remainder is due to carbon dioxide,
methane, and a few other minor gases.

It is the carbon dioxide concentration that is increasing, due to the
burning of fossil fuels (as well as from some rainforest burning). This
is the man-made portion of the greenhouse effect, and it is believed by
many scientists to be responsible for the global warming of the last 150
years.

Also, the concentration of methane, although small, has also increased
in recent decades. The reasons for this increase, though, are uncertain.
Interesting facts:
DOES THE GREENHOUSE EFFECT EVEN EXIST?The greenhouse warming
of the Earth's surface is believed by some people to be physically impossible.
They claim it would violate the 2nd Law of Thermodynamics, which basically
states that energy must flow from where there is more to where there is less.

The reason for this apparent violation is that the existence of greenhouse
gases in the COLDER layers of the atmosphere make the surface
WARMER, which would suggest energy flow from colder to warmer,
which would seem to violate the 2nd Law. But the greenhouse effect
is kind of like adding a lid to cover a pot of water on the stove...even
though the lid is colder than the water, its presence actually makes the
water warmer.

It's the TOTAL (net) flow of energy which must be from warmer to colder,
which is indeed the case in both the greenhouse effect, and adding a lid
to the pot of water on the stove.

With global warming still in the fore and still a big issue, a lot of people
are still uninformed properly about it! A lot of places are getting warm,
forcing quite a number of people to head off to the beach or fan 
themselves endlessly. Many are still under the assumption 
that greenhouse gases, which contribute to making the planet warm,
should really go. What they don’t know is that the primary purpose of
those gases is to prevent heat from escaping into space, preventing 
the world from turning into one huge snowball! If they didn’t exist, 
we wouldn’t be able to live on this planet. This little article will tell you
about the most powerful greenhouse gases in the world. Some may
even surprise you. 
1. Water vapor – Yes. Water. Right on top of the list. Water vapor
contributes from 36% to 66% of the world’s greenhouse effect. It’s
also the most abundant greenhouse gas! Concentrations of water
vapor fluctuate throughout the world, and humans don’t affect 
it directly on a large scale. In addition, warm air caused by the
greenhouse effect can carry more water vapor, amplifying the
greenhouse effect further. However, humidity is constant. The 
net effect is overall positive, and also protects against the excess
carbon dioxide.

2. Carbon Dioxide – Ah, the gas that many people blame for heating

up the earth. It contributes 9% to 26% of the greenhouse effect
depending on area. The world’s species and environmental cycles
produce this gas naturally, up to twenty times that of what we 
contribute! Nature cycles the carbon dioxide through plants and
weathering, but human production has speeded it up more than
nature can account for. Majority of manmade carbon dioxide 
comes from burning fossil fuels and deforestation.

3. Methane – This gas causes 4% to 9% of the greenhouse effect.

Human methane production mostly comes from livestock. By itself,
it is an effective greenhouse gas, but it can transforms to water
and carbon dioxide in the atmosphere, which makes it quite 
effective in warming the earth! If that isn’t enough, it also turns
into ozone, which is another greenhouse gas! This is why the 
amount of methane around is has been more or less constant,
and it is why its effect is considered small since many who measure
it do not include what it turns into.

4. Ozone – This gas we all know and love as protector against the

sun rays is also a greenhouse gas. It causes only 3% to 7% of the
greenhouse effect. Ozone causes irritation to the respiratory 
system at ground level, but is normally very light at that level, choosing 
instead to concentrate higher up. However, the concentration of
ozone at ground level is increasing, because of pollution! This is 
especially concentrated in populated areas. It decays quickly to
normal oxygen.

Now that you know a little bit more about these gases, the question

remains. What can we do? What we can, of course. How about you?
What do you know about greenhouse gases?

Well we'll talk dsiadvantages if greenhouse gases later first lets
see about function of greenhouse and its uses.

Function

Greenhouses made of glass allow solar radiation into the building,
but the warmth re-radiated by the plants and soil inside is emitted
in the infrared portion of the light spectrum, a longer wavelength
that is trapped inside by the glass. The resulting heat warms the
air at the bottom of the greenhouse. This air rises to the glass ceiling and 
remains inside. Cooler air replaces it near the ground and warms
until it rises, starting the cycle over again. This is how the 
temperature inside a greenhouse continues to climb and why
ventilation is so important.

Growing Flowers

Greenhouse growing allows flower lovers to harvest early cuts before the
blooming season, and winter cuts long after the outdoor summer annuals
have given up for the year. The warm, moist conditions are ideal for
tropical varieties like orchids, blood lilies and blue jacaranda, but they 
also tend to breed pests and disease, so managing your flower crop 
requires constant attention.



Some of the more common afflictions facing greenhouse flowers are root

rot, fungal infections and mildew. Pesticides, either organic or chemical,
are a must but keeping weed growth under control both inside and 
around the greenhouse can help to keep insect numbers down, 
according to the University of Kentucky College of Agriculture’s new crop
opportunity center.

Growing Plants

A greenhouse should be positioned so that it receives direct sunlight
from the spring and fall sun when it is lower in the sky. Inside, 
commercial potting soil works well for most large beds. Mixes should
include sand, peat moss, vermiculite and fir bark to aid in soil drainage.
There is no limit to the variety of plants you can grow in a greenhouse, 
but mixing too many different types could present a problem in
temperature management.



Ventilation systems can be fully automatic and expensive, or decidedly

low-tech. Spraying water on the floor and opening the ceiling vents is 
one cheap way to reduce the temperature inside rather quickly.

Growing Vegetables

Root vegetables like turnips, carrots and beets do very well in greenhouses. 
They can be kept in planter boxes and lined up around the perimeter 
under work spaces and benches. Use tubs for tomatoes, beans,
cucumbers and lettuce. Corn can take over a greenhouse, but the yield is
terrific. 

After this lets know about the greenhouse gases and its advantage and
disadvantages:

greenhouse gas is one of several gases that can absorb and emit 
longwave (infrared) radiation in a planetary atmosphere. This 
phenomenon is often termed the greenhouse effect. Of the sunlight
 that falls on the Earth's surface, approximately 40% of that energy 
is reradiated upward into the atmosphere in the form of longwave
radiation. Approximately 75% of that upward radiated longwave
energy is absorbed by water vapor, carbon dioxide, methane and other
greenhouse gases. Since this absorption process is molecular in nature,
 the subsequent reradiation of energy by these gases is multidirectional.
As a result, about 50% of the longwave emission is reradiated back 
toward the Earth where it is once again turned into heat energy. 
Through this process, greenhouse gases contribute to the amount of
heat energy released at the Earth's surface and in the lower atmosphere.
Since the beginning of Industrial Revolution, concentrations of carbon 
dioxide, methane, and nitrous oxide have all risen dramatically 
because of human activities. Fossil fuel combustion, land-use change,
increasingly intensive agriculture, and an expanding global human 
population are the primary causes for these increases. Other 
greenhouse gases found in our planet's atmosphere include water 
vapor, ozone, sulfur hexafluoride and chlorofluorocarbons.

To look at the small animation of greenhous effect goto:
http://www.climatechoices.org.uk/animation/greenhouse.swf