Greenhouse effect

The greenhouse effect is neccessary for life to exist on earth

We are more often hearing about the runaway greenhouse effect

The greenhouse effect is a natural process that allows life to exist on earth. Certain gases in the atmosphere prevent some of the reflected energy to escape the atmosphere as they hold on to these refelected rays of longer wavelength. These gases are water, carbon dioxide and methane (CH4)

The suns energy is converted into many different processes at the surface of the planet. Photosynthesis in plants, the water cycle and the knock on weather effect and the general heating of the planet.

The earth is a planet a rock that spins about the sun. If it was not for the athmosphere the place would be quite cold. The athmosphere is a mixture of gases, Nitrogen, Oxygen, Noble gases, Carbon Dioxide and others including Methane.

The most insulating gases, the ones that keep in the heat best are Methane and Carbon Dioxide. We need these gases like someone needs a duvet on a cold winters night.

However on a warm summers night we become too warm and want to throw off the duvet, this is the problem that we are having the earth is heating up.

As anybody living in Ireland will tell you that might seem like a good thing, in fact when this was 1st heard of in a popular manner the Dept of Agriculture looked into growing Mediterranean foods like grapes.

The problem is that a warmer climate will cause some huge side-effects. The Arctic and Antarctic ice will melt. The Arctic sea is frozen, and just like ice in a glass the water level will not change if it does melt. Unfortunately the Antarctic is a land mass and if it melts all the ice there will turn to water and run off the land and into the oceans, if it all melted the seas could rise by up to 18m. this will take away land from countries, completely drown other countries, such as India, home of 1 billion people.

Another side effect is that the air can now absorb and hold on to much more water. The floods in the west of Ireland 2009 were terrible but would represent a shower if the athmosphere could hold all this extra water.

Whats worse is that ice being white reflects much of the sunlight that hits it back into space, thus avoiding the extra heat build up in our athmosphere, if all the ice is melted then the world will heat up even quicker.

If all the ice melts then siberias Ice cover will go too. This ice holds in a huge amount of methane gas from entering the athmosphere, if this methane is allowed to enter the athmosphere it will heat up even quicker.

This extra hot athmosphere will cause the drier regions in the world to further go without water, wet regions will have more rainfall.

Following predictions made by studying ice core trends the world could enter an ice age many thousands of years before it would naturally, the earth rebalancing itself, as in the film the day after tomorrow!

If society was to reduce its energy demands by switching to energy effiecent appliances and by insulating homes we maybe able to address the sharp turn in CO2 emission that have been markedly on the rise since the dawn of the industrial era.

You can play your part,

TURN IT OFF AT THE SWITCH,

INSULATE YOUR HOME

CHANGE TO ENERGY SAVING APPLIANCES

what is global warming

Global warming is the of the planet above the natural temperature. It is also

http://www.eoearth.org/article/Global_warming

Roughly 20 percent of the electricity consumed worldwide is used to light homes, businesses, and other private and public spaces. Though this consumption represents a large drain on resources, it also presents a tremendous opportunity for savings. Improving the efficiency of commercially available light bulbs -- even a little -- could translate into dramatically lower energy usage if implemented widely.

Light emitting diodes emit monochromatic light when their electrons combine with holes to form “excitons”. Standard LEDs made from inorganic materials have already found widespread application in screens and commercial lighting because of their high efficiency. For example, the Water Cube swimming arena at the Beijing Olympics used nearly half a million red, green and blue LEDs.

A group of scientists at the Chinese Academy of Sciences is reporting an important step towards that goal with their development of a new type of light emitting diode (LED) made from inexpensive, plastic like organic materials. Designed with a simplified "tandem" structure, it can produce twice as much light as a normal LED -- including the white light desired for home and office lighting.

Found in everything from brake lights to computer displays, LEDs are more environmentally friendly and much more efficient than other types of light bulbs. Incandescent bulbs produce light by sending electricity through a thin metal filament that glows red hot. Only about five percent of the energy is turned into light, however. The rest is wasted as heat. Compact fluorescent bulbs, which send electricity through a gas

Bright white light from organic LEDs inside a tube, tend to do much better. They typically turn 20 percent or more of the electricity pumped through them into light. But compact fluorescents also contain small amounts of mercury vapor, an environmental toxin. LEDs on the other hand, are made from thin wafers of material flanked by electrodes. When an electric current is sent through the wafers, it liberates electrons from the atoms therein, leaving behind vacancies or "holes." When some of the wandering electrons and holes recombine, they create a parcel of light, or photon. These photons emerge from the side of the wafer as visible light. This turns 20 to 50 percent, or even more, of the input energy into light. LEDs also concentrate a lot of light in a small space. Producing LEDs that can compete with traditional light bulbs for cost and efficiency is one thing. Making LEDs that consumers want to use to light their homes is quite another. One of the main barriers to the widespread use of LED lights is the light itself. LEDs can easily be manufactured to produce light of a single color -- like red -- with applications such as traffic lights and auto brake lights. Indoor lighting though, requires "natural" white light. This quality is measured by the colorrendering index (CRI), which assigns a value based on the light source's ability to reproduce the true color of the object being lit. For reading light, a CRI value of 70 or more is optimal. LEDs can produce white light by combining a mixture of blue, green, and red light, or by sending colored light through a filter or a thin layer of phosphors -- chemicals that glow with several colors when excited. However, these solutions increase costs. To reach a larger market, scientists would like to make inexpensive LEDs that can produce white light on their own.

The City of San Jose is to spend around $2 million of stimulus funds received from the US government to help fund a project to replace streetlights with LED fixtures, according to an article in the Silicon Valley / San Jose Business Journal.

from physics.slss.ie