Posts from — December 2009

Greenhouse Gases and Climate Change

Glen Luckman Greenhouse Gases and Climate Change By Kevin Long

We all know that energy from the sun is required for sustaining life on earth. The outer atmosphere deflects approximately 30% of the sunlight that comes to the earth and this light is then scattered back in space. Remaining sunlight reaches the surface of the earth and gets reflected upwards in the form of slow moving energy known as infrared radiation.

Greenhouse gases absorb the heat caused by the infrared radiation like CO2, water vapor, methane and ozone, due to which it becomes difficult for the gases to escape the atmosphere.

According to experts, only 1% of the earth’s atmosphere is made up of greenhouse gases and these gases regulate the climate through heat trapping. This is known as the ‘greenhouse gas effect’. According to climate change experts, without the greenhouse gas effect, the average earth temperature will be colder by 30 degrees Celsius. This temperature will be too cold for the sustenance of our ecosystem. Therefore, the greenhouse effect is very much required for the earth; however it must be in a controlled manner.

How are we contributing to the greenhouse effect?

There is no doubt that the greenhouse effects is required for the ecosystem but it becomes a problem when the natural process gets distorted and accelerated by human activities and more greenhouse gases are created in the atmosphere which increase the temperature of the earth more than required. When we burn oil, coal, natural gas and gasoline the level of CO2 increases in the atmosphere. The level of harmful gases like nitrous oxide and methane also increases due to farming methods and changes in the use of land. Dangerous and long lasting industrial gases are produced from factories.

Greenhouse Effect and Global Warming

By Shampa Dey

The heat caused by infrared radiation from the sun which escapes from the Earth’s outer surface, is absorbed by “greenhouse gases” which trap the heat forming a kind of blanket of warm air that surround the planet. This occurrence is called the “green house effect”. It is suggested that the temperature on average would have been much lower compared to what is now. Survival of the ecosystem would have been difficult in such extreme condition.

UNDERSTANDING THE GREENHOUSE EFFECT

In the natural greenhouse effect, the type of the type of topograph the sunlight falls plays a key role. Different types of surfaces absorb or radiate heat differently. For example, white glaciers reflect maximum sunlight resulting in minimum heating of the surface and the lower atmosphere. On the other hand, sunlight is absorbed the maximum by dark desert soil causing more heating of the surface and the lower atmosphere. Clouds that cover the sky reduce the amount of solar radiation penetrating onto the earth’s surface and also reduce the amount of radiation emitted into space.

BASIC MECHANISM

About 50% of the solar radiation is absorbed by the earth’s surface and the rest is emitted as infrared radiation by the surface of earth. Green house gases absorb most of the infrared radiation and pass on to the other atmospheric gases by molecular interaction. The greenhouse gases too radiate some heat. Heat is radiated both upwards and downwards with some escaping into the space and some getting back to the earth surface. The earth surface and the lower atmosphere is thus aiding to the survival of life on earth.

Greenhouse gases such as carbon dioxide, methane, water vapor, nitrous oxide etc. are molecules formed by two atoms which are loosely bound and are thereby easily excited by solar radiation. The loose atoms then pass on the heat to other gases by molecular interaction. Major components of the atmosphere such as oxygen and nitrogen are formed my tightly bound atoms which are not easily excited and thus do not absorb heat.

EFFECTS ON GLOBAL WARMING

Though greenhouse effect is an essential environmental phenomenon, the trouble begins when human activities disturb or accelerate the natural process by creating more of the green house gases necessary for the optimum warming of the earth surface and thus raising the surface temperature above ideal one.

Higher the concentration of the green house gases more is the heat radiation towards the earth. The emission of green house gas such as carbon dioxide is mainly due to burning of fossil fuels such as oil, gas, petrol, kerosene etc.
Higher concentration of such man-made greenhouse gas causes considerable warming of the earth and the sea resulting in Global Warming.

HUMAN CONTRIBUTION

• Level of carbon dioxide is increased by burning of natural gas, coal, oil, petrol etc.
• Some agricultural and land-use methods increase the level of methane and nitrous oxide in atmosphere.
• Industrial wastes and gases contribute substantially to the green house effect and thus adding to global warming.
• Deforestation is one of the major causes of global warming today.
• Population explosion is another prime factor contributing towards global warming.

What is Global Warming?

Glen Luckman What is Global Warming? By Lisa Mills

Global warming is explained as an increase in the average temperature of the earth. Hurricanes, droughts and floods are more frequent and this is said to be the result of global warming.

Scientists claim that over the last 100 years or so the temperature near the earth’s surface has risen. This means the earth is now warmer than it has been for the last thousand years. What is more, the warmest years ever recorded have been in the last eight years.

There has always been climate change, but according to scientists increased temperature rises in recent years has been faster than ever before. They therefore feel that the global warming we are now experiencing is not a natural occurrence but one that is being brought on by man.

Throughout history temperatures have varied substantially depending upon the greenhouse gases in the atmosphere. Natural gases such as carbon dioxide, methane and nitrous oxide have always been in the atmosphere as without them Earth would be a very chilly planet!

Farmers around the world use nitrogen fertilizers and it’s use is increasing in order to feed the growing world population. These fertilizers are often washed away into lakes and oceans where algae feeds on them and the consequence is they bloom uncontrollably and eventually starve the water of oxygen creating a dead zone.

Since the industrial revolution carbon dioxide in the atmosphere has increased by nearly 40% which is the result of burning fossil fuels, deforestation and industrial production.

Some carbon dioxide stays in the atmosphere, the rest is absorbed into the sea and vegetation. CO2 should be compensated by plant absorption, but as the earth’s atmosphere becomes warmer plants close their pores to prevent the loss of water and switch to consuming oxygen and produce carbon dioxide instead.

Global warming can be compared to the inside of a car on a hot sunny day. The sun will heat the inside of the car but the heat will then be unable to escape, thus causing a greenhouse effect.

The greenhouse effect is the absorption and emission of infrared radiation by gases in the atmosphere which in turn warm the lower atmosphere of the surface of the earth. The issue of global warming is how the strength of the greenhouse effect changes when human activity increases the concentration of greenhouse gases in the atmosphere.

There are many natural causes of gas emissions into the atmosphere. Ruminant animals for instance produce methane gas which is 25% more potent than carbon dioxide. Global meat consumption has increased and is still rising, this in turn means more cows, more methane gas.

The Alternative View to Global Warming – What is Your Opinion?

Glen Luckman Alternative View to Global Warming By Ettaariane Wilson

Scientific evidence behind Global warming is being seriously challenged.

In sharp contrast to the theory that we face unprecedented disasters across the planet, some scientists dispute that global warming is caused by mankind.

They believe Global warming is a natural occurring event that follows this process every few hundred years. They also believe the predicted disasters will not be as severe as we have been led to believe.

Neither party is in the position to refute the fact that Global warming is increasing.

We are therefore in the horns of a dilemma. Do we ignore the increase of carbon dioxide and other gases in our atmosphere because it is a ‘natural occurrence’ or, do we do our best to reduce our carbon footprint all over the planet. If we take the latter path then our carbon footprint needs to be reduced by 80% and quickly.

However, this cannot happen without total Government co-operation world wide. It also needs the full co-operation of the people of this planet: recycle, recycle, recycle.

Lets open our own Court and look at the evidence of both parties.

We will begin with the theory that the Greenhouse effect is the end result of the burning of fossil fuels since the beginning of the Industrial revolution. Firstly, we need to have a clear idea of exactly what the Global warming effects are and how they are affected by the burning of fossil fuels, if,indeed,they are.

Global warming is caused by the increase of average temperature of Earths air and oceans. This began in the mid-20th century and is mainly believed to be caused by a concentration of greenhouse gases,(carbon dioxide, nitrous oxide and methane), in turn, caused by de-forestation and the burning of coal and other fossil fuels.

The heat from the sun is trapped in the Earths atmosphere and can’t get out. This greenhouse effect is good if it is controlled. However, if there are too many gases in the atmosphere then plants, animals and people will die.

Global warming is affecting the planets ecological system and causing breaks in the food chain. Other effects are wild weather systems: floods, typhoons, hurricanes, tsunamis, earthquakes. Etc. It also causes acid rain which, in turn, gradually destroys everything it touches.

Greenhouse gases are caused mainly through our need for electricity and transportation sending chemicals to pollute air, water and land, into the atmosphere. This ties in with the start of global warming commencing in the mid-20th century with new factories and transport around the globe.

Other causes of greenhouse gases are burning rubbish at landfill tips, and cutting down trees that would otherwise remove the carbon dioxide from the atmosphere, using electrical equipment in our homes and driving our cars when we could walk.

This is a tiny simplistic list of manmade causes of global warming, yet, this tiny list makes a significant difference to the amount of greenhouse gases in our atmosphere.

If you believe that mankind is the cause of global warming then you can help to reverse the effects in many ways. There are numerous websites on the internet and books in the local library plus advice from councils and agencies to help you decide how you can help the Earth by reducing your carbon footprint.

Let us take a look now at the evidence provided by the scientists who believe Global warming isn’t caused by mankind but is a natural occurrence, happening every so many hundred years.

In the other camp, scientists state, among other things, that this episode of global warming is just taking the temperature of the Earths atmosphere back to what it was in Medieval times. They also argue that the magnitude of the gas emissions involved is inadequate to answer to the magnitude of the Earths temperature increase.

They state: the climate change is controlled by cyclical eccentricities, which run in 100,000, 21,000, 11 year and 206 year cycles, in Earths orbit and rotation plus differences in the heat output of the Sun. Greenhouse gases just contribute in a very minor way.

Also attributable are atmospheric causes due to clouds, polar ice caps and volcanic dust. Tectonic causes-landmass movement, oceanic currents and sea floor spreading also contribute.

During the last hundred years two cycles of warming and cooling have occurred and we are in the second warming cycle. A fact that is seemingly well hidden from us.

The Economy of Solar Hot Water Heaters

Glen Luckman  Economy of Solar Hot Water Heaters By Jacob Mintz

Conversion of Sun Radiation to Heat

The physical principle of converting sun radiation into heat was known for generations. For many years people knew that liquid bottles are heated up when they are exposed to sun radiation. Greenhouse agriculture is known for centuries. As of the 20th century, Solar Hot Water Heaters based on the greenhouse effect were developed, and in countries like Spain or Israel almost every dwelling building is equipped with a Sun powered Water Heater System.

Water Heating is cheaper than Solar Power Generation

Residential Solar Power generation is based on the photovoltaic effect. Although the effect was known for over 200 years and was explained in the 1920s by Albert Einstein, commercial exploitation started seriously only in the 90s of this century. Solar Power generation is still an expensive technology because it is not as matured as the conversion of sun radiation to heat using the greenhouse effect. It is expected that within the next 5 to 10 years residential photovoltaic power generation panels will be sold at more affordable prices. Solar Water Heating systems are sold at very affordable prices right now, even the most expensive evacuated tubes collector type that is recommended for use in the colder less sunny regions carries a very affordable price tag. In most countries, the payback time on sun powered water heaters is 3 to 5 years, even for the most expensive systems

The Benefits

A typical household spend about 20% of the home energy bills on heating water whether the water heater is operating on electricity, gas or other fossil fuel. A sun powered water heater can eliminate 80% of this expense for the 15 to 20 years life span of the solar heater.

The household once equipped with the sun powered heater contributes to the environment by the evident reduction in CO2 and pollutants emissions.