Monday, 4 February 2008

A-Z of Global Warming- THE AMAZON

The Amazon Rainforest acts as a major store of Carbon and produces enormous amounts of oxygen. The Amazon has been referred to as "The lungs of the Earth" because of it’s effect on the climate. The way this is achieved is of course through photosynthesis, the process by which green plants/trees use the energy from sunlight to produce food by taking carbon dioxide (co2) from the air and water and converting them to carbon. The by-product of this is oxygen.
The Amazon therefore helps recycle carbon dioxide by turning it into oxygen, and its estimated that the Amazon produces about 20% of this essential gas for Earth’s atmosphere......

Why is the Amazon at risk? ( March 2008 )

A worrying trend is the fact that the Amazon has experienced two consecutive years of drought in 2005 and 2006.
The drought in 2006, left rivers dry, stranded thousands of villagers, and put regional commerce at a standstill, was the worst on record.
A second year of drought is of great concern to researchers studying the Amazon ecosystem. Field studies by the Massachusetts-based Woods Hole Research Centre in the USA, suggest that Amazon forest ecosystems may not withstand more than two consecutive years of drought without starting to break down....

A-Z of Global Warming- BIOFUELS ( April 2008 )

What are biofuels, are they really environmentally friendy...?

Biofuels can be described as any fuel that is derived from biomass ie
living organisms or their metabolic by-products. For example, crops such as corn and dung from living animals.

Although there is still somewhat of a scientific debate going on over the advantages of biofuels, it is thought that the main advantage over fossil fuels (coal,oil and gas), is that the burning of biofuels to release energy does not cause a net increase of CO2 levels in the atmosphere.

This is because the source of the biofuel, crops for example, have already taken a corresponding amount of CO2 out from the atmosphere during their
growth cycle when they photosynthesise. When this occurs, plants/crops release oxygen and retain the carbon to use as energy.The carbon is then released when the crop is eventually burnt in order to release its energy. As long as new crops are planted in place of the ones that are burnt, there will be no overall increase in the amount of CO2 released into the atmosphere. So, whilst crop based biofuels don't reduce the amount of CO2 in the atmosphere, they are thought to be more or less carbon neutral.

The difference with fossil fuel deposits such as coal is that the coal deposits have been formed in the earth over millions of years and are therefore considered to be energy deposits rather than part of the energy cycle. The burning of fossil fuels on a scale required to satisfy mankind's energy needs, over a relatively short period of time, hundreds of years as opposed to the millions of years it has taken the deposits to form, means that the burning of such fuels, adds considerably to the levels of CO2 in the atmosphere. This in turn adds to the greenhouse gases already present in our atmosphere, and contributes to the warming of the Earth's climate.

Despite the benefits of using biofuels, there is a drawback however, which is the amount of land required to grow the crops necessary for the biofuel in the first place. There are already concerns that vast tracts of tropical rainforest like the Amazon in Brazil, are being cleared to plant sugar cane and other crops for biofuel production.

Another problem is the cost of corn, an essential ingredient for basic food is also escalating causing further problems as the cost of certain products become unaffordable to many. It would surely be counter productive if such a situation were to develop where the CO2 absorbing tropical rainforests were being destroyed to plant crops to turn into environmentally friendly biofuels!

There is also a concern that as a by-product of growing the corn or other crop used for biofuel production environmental damage is caused by the fossil fuelled tractors, processes, fertilisers etc used in the growing process, meaning that they are not truly carbon neutral at all.

Recent research indicates that prairie grasses actually take out more carbon dioxide from the atmosphere during their growth than they emit when being converted to biofuel, meaning that they may well be truly carbon neutral.

It would seem more research is needed into biofuel production and use, but if grown responsibly, i.e not on land cleared of rainforest, a benefit may well be had for the environment by their use.

A-Z of Global Warming- CARBON DIOXIDE

Okay, so we are now well into our alphabetic A to Z journey on global warming. C for Carbon dioxide is one of the main players in the global warming problem. Carbon dioxide, chemical symbol co2 is a chemical compound composed of one carbon and two oxygen atoms.
CO2 is present in the Earth's atmosphere at a low concentration, around 0.038% by volume, and is one of many gases that make up Earth's atmosphere. CO2 is measured in parts per million by volume of air (PPMV). Atmospheric carbon dioxide derives from many natural sources including volcanic eruptions, the combustion of organic matter, the respiration of living aerobic organisms, and unfortunately from manmade (anthropogenic) sources, which we all know from the news is being linked to global warming and climate change.
Since the industrial revolution particularly the mid nineteenth century, the burning of fossil fuels for energy to provide electricity, power factories, homes and for all our transport needs has released massive amounts of carbon dioxide (CO2) into the atmosphere. Not only the burning of fossil fuels, but changes in the use of the land for agriculture and deforestation has further added to global manmade CO2 levels.
According to the World Wildlife fund some 29 gigatons which is 29 billion metric tons of CO2 was added to the atmosphere in 2004 alone from burning coal, oil and gas.
If we go back 250 years or so, to pre- industrial times, usually taken to be around 1750, CO2 levels in the atmosphere stood at around 280 parts per million by volume (ppmv). However levels of the gas have been increasing steadily ever since.
Well, pioneering scientist Charles Keeling (1928-2005) started taking atmospheric CO2 measurements in 1958 from Mauna Loa volcano in Hawaii. Those measurements have been recorded and are now known as The Keeling Curve. Charles Keeling was the professor of oceanography at the Scripps Institute of Oceanography (SIO) which is in San Diego, USA, and he followed the work of another eminent scientist and director of the SIO, Roger Revelle. Dr Revelle was instrumental in creating the Geophysical Year in 1958 and SIO's first programme looking at atmospheric CO2 back in 1956.
Monthly CO2 measurements were collected from a height of 3397 metres (11,140 feet) at the Mauna Loa Observatory situated on the slopes of Earth's largest volcano, Mauna Loa in Hawaii which was chosen for its remoteness to populations and vegetation so as not to skewer the readings.
Measurements have been taken over a 50 year period between 1958 and present, which show an increase in CO2 levels of 70 ppmv from around 315 ppmv to around their current level of 385 ppmv. The effects of CO2 in the atmosphere can even be measured on a cyclical basis, and this can be seen in the saw toothed keeling graph. Because there is greater land area, and thus far more plant life in the Northern Hemisphere compared to the Southern Hemisphere, there is an annual fluctuation of about 5 ppmv peaking in May and reaching a minimum in October. This corresponds to the Northern Hemisphere growing season. The amount of CO2 in the atmosphere drops towards spring when uptake by the plants and trees by photosynthesis is greatest. The opposite occurs in winter when the plants die off and CO2 levels rise again.
Continuous readings in this way have only been taken since 1958, however scientists have discovered that prior to the industrial era, circa 1750, CO2 levels stood at around 280 ppmv and this data has been revealed from air trapped in ice core records, taken from both the Antarctic and Arctic.
Perhaps most startling is the fact that CO2 levels are now around 85 ppmv higher than at any time during the last 650,000 years. Records from ice core records go back that far and have shown atmospheric CO2 levels to range from 180-300 ppmv during that period. The level of CO2 in our atmosphere now stands at 385 ppmv, and is increasing steadily.
The Keeling curve has become one of the most recognisable images in modern science as it shows with no uncertainty the effects of humankind's fossil fuel pollution of Earth's atmosphere.
CO2 levels have increased by 37% since pre-industrial times and have been increasing by an average of almost 1.4 ppmv a year since measurements began in 1958, although some months the figure has been higher, sometimes lower. In the last ten years however, the average increase appears to be around 1.9 ppmv each year, which indicates the rate of increase is increasing.
Whilst CO2 is a natural greenhouse gas, and important in natural concentrations to maintain Earth’s climate, anthropogenic CO2 is now pushing up Earth’s temperature. Earth’s natural sinks, like the Amazon rainforest and the oceans struggle to absorb the additional CO2 now being added to the atmosphere from the burning of fossil fuels. It is a know scientific fact that higher levels of greenhouse gases, of which CO2 is a component cause a warming of Earth’s atmosphere. If CO2 is not kept in check and continues to rise at current levels it will eventually cause Earth’s temperature to increase to levels which maybe critical to life on Earth.
Earth’s temperature has already increased by 0.74 degrees Celsius (1.33 Fahrenheit ) over the last 100 years……
Posted 04.05.08

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