climate change & it's effect on britian

By Hazel

 

There is little disagreement that the climate has changed, but where there is disagreement is why there has been this change. Is it wholly due to human activity, partially our fault or nothing to do with us?. Eminent scientists give very convincing arguments on all sides of this debate.

Climate is defined as an average of weather patterns over 30 years, so the change from a single year to another is just weather and tells us nothing about climate change. Climate models are a vast simplification of the real thing, as it is currently impossible to reconstruct the complexities of the atmosphere. A small underestimation in a variable can lead to a gross magnification over time, greatly skewing the end result. Many of the variables are also difficult to quantify. Long term data sets for global temperatures indicate a clear and consistent increase in global temperature, particularly since the industrial revolution. Also computer models used to predict the future course of global warming all show heavier rainfall, and 'extreme rainfall events', as one of its principle consequences here in Britain. Global warming is likely to lead to higher rainfall because a warming atmosphere contains more water vapour and more energy.

Average global temperatures are said to have risen by almost 1degree F in the past century. This may not sound like much, but at the peak of the last ice age (18,000 years ago) the average temperature was only 7 degree F colder than it is today and glaciers covered much of North America.

The factor most talked about is that of greenhouse gases. These gases are present in the atmosphere and allow sunlight to enter the atmosphere freely. When sunlight strikes the the Earth's surface, some of it is reflected back towards space as infrared radiation (heat). Greenhouse gases absorb this infrared radiation and trap the heat in the atmosphere. Many gases exhibit these greenhouse properties. Most have both natural and anthropogenic sourses (water vapour, carbon dioxide, methane, and nitrous oxide), while others are exclusively man-made (like gases used for aerosols). Since around the time of the industrial revolution in Western countries levels of carbon dioxide, methane and nitrous oxide have all risen dramatically. Fossil fuel combustion, increasingly intensive agriculture and an expanding global human population have been the primary cause for this rapid increase.

Concentrations of CO2 in the atmosphere are naturally regulated by numerous processes collectively known as the carbon cycle. This movement ( flux) of carbon between the atmosphere and the land and oceans is dominated by natural processes, such as plant photosynthesis. While these natural processes absorb some of the anthropogenic CO2 emisions there is a net increase added to the atmosphere annually. The Earth's positive inbalance between emission and absorbtion results in the continuing growth in greenhouse gases in the atmosphere. Once in the atmosphere CO2 lingers for hundreds of years.

Sulphate aerosols, though not greenhouse gases, nevertheless are very important in global climate. Sulphate in our atmospere has a net cooling effect and goes some way to reduce the warming effect of the greenhouse gases. The overall effect is one of net global warming, but the complex interaction of these positive and negative influences on globla warming make predicting future climate change difficult. This is further complicated by the cooling influence of such man made things as dust and aeroplane trails, which may reduce warming.

The above view is countered by the argument that it is the temperature levels that may lead to increased concentrations of Co2 and other greenhouse gases not the other way round. The greenhouse effect is mostly the result of surface temperature-driven weather; it is not the cause of weather and surface temperature. In other words it is the temperature that increase the gases, not the gases increasing the temperature. This is exacerbated by the fact that the warming of the oceans means that they are less able to absorb CO2 from the atmosphere. There is also a possibility that once the oceans reach a certain critical temperature, CO2 that is now held in a solid state will turn to gas and be released into the atmosphere.

One argument against the theory that increase in CO2 is responsible for climate change is that there also global warming on mars and pluto where there is no man made increase in CO2. However, sceptics of this theory point out that there has not been nearly enough evidence of long term warming on these planets to draw any conclusions. The conventional theory is that climate change on mars can be explained primarily by small alteration in the planet's orbit and tilt. All planets experience a few wobbles as they make their journey around the sun. On Earth these fluctuations change the tilt of its axis and its distance from the sun and are thought to be responsible for the waxing and waning of the ice ages on Earth.

The Sun may also be contributing to the rising temperatures. The output of the Sun's energy can be determined by measuring magnetic zones on the Sun's surface known as sunspots, which are believed to intensify the Sun's energy output. The Sun has been at its strongest over the past 60 years and may now be affecting the global temperature. The increase in solar brightness is not enough alone to cause the observed climate changes but may be contributing to them.

One of the consequences of global warming may well be a rise in sea levels. Like any object when heated, the oceans have expanded. This expansion, combined with the melting of Greenland and Arctic ice, will cause sea levels to rise considerably. The melting of any large area of ice will also have an effect on the temperature due to the highly reflective and insulating properties of ice.

Any climate change will inevitably alter the world's habitats and ecosystems. These depend on a delicate balance of rainfall, temperature and and soil type. Plants and animals can adapt to a slow change in conditions, but if global warming is truely happening the change will be rapid and the plants and animals will not have time to adapt or move elsewhere, which will have a destabilizing effect on the environment.

Climate change has been blamed for the collapse of nesting attempts by several species of seabird in Orkney and Shetland. Rise in sea temperatures led to the disappearance of the sand eel, which is a key part of the food chain. The teeming shoals of sand eel used to sustain larger fish, marine mammals and sea birds. It is believed that the microscopic plankton on which the tiny sand eel larvae feed are moving northwards as sea water warms, leaving the baby fish with nothing to feed on. This is being seen in the North sea in particular, where water temperature has risen by 2 degrees C in the past 20 years.

Even small shifts in the climate can have a big impact. Oak leaves unfurling 2 weeks earlier than 40 years ago mean that the caterpillars that, for example, blue tits feed on are hatching earlier and earlier. While invertebrates such as moths can adapt to change relatively quickly, birds breeding cycles take longer to evolve. However, having said that, this year has been a bumper year for both caterpillars, and, in turn blue and great tits. So it would seem that the tits, at least, have adapted to the change in climate, but other birds may well not be so adaptable and will suffer if the balance of their ecosystems change too rapidly.

Given the difficulty of predicting what changes there may be and at what speed they will occur, it is in turn, very difficult to predict what the effects will be on wildlife. Those that are at the edges of their range will be hardest hit. For example the ptarmigan has evolved to survive in fairly harse conditions and is camoflaged white in winter so it blends into the snowy background. As temperatures rise and the snow receedes it will stand out like a sore thumb against a dark background, making it easy prey for eagles.

If the temperatures continue to rise as predicted, waders such as redshank which are already in decline, will be hard hit as the marshes and wet meadows they thrive in dry out and the ground becomes too hard for them to dig for food. Southern England will become home to more exotic birds. The hoopoo is already a frequent visitor. The French bumble bee has already made its home here and wasps, aphids and the rat populations will be expected to explode because of the hotter summers forcast. British marine life, too, is expected to undergo dramatic changes, with our already vanishing cod heading for cooler water and being replaced by tuna, turtles and seahorses.

As the temperature rises plants may be hardest hit as they are unable to move northwards, and a lot will depend on how far their seeds can be carried.

In this article I have tried to give a balanced view, but the more I read the more views there seemed to be, and it was impossible to know who was right. One problem with this area is that there are a lot of vested interests, and there is big money in skewing results one way or the other, so it is even more difficult to know whose results are genuine.

Global warming is, undoubtedly, the buzz word of today, and governments and industry are all jumping on the CO2 band wagon, but the problem is much more complex. We live very much in a throw away society. We buy goods cheap and then throw them away rather than get them mended. We are also very wasteful, for example, buying more food than we need and throwing away alot, not using leftovers.

Even if you adhere to the theory that either climate change is not happening or that it is not our doing, there can be little doubt that we are all thoroughly abusing our planet and all the habitats within it. However, it is a veritable minefield knowing what to do to cause least strain on resourses. We are urged to recycle, but even this is very controversial. Perhaps the thing to do is to just use less; only buy what you need, use less packaging, buy quality goods that last and can be mended when they breakdown and reduce the number of journeys in your car.

If the scientists of the world cannot agree, how can we know what is the truth, so,it might be as well to bear in mind that the Earth's climate has been changing constantly over its 5 billion year history, and that ice ages are cyclical so one might expect warming at this time. Also some of you may remember there were big scares in the 1970s about global cooling and there was great concern that we were returning to an ice age.

So it is up to us to do what we can. If every body just did a little to help, the accumulated effect would be enormous. Surely it is our duty to leave this beautiful and diverse planet in a healthy state for future generations.

 

 

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why we do it

Once upon a time, there was a wise man who used to go to the ocean to do his writing. He had a habit of walking on the beach before he began his work.

One day, as he was walking along the shore, he looked down the beach and saw a human figure moving like a dancer. He smiled to himself at the thought of someone who would dance on the beach, and so he walked faster to catch up.

As he got closer, he noticed that the figure was that of a young man, and that what he was doing was not dancing at all. The young man was reaching down to the shore, picking up small objects, and throwing them into the ocean READ MORE

 

 

This page has been proof read by Sandra