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Discussing Causes Of Climate Change An Environmental Sciences Essay


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Climate has a great influence over our lives. All our normal routine actions are according to the climate we are living in. However the climate has been changing from past few decades, which in turn is changing our living patterns and thus, has made this world a more puzzled place to live in. In this essay the causes of climate change would be discussed, which are divided into two categories, either the climate is changing due to natural reasons or is forced to change by the human activities.

Naturally, the climate change is said to occur because of various reasons, mainly because of volcanic eruptions, ocean current, the solar variations, the earth's orbital change, and by many other natural reasons, which in turn produces various greenhouse gasses and in the end results into global warming. On the other hand, carbon emission done by humans is the greatest factor leading to global warming and then to climate change. Other activities like, chemicals used in agriculture, deforestation and other uses of energy in households also contribute in the greenhouse effect.

Climate can be defined as the long term weather conditions for a region, generally determined by 30 or more years of records. On contrast weather can be defined as the state of the atmosphere at a particular place and time. Moreover, the Green House effect is naturally in which certain atmospheric gases absorbs long wave radiation from the Earth's surface which in the end results in heating the earth's surface and the atmosphere. Hence global warming can be defined as the increase of Earth's average temperature which in then results into climate change. (Glossary: Nasa).

The Debate:

There is no doubt about the fact that the Earth's climate has become warmer over the twentieth century, however, there is still a dispute about whether the temperature increase is due to natural reasons or because of human activities. Two groups of UK scientists have recently investigated both types of effect. Mike Lockwood and colleagues at the Rutherford Appleton Laboratory (RAL) argue that the Sun's magnetic field has doubled over the century, and that this natural force of solar system has affected the earth's climate (Nature 399:437). On the other hand Simon Tett and colleagues from the UK's Meteorological Office in Reading and RAL argue that while solar forcing may have added to climate change, however, human activities have also been responsible for the temperature changes from many years (Nature 399:569). It has been stated that the Earth's average global temperature has increased by 0.6 Kelvin in the past 100 years. Four main processes that can affect the Earth's climate have been evaluated. Two of these are said to be small aerosol particles from volcanic eruptions and changes in solar luminosity. The other two, sulphate aerosols and greenhouse gases such as carbon dioxide, are due to increasing industrialization, in particular the burning of forests and fossil fuels. Lockwood and colleagues found that the total magnetic flux leaving the Sun has risen by a factor of 1.4 since 1964. Their results could provide support for the theory that changes in the solar wind could contribute to climate change. The solar wind and the Sun's magnetic field are very well linked with each other. According to the theory charged particles in the solar wind would deflect high-energy cosmic rays that would otherwise have ionized the Earth's lower atmosphere, leading to the formation of clouds. Since cloud cover determines the amount of solar radiation reflected by the Earth back into space, a more powerful solar wind implies less cloud cover which, in turn, suggests that the Earth would warm up. However, the paper by Tett and colleagues suggests that natural effects alone cannot account for the pattern of temperature change observed over the past 50 years. They used the HadCM2 computer model to predict the Earth's global temperature during five overlapping 50-year periods (1906-56, 1916-1966,), and then compared the results with observations. The program models both the oceans and the atmosphere, and also allows for changes in greenhouse emissions, surface albedo (i.e. reflectivity), volcanic aerosols and solar irradiance. They ran the programmers with a number of different solar models, including one that matched the effects highlighted by Lockwood. The results were similar for all cases: it is not possible to distinguish between the contributions of human activity and natural variations to global warming in the first half of the century, but after 1946 increases in the concentration of man-made greenhouse gases and sulphate aerosols was the dominant effect.

(News: Physics World, 1999)

Climate Change - Human Activities the Cause, Mea Culpa! But Consider 1816, the Year Without Summer!

The whole world seems to be getting involved with the facts of Global warming and Climate change. Nobel prizes were awarded to the UN's IPCC (Intergovernmental Panel on Climate Change) and Al Gore several years ago, followed by the Kyoto Protocol Climate Change Conference of 1997, and finally President Obama led leaders of 192 nations in agreement with its principles, promising heavy financial compensations to third world nations. Scientists have calculated that emissions of carbon dioxide by human activities amount to perhaps 30 billion tons per year because of various factors including fossil fuel burning, cement production, gas flaring, industrial operations and breathing etc. They also estimate that volcanic eruptions can on average emit about one-forty-five to two-fifty-five million tons of carbon dioxide into the atmosphere per year. This seems to specify that human activities may release perhaps 100 times the amount of carbon dioxide emitted by volcanoes, thus, this seems to be a realistic base for the universal concern, which is that human activities have a great negative impact on the climate of Earth. However, it seems like that nature itself is trying to make things worse as firstly admitting furor at Copenhagen by world leaders and President Obama in support of Global Warming then along came the coldest winter in recent decades. Then finally when Obama's EPA poised to levy severe pollutant restrictions and harsh financial penalties on American industry, a volcanic eruption in Iceland devastated the air-transport industry by closing down almost all flights over Europe for a week, which led to bankrupting major airlines, with absent bail-outs by governments. The major natural catastrophes: the recent eruption of Iceland's Eyjafjallajokull volcano along with many other including Krakatau, earthquakes, tsunamis, hurricanes, or cyclical changing of atmosphere of ocean, should be enough to warn decision-makers about climate change effects. After experiencing the incident of the Iceland volcano eruption, other than man-kind activities in the reference to global warming and climate change seems warranted. The summer of 1816 is considered to be one of the coldest on record which is studied by many weather scientists. The year is known as the "Year without a summer". It is also known as the "Poverty Year", due to widespread destruction of crops. Severe climate oddity during the summer destroyed crops in Northern Europe, Northeastern United States and Eastern Canada, and average global temperature decrease was sufficient enough to cause many agricultural failures around the world. The most likely cause of the severe climate change seems therefore, to be the volcanic influences because greatly increased volcanic activity causes immense amounts of ash and dust to be blown and trapped high in the atmosphere, which in turn cause increased reflection of solar radiation (instead of absorption at the Earth's surface), resulting in globally decreased temperatures on Earth. Therefore human activities seem minor and insignificant relative to the power of Nature. (Kolom)

How do we know that atmospheric build-up of green house gases is due to human activities?

Four lines of evidence prove conclusively that the recent buildup of carbon dioxide take place largely from human activities. The nucleus of carbon atoms in carbon dioxide released by burning coal, oil, and natural gas (fossil fuels) vary in their characteristics from the nucleus of carbon atoms in carbon dioxide emitted under natural conditions. Tens of millions of years ago, coal, oil, and natural gas were formed, and the portion of their nucleus, that was once radioactive, has long ago changed to non- radioactive carbon. However the carbon dioxide released from natural sources on the Earth's surface holds a measurable radioactive portion. As carbon dioxide has been emitted through fossil fuel combustion, the radioactive fraction of carbon in the atmosphere has decreased. Forty years ago scientists provided the first direct evidence that burning of fossil fuels was causing a buildup of carbon dioxide and thus reducing radioactive carbon in the atmosphere by measuring the decreasing portion of radioactive carbon-14 captured in tree rings, each year between 1800 and 1950. Moreover, scientists began making accurate measurements of the total amount of carbon dioxide in the atmosphere in any countries by late 1950s. Their data show convincingly that the levels of carbon dioxide have increased each year worldwide and these increases are dependable with other estimates of the rise of carbon dioxide emissions due to human activity over this period. In 1980, third evidence was added that the ice buried below the surface of the Greenland and Antarctic ice caps contains bubbles of air trapped when the ice originally formed. These samples of fossil air have been retrieved by drilling deep into the ice. Measurements from the youngest and most shallow segments of the ice cores produced carbon dioxide awareness to those that were measured directly in the atmosphere at the time the ice formed. But the older parts of the cores show that carbon dioxide amounts were about 25% lower than today for the ten thousand years previous to the onset of industrialization. The final evidence comes from the geographic pattern of carbon dioxide measured in air. Observations show that there is slightly more carbon dioxide in the northern hemisphere than in the southern hemisphere. The difference arises because most of the human activities that produce carbon dioxide are in the north and it takes about a year for northern hemispheric emissions to circulate through the atmosphere and reach southern latitudes. (Programme, 1997)


The debate on climate change is as what really caused the climate to vary with time and which affected us adversely. Some say that climate is changed by natural factors like ocean currents or volcanoes while others deny this fact and try to prove the point that human activities have forced the climate to change. I support the second opinion, human activities indeed made the climate to change and result into global warming.

The concentration of Carbon dioxide in the atmosphere has increased from 290ppm in 1880 to 352ppm in 1989 which can be concluded as the 20% increase. This increase is almost certainly a result of human activities (Ruddiman,2003).

There has been seen a sufficient increase in the emission of Greenhouse gases due to human activities. For example methane has an estimated rate of emission from human activity on the planet which is 375 million tons per year. For carbon dioxide, there is also an estimated rate of emission from human activity which is 7100 million tons per year. The anthropogenic emissions of these two gases are easier to estimate, because we know approximately how much oil, coal, and natural gas humans produce for consumption around the world each year. We also know approximately how much forest is burned and converted to agriculture each year. According to 'The state of the environment' published in 1991 by the Organization for Economic Co-operation and Development, human activities emit about 68 million tones of nitrogen oxides, 99 million tons of sulfur oxides, 177 million tons of carbon monoxide, and 57 million tones of particulates (dust). However, all these numbers are very approximate. On the other hand, sulfur oxides have been found to slightly counteract the greenhouse effect caused by other gases. Still, sulfur oxides are very harmful to the environment and are best known for causing acid rain. Carbon monoxide doesn't contribute to the greenhouse effect, but has significant effects on atmospheric chemistry. Dust is generally thought to cool the atmosphere close to Earth's surface, but this effect depends on various factors, including the size and color of the dust particles. (Davis, 2004)

The Intergovernmental Panel on Climate Change (IPCC) is a scientific body set up by the UN to look at climate change. It says that human activity is the main cause of the changes seen in climate. Recent reports from the IPCC have concluded that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. "From new estimates of the combined anthropogenic forcing due to greenhouse gases, aerosols, and land surface changes, it is extremely likely that human activities have exerted a substantial net warming influence on climate since 1750." (Uk governement's digital service: DirectGov)

The most important factor for the climate change is the speeding up of greenhouse effect by manmade activities, which is usually known as Global Warming. Basically, the Greenhouse effect is naturally caused by the emissions of gases like nitrous oxide, carbon-dioxide, methane, ozone and water vapor. However, anthropogenic activities like burning the fossil fuels and deforestation makes the greenhouse effect stronger. Which means more heat is trapped and the Earth's climate begins to change unnaturally.

The fossil fuels (coal, oil and natural gas) are burned for various human activities mainly used for transportation, manufacturing, heating, cooling, electricity generation etc. this can be summed up after the industrial revolution, in 18th century, and more of the fossil fuels were being burned frequently. Therefore, manmade gases were being emitted into the atmosphere, mostly in the form of carbon dioxide emissions, from the burning activity. These gases speed up the greenhouse effect, forcing the climate to change.

Another factor forced the climate to change and resulted into global warming is the act of deforestation.  Deforestation increases the amount of carbon-dioxide in the atmosphere. Also, due to the disappearance of trees, photosynthesis cannot take place which lowers the oxygen level in the atmosphere. Deforestation is rampant today due to the increase in human civilization. The levels of deforestation have increased by about nine percent in recent times. Moreover, the burning of wood also causes it to decay, therefore releasing more carbon-dioxide into the atmosphere, and carbon-dioxide being the main culprit in global warming increases.

Another man-made cause of the increase in the Green house effect due to the emission of such gases is the use of any electrical appliances. Even the refrigerator in the house emits gases which contribute to the Greenhouse effect. These gases are known as Chlorofluorocarbons (CFCs) and are used in refrigerators, aerosol cans, and some foaming agents in the packaging industry, fire extinguisher chemicals and cleaners used in the electronic industry. Some processes of the cement manufacturing industries also act as a cause towards the Greenhouse effect. 

Population growth also is an indirect contributor and one of the causes of the Greenhouse effect. With the increase in population, the needs and wants of the people increase. Therefore, this increases the manufacturing processes as well as the industry processes. This results in the increase of the release of industrial gases which catalyze the green house effect. The increase in population also results in the increase of agricultural processes. Most man-made machines, like the automobile also contribute to the green house effect.

In one of the recent articles global warming has been linked with the recent natural disasters. As almost fourteen million people have been affected by the torrential rains in Pakistan, making it a more serious humanitarian disaster than the South Asian tsunami and recent earthquakes in Kashmir and Haiti combined. The disaster was driven by a 'supercharged jet stream' that has also caused floods in China and a prolonged heat wave in Russia. Which comes after flash floods in France and Eastern Europe killed more than 30 people over the summer. Jean-Pascal van Ypersele, vice-president of the body set up by the UN to monitor global warming, the Intergovernmental Panel on Climate Change (IPCC), said the 'dramatic' weather patterns are consistent with changes in the climate caused by mankind. "These are events which reproduce and intensify in a climate disturbed by greenhouse gas pollution," he said, "Extreme events are one of the ways in which climatic changes become dramatically visible."

Professor Andrew Watson, a climatologist at the University of East Anglia, which was at the centre of last year's 'climate gate' scandal, said the extreme events are "fairly consistent with the IPCC reports and what 99 per cent of the scientists believe to be happening".

"I'm quite sure that the increased frequency of these kinds of summers over the last few decades is linked to climate change," he said. (Gray)

However , authors such as Lean and Rind (1996) believe that, although natural factors may be the reason for most temperature increase before the Industrial Revolution, ' the most likely cause of climate change since about 1850...is the growing concentration of greenhouse gases as the net atmospheric temperature increase, or 'forcing' is largely due to human (anthropogenic) activities .Interestingly, particulate emissions from volcanoes produce a net decrease in global temperatures, due to the reflective properties (albedo) of the sulfate aerosol particles formed in the stratosphere. (Bianchi, 2010)


The earth's climate is dynamic and always changing through a natural cycle but the anthropogenic activities make this cycle speed up unnaturally that create problems in the atmosphere as either the earth gets oddly warmer or the people have to face natural disasters. However if man has created all these problems, he should also try to make things better by finding practical solutions.

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