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Thursday, January 20, 2011

Global Warming


INTRODUCTION

Global warming is the increase in the average temperature of Earth's near-surface air and oceans. The gradual increase of the temperature of the earth's lower atmosphere is a result of the increase in greenhouse gases since the Industrial Revolution. The temperature of the atmosphere near the earth's surface is warmed through a natural process called the greenhouse effect.

Visible, shortwave light comes from the sun to the earth, passing unimpeded through a blanket of thermal, or greenhouse, gases composed largely of water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Infrared radiation reflects off the planet's surface toward space but does not easily pass through the thermal blanket. Some of it is trapped and reflected downward, keeping the planet at an average temperature suitable to life, about 60°F (16°C).
How those greenhouse gasses causing global warming? Greenhouse gases are closed related with global warming. The global warming is actually caused by the greenhouse gasses. The greenhouses gases are gases in an atmosphere that absorb and emit radiation within the thermal infrared range.

Growth in industry, agriculture, and transportation since the Industrial Revolution has produced additional quantities of the natural greenhouse gases plus chlorofluorocarbons and other gases, augmenting the thermal blanket. It is generally accepted that this increase in the quantity of greenhouse gases is trapping more heat and increasing global temperatures, making a process that has been beneficial to life potentially disruptive and harmful.
During the past century, the atmospheric temperature has risen 1.1°F (0.6°C), and sea level has risen several inches. Some projected, longer-term results of global warming include melting of polar ice, with a resulting rise in sea level and coastal flooding; disruption of drinking water supplies dependent on snow melts; profound changes in agriculture due to climate change; extinction of species as ecological niches disappear; more frequent tropical storms; and an increased incidence of tropical diseases.
The effects of global warming and climate change are of concern both for the environment and human life. Evidence of observed climate change includes the instrumental temperature record, rising sea levels, and decreased snow cover in the Northern Hemisphere. According to the IPCC Fourth Assessment Report, of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in [human greenhouse gas] concentrations.

It is predicted that future climate changes will include further global warming (i.e., an upward trend in global mean temperature), sea level rise, and a probable increase in the frequency of some extreme weather events. Ecosystems are seen as being particularly vulnerable to climate change. Human systems are seen as being variable in their capacity to adapt to future climate change. To reduce the risk of large changes in future climate, many countries have implemented policies designed to reduce their emissions of greenhouse gases.
Physically, global warming can cause extremely change to the weather and climate. Increase on temperature can lead to increase on evaporation rate. Beside, the changing of temperature on certain area change it atmosphere pressure and this can lead to local atmospheric climate.

GLOBAL WARMING PROCESS

All objects emit radiation because of their temperature. This is called "black body" radiation. The Sun, or any object at a temperature of 6000 K, emits most of its energy in the visible spectrum. The Earth, or any object at 285 K, emits most of its energy in the infrared part of the spectrum. Some gases in the air are called "greenhouse gases". These are gases, like water vapor and carbon dioxide, that are transparent to visible light (from the Sun), but absorb infrared light (from the Earth).

When visible light from the Sun hits the earth, it zips through the atmosphere, hits the earth, and warms the earth. The earth emits some of this energy back out into space, keeping the planet cool. But the energy we emit is in the infrared, and some of that is absorbed by greenhouse gases in the air instead of going back out into space. When that happens, the air gets warmer - and the planet as a whole gets warmer too.

We humans used to burn wood for fuel. When we burned wood, the carbon dioxide we were releasing was the same carbon dioxide that the tree extracted from the air when it was growing; so the net effect was zero: as long was we planted a new tree to take the place of the old one, no "extra" carbon dioxide got into the air.

But since about 1750, when the steam engine was invented, we have been burning coal, oil, and other fossil fuels at faster and faster rates. This has released a lot of new carbon dioxide into the air, carbon that hasn't been in the atmosphere for millions of years. Right now, there is more carbon dioxide in the air than at any time in the last 20 million years or more. This has caused more and more of the earth's cooling radiation to be absorbed by the air, warming the planet.

Causes of Global Warming

Global warming is caused by several things, which include man-made or anthropogenic causes, and global warming is also caused by natural causes.

a) Natural Causes

Natural causes are causes that are created by nature. One natural cause is a release of methane gas. Methane is a greenhouse gas and a very dangerous gas to our environment. A greenhouse gas is a gas that traps heat in the earth's atmosphere. Methane is created when bacteria break down organic matter under oxygen-starved conditions. This occurs when organic matter is trapped underwater, as in rice paddies. It also takes place in the intestines of herbivorous animals, such as cows, sheep, and goats. Because human agriculture has grown over time to engulf most of the arable land on the planet, it is now adding a lot of methane to the atmosphere. Landfills and leakage from natural gas fields (methane is a component of natural gas) are also significant sources of methane. Another natural cause is that the earth goes through a cycle of climate change. This climate change usually lasts about 40,000 years. Even though nature contributes to global warming, this contribution is very insignificant when compared to human contribution for this hazard.

b) Man-made or Anthropogenic Causes of Global Warming

Man-made causes probably do the most damage to our planet. There are many man-made causes of global warming such as pollution, population, transportation, buying suburban home, deforestation, agriculture and so on. Pollution is one of the biggest man-made problems. Pollution comes in many shapes and sizes. Burning fossil fuels is one thing that causes pollution. Fossil fuels are fuels made of organic matter such as coal, or oil. When fossil fuels are burned they give off a green house gas called CO2. Also, mining coal and oil allows methane to escape. Methane is naturally in the ground. When coal or oil is mined you have to dig up the earth a little bit. When you dig up the fossil fuels you dig up the methane as well letting it escape into the atmosphere.

Another major man-made cause of Global Warming is population. More people mean more food, and more methods of transportation. That means more methane because there will be more burning of fossil fuels (if you're into gas burning cars like our planet is), and more agriculture. If you've been in a barn filled with animals and you smelled something terrible, you were smelling methane. Another source of methane is manure. Because more food is needed to feed the population we have to raise food. Animals like cows are a source of food which means more manure and hence more methane.

Another problem with the increasing population is transportation. More people mean more cars and more cars means more pollution. Also, many people have more than one car. Driving car requires combustion of tremendous amounts of fossil fuels. These fuels have been storing carbon for thousands, possibly millions of years. When your car burns them, that carbon is instantly released as carbon dioxide into the atmosphere. There are definitely ways of raising animals and farming that use no manure and no methane. Once we realized the problem we should have stopped immediately using manure. Instead we choose to continue killing the planet. We are a very stubborn race.

Since CO2 contributes to global warming, the increase in population makes the problem worse because we breathe out CO2. Also, the trees that convert our CO2 to oxygen are being cut down because we're using the land that we cut the trees down from as property for our homes and buildings. We are not replacing the trees (trees are a very important part of our eco-system), so we are constantly taking advantage of our natural resources and giving nothing back in return. The buildup of carbon dioxide in the atmosphere, mainly from your fossil fuel emissions, is the most significant human cause of global warming. Carbon dioxide is released every you burn something, be it a car, airplane or coal plant. This means you must burn less fossil fuel if you want the Earth's climate to remain stable! And unfortunately, we are currently destroying some of the best known mechanisms for storing that carbon plants.

Deforestation increases the severity of global warming as well. Carbon dioxide is released from the human conversion of forests and grasslands into farmland and cities. All living plants store carbon. When those plants die and decay, carbon dioxide is released back into the atmosphere. As forests and grasslands are cleared for your use, enormous amounts of stored carbon enter the atmosphere.

Buying your suburban home whose lot was cleared of existing trees and plants that were actively storing carbon. When those plants were killed to build your home, they stopped storing carbon and released all the carbon they had accumulated over tens or even hundreds of years.
The next causes of global warming that cause by man-made are agriculture. Nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide, and we release them every time we apply fertilizer to soil. A recent United Nations Food and Agriculture Organization study found that modern farming is contributing more too global warming than the entire transportation sector combined. This is due partly to the fuel burned in modern farming, but more significantly, to the release of methane and nitrogen oxides

CFCs and HCFCs (chlorofluorocarbons and hydro chlorofluorocarbons) used in refrigeration are also powerful greenhouse gases. These gases occur in lower concentrations in the atmosphere, but because they are so much more potent than carbon dioxide in some cases hundreds of times more potent per unit of volume they contribute to global warming as well.

Effects of Global Warming

1) Rise in Sea Level

Increase in temperatures effect sea levels in at least two ways. First, higher temperatures enhance the melting of ice sheets and glaciers, adding water to the oceans. Second, because liquid water density decreases with increasing temperature, higher temperature cause water to expand and sea levels to rise. Historical changes in global temperature have been correlated with changes in sea levels. When temperatures peaked up, during the mid-Cretaceous period, the Earth’s polar caps melted, sea levels rose to unprecedented levels, and 20 percent of continental land flooded. Today, snow and ice cover 3.3 percent of the Earth’s total surface area. The total ice volume is about 25 million km3. If this ice melts, the sea level will rise 65 m above its current level. During the twentieth century, the sea level rose by about 10 to 25 cm. By the year 2100, the sea level is expected to rise by another 10 to 90 cm (IPCC, 2001).

Although the melting of ice sheets, glaciers, and sea ice and the corresponding rise in sea level are of concern, a large increase in sea level is unlikely to occur during the next 500 years. The largest sources of sea level rise would be the melting of the East and West Antarctic Ice Sheets, the Greenland Ice Sheet, sea ice over the Arctic, the large valley and piedmont glaciers of southeast Alaska, and the glaciers of central Asia. The West Antarctic Ice Sheet, based over water, is an order of magnitude smaller than is the East Sheet, based over land. Thus, the West Sheet is less stable than is the East Sheet (Stuiver et al., 1981). If melted, the East and West Sheets would raise the sea level 55 to 60 m (Denton et al., 1971), with the West Sheet responsible for about 5 m of this rise (Mercer, 1987). If extreme global warming occurs, the West Sheet, as a result of its relative instability, is more likely to collapse than is the East Sheet. A collapse of the West Sheet would probably take about 500 years (Bentley, 1984). Currently, the East Sheet may be increasing in size because of an increased water vapor supply to the sheet resulting from higher global temperatures (Bentley, 1984). Extended global warming could reverse this trend and ultimately cause a collapse of the sheet, increasing sea levels by 50 to 55 m. Such a process, though, is likely to take thousand of years (Crowley and North, 1991).
The main effect of sea level rise, even in small quantities, is the flooding of low-lying coastal areas and the elimination of a few flat islands that lie just above sea level. Bangladesh, the most densely populated country in the world, is particularly at risk. A 1 m rise in sea level would displace about 17 million people from their homes. New Orleans, Lousiana, which already lies below sea level, would similarly face a danger of flooding. Tuvulu is a chain of nine coral atolls in the South Pacific Ocean, about halfway between Hawaii and Australia. Tuvulu has total land area of 26 km2, about 0.1 times the size of Washington DC, a coastline that stretches for 24 km and a population of about 10000. An increase in sea level of 2 m could eliminate the country.

2) Changes in Regional Climate and Agriculture

Global warming is likely to cause regional and temporal variations in temperature. The number of extremely hot days is likely to increase and the number of extremely cold days is likely to decrease. Droughts will increase in some areas and flood in others. Precipitation intensity, averaged over the globe, and the number of extreme rainfall events are expected to increase (IPCC, 1995). Changes in regional climates are likely to shift the location of viable agriculture. Crops may flourish in areas that were once too cold or dry, but they may also die in regions that become too hot or too wet. It is difficult to determine whether global warming will cause a net long-term increase or decrease in food supply, but it is fairly certain that locations crop viability will shift (Wuebbles, 1995). Because plants grow faster when temperatures, carbon dioxide levels, or water vapor levels mildly increase (plant-carbon dioxide negative feedback), it is expected that in areas where only mild changes in temperature and moisture occur, agriculture will flourish. In areas where extreme variations occur, agriculture will die out. Of particular concern are subtropical desert regions of Africa, where temperature are already hot. In these regions, agriculture is subject to the whims of the climate, and millions of people depend on the local food supply. Small change in climate could trigger famine, as has occurred in the past.
Low-latitude areas are at most risk of suffering decreased crop yields. Mid- and high-latitude areas could see increased yields for temperature increases of up to 1-3°C (relative to the period 1980-99). According to the IPCC report, above 3°C of warming, global agricultural production might decline, but this statement is made with low to medium confidence. Most of the agricultural studies assessed in the Report do not include changes in extreme weather events, changes in the spread of pests and diseases, or potential developments that may aid adaptation to climate change. An article in the New Scientist describes how rice crops might be strongly affected by rising temperatures. At a 2005 Conference held by the Royal Society, the benefits of increased atmospheric carbon dioxide concentrations were said to be outweighed by the negative impacts of climate change.

3) Change in Ecosystems

Rapid, continuous increase in temperature could lead to the extinction of many species that are accustomed to narrow climate conditions and are unable to migrate faster than the rate of climate change. Although enhanced CO2(g) levels invigorate forests, sharp increase in temperature could lead to forest dieback in tropical regions, affecting the rates of CO2(g) removal by photosynthesis and emission by respiration. Studying the association between Earth climate and extinctions over the past 520 million years, scientists from the University of York write, "The global temperatures predicted for the coming centuries may trigger a new ‘mass extinction event’, where over 50 per cent of animal and plant species would be wiped out." Marine invertebrates enjoy peak growth at the temperatures they have adapted to, regardless of how cold these may be, and cold-blooded animals found at greater latitudes and altitudes generally grow faster to compensate for the short growing season. Warmer-than-ideal conditions result in higher metabolism and consequent reductions in body size despite increased foraging, which in turn elevates the risk of predation. Indeed, even a slight increase in temperature during development impairs growth efficiency and survival rate in rainbow trout. A 2002 article in Nature surveyed the scientific literature to find recent changes in range or seasonal behavior by plant and animal species. Of species showing recent change, 4 out of 5 shifted their ranges towards the poles or higher altitudes, creating "refugee species". Frogs were breeding, flowers blossoming and birds migrating an average 2.3 days earlier each decade; butterflies, birds and plants moving towards the poles by 6.1 km per decade. A 2005 study concludes human activity is the cause of the temperature rise and resultant changing species behavior, and links these effects with the predictions of climate models to provide validation for them. Scientists have observed that Antarctic hair grass is colonizing areas of Antarctica where previously their survival range was limited.

4) Effect on Human Health

If global temperature increase, people living in locations where temperatures are already hot are likely to experience more stress and heat-related health problems than are people living in milder climates. People currently living in cold climates are likely to experience less stress. Heat-related health problems, such as heat rash and heat stroke, generally affect the elderly and those suffering from illness more than they affect the general population. Increases in precipitation as a result of global warming could increase the populations of mosquitoes and other insects that carry diseases. CO2(g), CH4(g), and N2O(g) cause no direct harmful health problems at ambient mixing ratios. Nevertheless, increases in the mixing ratios of these gases will affect human health indirectly through the effects of these gases on climate change and the effect of the resulting climate change on health. Particulate BC, another agent of global warming, will affect human health directly. BC is emitted primarily in submicron particles. Epidemiological studies have shown that long-term exposure to particles ≤2.5 ┬Ám in diameter above background levels causes increased mortality, increased disease, and decreased lung function in adults and children (Ozkatnak and Thurston, 1987; U.S EPA, 1996; Pope and Dockery, 1999).
The negative health impacts of climate change will outweigh the benefits, especially in developing countries. Some examples of negative health impacts include increased malnutrition, increased deaths, disease and injury due to heat waves, floods, storms, fires and droughts, and increased frequency of cardio-respiratory diseases. According to a 2009 study by UCL academics, climate change and global warming pose the biggest threat to human health in the 21st century.

5) Effects on Stratospheric Ozone

Global warming has caused a warming of near-surface air and it has caused a cooling of the stratosphere. Cooling of the stratosphere is affecting the ozone layer in at least three ways. First, cooling affects the rates of chemical reaction that produce and destroy ozone. Whereas many reactions proceed more slowly when temperatures decrease, the reaction O(g)+O2(g)+M O3(g)+M proceeds more rapidly when temperatures decrease. Thus, when gas chemistry alone is considered, a cooling of the stratosphere slightly increase global stratospheric ozone.
Second, cooling decrease the saturation vapor pressure (SVP) of water, allowing sulfuric acid-water aerosol particles in the background stratosphere to grow larger. The increase in size of these aerosol particles will increases the rates at which heterogeneous reaction occur on their surfaces. Because such reaction produce chlorine gases that photolyze to products that destroy ozone, a decrease in stratosphere temperatures reduces global stratospheric ozone when only this effect is considered. Third, a cooling of the stratosphere increases the occurrence, size, and lifetime of Polar Stratospheric Clouds (PSCs). Type I PSCs form at below 195 K and Type II PSCs form at below 187 K. Stratospheric cooling decreases temperatures below these critical levels during winter more frequently and for a longer period than when no cooling occurs, increasing Type I and II PSC lifetime, and size, enhancing Antarctic and Arctic ozone destruction during Southern and Northern Hemisphere springtime, respectively. In sum, stratospheric cooling from near-surface global warming has opposing effects on ozone in the global stratosphere, but it causes a net destruction of ozone over the Antarctic and Arctic.

What We Can Do to Overcome The Global Warming

There are several methods to overcome the global warming. Firstly, we must learn to drive smartly. A well-tuned car with properly inflated tires burns less gasoline, so this cuts pollution and saving us money at the pump. Better yet, skip the drive and take public transit, walk or even cycle if it’s a short journey.

Secondly, we can save the earth at our own backyard by planting trees. Protecting forests is a huge step on the road to curbing global warming. Planting shade trees around our home will not make our landscape much better but it will also help us to absorb carbon dioxide.
Thirdly, we should learn the ‘3R’ methods which is Reduce, Reuse and Recycle. Paper, glass and metal products made from recycled materials saves 70% to 90% of energy and pollution. Recycling a stack of newspapers only four feet high will save a good size tree. Then, we must also do not leave electrical appliances on standby mode. Normally, teenagers like us love to watch television overnight. So once we sleepy we will just press the ‘on or off’ button on the remote control to switch off the television. Actually, a television set that’s switched on for three hours a day and in standby mode for the remaining 21 hours uses about 40% of its energy in standby mode.

Lastly, we must cover the pot when cooking. It is because doing so can save a lot of energy needed for the preparation of a dish. Even pressure cookers and steamers, they can save energy about 70%.

CONCLUSION

After we read about all the things about the global warming, we understand how we affect planet`s health. We know that global warming is majorly cause by greenhouse gases. Greenhouse gases are gases in the atmosphere that absorb and emit radiation within the thermal infrared range such as chlorofluorocarbon (CFC) and many more.The process of the global warming is simple. When visible light from the Sun hits the earth, it passes through the atmosphere, hits the earth, and warms the earth. The earth emits some of this energy back out into space, keeping the planet cool. But the energy we emit is in the infrared, and some of that is absorbed by greenhouse gases in the air instead of going back out into space. When that happens, the air gets warmer - and the planet as a whole gets warmer too.

There are so many causes that can cause global warming. We can divide these causes into two major branches. Natural and Anthropogenic (Man-Made) .The example of natural cause is the release of methane gas that is dangerous to our environment and it is released when bacteria break down organic matter under oxygen-starved conditions usually happen at landfills. The most popular causes that contribute to global warming are man-made causes such as pollution, population, transportation waste, deforestation and many more. All of these causes mostly give off a green house gas called CO2 which is harmful to human being if it is in excess amount.

The effect of global warming upon us is very obvious. One of the effects is the rise in sea level. It is cause by the melting of ice sheets and glaciers, adding water to the oceans. Next are changes in regional climate and agriculture. The number of extremely hot days is likely to increase and the number of extremely cold days is likely to decrease. Droughts will increase in some areas and flood in others. The next effect is change in ecosystems. Rapid, continuous increase in temperature could lead to the extinction of many species and will change the entire ecosystem and maybe this could lead to human extinction too. Human health will be affected by global warming too. If global temperature increase, people living in locations where temperatures are already hot are likely to experience more stress and heat-related health problems than are people living in milder climates. The last effect of global warming we can discuss here is effect on stratospheric ozone layer. Global warming has caused a warming of near-surface air and it has caused a cooling of the stratosphere. The cooling of stratosphere layer will increasing the rates of chemical reaction that produce and destroys ozone layer. There are laws to prevent the global warming from becoming worst from time to time. First is Kyoto Protocol which is their main issue is to fight global warming. The goal of this protocol is to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would minimize dangerous anthropogenic interference with the climate system”. The second law is The Montreal Protocol. It is a landmark of international agreement designed to protect the stratospheric ozone layer. Montreal Protocol stipulates that the production and consumption of compounds that deplete ozone in the stratosphere--chlorofluorocarbons (CFCs), halons, carbon tetrachloride, and methyl chloroform--are to be phased out by 2000 (2005 for methyl chloroform).

Global warming has become global issue. Everything we work in , we work for seem to have impact on the global warming. It has become a cycle of issue and the outcome of this simple cycle is the releasing of greenhouse gases that lead to global warming. It started with the climate change that will create ocean transport carbon. However ocean cannot sustain exceeded amount of carbon so the ocean become acidic. When the evaporation happen on the surface of the ocean, acidic ocean release back carbon dioxide which is one of the greenhouse gases and will contribute to global warming. Global warming has become a very popular topic among scientist to discuss about. Everyone is racing with each other against time to find the most effective way on how to reduce the global warming effect on the earth. Everyone think the earth will finish if no instant action is taken to slow down global warming and bring it back to the normal tempo. Every second passed is very valuable to us to find the way to slow down global warming and we should pray together that all our effort all this while can save the earth from other destruction cause by global warming.


4 comments:

  1. perghhhhhhhhhhhhhhh..
    panjang siot..
    omputih lak tu..
    malas nak bace..
    sekian!
    =.=

    ReplyDelete
  2. sorry beb, assignment aq kene omputeh...
    hehehe.....

    ReplyDelete
  3. Thank you for sharing this information.
    It will really helpful to solve my confusion

    Process $ Chemical Engineering

    ReplyDelete