GLOBAL WARMING

ABSTRACT

 Global Warming is caused by an increase in the greenhouse effect. The greenhouse effect is not a bad thing by itself -- it's what allows Earth to stay warm enough for life to survive.Global warming is the observed increase in the average temprature of the Earth’s Atmosphere and oceans in recent decades. The Earth's average near-surface atmospheric temperature rose 0.6 ± 0.2 °celsius or1.1 ± 0.4 °Fahrenheit in the 20th century. The current scientific consensus is that "most of the observed warming over the last 50 years is likely to have been due to human activity.

The primary causes of the human-induced component of warming are the increased amounts of carbon dioxide(CO₂) and other greenhouse gases(GHGs) They are released by the burning of coventional fuels, land clearing and aersols, etc. and lead to an increase in the greenhouse effect.The term "global warming" is a specific case of the more general term "climate change" (which can also refer to "global cooling," such as occurs during ice age). In principle, "global warming" is neutral as to the causes, but in common usage, "global warming" generally implies a human influence. However, the UNFCCC (United nations framework convention on climate change) uses "climate change" for human-caused change, and "climate variability" for other changes. Some organizations use the term "anthropogenic climate change" for human-induced changes.

1: INTRODUCTION

Increase in levels of Co2 during the last 400,000 years and the rapid rise by which it has almost trippled since the Industrial Revolution has contibuted to global warming. The climate system varies both through natural, "internal" processes as well as in response to variations in external "forcing" from both human and non-human causes, including activity such as,volcanic emissions, and greenhouse gases. Climatologists agree that the earth has warmed recently. The detailed cause of this change remains an active field of research, but the scientific consensus identifies greenhouse gases as the primary cause of the recent warming. Outside of the scientific community, however, this conclusion can be controversial. Adding CO₂ or Methane(CH₄) to Earth's atmosphere, with no other changes, will make the planet's surface warmer; greenhouse gases create a natural greenhouse effect without which temperatures on Earth would be an estimated 30 °C (54 °F) lower, and the Earth uninhabitable.Another important feedback process is ice-albedo feedback. The increased CO₂ in the atmosphere warms the Earth's surface and leads to melting of ice near the poles. As the ice melts, land or open water takes its place. Both land and open water are less reflective than ice, and so absorb more solar radiation. This causes more warming, which in turn causes more melting, and the cycle continues. Climate studies indicate that, even if greenhouse gases were mitigated at present day levels, a further warming of perhaps 0.5 °C to 1.0 °C (0.9–1.8 °F) would still occur.due to the thermal inertia of earths oceans and slow response of indirect effects which  is caused due to the earths climate not being in equilibrium.

DIAGRAM 1. GREENHOUSE EFFECT

1.1: GREENHOUSE GASES  

Greenhouse gases are transparent to shortwave radiation from the sun, the main source of heat on the Earth. However, they absorb some of the longer infared radiaton emitted by the Earth, thereby reducing radiational cooling and hence raising the temperature of the Earth. How much they warm the world by is shown in their global warming potiential. About three-quarters of the anthropogenic (man-made) emissions of carbon dioxide to the atmosphere during the past 20 years are due to fossil fuel burning. The rest of the anthropogenic emissions are predominantly due to land-use change, especially deforestation which has led to the increase of co2.

1.2:  RELATION BETWEEN GLOBALWARMING & OZONE LAYER

1)The same carbon dioxide radiative forcing that produces near-surface global warming is expected  to cool the stratosphere. This, would lead to a relative increase in ozone depletion and the frequency of ozone holes.

2) Conversely, ozone depletion represents a radiative forcing of the climate system. the IPCC concludes that observed stratospheric o3 losses over the past two decades have caused a negative forcing of the surface-troposphere system  of about −0.15 ± 0.10 W/m²

3) Decreased ozone leads to an increase in ultraviolet levels. Ultraviolet radiation may be responsible for the death of ocean algae, which operate as a carbon dioxide sink in the ocean. Increased UV, therefore, may lead to a decrease in carbon dioxide uptake, thereby raising global carbon dioxide levels

2: EFFECTS OF GLOBAL      WARMING

1)       Effects on ecosystems : Both primary and secondary effects of global warming  such as higher temperatures, lessened snow cover, rising sea levels and weather changes  may influence not only human activities, but also ecosystems. Some species may be forced out of their habitats(possibly to extension) because of changing conditions, changes in timing of life patterns, such as annual migration dates, may alter regional preaditor prey balance. The effect of advanced spring arrival dates in scandinavia on birds that over winter in sub-Saharan Africa has been ascribed to evolutionary adaptation of the species to climatic warming. Ocean PH is lowering as a result of increased carbon dioxide levels. Lowering of ocean pH, along with changing water temperature and ocean depth will have a damaging effect on coral reefs.

2)       Effect on glaciers: Global warming has led to negative glacier mass balance causing glacier retreat around the world Of particular concern is the potential for failure of the Hindu Kush and Himalayan glacial melts. The melt of these glaciers is a large and reliable source of water for China, India and much of Asia and these waters form a principal dry-season water source. Increased melting would cause greater flow for several decades, after which "some areas of the most populated region on Earth are likely to 'run out of water'.

3)       Sea level rise and environmental refugees : Rising global temperatures will melt glaciers and expand the water of the seas through the mechanism of thermal expansion leading to sea level rise. Even a relatively small rise in sea level would make some densely settled coastal plains uninhabitable and create a significant refugee problem. If the sea level were to rise in excess of 4 meters almost every coastal city in the world would be severely affected, with the potential for major damage to world-wide trade and economy. global warming during that time may lead to irreversible changes in the Earth's glacial system and causesignificant rise in sea level. It is estimated that around 200 million people could be affected by sea level rise, especially in south-asia.

4)       Spread of disease:             Global warming may extend the range of vectors conveying infectious diseases such as maleria. A warmer environment boosts the reproduction rate of mosquitoes and the number of blood meals they take, prolongs their breeding season, and shortens the maturation period for the microbes they disperse Global warming has been implicated in the recent spread to the north mediteranian region theblue tounge dsease in sheep associated with mite bites . Hanta virius infection , crimerian-congo hemorragic fever, tularameia and rabies increased in wide areas of Russia.

5)       Financial cost: Financial institutions, including the world's two largest insurance companies, Munich Re and Swiss Re warned in a 2002 study that "the increasing frequency of severe climatic events, coupled with social trends" could cost almost US$150 billion each year in the next decade. These costs would, through increased costs related to insurance and disaster relief, burden customers, taxpayers, and industry alike. one percent of global GDP is required to be invested in order to mitigate the effects of climate change, and that failure to do so could risk a Recession worth up to twenty percent of global GDP.

3:MITIGATION

The likelihood that global temperatures will continue to significantly increase has led to proposals to mitigate global warming. Mitigation covers all actions aimed at reducing the negative effects or the likelihood of global warming.

There are five categories of actions that can be taken to mitigate global warming.

1. Conservation of energy use
2. Shifting from carbon-based conventional fules to renewable resources
3. capture and storage of carbon
4. carbon sequenceration
5. Planetrary engineering to cool the earth, including screen out sunlight or increasing ice-albedeo ratio.

The world's primary international agreement on combating climate change is the The Kyoto Protocol which  is an amendment to the UNFCCC (United nations framework convention on climate change). Countries that ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emission trading if they maintain or increase emissions of these gases.

Strategies for mitigation of global warming include development of new technologies, carbon offsets; Renewable energy such as Biodesiel, Wind power, and Solar power Electric power, Nuclear power, Hybrid, Fuel cell, pollution control ,Carbon Sinks; Carbon taxes and Carbon Capture and storage. Many environmental groups encourage individual action against global warming often aimed at the consumer, and there has been bussiness action on climate.

 DIAGRAM 2: WIND ENERGY

 DIAGRAM 3  PREDICTION OF MELTING OF POLAR ICE CAPS IN 50 YEARS

4:CONCLUSION

1) By reducing pollution from vehicles and power plants. We should put existing technologies for building cleaner cars and more modern electricity generators into widespread use. We can increase our reliance on renewable energy sources such as wind, sun and geothermal. And we can manufacture more efficient appliances and conserve energy, these technologies exist, the corporate and political will to put them into widespread use does not. Many companies in the automobile and energy industries put pressure on the Goverment to halt or delay new laws or regulations -- or even to stop enforcing existing rules -- that would drive such changes.

2) OUR CONTRTIBUTION TO MIGITATE GLOBAL WARMING

1. using compact fluorescent light bulb over an incandescent bulb, for example, you'll lower your energy bill and keep nearly 700 pounds of carbon dioxide out of the air over the bulb's lifetime.
2. reducing the use of  vehicles for short run.
3. educating people about global warming.
4. using more eco friendly refrigerants
5. banning the use of thermerform plastics.
6. saving power by switing of lights and switchs when not in use.
7. recycling waste products

3) NEED FOR MITIGATION

1)       earth can satisfy our needs but not our greed so please we must use our resources carefully and sensibilly.

2)       Unlike nations natural calamities and climate change know  no borders

3)       The clock is ticking  and the time to act is now or  face our doom tomorrow.

       4) We must understand that for our actions (explotation of  our planets resources) we are the only people answerable to nature and it’s course of actions.