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In my seminar work I will try to explain you what is happening to global climate, which are the consequences and what can we do to stop changing our climate. Humans are heating the planet. Official confirmation for that came in 1995, when the Inter-Governmental Panel on Climate Change (IPCC) the official scientific body established in 1988 by the UN to investigate climate change - published its Second Assessment Report, written and reviewed by some 2 000 scientists. A consensus now undeniably exists that human-induced climate change is real and has to be tackled. Governments and scientists alike have agreed that the problem is real, and serious. At the climate summit in Kyoto in late 1997, industrialized countries agreed, at least on paper, to reduce the amount of carbon dioxide and other greenhouse gases they pump into the atmosphere.
Greenpeace has identified global climate change as one of the greatest threats to the planet. 2. HOW AND WHY IS OUR CLIMATE CHANGING Energy from the sun drives the earths weather and climate, and heats the earths surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse. Without this natural greenhouse effect, temperatures would be 33 C lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earths average temperature is a more hospitable.
However, problems may arise when the atmospheric concentration of greenhouse gases increases. Since the beginning of the industrial revolution, atmospheric concentrations of carbon dioxide have increased nearly 30 %, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15 %. These increases have enhanced the heat-trapping capability of the earths atmosphere. Sulfate aerosols, a common air pollutant, cool the atmosphere by reflecting light back into space; however, sulfates are short-lived in the atmosphere and vary regionally. Why are greenhouse gas concentrations increasing? Scientists generally believe that the burning of fossil fuels, destruction of natural forests and other human activities are the primary reason for the increased concentration of carbon dioxide.
Plant respiration and the decomposition of organic matter release more than 10 times the CO 2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans. What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98 % of carbon dioxide emissions, 24 % of methane emissions, and 18 % of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions. In 1997, the United States emitted about one-fifth of total global greenhouse gases, but Slovenia is not far away if we look proportional on expanse ofcourse. Estimating future emissions is difficult, because it depends on demographic, economic, technological, policy, and institutional developments.
Several emissions scenarios have been developed based on differing projections of these underlying factors. For example, by 2100, in the absence of emissions control policies, carbon dioxide concentrations are projected to be 30 - 150 % higher than todays levels. Global mean surface temperatures have increased 0. 45 - 0. 6 C since the late 19 th century. The 20 th century's 10 warmest years all occurred in the last 15 years of the century. Of these, 1998 was the warmest year on record. The snow cover in the Northern Hemisphere and floating ice in the Arctic Ocean have decreased.
Globally, sea level has risen 15 - 20 cm over the past century. Worldwide precipitation over land has increased by about one percent. The frequency of extreme rainfall events has increased throughout much of the World. Trends Data on a wide variety of environmental indicators are consistent with the consequences that scientists generally expect to result from increasing concentrations of greenhouse gases. - Temperature Global temperatures are rising. Observations collected over the last century suggest that the average land surface temperature has risen 0. 45 - 0. 6 C in the last century. - Precipitation Precipitation has increased by about 1 percent over the world's continents in the last century. High latitude areas are tending to see more significant increases in rainfall, while precipitation has actually declined in many tropical areas. - Sea Level Sea level has risen worldwide approximately 15 - 20 cm in the last century.
Approximately 2 - 5 cm of the rise has resulted from the melting of mountain glaciers. Another 2 - 7 cm has resulted from the expansion of ocean water that resulted from warmer ocean temperatures. Emissions Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through changing agricultural and industrial practices. Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere. What Are Greenhouse Gases?
Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases: Carbon dioxide is released to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), and wood and wood products are burned. It is the most important greenhouse gas apart from water vapour. Carbon dioxide concentrations has increased more than 30 per cent from 280 ppm (parts per million by volume) in the pre-industrial era to 365 ppm by the late 1990 s.
The current rate of increase is around 1. 5 ppm per year. Unfortunately, a large proportion of the carbon dioxide we put into the atmosphere remains there, warming the planet, for around 200 years. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. An a weight-per-weight basis it is some 20 times more powerful as greenhouse gas than carbon dioxide. Methane has more than doubled its concentration, from 700 to 1720 parts per billion, by volume, (prev), primary because of deforestation and the growth in rice and cattle production.
Natural gas leaks are another source. Methane's residence time in the atmosphere is relatively short approximately 12 years. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels. It is associated with modern agriculture and the heavy application of chemical fertilisers. The concentration of nitrous oxide has increased from preindustrial levels of 275 prev to 310, with a current annual growth rate of 0. 25 per cent. On a weight-per-weight basis it is more than 200 times more powerful as a greenhouse gas compared with carbon dioxide.
Its residence in the atmosphere is around 120 years. Very powerful greenhouse gases that are not naturally occurring include chlorofluorocarbons, CFC 11 and CFC 12, both with growth rates of 4 per cent per year during the past decade, have now reached levels of 280 parts per trillion by volume (put) and 484 put respectively. They have a greenhouse gas potential that is many thousands of times greater than carbon dioxide on a weight-per weight basis, and they remain in the atmosphere from several thousands years. They (CFC 11 and CFC 12) are generated in a variety of industrial processes. Each greenhouse gas differs in its ability to absorb heat in the atmosphere. CFCs are the most heat-absorbent.
Methane traps over 21 times more heat per molecule than carbon dioxide, and nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. When we take the residence time in the atmosphere of the different gases and their specific effectiveness as greenhouse gases into account, carbon dioxides contribution is some 55 per cent of the whole, compared with 17 per cent for the two CFcs and 15 per cent for methane. Other CFCs and nitrous oxide account for 8 and 5 per cent respectively of changes in radioactive forcing. The relationship between greenhouse gases and climate that has now been established is supported by evidence from isotopic studies of ice-core material from both Antarctica and Greenland. The evidence shows that every period of global cooling has gone hand-in-hand with a drop in both carbon dioxide and methane in the atmosphere, and every time the planet has thawed, a surge has taken place in those same gases. 3. CONSEQUENCES Rising temperatures are already the clearest sign of climate change.
So far global average temperatures have risen 0. 6 C above the pre-industrial average. If emissions continued to rise on current trends, greenhouse gas concentrations would reach double pre-industrial level higher than for several million years by 2080. Where this so, we would see a global average increase of 2. 5 C, with perhaps 4 C over land masses. If the increase in temperature seem modest, it should be noted that 3 C cooling brought on the most recent ice age.
The implications for life are immense. With higher temperatures, there is more energy driving the Earths climatic systems, which in turn causes more violent weather events. Severe storms. Floods, droughts, dust storms, sea surges, crumbling coastlines, salt water intrusion of groundwater, failing crops, dying forests, the inundation of low-lying islands, and the spread of endemic diseases such as malaria, dengue fever Agriculture worldwide would face severe disruption and economies could tumble. There would be also millions upon millions of environmental refugees people fleeing from the intruding sea, or equally from the deserts they have left in their wake after stripping the land of its vegetation. Most of the World is expected to warm.
Scientists currently are unable to determine which parts of the World will become wetter or drier, but there is likely to be an overall trend toward increased precipitation and evaporation, more intense rainstorms, and drier soils. Unfortunately, many of the potentially most important impacts depend upon whether rainfall increases or decreases, which can not be reliably projected for specific areas. 4. WHAT CAN I / WE DO TO STOP CHANGING OUR CLIMATE What difference can I make? When faced with this question, individuals should recognize that collectively they can make a difference. Think back to the days before recycling became popular when everyone threw everything out in the trash. In less than 20 years, most households have gone from recycling little to nothing to recycling newspapers, plastics, glass and metal.
Many businesses recycle paper and buy recycled products and many industries practice source reduction. An entire mindset has changed in one generation! Taking action on global warming (or climate change) is similar. In some cases, it only takes a little change in lifestyle and behavior to make some big changes in greenhouse gas reductions.
For other types of actions, the changes are more significant. When that action is multiplied by the 6 billion people worldwide, the savings are significant. "Individuals Can Make A Difference" identifies actions that many households can take that reduce greenhouse gas emissions in addition to other benefits, including saving you money! The actions range from changes in the house, in the yard, in the car, and in the store. Everyone's contribution counts so why don't you do your share? 5. CONCLUSION The world has a choice. Either we can all continue to waste energy and resources.
Global warming will accelerate. Our environment will worsen. People's health, prosperity, peace and security will be threatened. We will all suffer. Or we can all work with one another to have a better environment. By addressing social, economic and environmental issues together, we can help our world to develop in a sustainable way.
Our environment will be healthier. We will have a better quality of life. We will all benefit.
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