REFLECTION According to former Vice President of the United States Al Gore, global warming is the observed and projected increases in the average temperature of Earths atmosphere and oceans. It is a complex phenomenon, and its full-scale impacts are hard to predict far in advance. It is bad because in the most likely scenarios, climate change would cause some kind of regional or continental disruption, like a major crop failure; this disruption would cascade through the world’s tightly connected economic and political systems to produce a global effect. It can cause an economically critical region to exhaust its water reserves, forcing people to leave en masse and precipitating a crisis that reverberates through the world economy. Already the severe weather events that have occurred have had major effects on international politics, commodity markets and the stability of various regions. Millions of people have died or been made homeless or lost their livelihoods as a result of these natural disasters.Global warming is caused by many things. The causes are split up into two groups, man-made and natural causes. One natural cause is a release of methane gas from arctic tundra and wetlands. Methane is a greenhouse gas. A greenhouse gas is a gas that traps heat in the earths atmosphere. Another natural cause is that the earth goes through a cycle of climate change. Man-made causes probably do the most damage. Pollution is one of the biggest man-made problems. 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. When you dig up the fossil fuels you dig up the methane as well. 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, and more agriculture. Another source of methane is manure. Another problem with the increasing population is transportation. More people mean more cars and more cars means more pollution. The main cause of global warming is our treatment of nature. There are many evidences that support global warming.The sun is heating the newly open water, so it will take longer to refreeze this winter, and the resulting thinner ice will melt more easily next summer. The effects of global warming are increase of temperature on the earth and rise of sea levels due to thermal expansion of the ocean, in addition to melting of land ice. Amounts and patterns of precipitation are changing, increasing the frequency, duration,and intensity of other extreme weather events, such as floods, droughts, heat waves, and tornadoes.Other effects of global warming include lower agricultural yields, affecting food security and exacerbate malnutrition, further glacial retreat, reduced summer stream flows and species extinctions. As a further effect of global warming,diseases like malaria are returning into areas where they have been extinguished earlier. Climate change is projected to compound the pressures on natural resources and the environment, associated with rapid urbanization, industrialization and economic development.It is more likely that the future of our planet is that global warming will worsen because the carbon dioxide is released to the atmosphere. I look at the presentation as of today, an apparent phenomenon in our planet Earth.The effects of global warming showed in the presentation were true and were not a mere exaggeration. It served as a magnifying glass to what our planet Earth looks like at this particular moment. There is indeed a problem and I can help solve the problem in my own way. I live with the false fantasy that individuals determine the future course of events, not the collective actions of billions of people. We should reduce carbon dioxide emissions. We should put existing technologies for building cleaner cars and more modern electricity generators into widespread use. I can increase my reliance on renewable energy sources such as wind, sun and geothermal. And we can manufacture more efficient appliances and phase out the decades-old, coal-burning power plants that generate most of our electricity and replace them with cleaner plants. Modesty and humility, admiration and respect for all life on Earth instead of arrogance and haughtiness. The ultimate global warming solution is to behave as part of a larger whole. It is impossible to get in perpetual harmony with myself and with the environment if I do not limit my negative footprint to an acceptable level. CONTENT GLOBAL WARMING EXAMPLE: AIR POLLUTION The “Greenhouse Effect” The Earth’s surface thus receives energy from two sources: the sun & the atmosphere – As a result the Earth’s surface is ~33°C warmer than it would be without an atmosphere Greenhouse gases are transparent to shortwave but absorb long wave radiation – Thus the atmosphere stores energy CLIMATE CHANGE Climate change is changing our economy, health and communities in diverse ways. Scientists warn that if we do not aggressively curb climate change now, the results will likely be disastrous. FLASH FLOOD EXAMPLE OF CLIMATE CHANGE El Niño While El Niño is not evidence of climate warming, its increased frequency and intensity might be. The two strongest El Niño events on record were in 1982/83 and 1997/98. And prediction of El Niño would be a powerful test of the complex computer models needed to look at climate patterns more than a few days or weeks ahead. Peruvian fishermen have known the disruptive effects of the Christmas El Niño on anchovy populations for hundreds of years. But they did not know when it was coming until it was too late. And when the 1982/83 El Niño caused an estimated $13 billion of damage world-wide and over 2000 deaths, the international science community found their governments keen to back research. If they could see an El Niño coming six months or a year ahead, farmers could plant crops resistant to drought or to high rainfall, while governments could prepare for severe weather, food and water shortages. Scientists faced some major obstacles - especially a lack of data and an incomplete understanding of what drives world climate. The main problem is one of scale. We can currently model weather disturbances where the elements are fairly large, like land masses and ocean hundreds of kilometres across. But to get down to a resolution of even 50 km needs computing power we do not yet have. Meanwhile, scientists know that even minute cloud particles can influence weather. But to incorporate these in models will need computers over 1000 times more powerful than todays supercomputers. With so many variables, the mathematical models can only be approximations, averaging ocean and atmospheric values over areas about 300 km across. But to obtain even this resolution needs a dense array of observations. INTRODUCTION CLIMATE CHANGE Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as global warming. Climate change is a complex phenomenon, and its full-scale impacts are hard to predict far in advance. But each year scientists learn more about how climate change is affecting the planet and our communities, and most agree that certain consequences are likely to occur if current trends continue. In addition to impacting our water resources, energy supply, transportation, agriculture, and ecosystems, the United States Global Change Research Program concludes that climate change also poses unique challenges to human health, such as: • Significant increases in the risk of illness and death related to extreme heat and heat waves are very likely. • Some diseases transmitted by food, water, and insects are likely to increase. • Certain groups, including children, the elderly, and the poor, are most vulnerable to a range of climate-related health effects. CAUSES OF CLIMATE CHANGE Factors that can shape climate are called climate forcings or forcing mechanisms. These include processes such as variations in solar radiation, variations in the Earths orbit, variations in the albedo or reflectivity of the continents and oceans, mountain-building and continental drift and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond more slowly in reaction to climate forcings, while others respond more quickly. There are also key threshold factors which when exceeded can produce rapid change. Forcing mechanisms can be either internal or external. Internal forcing mechanisms are natural processes within the climate system itself (e.g., the thermohaline circulation). External forcing mechanisms can be either natural (e.g., changes in solar output) or anthropogenic (e.g., increased emissions of greenhouse gases). Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast (e.g., a sudden cooling due to airborne volcanic ash reflecting sunlight), slow (e.g. thermal expansion of warming ocean water), or a combination (e.g., sudden loss of albedo in the arctic ocean as sea ice melts, followed by more gradual thermal expansion of the water). Therefore, the climate system can respond abruptly, but the full response to forcing mechanisms might not be fully developed for centuries or even longer. GLOBAL WARMING What is Global Warming? Global Warming is the increase of Earths average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth. This is a type of greenhouse effect. Is global warming, caused by human activity, even remotely plausible? Earths climate is mostly influenced by the first 6 miles or so of the atmosphere which contains most of the matter making up the atmosphere. This is really a very thin layer if you think about it. In the book The End of Nature, author Bill McKibbin tells of walking three miles to from his cabin in the Adirondacks to buy food. Afterwards, he realized that on this short journey he had traveled a distance equal to that of the layer of the atmosphere where almost all the action of our climate is contained. In fact, if you were to view Earth from space, the principle part of the atmosphere would only be about as thick as the skin on an onion! Realizing this makes it more plausible to suppose that human beings can change the climate. A look at the amount of greenhouse gases we are spewing into the atmosphere (see below), makes it even more plausible. What are the Greenhouse Gases? The most significant greenhouse gas is actually water vapor, not something produced directly by humankind in significant amounts. However, even slight increases in atmospheric levels of carbon dioxide (CO2) can cause a substantial increase in temperature. Why is this? There are two reasons: First, although the concentrations of these gases are not nearly as large as that of oxygen and nitrogen (the main constituents of the atmosphere), neither oxygen or nitrogen are greenhouse gases. This is because neither has more than two atoms per molecule (i.e. their molecular forms are O2 and N2, respectively), and so they lack the internal vibrational modes that molecules with more than two atoms have. Both water and CO2, for example, have these internal vibrational modes, and these vibrational modes can absorb and reradiate infrared radiation, which causes the greenhouse effect. Secondly, CO2 tends to remain in the atmosphere for a very long time (time scales in the hundreds of years). Water vapor, on the other hand, can easily condense or evaporate, depending on local conditions. Water vapor levels therefore tend to adjust quickly to the prevailing conditions, such that the energy flows from the Sun and re-radiation from the Earth achieve a balance. CO2 tends to remain fairly constant and therefore behave as a controlling factor, rather than a reacting factor. More CO2 means that the balance occurs at higher temperatures and water vapor levels. How much have we increased the Atmospheres CO2 Concentration? Human beings have increased the CO2 concentration in the atmosphere by about thirty percent, which is an extremely significant increase, even on inter-glacial timescales. It is believed that human beings are responsible for this because the increase is almost perfectly correlated with increases in fossil fuel combustion, and also due other evidence, such as changes in the ratios of different carbon isotopes in atmospheric CO2 that are consistent with anthropogenic (human caused) emissions. The simple fact is, that under business as usual conditions, well soon reach carbon dioxide concentrations that havent been seen on Earth in the last 50 million years. Combustion of Fossil Fuels, for electricity generation, transportation, and heating, and also the manufacture of cement, all result in the total worldwide emission of about 22 billion tons of carbon dioxide to the atmosphere each year. About a third of this comes from electricity generation, and another third from transportation, and a third from all other sources. This enormous input of CO2 is causing the atmospheric levels of CO2 to rise dramatically. The following graph shows the CO2 levels over the past 160 thousand years (the upper curve, with units indicated on the right hand side of the graph). The current level, and projected increase over the next hundred years if we do not curb emissions, are also shown (the part of the curve which goes way up high, to the right of the current level, is the projected CO2 rise). The projected increase in CO2 is very startling and disturbing. Changes in the Earths average surface temperature are also shown (the lower curve, with units on the left). Note that it parallels the CO2 level curve very well.
Posted on: Tue, 09 Dec 2014 16:01:20 +0000
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