Nowadays, a climate change is the greatest threat to humanity and nature. Changes of climate are happening everywhere. In many parts of the globe, there are the effects of changes of climate: severe storms, melting glaciers, heavy flooding, rising sea levels, severe drought in the south, and reduced snowfall in the north. Recently, the world community has expressed increasing a concern about climate changes of the Earth. The main thing in changes is a rise of the average temperature in the atmosphere and in a surface layer, which may adversely affect both natural ecosystems and human ones. It can be said without an exaggeration that nowadays the problem of global warming assumes the character of one of the most significant problems of survival of mankind. The aim of this work is to study the problem of the climate change on the Earth.
Causes of the Climate Change
One cannot disagree with the fact that the Earth’s climate is changing. It is becoming a global problem for all humanity. The problem of the overall climate change is affirmed by observations of scientists and not questioned by the most of scholars. However, even nowadays, some people are not concerned about this problem. “Global climate change is a major social issue that many citizens do not understand, do not take seriously, and do not consider to be a major public-policy concern” (DiMento and Doughman 1). However, the evidences of the climate change are well known. It is already noticeable without any instruments: increasing the global average temperature (mild winters, hot and dry summer months), melting of glaciers and rising sea level, as well as increasingly emerging and more destructive typhoons and hurricanes, floods in Europe and droughts in Australia.
The climate of the Earth is changing constantly. Everyone knows about the glacial periods. “A mild warming seems to be a part of a natural 1.500-year climate cycle that goes back at least one million years” (Singer and Avery 1). Nowadays, the average temperature on the Earth is about +14°C. It is still quite far from maximum. Scientists are concerned about the fact that to the natural causes of the climate change, another factor – anthropogenic was added. This factor is the outcome of a human activity. According to some researchers, the impact of the anthropogenic factor on the climate change is getting stronger every year (Singer and Avery 1).
The sun is the main driving force of climate. For example, the irregular heating of the earth’s surface is the most probable reason of ocean currents and winds. The periods of the increased solar activity are accompanied by magnetic storms and warming. In addition, the change of the orbit of the Earth, its magnetic field, volcanic eruptions, as well as the size of continents and oceans affect the climate. All these are natural reasons of the climate change. Until recently, only these factors have determined the climate change including the beginning and end of long-term climate cycles, such as the ice ages. The half of temperature changes to 1950 can be explained by the solar and volcanic activity. The volcanic activity leads to decrease of temperature, and solar – to increase. Recently, another factor caused by human activities has been added to natural factors. The main anthropogenic influence is enhanced by the greenhouse effect, which has influenced on the climate change in the last two centuries. It is 8 times higher than the effect of changes of the solar activity.
Concept and Essence of the Greenhouse Effect
Nowadays, many scientists and ordinary people are concerned about the problem of greenhouse effect. Greenhouse effect is a delay of the thermal radiation of the planet in the Earth’s atmosphere. All people have watched the greenhouse effect. In hotbeds or greenhouses, the temperature is always higher than outside. The same one is observed in the scale of the Earth. The solar energy passing through the atmosphere warms the Earth’s surface. However, the heat energy emitted by the Earth cannot evaporate back into space, as the atmosphere of the Earth holds it acting like polyethylene in greenhouse. It admits short light waves from the Sun to the Earth and retains long (or infrared) heat waves emitted by the Earth’s surface. Therefore, the greenhouse effect occurs. This effect occurs due to the presence of gases in the atmosphere, which have the ability to detain long waves. They are called greenhouse or hothouse gases.
“Greenhouse gases are very effective at absorbing thermal radiation expelled from the earth’s surface” (DiMento and Doughman 22). Greenhouse gases were present in the atmosphere in small amounts (about 0.1%) since its formation. This amount was sufficient to maintain the Earth’s heat balance at such a level suitable for life due to the greenhouse effect. It is the natural greenhouse effect. It does threaten neither the Earth nor humanity, since the total amount of greenhouse gases is maintained at the same level due to a cycle of nature. However, the rise of concentrations of greenhouse gases in the atmosphere leads to the enhancement of the greenhouse effect and the disruption of the heat balance on the Earth. It happened in the last two centuries of the development of civilization. Automobile exhausts, coal-fired power plants, and factory smokestacks emit about 20 billion tons of greenhouse gases per year.
The best known and most common greenhouse gases are nitrous oxide (N2O), water vapor (H2O), methane (CH4), and carbon dioxide (CO2). “The greenhouse gases have a profound influence on the Earth’s climate” (Hardy 20). These gases are of a direct action. Most of them are formed during the combustion of fossil fuels. In addition, there are two groups of greenhouse gases of the direct action: halocarbons and sulfur hexafluoride (SF6). Their emissions in the atmosphere are connected with modern technology and process industries (electronics and refrigeration equipment). Their number in the atmosphere is quite small. However, their influence on the greenhouse effect is stronger than CO2.
Water vapor is the most substantial greenhouse gas. It is responsible for more than 50% of the natural greenhouse effect. An anthropogenic increase of its concentration in the atmosphere has not yet mentioned. However, an increase of the Earth temperature caused by other factors increases the evaporation of ocean water. It can lead to the increase of the concentration of water vapor in the atmosphere, and – to the greenhouse effect. On the other hand, clouds in the atmosphere reflect the direct solar light. It reduces the energy input to the Earth and, thus, reduces the greenhouse effect. Carbon dioxide is the most famous one of greenhouse gases. Natural sources of CO2 are volcanic emissions and a vital activity. Anthropogenic sources are the combustion of fossil fuels (including forest fires) and a number of industrial processes (production of cement or glass). According to most researchers, carbon dioxide is primarily responsible for global warming caused by the greenhouse effect (Hardy 11). “During the past 150 years and especially during the past few decades, humans greatly increased the concentration of atmospheric CO2” (Hardy 11). For two centuries of industrialization, the CO2 concentration has increased by more than 30% and is correlated with some changes in the average temperature. Methane is the second most important greenhouse gas. It is allocated due to a leak in the development of deposits of coal and natural gas, from pipelines and biomass burning, on landfills (as a part of the biogas), as well as in agriculture (animal husbandry or rice cultivation). Animal husbandry, coal combustion, and other sources provide about 250 million tons of methane per year. The amount of methane in the atmosphere is small. However, its greenhouse effect or global warming potential is stronger than in CO2.
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Global warming is one more cause of anxiety of the majority of scientists. It is a gradual increase in the average temperature of the Earth caused by rising concentrations of greenhouse gases in the planet’s atmosphere. According to climate observations (the temperature changes over the last two hundred years), the average temperatures on the Earth have increased (Singer and Avery 2). Although, the causes for this increase are still a matter of debates, but one of the most extensively discussed reason is the anthropogenic greenhouse effect. Anthropogenic increase of the concentration of greenhouse gases in the atmosphere disturbs the natural heat balance of the planet, enhances the greenhouse effect, and causes global warming. This process is gradual and slow. Thus, over the past 100 years, the average temperature of the planet has raised by just 1°C. However, it was enough to cause the melting of the polar ice caps and rising sea levels with all the ensuing consequences. Some processes are easier to start than stop. For example, as a result of melting of permafrost in Subarctic, huge amounts of methane enter the atmosphere. It further enhances the greenhouse effect. Desalination of the ocean due to melting ice will change the warm Gulf Stream. It will affect the climate of Europe. Thus, global warming provokes some changes, which, in their turn, accelerate the climate change.
An idea of the significant contribution of humanity to the greenhouse effect (and, hence, global warming) is supported by most governments, scientists, public organizations, and the media. However, it is not yet a definitively established truth. Some people argue that the concentration of methane and carbon dioxide in the atmosphere since pre-industrial period (since 1750) has increased by 34% and 160% respectively. Moreover, it did not reach this level for hundreds of thousands of years. It is obviously due to an increase in fuel consumption and the development of industry. It is also confirmed by the coincidence of the graph of growth in carbon dioxide concentration with a schedule of the temperature rise. Other scientists object that in the surface layer of oceans, there is a larger amount of carbon dioxide than in the atmosphere. Compared to this, the impact of humans is simply negligible. In addition, the ocean has an ability to absorb CO2 and thereby compensate the effects of people. Recently, however, there have been growing evidences in favor of the influence of human activities on global climate changes.
Consequences of Global Warming
Global warming will greatly affect the lives of some animals. For example, polar bears, seals, and penguins will be forced to change their place of residence as the polar ice caps will disappear. Many plant and animal species will also disappear. They will not adapt to a rapidly changing environment. 250 million years ago, global warming killed three quarters of the whole life on the Earth. In the book Unstoppable Global Warming: Every 1.500 Years, authors affirm that “The major effect of global warming will be more biodiversity of in the forests, as more trees, plants, birds and animals extend their rages” (Singer and Avery 16). Global warming will change climate on a global scale. It is expected the growth in the number of climatic disasters, the increasing number of floods due to hurricanes, desertification, and reduction of summer precipitation by 15-20% in the main agricultural areas, raise of the level and temperatures of oceans, and the boundaries of natural areas will move to the north. Moreover, according to some predictions, global warming will cause the onset of the small ice age. In the 19th century, the cause of this cooling was the eruption of volcanoes. In the 21st century, there is another reason desalination of the world’s ocean from melting glaciers (Singer and Avery 3).
The climate on the planet is changing fast enough. Every scientist proves this statement. In recent years, the greenhouse effect problem is becoming more and more acute. Climatic conditions in the world require an urgent action. Some of the consequences of the greenhouse effect that appear today can be a proof of this. Despite various natural warnings, humanity does not take measures to reduce emissions. If people continue to behave so irresponsibly towards the planet, it is not known, which disasters can be in future.