The climate is changing. The earth is warming up, and there is now overwhelming scientific consensus that it is happening, and human-induced. With global warming on the increase and species and their habitats on the decrease, chances for ecosystems to adapt naturally are diminishing. Many are agreed that climate change may be one of the greatest threats facing the planet.
Recent years show increasing temperatures in various regions, and/or increasing extremities in weather patterns. The subjects of “global warming” and “climate change” have become parts of both the popular dictionary and the public discourse.Discussions of global warming often induce responses and debates between believers to different views of the threat posed. Yet there are many degree regarding global warming, climate change, and the threats they represent that are not well understood by the public.
The public’s conceptual understanding relies largely on images and paradigms within the underlying scientific concepts. To appreciate the potential threat that climate change and global warming represent to human society, living things, and our environment, it is necessary that we first understand the true science underlying these phenomena.The purpose of this report is to review the implications of climate change for the welfare of human society and our environment. First to discuss is the science underlying global warming, climate change, and the connections between these two phenomena. Next, the various variations considering climate change and global warming will be talked about. Then the report explores what climate changes are projected for the future under various possible scenarios of future human behavior, and what impacts these changes are likely to have on society, ecosystems, and our environment.
Finally, opinions and conclusions will be given.Discussion I. Scientific Background 1Many people in the media and elsewhere use the terms "climate change" and "global warming" interchangeably, as if they were the same thing. But there are differences between the meanings of the two terms. Getting a better handle on the definitions of and differences between "global warming" and "climate change" will help us understand why the threat caused by continued warming of the planet is so serious. The meaning of climate change is fairly straightforward—a clear, sustained change in the components of climate, such as temperature, precipitation, atmospheric pressure, or winds.
Such changes must constitute a clear trend, and be clearly distinguished from the small random variation in these parameters that takes place all the time. Climate may change in a single region or across the whole planet. These changes can be brought about by a variety of factors such as natural external factors, natural internal processes of the climate, or human-induced (anthropogenic) factors. These causes will be further discussed in the preceding section. Global warming on the other hand refers to an increase in the average temperature at the surface of the earth, or the lower part of the atmosphere.
Most climatologists consider that the global warming experiencing by the most is mainly the result of human actions changing the composition of the atmosphere. However, global warming and cooling have occurred naturally throughout the history of the earth, as a result of natural climate variability. Such changes in the past were usually much slower than the rate of warming that has occurred in the last few decades. A.
Energy Balance 2The Earth receives energy solely from the Sun, in the form of light and ultraviolet (UV) radiation, and releases energy back to space, in the form of infrared heat.The Earth's climate is determined by the "Earth's stored Energy" which is the difference in the amount of energy received from the Sun and the amount the Earth releases back to Space. That is: Earth’s “stored” Energy = Energy from Sun – Energy released to space (The Global Energy Balance) Any process or activity that influences this global energy balance either by increasing or decreasing the "Earth’s stored Energy" contributes to climate change and is qualified to be called a "climate forcing process". 3Climate Changes are caused by several climate forcing processes.
Climate forcing processes could be internal and/or external. Internal processes are processes operating on the global energy balance from within the Earth, while external processes operate from outside planet Earth. These two processes and how they contribute to climate change are discussed below: B. The External Climate Forcing Process 1.
Variations in the amount of energy received from the Sun About 30-40% of the UV energy from the Sun is believed to be reflected back into space after hitting Earth's upper atmosphere, while the remaining 60-70% gets through to the Earth.This ratio could change however, due to variations in Sun’s characteristics from time to time, thus leading to changes to the global energy balance above and hence changes in our climate 2. Variations in the Earth’s orbit around the Sun Changes in the tilt of the Earth’s axis, changes in the shape of Earth's orbit (i. e.
eccentricity) and the shifting of the equinoxes (i. e. precession) play major roles in determining variations in the amount of Sun’s energy reaching the Earth and hence lead to variations in the Earth’s climate.C. The Internal Climate Forcing Process 1.
The Oceans Oceans cover up to 70% of the Earth. They are the key source of moisture in the air through interactions with the atmosphere and also storage of heat efficiently, transporting it to thousands of miles thus redistributing heat in time and space. The oceans and marine life consume huge amounts of carbon dioxide which exert tremendous influence on global climate and accounts for the variations. 2. Continental Drift The surface of our earth is mostly (3/4 th) covered by water.Our current day earth is made up of 7 continents (Australia, North America, South America, Asia, Africa, Europe and Antarctica) - big landmasses separated apart by oceans.
A close look at the shape of the earth, one will think that the continents look like the pieces of a jig-saw puzzle that fits into a solid mass when brought together. Actually, scientists believe that several millions of years ago, the whole earth consisted of 1 big continent surrounded by a big ocean. Over time, it is believed that the big landmass (earth) slowly broke up and takes the current form it has today.Scientists’ proofs for this theory are: similarity between plant and animal fossils and broad belts of rocks found on the eastern coastline of South America and western coastline of Africa, which are now widely separated by the Atlantic Ocean.
The discovery of fossils of tropical plants (in the form of coal deposits) in Antarctica has led to the conclusion that this frozen land at some time in the past, must have been situated closer to the equator, where the climate was tropical, with swamps and plenty of lush vegetation. Scientists consider that the earth is still slowly drifting and constantly changing.This constant drifting is believed to have impact on the climate because it changes the physical features of the landmass, their position and the position of water bodies. The separation of the landmasses changed the flow of ocean currents and winds, which affects the climate. 3. The Atmosphere The atmosphere stores a lot of heat or energy which comes from the Sun.
This energy regulates the Earth's climate.Furthermore, the atmosphere composes of small particles and several gases such as oxygen, nitrogen, carbon dioxide. Some of the gases (e. g. arbon dioxide vapor, carbon dioxide, methane and nitrous oxide) are known to trap heat in the atmosphere thus increasing the net “energy” stored and contributing to Earth warming.
The later forms of gases are referred to as “greenhouse gases (GHG)”. The Earth climate is also affected by the particles in the atmosphere which tend to block sunlight reaching the Earth. 4. Water Cycle, Clouds, Ice and Snow Higher air temperatures can increase water evaporation and melting of ice. And while water vapor is the most potent greenhouse gas, clouds also affect evaporation, creating a cooling effect.
Clouds reflect solar energy which cools the Earth and thereby trapping heat being radiated up from the surface hence warms the Earth. Clouds variability contribute to climate change. The whiteness of ice and snow reflects heat out, cooling the planet. When ice melts into the sea, this drives heat from the ocean causing variability in climate. 5. Land Surfaces Mountain ranges can block clouds, creating "dry" shadows downwind.
Sloping land allows more water runoff, leaving the land and air drier. A tropical forest will soak up carbon dioxide, but once cleared for cattle ranching, the same land becomes a source of methane, a greenhouse gas. . Volcanic Eruptions A volcanic eruption, lasting for few days, emits large volumes of sulphur dioxide (SO2), water vapor, dust, and ash into the atmosphere that influence climatic patterns for years. The gases and dust particles partially block the incoming rays of the sun, leading to cooling.
D. Human-induced (Anthropogenic) factors Human industrial activities are believed to be adding to the amount of "greenhouse gases" naturally present in the atmosphere. These gases trap heat that is otherwise supposed to be lost to the space from the Earth and consequently warm up the Earth.Human activities in the Industry and the agricultural sectors are believed to be responsible for the increasing quantities of carbon dioxide, methane and other greenhouse gases in the atmosphere.
E. The Green House Effect vs. The Human Green House Effect 4If the only considerations determining the Earth’s surface temperature were those described above, the Earth would be a frozen (and likely lifeless) planet. There is an additional factor, the so-called greenhouse effect, which leads to a warming of the lower atmosphere. The existence of the greenhouse effect is not controversial; in fact, without it, the Earth likely would not be habitable.Trace gases with certain chemical properties (the so-called greenhouse gases) absorb some of the infrared radiation produced by the Earth’s surface.
Due to this absorption, some fraction of the original 70 units does not directly escape to space, but is instead absorbed by these gases. Because greenhouse gases emit the same amount of radiation they have absorbed, but equally in all directions (i. e. , as much downward as upward), the net effect of absorption by greenhouse gases is to increase the total amount of radiation downward toward the Earth's surface and lower atmosphere.
To maintain equilibrium, the Earth must therefore emit more than the original 70 units of radiation, which in turn means that surface temperature must increase. This is the atmospheric greenhouse effect. The analogy with how a true greenhouse works is loose—the precise processes involved are actually different. However, the end effect is similar. The presence of greenhouse gases leads to a warming of the Earth’s lower atmosphere. The Earth’s surface temperature is about 60°F warmer (60°F) than it would otherwise be (0°F).
It is essential to distinguish the human greenhouse effect from the natural greenhouse effect described above.The natural greenhouse effect results from the natural presence of greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the atmosphere. Their presence in our atmosphere is a result of the balance between natural biological and geochemical processes which maintain modest background levels of these gases in our atmosphere. In addition to these background greenhouse gas concentrations, human beings have been increasing greenhouse gas concentrations, principally in the form of carbon dioxide and methane, through industrial activity, primarily in the form of fossil fuel burning and agriculture, respectively.It is this enhanced or human greenhouse effect which is primarily responsible for human-caused (anthropogenic) climate change.
II. Causes of Global Warming to the Environment and Society 5One of the biggest issues facing us right now is global warming. Its effects on animals and on agriculture are indeed frightening, and the effects on the human population are even scarier. The facts about global warming are often debated in politics and the media, but, unfortunately, even if we disagree about the causes, global warming effects are real, global, and measurable.
The causes are mainly from us, the human race, and the effects on us will be severe. Carbon dioxide emissions from fossil fuel burning power plants. Our ever increasing addiction to electricity from coal burning power plants releases enormous amounts of carbon dioxide into the atmosphere. 40% of U. S. CO2 emissions come from electricity production, and burning coal accounts for 93% of emissions from the electric utility industry.
Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal and commercial electrical supply.Carbon dioxide emissions from burning gasoline for transportation. Our modern car culture and appetite for globally sourced goods is responsible for about 33% of emissions in the U. S.
[EPA pg. 8] With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing. Our consumption is outpacing our discoveries of ways to mitigate the effects, with no end in sight to our massive consumer culture. Methane emissions from animals, agriculture such as rice paddies, and from Arctic sea beds.
Methane is another extremely potent greenhouse gas, ranking right behind CO2. When organic matter is broken down by bacteria under oxygen-starved conditions (anaerobic decomposition) as in rice paddies, methane is produced. The process also takes place in the intestines of herbivorous animals, and with the increase in the amount of concentrated livestock production, the levels of methane released into the atmosphere is increasing. Another source of methane is methane clathrate, a compound containing large amounts of methane trapped in the crystal structure of ice.As methane escapes from the Arctic seabed, the rate of global warming will increase significantly. Deforestation, especially tropical forests for wood, pulp, and farmland.
The use of forests for fuel (both wood and for charcoal) is one cause of deforestation, but in the first world, our appetite for wood and paper products, our consumption of livestock grazed on former forest land, and the use of tropical forest lands for commodities like palm oil plantations contributes to the mass deforestation of our world.Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts of carbon, as well as reducing the amount of carbon capture on the planet. Increase in usage of chemical fertilizers on croplands. In the last half of the 20th century, the use of chemical fertilizers (as opposed to the historical use of animal manure) has risen dramatically.
The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide) and the run-off of excess fertilizers creates ‘dead-zones’ in our oceans. In addition to these effects, high nitrate levels in groundwater due to over-fertilization are cause for concern for human health. Increase in population. More people mean more need of industry, agriculture, and transportation. That indicates more methane and carbon dioxide is produced.
