The term ‘Global Warming’ in simple terms refers to the phenomenon of the planet earth heating up, and fast. The term is used to refer to the increase in the average temperature of global surface air and oceans since about 1950, and to continuing increases in those temperatures. Global warming is a significant increase in the Earth’s climatic temperature over a relatively short period of time as a result of the activities of humans. In specific terms, an increase of 1 or more degrees Celsius in a period of one hundred to two hundred years would be considered global warming. Over the course of a single century, an increase of even 0.4 degrees Celsius would be significant.”
Global warming is one of the most important issues of modern times and if not taken seriously, it is all set to annihilate all life forms from the surface of the earth. Global warming definition may look very simple but the phenomenon has started taking its toll, as the climatic conditions all over the earth are changing very rapidly. As per NASA, “the global average surface temperature rose 0.6 to 0.9 degrees Celsius (1.1 to 1.6° F) between 1906 and 2005, and the rate of temperature increase has nearly doubled in the last 50 years. Temperatures are certain to go up further.” It seems that the temperature is rising at a rate faster than ever before. Human activities like burning of fossil fuels, deforestation, industrialization and increase in pollution are considered as few of the factors responsible for rise in global warming.
Global warming is the increase of earth’s average surface temperature and its oceans due to greenhouse gases released as people burn fossil fuels. These greenhouse gases such as carbon dioxide and methane absorb heat that would otherwise bounce off the Earth’s surface. Global warming has emerged as one of the biggest environmental issues in the last two decades. Greenhouse gases, being lighter than air, naturally rise up the outer limits of the earth’s atmosphere and then settle there, creating an impenetrable barrier that traps heat from being able to escape into space and warming the temperature.
Scientists often use the term "climate change" instead of global warming. This is because as the Earth's average temperature climbs, winds and ocean currents move heat around the globe in ways that can cool some areas, warm others, and change the amount of rain and snow falling. As a result, the climate changes differently in different areas.
Global warming can have many different causes, but it is most commonly associated with human interference, specifically the release of excessive amounts of greenhouse gases. Gases, such as carbon dioxide (CO2), methane (CH4), water vapour, and fluorinated gases, act like a greenhouse gases around the earth. This means that they allow the heat to come from the Sun into the atmosphere, but do not allow the heat to escape back into space. The more the greenhouse gases, the larger the percentage of heat that is trapped inside the earth’s atmosphere.
The earth could not exist in its present state (that is, with life) without the presence of some naturally occurring greenhouse gases, such as carbon dioxide, methane and water vapour. Without any greenhouse gases no heat would be trapped in atmosphere, so the earth would be extremely cold. Naturally occurring greenhouse gases (non-fluorinated gases) are good in naturally occurring amounts; it’s when people start contributing excessive amounts of them that greenhouse gases become a problem. With excessive greenhouse gas buildup, the earth’s atmosphere warms to unnatural temperatures which causes, sea surface temperatures to rise, precipitation patterns to change etc.
The root cause of global warming is the emission of carbon dioxide due to burning of fossil fuels. The main culprits are for this the power plants that burn coal to produce electricity and in the process emit huge amounts of carbon dioxide. This carbon dioxide envelops earth and does not allow heat of the sun to escape into the atmosphere, giving rise to the temperature.
Origin of Global Warming:
Global warming is the process, which started long and long ago, in the times much earlier before human’s devised international treaties and even much earlier before we learned to burn first fossil fuel, which was wood. It was about the second half of the 20th century, when the global warming had become a talk of the town. In year 1997, the problem of global warming, or to be more exact, the problem of human contribution into this natural phenomenon, was addressed officially, when the world’s largest industrialized countries agreed to reduce greenhouse gases emissions as the effort to stop the rapid progression of the global warming.
Carbon dioxide is not the only Greenhouse Gas. While carbon dioxide may be primary greenhouse gas, methane actually is 20 times more effective at trapping heat in the Earth’s atmosphere. Emissions of methane released into our atmosphere have risen 145% in the last 100 years. Methane naturally occurs as part of the biological processes behind everything from bovine flatulence to the organic bacteria and sulfur’s commonly found in bogs, springs and wells. Methane is a natural form of gas that is released in rice paddies as well as the composting and decomposition of organic matter. However, methane gas is also released during the processing and preparation of fossil fuels.
Water vapour is responsible for two-third of the heat currently trapped in the Earth’s atmosphere by all greenhouse gases. The hotter the atmosphere gets, the higher the level of “relative humidity” which holds the heat in even better.
Nitrous oxide is another Greenhouse Gas. It is a colourless, non-flammable gas with a slightly sweet odour. Most commonly known as “laughing gas”, it is used as a medical anesthetic. Nitrous oxide is naturally produced by oceans and rainforests. Nitrous oxide is naturally broken down in the atmosphere through chemical reactions that occur with sunlight. Some of the most prevalent “man-made” sources of nitrous oxide are agriculture fertilizers, nylon, catalytic converters and nitric acid, along with the burning of organic matter.
Causes of Global Warming:
Over the past century, our planet has slowly been warming up. Since the beginning of the 20th century, the average temperature around the world has gradually risen by one degree fahrenheit. Though this minimal warming might not seem so significant, but the over-all impact will most certainly prove to the devastating if this continual warming process is not somehow abated.
The issue of global warming is most often blamed on human beings’ ecologically irresponsible practices and technologies. In fact, global warming is quite a complex phenomena brought about not only by us but also by nature itself. In fact, mankind and technology actually aren’t the only significant causes of global warming. There are actually a wide variety of natural causes, ranging from volcanic eruptions, solar radiation and natural thawing of the Earths “permafrost” and glaciers.
In other words, the planet’s temperature, just like most other things in life and natural science, simply tends to fluctuate through natural, rhythmic, “ebbs and flows” and highs and lows that are caused and by sources within the planet itself, as well as the vacillating environment of the solar system and universe. Several “man-made” causes also play a significant role in global warming trend.
Natural Causes of Global Warming:
(i) Forest Fires:
Among the most common and most significant contributors to global warming is deforestation caused by forest fires. Fires are natural occurrences in many forests as it is nature’s way to clear to up old growth to encourage new ones.The fires also cause much carbon-filled smoke to rise from the forests to the atmosphere. Both results have dramatic effects on the rate at which global warming is currently occurring.
Oceans are also significant contributors to global warming as it naturally contains much polluting carbon due to the ecosystems they support. The top layers of oceans contain more pollution than the Earth’s atmosphere and much of that pollution rises.
(iii) The north and south poles:
Both the North and South poles also contribute a lot to global warming. It is in those areas where permafrost contains large amounts of carbon that have frozen over time.
Man Made Causes of Global Warming:
(i) Power plants:
Nearly 40% of our carbon dioxide emissions come directly from the process of burning “fossil fuels” in order to generate electricity. Of that almost 40% of our carbon dioxide emissions directly attributed to generating power, over 90% of it come from the burning of coal. Coal emits 25% more carbon per “unit of energy” than oil and 70% more carbon than natural gas.
Approximately 1/3 of the carbon dioxide emissions released into our environment comes from the burning of gasoline in internal- combustion engines of automobiles, buses, motorcycles, recreational vehicles, trucks and motor sports.
The United Nation’s Inter governmental Panel on Climate Change estimates that aviation currently is responsible for just under 5% of global warming and that the figure could very well rise to approximate 15% by the year 2050.
The regular maintenance, temperature control and cleaning of buildings structure actually account for nearly 12% of carbon dioxide emissions.
Deforestation is the 2nd most prolific cause of atmospheric carbon dioxide influx. Deforestation is responsible for nearly 1/4 of all carbon emissions entering the atmosphere. The planet cuts and burns nearly 34 million acres of trees each year, including millions of acres of “rainforests”.
The process of deforestation is “doubly” dangerous for the planet, because not only millions of tons of carbon dioxide are added into the atmosphere each year, but also wiping out the most effective cleansers of that deadly carbon dioxide gas, the trees and plants that naturally “thrive” by consuming the carbon dioxide and offering up pure, clean, breathable oxygen as a free byproduct of the plant life cycle.
(vi) Melting permafrost:
Permafrost is the frozen soil throughout the Arctic and sub-arctic regions, that contain all kinds of organic matter such as all kinds of frozen plants and animals that have been frozen solid and held inert for 30,000 years. Approximately 25% of the land mass of the Northern Hemisphere is “permafrost”, or soil with a temperature of 32 degrees Fahrenheit or less. Permafrost has acted like a jail cell for carbon, methane and other greenhouse gases for several thousand years. As glacial regions and permafrost begin to melt, the 50 billion tons of carbon held inactive under the frozen surface of the tundra, will begin and continue to be released into our atmosphere, creating a greenhouse effect that would make the residents of the hottest and most humid tropical islands faint in a minute.
Effects of Global Warming
i. Polar Ice Caps:
The effects of global warming are strongest at the poles. Ice all over the world is melting. This includes the ice of mountain glaciers, Arctic sea ice and ice sheets covering West Antarctica and Greenland. The melting ice increases the sea level and this causes flooding of low-lying areas.
Precipitation in the form of rain and snow has on average, increased across the whole world.Irregular weather patterns have an effect on humans. Rain is not only an inconvenience for humans, but also damage human property. The increase in heat will increase evaporation which is why there will be more rain.Animals and plants cannot easily adapt to increased rainfall or snowfall and many animals migrate to other areas. More extreme weather is already occurring. Cyclones have gained in strength since 1970. Rainfall associated with such weather has increased by 7%.
iii. Food Production:
As temperatures around the world will increase, plants will find it harder to cope and they will die. Some of the plants are used by humans for food and so a food shortage may occur. Agriculture would be severely affected because there is no water for plants to grow due to higher temperature. When there are no plants, humans have nothing to eat. There are also no plants to feed animals and so humans cannot eat animals either.
Animals have been migrating to adapt to new conditions. This migration destroys ecosystems and their biodiversity. As parts of the food chain are lost from an ecosystem the whole ecosystem can easily collapse. Ecosystems and their biodiversity are important to humans. Humans get food, employment, raw materials and pharmaceutical products from the environment. Ecosystems will definitely change. So species will migrate to more suitable conditions while some will stay and try to adapt. Not all will succeed and more species will become extinct. It is predicted that 25% of all mammals and 12% of bird’s species will be extinct within the next 30 years.
Rising temperatures have an effect on the health of humans. Heat strokes are likely to increase as temperature gets hotter.Diseases such as malaria are likely to spread. Parasites that originate in tropical regions may migrate to temperate regions as become warmer. Mosquitoes are an example and it is predicted that malaria will spread around world. Hurricane Katrina was famous hurricane for decimated the city of New Orleans, destroying structures, killing people and displacing.
Between 1880 and 2000 a 20 cm. rise in ocean levels has been recorded — now occurring at 0.2 mm per year. This is due to ocean water expansion through its warming and water from melting glaciers and polar ice. Oceans have absorbed about half the human-made CO2 emissions since 1800. A higher CO2 content makes the oceans more acid. This has adverse effects on coral, fish and plankton.Warmer ocean water and volumes of fresh water from melting glaciers could disrupt the Gulfstream which influences Northern European weather. A cooling effect could occur. Rising oceans cold swallow low-lying islands and coastal areas.
vii. Water Availability:
Reduced rainfall, droughts, and vanishing glaciers will severely reduce the availability of drinking water.
viii. Further Global Warming:
Melting glaciers and permafrost may be at a stage where there is no turning back. As they contribute their fresh water to the oceans and as methane gas is released these events will further accelerate global warming. This is called the positive feedback effect.
ix. Coral Reefs:
Corals get their food from an algae called zooxanthellae, which lives in the coral. This algae is extremely sensitive to temperature changes, and “an increase of just 1.8 degrees Fahrenheit can cause corals to expel their algae, or ‘bleach’. Over a prolonged period of time, bleaching leads to death.A second contributing factor to the current sea-wide decline in coral reefs is that, as atmospheric concentrations of carbon dioxide (CO2) increasing oceans are becoming more acidic. This “reduces the availability of free carbonate ions in the water,” making it more difficult for the polyps that build coral reefs to extract the calcium carbonate they need to survive.
As global warming causes climate change, many great deserts like the Sahara are no longer able to sustain their animal population. Loss of habitat is most vividly seen in the Arctic, where global warming is melting the glaciers, pushing the polar bears into extinction. The melting glaciers have caused water levels to rise in many oceans, threatening to drown many tropical islands and forests that have animal life.
How to reduce global warming
The planet is warming due to human influence, but can human innovation save it? The evidence that humans are causing global warming is strong, but the question of what to do about it remains controversial. Economics, sociology, and politics are all important factors in planning for the future. Containing the release/emission of Greenhouse Gases is the most effective way to reduce global warming. Many people and governments across the globe are already working hard to cut greenhouse gases, and every person can help in this stupendous task of protecting the globe. The methods to reduce global warming include the following.
Global warming has become one of the most serious issues in current affairs, politicians and environmentalists due to the various risks and effects associated with it. Despite the fact that global warming is increasing at an alarming rate and it might be too late to restore the damage it has caused, it is believed that developing an aggressive plan of action can help reduce its negative impact. Unless the critical issue of global warming does not hit every person on earth, it will be very difficult to prevent the world from burning due to global warming in the near future.
(With inputs from NASA and National Geographic magazine, USA)