Tag Archives: Environment

What is the difference between Natural Greenhouse Effect and Enhanced Greenhouse Effect?

The Sun is the primary source of energy for Earth. The energy reaches the planet in the form of sunlight. The light, which is an electro-magnetic wave, is mainly composed of infrared rays, visible light and ultraviolet rays. A major portion of the UV rays will be absorbed by the ozone layer around the Earth. The remaining rays will reach the planet along with the visible light and warm the Earth’s surface. These rays are of relatively smaller wavelength. The infrared rays, which have a greater wavelength, will be reflected by the hot surface of Earth.
These infrared rays, which have to escape the atmosphere, are but absorbed by some of the gases in the air. They then re-radiate these rays in different directions, mostly back to the Earth. These rays possess a large amount of energy and cause a rise in the atmospheric temperature. This phenomenon is much like what happens in a natural green house and hence is called the Greenhouse Effect.
The gases which have the ability to absorb the infrared rays are called greenhouse gases. A number of greenhouse gases are naturally found in atmosphere but others are the products of various human activities. Vapor, Carbon Dioxide, Methane, Nitrous Oxide, Ozone and Chlorofluorocarbons are the major greenhouse gases.
The idea of the greenhouse effect was put forward for the first time in 1824. A scientist named Joseph Fourier was the person who gave the first indications of the phenomenon. Another scientist, John Tyndall, took the studies further. He discovered how the heat radiations affect the gases and proved the phenomenon of greenhouse effect scientifically in 1859.
Carbon dioxide is one of the most dangerous among the greenhouse gases. It is a naturally occurring gas but the increasing industrial activities and deforestation are triggering an accelerated rise in the amount of the gas in the atmosphere. The share of carbon dioxide in greenhouse effect is between 9% and 26%.
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Although the Natural Greenhouse Effect is instrumental in preserving the biosphere, its growth leads to Global Warming, which is the result of Human Enhanced Greenhouse Effect. The phenomenon of Global Warming is one of the worst threats to nature now. The atmospheric temperature is on the rise every year. It is the cause of the melting of glaciers in Polar Regions and the rise in sea level, causing strong climatic changes. A number of low-level islands have disappeared and some are about to be drowned. The world nations have now understood the danger of global warming and begun to tackle the emission of carbon dioxide and other greenhouse gases.

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How is noise pollution killing whales?

There are many reasons behind whales meeting their death on the shores. Sometimes they lose their way and move towards the beach. Some whales, swimming too close to the shores, are beached when there’s steep decline in water level during low tide. Whale is endowed with a natural compass in its head. This compass, which works on the basis of Earth’s magnetic field, helps it to navigate through the sea. Unfortunately for the whales, the magnetic field is not the same everywhere. It is greater near the poles and weaker near the equator. It affects the whales’ built in compass which does not work perfectly in areas where the magnetic field is weak. Many a times the whale unknowingly approaches the sea shore due to navigation error and if it is stranded on the land, there is no chance for its survival. Its body collapses under its own weight and soon it dies of dehydration.
Beached whales
While the whale navigates using its natural compass, it finds its way under the water using its natural sonar. The whale emits high-pitched sound waves in the water. These waves bounce back from the sea-bed (or predator) and upon receiving them the whale decodes its route. This way of finding the directions is known as echolocation; and it works perfectly when the sea is calm.
Unfortunately, seas around the world are not as peaceful as they used to be a few decades ago. There has been a great increase in the level of noise pollution in the seas and oceans across the globe due to industrialization. Drilling of deep sea oil wells creates a deafening sound under the water. Propellers of giant military as well as cargo ships, submarines, oil tankers etc. produce jarring sounds. Military submarines’ and ships’ sonar equipments transmit low-frequency sound to locate the enemy ship or submarine. This sound is not less than 230 decibels — nearly twice the sound produced by jet engine of a combat aircraft.
All these factors add to the ever increasing levels of noise pollution in the sea. The natural sound waves emitted by the whale in order to map its route through the water therefore get scattered. The whale cannot receive them back. It loses its course due to lack of mapping, and sometimes swims towards the shallow shores — only to meet a painful death. While about 360 whales died due to beaching in 1994, the figure rose to 782 in 2004, and 2,000 in the year 2010. This clearly indicates the increase of noise pollution by humans in the ocean water. This also indicates to what extent human interference with environment can cause damage to the ecology.

Additional reading:
Beached whale (Wikipedia)

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Why do we experience rich and refreshing earthy smell after a rainfall?

If you live in the area surrounded by countryside, you will know that one of the most magical smell comes after a rainfall.
The smell is actually the waste products of bacteria in soil called streptomycets. As the tiny pockets of air between grains of soil get filled with water, the bacteria’s gases are pushed out of the ground an into the air. Be it a waste product, but it makes you feel better by causing a change in your brain wave pattern. How this happens is not clearly understood, but who cares?

Additional reading:
Petrichor (Wikipedia)

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What is a hurricane? How is it different from a typhoon?

Both of these names apply to great tropical storms that begin in the oceans near the Equator, that is, in all the great oceans except the South Atlantic. Such storms in the West Indies are called hurricanes from the Carib Indian name for them. In the China Sea and the East Indies they are called typhoons; in the Indian Ocean, cyclones; and in Australian waters, willy-willies.
Such storms usually blow up in the autumn; the wind, which has a speed of more than 110 kilometres, is often accompanied by thunder, lightning and rain. Before the days of steamships, sailors used to look forward with dread to these storms. Often seamen would battle with the elements for days together. The sails would be torn to shreds by the fury of the wind. Mighty, foaming seas would charge upon the ship like an invading host, beating with terrific force upon the decks, sometimes carrying away the masts. These storms are not such a danger to shipping as they once were, for nowadays steamships are given warning by radio of approaching hurricanes, so that they are often able to get out of the way of the great storms.

Additional reading:
Typhoon (Wikipedia)

How high up do the highest clouds float?

Clouds of the kind called cirrus, which is the Latin word for ‘curl’, float higher than those of any other kind, their average height above sea-level being about 10,000 meters (33,000 feet) – quite more than that of the world’s highest mountain. They are made up of tiny particles of ice, and are always white. They resemble, feathers or ribbons, spreading out like the ribs of a fan, and are sometimes called mare’s tails. Cirrus clouds are usually regarded as a sign of coming wind.

Additional reading:
Cirrus cloud (Wikipedia)
List of cloud types (Wikipedia)

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What is El Nino? How does it affect the climate?

In June 1982, oceanographers noticed a temperature rise in the surface waters of the eastern and central Pacific. The change, though barely discernible, marked the start of the most extensive climatic disturbance on record, affecting places as far apart as Chile and Alaska, Indonesia and New York. According to climatologists, the freakish weather worldwide sprang from conditions that give rise on a smaller scale to El Nino (the Christ Child), a periodic weather pattern that appears off South America shortly after December. Scientists are now trying to determine how El Nino relates to the Southern Oscillation, a major seesawing in temperature and atmospheric pressure across the southern pacific.
According to theory, El Nino arises when the trade winds slacken. Normally, these winds blow toward Asia, pilling up water in the western Pacific. If they die down, warm water flows back towards South America, displacing the cold Humboldt Current, which travels up the coast carrying nutrients vital to the marine food chain. As a result, fish and bird life are decimated and the Peruvian anchovy and guano industries ruined. Sometimes the trade winds give out altogether, and associated changes in air pressure brings torrential rains to Peru and Ecuador and drought to Indonesia and Australia at the other end. A major reversal in the seesaw would even affect the weather in the Northern Hemisphere. The El Nino occurs due to abnormal transfer of heat between the ocean and atmosphere – but just what causes this imbalance is yet to be known completely. So far, researchers are nowhere near a complete analysis of the El Nino cycle.

More reading:
El Niño-Southern Oscillation (Wikipedia)

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Why is there a runaway greenhouse effect on planet Venus?

Blame it on carbon dioxide/CO2 which constitutes 96% of Venusian atmosphere. The 250 kilometers thick gaseous envelope of this oddball planet has enough CO2 to fill about 1,00,00,00,000 billion fire extinguishers. Composed of molecules having one atom of carbon and two atom of oxygen, CO2 is a strong greenhouse gas; whereas nitrogen, the most abundant molecule in the Earth’s atmosphere, is not. However, this does not mean that Venus as a whole is richer in CO2 than the Earth. This gas which might otherwise be in the Earth’s atmosphere has largely been removed by various plants and is locked up in deposits of limestone.

Moving around the Sun at an average distance of 108.2 million kilometers, Venus is truly smoldering greenhouse, where no astronaut would survive the hellish environment. At 470º Celsius the surface temperature of Venus is more than enough to melt the lead and still have 100º left over to make the steel red hot. Even at an altitude of 49 kilometers, where the dense clouds begin, the temperature drops only to 70º Celsius. At about 68 kilometers above Venus, however, the temperature finally drops to nearly 0º Celsius.

It was in 1960s that earthbound radars indicated the piping hot Venusian environment; although many scientists were skeptical at that time. The result, however, were verified by the increasingly sophisticated Venus space probes a decade later.  The planet Venus, it turns out, is a greenhouse without a keeper, whose thermostat has broken down long in the past. Sunlight comes in as short wave radiation and heats up the atmosphere as well as the surface, but the heat is then trapped. (See diagram above.) Very little reflected heat, now in the form of long wave infrared, can escape through the dense atmosphere of carbon dioxide.

This process has been called the runaway greenhouse effect which goes on without being regulated by any checks and balances. It is a self-feeding machine which requires no further input of CO2 to keep it up. Presently, our own planet seems to be heading for the similar disaster. Unless the mankind immediately puts an end to carbon dioxide emissions, the Earth will eventually go the way planet Venus went in the past.

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Is Maldives going to submerge in the ocean due to rising sea-levels? How much time it has?

Yes. Maldives unfortunately holds no future for its inhabitants. This country which is basically a group of islands is slowly getting engulfed by the ocean. About 30 islands have already been evacuated since all of them are going to submerge in the ocean in the near future. Due to the global warming the glaciers are melting and thus resulting in increasing sea levels which ultimately will lead to the disappearance of the remaining islands as well.

Maldives would also be the first country to be submerged in the sea. However, experts are not able to figure out the exact deadline as there are two factors which may misinterpret their calculations. The average water levels of the sea have risen by 5.5 centimeters in the past 15 years. The major reason for this to happen is the rising average temperature of the Earth which heats the ocean water, leads to thermal expansion and further results into elevated water levels. (For example: The hot water level of the Gulf Stream is a little above than the level of the water of the nearby Pacific Ocean by few centimeters.) Scientifically we can correlate the 5.5 centimeters increased level of the water with the proportionate increase in the temperature of the Earth. This has no contribution of the melting glaciers – not at least in the past 15 years. Experts now believe that the effect of the melting glaciers will henceforth overtake the effect of thermal expansion. However, it is difficult to further anticipate its exact effect on the water levels as it is not possible to accurately measure the exact amount of the melted ice and its annual rate of melting. The exact interpretations would be possible only after studying the increased water levels after a few years. It is, therefore, not possible to know the exact doomsday for Maldives but certain researchers claim it to be in the next 20 years.

This probably is the reason as to why the president of Maldives has started accumulating funds to acquire land in India, Sri Lanka or Australia for the 3,86,000 potential migrants of Maldives.

More reading:
Maldives (Wikipedia)
Greenhouse effect (Wikipedia)
Current sea level rise (Wikipedia)
Effects of global warming (Wikipedia)

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What is smoke made of?

Smoke is the result of imperfect burning. Most of the substances from which we get much smoke would form nothing but gases if they were properly burned; gases which we could not see and which would very soon disappear. But man has not yet invented a furnace that will burn a fuel completely, without any smoke, though some factories have installed devices that almost do the trick. So we burn the coal or wood or oil or other substance only partly, and small specks of it, unburned, are carried up the chimney. The solid substance in smoke is simply fuel in the form of small specks.

Smoke makes black fogs in many cities, and cuts off a great quantity of daylight, besides making everything dirty, destroying plants and trees, and filling our lungs with dirt that we can never get rid of.

More reading:
Smoke (Wikipedia)

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