Green House Effect

 Definition of Green House Effect:

The greenhouse effect occurs when certain gases in the atmosphere (the air around the Earth) entrap infrared radiation. This effect makes the planet warmer, in the same way a greenhouse keeps its inside temperature warmer.

Greenhouse Gases:

1. Water Vapor - It is the most abundantly found greenhouse gas constituting around 36―70% of all the gases contributing to greenhouse effect. Increase in temperature results in a relatively high presence of water vapor in the atmosphere.

2.Carbon Dioxide - Although this gas is present in a small amount naturally, urbanization, industrial revolution, and other human activities have largely contributed to the levels of carbon dioxide present in the atmosphere today. It roughly amounts to 9―26%.

3. Methane - Atmospheric methane is present as a result of both natural and anthropogenic sources. While manure of domestic livestock is one of the major natural contributors, landfills is the prime example of anthropogenic sources. Methane contributes 4―9% to the greenhouse effect.

3.Nitrous Oxide - This gas is produced by agricultural activities, landfills, and burning of fossil fuels.

4. Chlorofluorocarbons (CFCs) - CFCs have an entirely anthropogenic origin, primarily industries. Until recently, they were also used in refrigerators, aerosols, fire extinguishers, and air conditioners.

                                                  

Causes:

Deforestation
» Forests help in maintaining the balance of nature by absorbing the excess carbon dioxide present in the atmosphere. Cutting down of trees, thus, leads to an increase in the carbon dioxide level in the atmosphere, eventually enhancing the greenhouse effect.

Burning of Fossils
» Greenhouse gases can also be released into the atmosphere due to the burning of fossil fuels, oil, coal, and gas.

» These materials are used increasingly and rampantly in industries. Most factories produce certain gases which last for a longer time in the atmosphere.

» Increase in the average temperature is then observed which amounts to global warming.

Electrical Appliances
» Other man-made causes of the increase in the greenhouse effect is the emission of greenhouse gases by electrical appliances. These gases, chlorofluorocarbons (CFCs), are used on a large scale in the electronic industry.

» Some processes of the cement manufacturing industries also act as a cause towards the greenhouse effect.

Population Growth
» Population growth is an indirect contributor and one of the major causes of the greenhouse effect.

» With the increase in population, the needs and wants of people increase which consequently increases deforestation, manufacturing, and industry processes.

» This results in the increase of the release of industrial gases which catalyze the greenhouse effect.

THE EFFECTS:

With more heat trapped on Earth, the planet will become warmer, which means the weather all over Earth will change. For example, summers will get hotter, and winters too. This may seem a good idea, but the conditions we are living in are perfect for life, and a large rise in temperature could be terrible for us and for any other living thing on Earth.
At the moment, it is difficult for scientists to say how big the changes will be and where the worse effects will occur.

The Weather
In Britain, winter and summer temperatures will increase and the weather will be warmer. In winter it may also rain more but in summer it may become drier.
In other parts of the world, the effects will be different, some places will become drier and others will be wetter. Although most areas will be warmer, some areas will become cooler. There may be many storms, floods and drought, but we do not know which areas of the world will be affected.
All over the world, these weather changes will affect the kind of crop that can be grown. Plants, animals and even people may find it difficult to survive in different conditions.


Sea Levels
Higher temperatures will make the water of the seas and oceans expand. Ice melting in the Antarctic and Greenland will flow into the sea.
All over the world, sea levels may rise, perhaps by as much as 20 to 40 cm, by the beginning of the next century.
Higher sea levels will threaten the low-lying coastal areas of the world, such as the Netherlands and Bangladesh. Throughout the world, millions of people and areas of land will be at danger from flooding. Many people will have to leave their homes and large areas of farmland will be ruined because of floods. In Britain, East Anglia and the Thames estuary will be at risk from the rising sea.

Farming
The changes in the weather will affect the types of crops grown in different parts of the world. Some crops, such as wheat and rice grow better in higher temperatures, but other plants, such as maize and sugarcane do not. Changes in the amount of rainfall will also affect how many plants grow.
The effect of a change in the weather on plant growth may lead to some countries not having enough food. Brazil, parts of Africa, south-east Asia and China will be affected the most and many people could suffer from hunger.

Water
Everywhere in the world, there is a big demand for water and in many regions, such as the Sahara in Africa, there is not enough water for the people. Changes in the weather will bring more rain in some countries, but others will have less rain.
In Britain, the Southeast will be at risk from drought.

IN DANGER!

Plants & Animals
It has taken million of years for life to become used to the conditions on Earth. As weather and temperature changes, the homes of plants and animals will be affected all over the world.
For example, polar bears and seals, will have to find new land for hunting and living, if the ice in the Arctic melts.
Many animals and plants may not be able to cope with these changes and could die. This could cause the loss of some animal and plant species in certain areas of the world or everywhere on Earth.

People
The changes in climate will affect everyone, but some populations will be at greater risk. For example, countries whose coastal regions have a large population, such as Egypt and China, may see whole populations move inland to avoid flood risk areas. The effect on people will depend on how well we can adapt to the changes and how much we can do to reduce climate change in the world.

PREVENTIVE MEASURES:

1.Reduce carbon dioxide emissions. Walk, take public transportation or ride your bike instead of driving. Carpool with others whenever possible if you must travel by car. Buy locally grown or produced foods; doing so decreases energy use associated with transportation of these products.

2.Conserve electricity by switching off the TV, computer, radio and lights whenever possible. Unplug electronics from the socket when you are not using them. Use compact fluorescent light (CFL) bulbs, which can reduce energy consumption by approximately 60 percent, in place of incandescent light bulbs. Opt for energy-efficient appliances when shopping. Such products are often marked with the Energy Star label.

3.Plant trees; they contribute to the absorption of excess carbon dioxide. Providing shade and windbreaks, trees also contribute to creating even temperatures for buildings, thereby reducing the energy requirement for heating or cooling

4.Avoid buying heavily packaged items, decreasing the amount of garbage that you contribute. Research conducted by the U.S. Climate Change Science Program suggests that garbage breakdown in landfills is the top source of human-induced methane emissions.

5.Keep in mind that heating water requires energy. Reduce your consumption of hot water by washing clothes in cold or warm water. Wait until the dishwasher is full to run it and activate the energy-saving feature if available on your machine. Invest in a low-flow showerhead, which has a lower water flow rate than normal showerheads. Dry your clothes, whenever possible, on a clothesline as opposed to using a mechanical dryer

6.Reduce nitrous oxide emissions, the majority of which result from agricultural practices. Choose slow-release, low nitrogenous-emitting fertilizers

7.Support international global warming legislation. Examples include the Montreal Protocol, which seeks to eliminate the production of CFCs, and the Kyoto Protocol, which aims to limit emissions of the other greenhouse gases such as carbon dioxide and methane. Even though the U.S. did not sign the treaty, much of what was ratified in it will help combat the greenhouse effect.

Practice Exercise:

Q1. The largest source of anthropogenic greenhouse gases in the United States is ________, followed by ________.

A) agriculture; transportation

B) electricity generation; agriculture

C) electricity generation; industry  

D)electricity generation; transportation

E) agriculture; electricity generation

Q2.The atmosphere around Earth is warmed because ________.

A) warm air cannot escape, as in a greenhouse

B) molecules in the atmosphere are warmed by radiation from Earth and retain that heat

C) fossil fuels release heat

D) plants absorb CO2  

E) plants release CO2

Q3.Earth's climate ________.

A) has been stable over the history of the planet

B) is changing as a result of natural and human processes

C) will stabilize over the next century, according to the predictions of most scientists

D) has been documented to have changed once due to the evolution of green photosynthesizing plants

E) history is undeterminable because there is no method of studying climatic history of the planet

Q4) Of the following greenhouse gases, ________ concentrations have increased the most since 1750.

A) water vapor

B) carbon dioxide

C) nitrous oxide

D) ozone

E) methane

Q5) Carbon dioxide is ________.

A) the most potent (per molecule of gas) of the greenhouse gases

B) the most abundant greenhouse gas

C) more potent (per molecule of gas) than methane

D) the main anthropogenic greenhouse gas produced in the United States

E) the only greenhouse gas presently increasing in the atmosphere

Answer Key: 1. D 2. B 3. B 4 E 5 D

Acid Rain: 

What is Acid Rain?


Acid rain is rain that has been made acidic by certain pollutants in the air. Acid rain is a type of acid deposition, which can appear in many forms. Wet deposition is rain, sleet, snow, or fog that has become more acidic than normal. Dry deposition is another form of acid deposition, and this is when gases and dust particles become acidic. Both wet and dry deposition can be carried by the wind, sometimes for very long distances. Acid deposition in wet and dry forms falls on buildings, cars, and trees and can make lakes acidic. Acid deposition in dry form can be inhaled by people and can cause health problems in some people.

                                    

 Causes of Acid Rain :


Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Sulfur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result, the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that we experience on certain days. Human activities are the main cause of acid rain. Over the past few decades, humans have released so many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain

How Acid Rain Is Caused?

Nature depends on balance, and although some rain is naturally acidic, with a pH level of around 5.0, human activities have made it worse. Normal precipitation—such as rain, sleet, or snow—reacts with alkaline chemicals, or non-acidic materials, that can be found in air, soils, bedrock, lakes, and streams. These reactions usually neutralize natural acids. However, if precipitation becomes too acidic, these materials may not be able to neutralize all of the acids. Over time, these neutralizing materials can be washed away by acid rain. Damage to crops, trees, lakes, rivers, and animals can result.

Effects of Acid Rain:

1.Acid Rain Can Cause Health Problems in People:
Air pollution like sulfur dioxide and nitrogen oxides can cause respiratory diseases, or can make these diseases worse. Respiratory diseases like asthma or chronic bronchitis make it hard for people to breathe. The pollution that causes acid rain can also create tiny particles. When these particles get into people’s lungs, they can cause health problems, or can make existing health problems worse. Also, nitrogen oxides cause ground-level ozone. This ground-level ozone causes respiratory problems, like pneumonia and bronchitis, and can even cause permanent lung damage. The health effects that people have to worry about are not caused by the acid rain, but are caused when people breathe in these tiny particles or ozone. Swimming in an acidic lake or walking in an acidic puddle is no more harmful to people than swimming or walking in clean water.
2. Acid Rain Harms Forests:
Acid rain can be extremely harmful to forests. Acid rain that seeps into the ground can dissolve nutrients, such as magnesium and calcium, that trees need to be healthy. Acid rain also causes aluminum to be released into the soil, which makes it difficult for trees to take up water. Trees that are located in mountainous regions at higher elevations, such as spruce or fir trees, are at greater risk because they are exposed to acidic clouds and fog, which contain greater amounts of acid than rain or snow. The acidic clouds and fog strip important nutrients from their leaves and needles. This loss of nutrients makes it easier for infections, insects, and cold weather to damage trees and forests.
3.Acid Rain Damages Lakes and Streams:
Without pollution or acid rain, most lakes and streams would have a pH level near 6.5. Acid rain, however, has caused many lakes and streams in the northeast United States and certain other places to have much lower pH levels. In addition, aluminum that is released into the soil eventually ends up in lakes and streams. Unfortunately, this increase in acidity and aluminum levels can be deadly to aquatic wildlife, including phytoplankton, mayflies, rainbow trout, small mouth bass, frogs, spotted salamanders, crayfish, and other creatures that are part of the food web.
This problem can become much worse during heavy downpours of rain or when the snow begins to melt in the spring. These types of events are known as episodic acidification.
4.Acid Rain Damages Buildings and Objects:
Acid rain can also have a damaging effect on many objects, including buildings, statues, monuments, and cars. The chemicals found in acid rain can cause paint to peel and stone statues to begin to appear old and worn down, which reduces their value and beauty.
Preventive Measures: 

Understand the Problem:
The first step you can take to help control acid rain is to understand the problem and its solutions. Now that you have learned about this environmental issue, you can tell others about it. By telling your classmates, parents, and teachers about what you learned on this site, you can help educate them about the problem of acid rain. You CAN make a difference!
Conserve Energy:
Since energy production creates large amounts of the pollutants that cause acid rain, one important step you can take is to conserve energy. You can do this in a number of ways:

• Turn off lights, computers, televisions, video games, and other electrical equipment when you're not using them.
  
• Encourage your parents to buy equipment that uses less electricity, including lights, air conditioners, heaters, refrigerators, and washing machines. Such equipment might have the Energy Star label.
  
• Try to limit the use of air conditioning.
  
• Ask your parents to adjust the thermostat (the device used to control the temperature in your home) when you go on vacation.

Minimize the Miles:

Driving cars and trucks also produces large amounts of nitrogen oxides, which cause acid rain. To help cut down on air pollution from cars, you can carpool or take public transportation, such as buses and trains. Also, ask your parents to walk or bike with you to a nearby store or friend’s house instead of driving

acidrain animation.


Learning Activity:

Q1. Acid rain is formed due to contribution from the following pair of gases
     a.  Methane and ozone
     b.  Oxygen and nitrous oxide (Ans)
     c.  methane and sulpher dioxide
     d.  Carbon dioxide and sulpher dioxide

Q2.	What is sulfur dioxide?

a.       colourless, prudent gas released as a by-product of combusted fossil fuels containing sulfur.(Ans) b.      oxygen in the air c.       acid precipitation

Q3.	What does SO2 (sulphur dioxide) and NOX (nitrous oxides)makes?

a.	Oxygen in the air

b.	acid rain (Ans)

c.

water molecules

Q4.

Can acid rain go undetected in an area for years?

a.

Yes (Ans)

b.

No

c.

Depends

Q5.	How can you reduce acid rain?

a.	Walk when you can

b.	Conserve energy (Ans)

c.	Choice A and B