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বৃহস্পতিবার, ৩ ফেব্রুয়ারী, ২০১১

Recycling

Recycling is processing used materials (waste) into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution (from incineration) and water pollution (from landfilling) by reducing the need for "conventional" waste disposal, and lower greenhouse gas emissions as compared to virgin production. Recycling is a key component of modern waste reduction and is the third component of the "Reduce, Reuse, Recycle" waste hierarchy.

Recyclable materials include many kinds of glass, paper, metal, plastic, textiles, and electronics. Although similar in effect, the composting or other reuse of biodegradable waste – such as food or garden waste – is not typically considered recycling. Materials to be recycled are either brought to a collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials bound for manufacturing.
Recycling Process:
1. Collection:
A number of different systems have been implemented to collect recyclables from the general waste stream. These systems lie along the spectrum of trade-off between public convenience and government ease and expense. The main categories of collection are "Recycling-banks", "drop-off centres", "buy-back centres" and "curbside collection"


2.Sorting:
After the collection the recyclables are delivered to a central collection facility where different types of materials are sorted. This job is done with a few automated processes, thus the time for sorting decreases greatly.Next, automated machinery separates the recyclables by weight, splitting lighter paper and plastic from heavier glass and metal. Cardboard is removed from the mixed paper, and the most common types of plastic, PET (#1) and HDPE (#2), are collected

Strong magnets are used to separate out ferrous metals, such as iron, steel, and tin-plated steel cans ("tin cans"). Non-ferrous metals are ejected by magnetic eddy currents. Finally, glass must be sorted by hand based on its color: brown, amber, green or clear.

And finally different materials are taken through different recycling processes. One of them is illustrated  below.




The recycling process can save our time, money and environment. So, start recycling.

বৃহস্পতিবার, ২৭ জানুয়ারী, ২০১১

Greenhouse Effect at Brief


Greenhouse Effect:
Greenhouse effect is the process of absorbing thermal radiation by atmospheric greenhouse gases of a planet. This thermal radiation is usually reflected from the planet's surface.
The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.
The Process of Greenhouse Effect:
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slow-moving energy called infrared radiation which have larger wavelength than the sunlight.

Greenhouse gases trap some of the infrared radiation that escapes from the Earth, making the Earth warmer that it would otherwise be.  Greenhouse gases can be considered as sort of a "blanket" for infrared radiation-- it keeps the lower layers of the atmosphere warmer, and the upper layers colder, than if the greenhouse gases were not there. This phenomenon is the greenhouse effect.


About 80-90% of the Earth's natural greenhouse effect is due to water vapor, a strong greenhouse gas. The remainder is due to carbon dioxide, methane, and a few other minor gases.



It is the carbon dioxide concentration that is increasing, due to the burning of fossil fuels (as well as from some rainforest burning). This is the man-made portion of the greenhouse effect, and it is believed by many scientists to be responsible for the global warming of the last 150 years.

Also, the concentration of methane, although small, has also increased in recent decades. The reasons for this increase, though, are uncertain.


Click here for animated global warming.



রবিবার, ২৩ জানুয়ারী, ২০১১

The Kyoto Protocol



Global warming is a word that concerns everybody now. But does it concerns world leaders? The answer is that, yes, it does. The Kyoto Protocol is the proof of the world leaders concern about global warming.

What is the 'Kyoto Protocol?'
 The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), aimed at fighting global warming. The UNFCCC is an international environmental treaty with the goal of achieving "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."

The Protocol was initially adopted on 11 December 1997 in Kyoto, Japan and entered into force on 16 February 2005. As of July 2010, 191 states have signed and ratified the protocol.

Under the Protocol, 37 countries ("Annex I countries") commit themselves to a reduction of four greenhouse gases (GHG) (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride) and two groups of gases (hydrofluorocarbons and perfluorocarbons) produced by them, and all member countries give general commitments. Annex I countries agreed to reduce their collective greenhouse gas emissions by 5.2% from the 1990 level. Emission limits do not include emissions by international aviation and shipping, but are in addition to the industrial gases, chlorofluorocarbons, or CFCs, which are dealt with under the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer.


Objectives of the Protocol:
The five principal concepts of the Kyoto Protocol are:
  • Commitments to the Annex-countries. The heart of the Protocol lies in establishing commitments for the reduction of greenhouse gases that are legally binding for Annex I countries. Dividing the countries in different groups is one of the key concepts in making commitments possible, where only the Annex I countries in 1997, where seen as having the economic capacity to commit themselves and their industry. Making only the few nations in the Annex 1 group committed to the protocols limitations.
  • Implementation. In order to meet the objectives of the Protocol, Annex I countries are required to prepare policies and measures for the reduction of greenhouse gases in their respective countries. In addition, they are required to increase the absorption of these gases and utilize all mechanisms available, such as joint implementation, the clean development mechanism and emissions trading, in order to be rewarded with credits that would allow more greenhouse gas emissions at home.
  • Minimizing Impacts on Developing Countries by establishing an adaptation fund for climate change.
  • Accounting, Reporting and Review in order to ensure the integrity of the Protocol.
  • Compliance. Establishing a Compliance Committee to enforce compliance with the commitments under the Protocol.



Present Condition of the Protocol:
The countries following and not following the protocol and the countries which have not decided yet are given below.



Maintaining the Kyoto Protocol properly can ensure us a safe earth for living in the future. So the developed countries of the world should take responsibility of following it properly.

শনিবার, ২২ জানুয়ারী, ২০১১

How To Reduce Global Warming



'Global Warming'- cannot be stopped completely. But there is nothing to worry, because we can reduce it to an acceptable level, which will not harm the peaceful and glorious lives of our future generation. To do this we simply need to modify some of our habits in our daily life. Our main goal is to reduce the emission of carbon dioxide in the atmosphere which in turn will reduce global warming.
 A few tips that will emit less CO2 in the air:

1. Reduce, Reuse, Recycle: 

Reducing waste by using reusable products instead of disposables will be handy to prevent global warming. Recycling paper, plastic, newspaper, aluminum cans etc. is also useful. If there is no recycling program in your community, start one today. This simple tasks will reduce 2400 pounds of CO2 annually. 

2. Replace a Light Bulb:

Replacing a regular light bulb with a compact fluorescent light (CFL) will save lots of money and reduce a huge amount of greenhouse gases. From survey it has been seen that if every US family replaces one regular bulb 90 billion pounds of greenhouse gases will be eliminated from the air, the same as taking 7.5 million cars off the road.

3. Energy-efficient Products:  

Energy-efficient products such as a car offering good mileage or home appliance with energy efficient models or a CFL bulb can provide in decreasing global warming. Products that come with access packaging such as molded plastic and other packaging that can't be recycled should be avoided.  By reducing 10% of our household garbage we can stop 1200 pounds of COfrom emitting in the air annually.

4. Planting Trees:

During Photosynthesis, trees absorb COand give off Oxygen. In this way they reduce CO2 in the atmosphere but they are too few to fully counter the increase in CO2 in atmosphere. So start planting today.The process of Photosynthesis is quite interesting. It's simple pictorial view looks like below:


5. Usage of the 'OFF' switch:

Save electricity by turning off lights, television, video player, stereo and computer when they are not in use.

6. Drive less and Walk more:

Less driving means fewer emissions and saving of gasoline. Walk and ride bicycles for traveling a short distance. They are a great form of exercise too.

7. Eating:

Eat less meat and more organic food. This habit is good for both health and environment.

8. Encourage Others:

Encourage others to help in preventing global warming. Share information about recycling and energy conversion among your community.


Following these steps will take someone a long way towards reducing energy usage. Less energy means less fossil fuel that creates greenhouse gases and contribute global warming. So following these few steps will surely help in reducing global warming. 








 

 

 

 

রবিবার, ৯ জানুয়ারী, ২০১১

Global Warming - Global Headache



What is Global Warming:

Global warming is a word heard everywhere nowadays. But what does it mean? Simply global warming means the average temperature increase of Earth-surface, oceans and the air near earth surface. In the 20th century, the average temperature of earth's surface has increased about 1 degree centigrade. this does not seem much, but one can not even imagine how much danger does this global warming will bring to us in the near future.

Causes of Global Warming:

The Earth has experienced many phases of warming and cooling over billions of years. Many natural factors contribute in these warming and cooling, but the effects of these factors take place very slowly, even in millions of years. So these factors are not accounted for the extra warming we currently observing in our planet. Actually it is us, the Humans, who are mainly responsible for global warming. We are accelerating the phenomenon of global warming with our human created emissions of greenhouse gases. Over the last 50 years, most of the observed temperature increase was due to the increase of greenhouse gases in atmosphere. Greenhouse gases are those which contribute to the greenhouse effect (see below). Gases such as Water vapor, Carbon dioxide, Methane, Ozone, Nitrogen oxides etc. are greenhouse gases.

Greenhouse Effect:

When sunlight reaches our earth’s surface, some percentage of them is observed by earth’s surface and they warm the earth. Rest of them are reflected and radiated back to atmosphere with a higher wavelength. These radiations would have been lost in space if there were no greenhouse gases. But greenhouse gases are present there, and they absorb some of the radiations of higher wavelength before they are lost in space. The absorption of this long wave radiant energy warms the atmosphere. In this way, the greenhouse gases act like a mirror and reflect some of the heat energy to the earth which would otherwise lost to the space. This phenomenon of reflecting back the heat energy is known as the ‘Greenhouse effect’. The gases contributing most in greenhouse effect are water vapor (36-70%), carbon dioxide (9-26%), methane (4-9%), ozone (3-7%) etc.

Greenhouse Effect at a Glance:



Global Warming by Greenhouse Effect:

Greenhouse gases act like a mirror and reflect back to earth a part of the heat radiation. These radiations would otherwise have radiated to space. The higher the concentration of greenhouse gases in atmosphere, the more heat energy is reflected back to earth. As a result the temperature of earth is increased. So the increased greenhouse gas concentration (mainly CO2) led to a substantial warming of earth and sea, and this incident is known as global warming.

Sources of Greenhouse Gases:

The main sources of greenhouse gases are:
  1.  Carbon Dioxide from:
    1. Fossil Fuel
    2. Deforestation
    3. Failing Sinks
  2. Methane from:
    1. Cattle and Rice Paddies
    2. the Artic Tundra
    3. Clathrates
  3. Nitrogen Oxides from Farming
  4. Other Gases

Now let’s see the greenhouse gas emission by different sectors:


Effects Of Global Warming:


The harmful effects of global warming cannot be described in one word. Because of it the Arctic glaciers will melt, as a result the height of sea levels will increase and many place in the world will go under water. It will expand the area of subtropical deserts. Many species of animals in earth will face extinction. Agricultural productivity will be harmed. So steps must be taken to prevent this harmful phenomenon.


বুধবার, ৫ জানুয়ারী, ২০১১

Global Warming and Bangladesh






The country of Bangladesh possesses one of the greatest threats produced by global warming.The major impact of global warming on Bangladesh can be divided into a few categories. They are:

           1. Climate change
           2. Sea Level change
           3. Changes in the pattern of distribution and density of population.

                                                Climatic change:
In the next 50 years, that is, by 2050 AD the temperature in Bangladesh is expected to rise by 1.5°-2.0°C. As temperature increases on a global scale, the hydrologic cycle will intensify and the rate of evaporation is expected to increase by 12%. This, in turn, will increase the level of precipitation globally. Climate models developed by IPCC indicate that Bangladesh may experience 10-15% more rainfall by 2030 AD. Bangladesh is visited by devastating floods quite frequently. In the past two decades, extensive flooding had occurred in 1987, 1988 and 1998 leading to colossal damages to infrastructures and the destruction of standing crops. An increase in rainfall will only worsen the situation.
Scientists also predict that global warming will increase the frequency and intensity of tropical storms. A high surface temperature of over 27°C of the sea helps in the formation of cyclones. Global warming will raise the sea surface temperature more than what it is now, thus increasing the possibility of cyclone occurrences. Bangladesh has already been experiencing catastrophic cyclones. The one that hit Bangladesh in 1991 claimed 150,000 lives and caused staggering losses to livestock and property. A warmer climate, by increasing the frequency of natural hazards such as floods and cyclones, will further aggravate such situations and negate the development efforts of the country.

                                                Sea level change:
Long-term sea level changes will occur due to changes in the global climate. Global warming will cause a thermal expansion of the seawater. A rise in temperature will also melt the polar and alpine glaciers. Since Bangladesh is deltaic, vast areas of the country will be submerged with the rise of the sea level. A Taskforce report predicts that one metre rise in the sea level will lead to loss of about 22,889 sq km of land, which is about 15.8% of the total area of Bangladesh. Furthermore, coastal areas will experience erosion and inundation due to intensification of tidal action. Again, a rise in sea water will enable saline water to intrude inland destroying agricultural land and sweet water sources.


Now let's take a quick look at the effect of sea level rising over Bangladesh:






.


Changes in the pattern of distribution and density of population: 




 Rising sea levels will drown a huge amount of land from the southern coast; as a result about 20 million people will be forced to migrate from there over the year 2050. This will cause serious humanitarian problems in the country:



 To sum up, for Bangladesh, the climate changes caused by global warming may lead to more rainfall, massive floods, great cyclones and droughts. However, conservation of the environment and sustainable development strategies will definitely protect the earth and its environment and will particularly save countries like Bangladesh from the catastrophe which can be induced by global warming.