OVERVIEW OF CLIMATE CHANGE

The climate system is a complex, interactive system consisting of the atmosphere, land surface, surface, snow and ice, oceans and other bodies of water and living things. The atmosphere component of the climate system most obviously characteristics climate; climate is often defined as ‘average weather’. Climate is usually described in terms of the mean and variability of temperature, precipitation and wind over a period of time, ranging from months to millions of years (the classical period is 30 years). The climate system evolves in time under the influence of its won internal dynamics and due to changes in external factors that affect climate (called ‘forcings’). External forcings include natural phenomenon such as volcanic eruptions and solar variations, as well as human induced changes in atmospheric composition. Solar radiation powers the climate system.

There are three fundamental ways to change the radiation balance of the Earth:

1) By changing the incoming solar radiation (e.g., by changes in Earth’s orbit or in the Sun itself)

2) By changing the fraction of solar radiation that is reflected (called ‘albedo; e.g ., by changes in cloud cover, atmospheric particles or vegetation);

3) By altering the long wave radiation from Earth back towards space (e.g., by changing greenhouse gas concentrations).

4) Climate, in turn, responds directly to such changes, as well as indirectly, through a variety of feedback mechanisms.

The amount of energy reaching the Top of Earth’s atmosphere each second on a surface area of one square metre facing the Sun during daytime is about 1,370 Watts and the amount of energy per square metre per second averaged over the entire planet is one-quarter of this. About 30% of the Sunlight that reaches the Top of the atmosphere is reflected back to space. Roughly two thirds of this reflectivity is due to clouds and small particles in the atmosphere known as ‘aerosols’. Light-coloured areas of Earth’s Surface – mainly snow, ice and deserts – reflect the remaining one-third of the sunlight. The most dramatic change in aerosol-produced reflectivity comes when major volcanic eruptions eject material very high into the atmosphere. Rain typically clears aerosols out of the atmosphere in a week or two, but when material from a violent volcanic eruption is projected far above the highest cloud, these aerosols typically influence the climate for about a year or two before falling into the troposphere and being carried to the surface by precipitation. Major volcanic eruptions can thus cause a drop in mean global surface temperature of about half a degree Celsius that can last for months or even years. Some man-made aerosols also significantly reflect sunlight.

The energy that is not reflected back to space is absorbed by the Earth’s Surface and atmosphere. The amount is approximately 240 Watts per square metre. To balance the incoming energy, the Earth itself must radiate, on average, the same amount of energy is transmitted back to Space. The Earth does this by emitting outgoing long wave radiation. Everything on Earth emits outgoing long wave radiation. That is the energy, one feels from a fire; the warmer an object, the more heat energy it radiates. To emit 240 Watts Per Square Meter, a surface would have to have a temperature of around -19 degree centigrade. This is much colder than the conditions that actually exist at the Earth’s surface (the global mean surface temperature is about 14 degree centigrade). Instead, the necessary -19 degree centigrade is found at an altitude about 5 Km above the Surface.

This easily states as to why the Earth’s Surface is this warm is the presence of greenhouse gases, which acts as a partial blanket for the long wave radiation coming from the surface. This blanketing is known as the natural greenhouse effect. The most important greenhouse gases are water vapor and carbon dioxide. The two most abundant gases of the atmosphere – nitrogen and oxygen have no such effects. Clouds, on the other hand, do exert a blanketing effect similar to that of the green house gases; however, this effect is offset by their reflectivity, such that on average, clouds tend to have a cooling effect on climate (although locally one can feel the warming effect; cloudy nights tend to remain warmer than clear nights because clouds radiate long wave energy back down to the surface).

Human activities intensify the blanketing effect through the release of green house gases.

Let’s therefore practice some methods so that we can reduce the green house gases and help stabilize our climate:

Read this in detail and lets make a Disaster Free World.

In order, to tackle global warming, there is a need for DISASTER RISK REDUCTION programmes. Most important part of these DRR programmes is creation of flood shelters, with proper engineering methods. It is basically a raised platform, which can withstand any form of water pressure below. It is made for different capacities. According to United Nations, severe flood which have taken place in South Asia and Europe this year illustrate the need to spend more on reducing the risks communities face from natural disasters. International Strategy for Disaster Reduction states that sturdy houses must be built away from low –lying areas and early warning systems should be set up to save lives in line with an agreement backed by 168 countries in 2005 in Kobe, Japan.

According to Reuters news; ISDR expert Reid Basher told reporters that, “It is not rocket science. It is plain and simple stuff about building stronger houses, putting in warning and educating the public so we’re not flat-footed when these events come.”

Global Warming can be reduced at our personal levels by doing the following things:

1) Usage of Fluorescent Bulbs: These compact fluorescent bulbs help to reduce the level of carbon dioxide usage. It saves about 300 lbs of carbon dioxide and approximately dollar 60 a year.

2) Check your car’s air filter monthly. This will save 800 lbs of carbon dioxide.

3) Usage of Recycled Paper: Stress on the usage of recycled paper. This saves about 100 lbs of carbon-dioxide and almost dollar 40 a year.

4) Install a Low-Flow Showerhead: Usage of less water in the shower means less energy to heat the water. This helps to save 350 lbs. of carbon dioxide and dollar 150 a year.

5) Take Shorter Showers: Taking shorter showers can save 350 lbs. of carbon dioxide and dollar 99 per year.

6) Thermostat should be adjusted: Move your heater thermostat down two degrees in winter and up two degrees in the summer. Save 2000 lbs of carbon dioxide and dollar 98 per year.

7) Buy Energy Certificates: Help spur the renewable energy market and cut global warming pollution by buying wind certificates and green tags.

8) Plant a Tree: Trees suck up carbon dioxide and make clean air for us to breathe. Save 2,000 lbs. of carbon dioxide per year.

9) Unplug Un-Used Electronics: Even when electronic devices are turned off, they use energy. Save over 1,000 lbs of carbon dioxide and $256 per year

10) Bring Cloth Bags to the Market: Using your own cloth bag instead of plastic or paper bags reduces waste and requires no additional energy.

Among other actions that can be taken are:

· Start a Club

Start a global warming club at your locality or with your friends or your next door neighbors and set goals to curb your energy use.

· Speak Out

Run for global warming platforms. Place your views about what you are doing to curb global warming emissions.

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