Hey kids!
Let's try talking about something important and interesting that we observe everyday,
Before moving on to the topic , let's think about what we are experiencing these days
Usually, during May vacations, we hear people say, this time it is just too hot compared to the last time
and every year this statement keeps on repeating itself, that means
every year turns hotter compared to the previous one, correct?
But have you ever wondered why is this happening so?
Well the only logical explanation for this is the concept of global warming
Let's try to think what exactly is this concept and then get to it
For example, let's say
This is our earth, okay? This is earth
This around it
is my atmosphere, yes, various layers
of the atmosphere, correct?
Now, this atmosphere near the earth, the layers, near the earth
will be made of several types of gases, correct?
So, let's imagine, atmosphere having several type of gases inside it.
Various types of gases.
What kind of gases will be included? Well, that will have CO2
CH4 and so on. Yes, carbon dioxide and methane. Now, do you think they are important to us?
Yes. Why? Because, let's assume. Let's assume this
sun has to be bigger than earth , right? So, let's consider
only this much portion of the board
yes.
Let's consider this is half of the sun
right? Yes, This sun
is giving out tremendous amount of radiations, correct?
In the form of heat and light
These radiations are directly reaching the earth, right
They are reaching planet earth
They bang with this, what do you say, atmosphere layer
They enter and they reach till here, correct?
Now that, it has reach till here
It has the tendency, the rays of heat and the rays of light
they have tendency to bounce and go back especially heat
has the tendency to hit the earth;s surface and go back
Now, what will happen, if there are suppose
50 rays of heat coming on the earth surface
and all 50 going back
Do you think we will be able to survive better?
Well just think about it.
What happens if the suns rays, the suns heat hits the earth surface and goes back. It bounces back. It doesn't reach us.
What will happen? The temperature on earth will be
extremely cold
We will not be able to survive that particular cold temperature
correct? That is the reason why
Trapping of the heat rays is necessary
Now, who does this for us?
Yes, it is carbon dioxide , CH4 , that is methane
all these gases around atmosphere, in the layer around
will trap some heat rays and trap others
For example, we saw 50 rays coming on earth
Out of the 50, yes, these
gas will try to trap 30 and give back 20 rays
Why? Because only 30 is necessary for us
For example, if, if
30 rays are required for us
for us on the earth
to survive as a complete planet, right?
Now, just imagine, the number of these gases, the gases, CO2,
CH4, methane, these gases are called as green house gases, you know this?
Correct? Now, if the number of green house gases in the atmosphere increases.
Fifty rays coming eggs amount of green house gases  giving twenty rays back, keeping thirty back on the earth correct.
Now if amount of green house gases increases, will it calculate that the earth requires only thirty raise of heat?
No, more the amount of green house gases
more will be the heat which is trapped. So now when fifty rays are coming on the earth surface
green house gases because they have increased
they will trap almost forty five heat rays which are coming on the earth.
Now what will happen temperature will increase beyond expections.
Correct. We require thirty . Thirty five is bearable  but what about forty five rays. What are we gonna  do with so much of rays?
That is going to heat up the complete planet.
Correct? That exactly gets us to this concepts of global warming.
Why? Because why is the globe warming?
It is warming because more heat radiations are incident and they remain trapped in the complete earth's atmosphere.
That's the reason why temperature increases year after year unnoticed by us.
Correct. This is the concept of green house gases and global warming. Well fifty rays of heat,
twenty rays of heat, this were all just vague numbers for us to understand the concept.
It's the concept that we need to understand. It's not fifty rays of heat coming on the earth and thirty being trapped. No.
Well it is the green house gases which help in trapping some amount of heat on the earth.
But now if the number of green house gas increases , the amount of heat which is trapped
that will also increase. Correct?
That results in the increase in temperature of the complete globe.
And that's the reason why planet is warming . It's global warming that is  happening or that is taking place.
This gives rise to increase in temperature on planet . So what will happen if temperature increases?
Yes, we have air conditioners for us.
Correct. No , when increase in temperature takes place ability of water decrease. Yes because increase in intake of water increases right.
Temperature increase is causing severe problem heat burns, sun's stroke everything in us also and other animals also.
Yes, other animals are also used to , they are adapted to living in one particular temperature yes.
You and me may have the capacity to a certain extend but all organism, small little organisms  don't have that much capacity.
There life get effected to a great extend.
So what if their life gets effected to a great extend?
Well, that disturbs the complete ecosystems.
Food chain, food web, everything will get messed up.
Hence balance in the nature is when all the organisms are living happily in harmony with each other.
And that is why this concept of global warming is this days a very serious issue.
Very serious matter of concern for all of them in the planet.
Green house gases, yes, all this gases which are good in certain way but now
we have this vehicles, industries which lead to emission of carbon dioxide
then formation of methane gas and so many to very great extend.
That is increasing, the green house gas are increasing which is responsible for increase in the trapping of heat radiation
as the result of which the complete global warning phenomenon is taking place.
That is all about the concept of global warming , how it takes place,
because of what it is taking place and what is it that we need to do.
We need to decrease the emission of CO2 , methane and all this substances which will help in decreasing the green house gases.
The amount green house gases now has to be controlled.
That's the only thing that we can do? Yes that's the only thing we can do on our level.
Correct. This was all about the concept of global warming and the concept of green house gases.
Meet you all up in the next lesson when we talk about another serious major issue of  acid rains.
Thank you!
