PrintIn the first lesson, we saw that energy can be transformed from one form to another, and during this conversion, all the energy that we put into a device comes out. However, all the energy that we put in may not come out in the desired form. Please watch the following presentation:
What is the greenhouse effect?
Earth is a comfortable place for living things. It’s just the right temperatures for plants and animals – including humans – to thrive.
Why is Earth so special? Well, one reason is: the greenhouse effect! A greenhouse is a building with glass walls and a glass roof. The clear glass allows sunlight to shine into the greenhouse, while also trapping the Sun’s heat inside. This is how a greenhouse keeps plants warm, even at night and in the winter.
The greenhouse effect keeps Earth warm in pretty much the same way. Earth isn’t surrounded by glass, but it is surrounded by a jacket of gases called the atmosphere. In the daytime, the Sun shines through the atmosphere warming Earth’s surface. After the Sun goes down, Earth’s surface cools. This releases heat back into the air. But, some of that heat is trapped by the gases in the atmosphere. These heat-trapping gases are called greenhouse gases. Carbon dioxide, water vapor and methane are all examples of greenhouse gases.
Earth needs a balance of greenhouse gases to maintain just the right temperature for living things. But, some human activities are changing Earth’s natural greenhouse effect. For example, burning fossil fuels – like coal and oil – releases more carbon dioxide into our atmosphere. These extra greenhouse gases can cause the atmosphere to trap more and more heat, leading to a warmer Earth.
NASA satellites are constantly measuring the gases in our atmosphere from space. They have observed increases in the amount of carbon dioxide and other greenhouse gases. The information from NASA satellites can help scientists figure out where greenhouse gases are coming from and how they are ending up in our atmosphere. This information will help us better understand the impact that greenhouse gases have on our climate. And help us better understand this very special greenhouse that we call home.
Find out more about our Earth at NASA Climate Kids!
As can be seen from the Figure below, the amount of CO2 currently in the atmosphere is dramatically higher than previous levels even if we go back 800,000 years!
The onset of this dramatic rise corresponds to the industrial revolution and humanities increased use of CO2 producing fuels.