Understanding Global Warming and the Greenhouse Effect

Questions and Answers

What is the main purpose of this episode of Top Five Things to Know?

To explain the concept of global warming and separate facts from scare tactics (correct)

To blame human activities for global warming

To discuss the opinion of celebrities about global warming

To talk about the effects of global warming on polar bears

What do gases such as CO2 and CFCs do in the atmosphere?

Absorb ultraviolet radiation from the sun

Convert heat into light

Trap infrared radiation in the atmosphere (correct)

Reflect infrared radiation back into space

What is global warming?

An increase in the average temperature of the earth's atmosphere (correct)

A decrease in the average temperature of the earth's atmosphere

A change in the earth's rotation speed

A shift in the earth's axis

What is the main function of the greenhouse effect?

To regulate extreme temperature fluctuations on earth Signup and view all the answers

What is the correct sequence of events in the greenhouse effect?

Light strikes the earth's surface, heat is generated, and infrared radiation is trapped Signup and view all the answers

What type of radiation is converted to heat when it passes through the atmosphere?

Shortwave radiation Signup and view all the answers

What is the primary reason the greenhouse effect works?

Because of the presence of gases in the atmosphere Signup and view all the answers

What is the current trend in the concentration of carbon dioxide in the atmosphere?

It is increasing Signup and view all the answers

What is the relationship between the Earth's temperature and carbon dioxide levels?

They have a direct correlation Signup and view all the answers

What is the main factor that determines whether the Earth experiences warming or cooling?

The concentration of greenhouse gases Signup and view all the answers

What is a natural factor that contributes to changes in the Earth's temperature?

Changes in the sun's intensity Signup and view all the answers

Why are fossil fuels the most popular energy source?

They are the least expensive to use Signup and view all the answers

What is a byproduct of trash decomposition?

Methane gas Signup and view all the answers

What is a human contribution to greenhouse gas concentrations?

Burning of fossil fuels Signup and view all the answers

Why is methane gas often released to the air from landfills?

To prevent dangerous buildup in the landfill Signup and view all the answers

Study Notes

Global Warming Background

Global warming refers to an increase in the average temperature of the earth's atmosphere near its surface, resulting from natural or human causes, which may lead to a change in global climate patterns.

Greenhouse Effect

The greenhouse effect is the normal trapping of the earth's heat in the lower atmosphere, due to the conversion of light into heat as it strikes the earth's surface.
Visible light passes through the atmosphere and is converted to infrared radiation (heat), which is then trapped and reflected back to the earth by gases in the atmosphere.

Greenhouse Gases

Greenhouse gases, including carbon dioxide (CO2), methane (CH4), water vapor, nitrous oxide (N2O), and CFCs, trap heat in the atmosphere.
The concentration of these gases can change, leading to an increase or decrease in the amount of heat trapped.

Greenhouse Gas Emissions

The concentration of carbon dioxide in the atmosphere has risen from 315 parts per million (ppm) in 1960 to 391 ppm in 2012.
The estimated CO2 concentration during pre-Industrial Revolution times was 280 ppm.
Natural causes of greenhouse gases include volcanoes and animal waste, while human causes include combustion of fossil fuels and increased animal waste production from livestock.

Temperature Fluctuations

The average global temperature fluctuates over time, with evidence of past ice ages and warming periods.
Scientists have combined data from various sources to create a timeline of the earth's average temperature, showing regular fluctuations.

Causes of Global Warming

Global warming can have natural or human causes, with natural causes including an increase in greenhouse gases and cooling cycles led by a decrease in greenhouse gases.
Human contributions to greenhouse gas concentrations include burning fossil fuels and decomposition of trash, leading to an increase in carbon dioxide and methane concentrations.