Global Warming:What is climate change?

It is caused by humankind?

Weather and Climate

Weather can change from day to day, and even minute to minute.

Climate remains relatively stable over many years, but we are experiencing climate change.

Weather

Weather refers to current conditions

such as temperature, pressure, humidity and precipitation.

Climate

Climate refers to average weather over

time and space. Seasons have a typical

climate associated with them.

High frequency rays of light travel from the sun towards the earth, carrying energy. The high frequency rays are able to penetrate the earth’s atmosphere.

The high frequency rays of light strike the earth, causing it to warm up.

The heat radiates from the earth back towards the atmosphere. However, this energy has a lower frequency than the original rays of light.

The Greenhouse Effect: What is it?

Not all of this lower frequency energy can escape from the earth back into space – some of it is held in by the earth’s atmosphere.

As a result, the earth experiences a general warming effect; more heat energy is able to radiate onto the earth than is able to escape.

This is known as the greenhouse effect because it is similar to what happens when sun light radiates through a pane of glass into a greenhouse.

Greenhouse Effect Continued...

This is a diagram

illustrating the

greenhouse effect.

Question

In relation to the atmosphere, how could the greenhouse effect be

intensified?

What would this lead to in terms of global climate?

What are greenhouse gases?

Greenhouse gases are gases in the atmosphere that tend to absorb heat and prevent it from travelling back into space. They typically include water vapour, methane, and carbon dioxide as well as ozone.

Increasing Greenhouse Gases

How have humans contributed to global warming?

What greenhouse gas is associated with an increase in global temperature?

What do humans do that causes the production of this gas?

What are combustion reactions?

Human Contribution to Global Warming

What You May Not Have Heard Much

About...Natural Causes of Global Warming and Increased Greenhouse Gases

Methane gas (a greenhouse gas) is regularly released from Tundra and Wetlands areas, contributing to increased greenhouse effect.

Volcanic eruptions result in thick clouds of dust and gases that contribute to the greenhouse effect.

Changes in the earth’s solar radiation levels (sunspots) can have an impact on climate.

Natural Causes of Global Warming

The earth wobbles: Although the earth rotates, it does not achieve perfect rotation. As a result, northern and southern areas are alternately exposed to increasing levels of heat. This effects climate for long periods of time.

Climate cycles are a regular occurrence on earth; there have been ice ages and periods of increased global temperature before.

Natural Causes Continued...

So, The Big Question:

Who or what is mainly responsible for climate change?