Lesson 2:

Evidence of Climate Change

What you should know by the end of this lesson:

How we know Climate Change is happening

Background

The Earth's climate has always changed!

In the past changes have been attributed to natural causes. However, the term climate change is now generally used when referring to the rapid climate changes which have been identified since the early 1900s.

These recent changes are thought to be mainly as a result of human behaviour rather than due to just natural changes in the atmosphere.

Digital Workbook and Paper Jotter

Study the graphs below.
Describe in detail the global temperature pattern shown in each graph. (4)

Evidence of Global Climate Change

Digital Workbook and Paper Jotter

Read through the next 7 sections
They contain different pieces of information about climate change. Take the notes you need but there will be a quiz a the end to see how you have gotten on.

1. Global Temperature Change

This graph shows a steady increase in both the Global Temperature and the Concentration of Carbon Dioxide (a greenhouse gas) since the end of the 19th century. This is the same time the industrial revolution began.

2. Artic Ice Extent

Scientists have been keeping a clear track of the artic ice extent since 1979. They have done this every September, so that it is valid evidence. If they take the measurements at the same time every year then there will be no variation in Summer and Winter. However, September is when it is the smallest size as it is at the end of the summer months.

3. Changes in Biodiversity

Marmots are becoming bigger & more populous as they hibernate for a shorter period of time because winters are shorter in Canada and the Rockies.

Tree-eating wood beetles are likely to benefit from a warmer climate.

These images show damage to White Spruce trees in Alaska caused by the pests.

4. Photographic Evidence

Photos show the rising sea levels. Be careful of some evidence though, as the sea level is not rising this quickly and there are other forces in the world that might cause this to happen, such as a destructive coastline.

5. Melting Glaciers

Glacial retreat can be judged from photographs taken from the same location decades (much more significant time period) apart

6. Tree Ring Anaylsis

Tree rings show how old a tree is, as every ring shows the growth of a tree through a growing season. Larger tree rings indicate a longer growing season. As trees can be around 100 years old, this can show the change in lengths of growing seasons.

1490 Evidence of climate change.flv

7. Ice Core Anaylsis

Air samples are trapped inside layers of ice from thousands of years ago. This allows us to work out how much CO2 was in the air or what the make-up of the atmosphere was.

So while the science of Jurassic Park might be a little stretched, it is based on the science that we use to obtain atmospheric samples from thousands of years ago.