Evidence for Climate Change

What are greenhouse gases?

• gases that cause climate change
• gases that emit green smoke
• gases that are used to make green colored glass

Which of the following is the best conclusion that can be made from this graph?

• atmospheric carbon dioxide levels have been decreasing since 1960
• Hawaii has a lot of carbon dioxide
• humans have been working hard to decrease carbon dioxide levels
• atmospheric carbon dioxide levels have increased steadily since 1960

Scientists determine climate conditions today by...

• Making direct measurements.

• Creating computer models.

• Examining ice cores.

• Using dendrochronology.

To learn what climates were like in the past, scientists investigate the following types of evidence that serve as substitutes for direct measurement.

• Computer models

• Proxy indicators

• Topography

• Carbon footprints

Scientists can extract samples of ancient air from ice cores

• True
• False

How do scientists collect evidence about climate?  

• using remote sensing from space with satellites
• by ground-based measurements of surface temperatures, carbon dioxide concentration and sea level
• by collecting “proxy data” from tree rings, ice cores, and historical records
• all of the above

By examining ice cores, we know that when carbon dioxide levels are high, temperatures are also higher.

• True

• False

Thicker tree rings indicate poor growing conditions for plants and trees.

• True

• False

How can monitoring glaciers provide evidence for climate change?

• When climate gets warmer, glaciers get larger.

• When glaciers retreat it means that it is getting colder.

• Glaciers contain old thermometers to measure temperatures.

• When climate is warmer, glaciers retreat. When climate is colder, glaciers expand and get larger.

Direct evidence in science is evidence that

• is measured or visibly evident
• is not available for most questions
• is evidence that is difficult to find