Warming the Earth

Most places on Earth are warmer than they were 100 years ago.

• True

• False

Answer explanation

Although most locations on the planet have recorded increased temperatures since 1880, changes in global ocean and atmospheric circulation patterns have created small-scale temperature decreases in a few local regions.

Where have some of the strongest and earliest impacts of global warming occurred?

• Near the equator

• Around the North Pole

• All over the Earth evenly

Answer explanation

Some of the fastest-warming regions on the planet include Alaska, Greenland and Siberia. These Arctic environments are highly sensitive to even small temperature increases, which can melt sea ice, ice sheets and permafrost, and lead to changes in Earth's reflectance ("albedo").

How do scientists collect evidence about climate?

• Using satellites from space

• Measuring the temperature of the Earth and and sea levels

• Collecting historical data from tree rings and glaciers

• All of the above

Some kinds of air pollution can actually cool the planet by reducing the amount of radiation

from the Sun that reaches Earth.

• True

• False

If you removed the atmosphere's natural greenhouse effect, and everything else stayed the same, Earth's temperature would be:

• 10 degrees warmer

• 20 degrees warmer

• 10 degrees cooler

• 20 degrees cooler

Answer explanation

The greenhouse effect is a naturally occurring physical process that warms the Earth's surface with energy from the atmosphere. Without the effect, Earth's average surface temperature would be well below freezing.

Which of the following gases is not a greenhouse gas?

• Carbon dioxide

• Nitrogen

• Water vapour

• Methane

Today's global warming has not been seen in the last...?

• 100 years

• 500 years

• 1000 years

• 2000 years

Answer explanation

Tools for learning about Earth's ancient atmosphere include growth rings in trees, which keep a rough record of each growing season's temperature, moisture and cloudiness going back about 2,000 years. Corals also form growth rings that provide information about temperature and nutrients in the tropical ocean.

When average global temperature rises...

• Average rainfall increases

• Average rainfall decreases

• Rainfall is not affected

Answer explanation

• Average precipitation increases

Higher temperatures give rise to a more active water cycle, which means faster and greater evaporation and precipitation and more extreme weather events.

Which greenhouse gas is the main driver of Earth’s current warming?

• Methane

• Carbon dioxide

• Nitrogen oxide

• Water vapour