Question

• What is the recent and ancient evidence that recent warming and CO2 levels are unusual?

• How does the greenhouse effect work? What are some natural processes that affect climate?

Answer 1

What is the recent and ancient evidence that recent warming and CO2 levels are unusual?

1) Global temperature rise: The planet's average surface temperature has risen about 2.0 degrees Fahrenheit since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions.

2) Warming oceans

3) Shrinking ice sheets

4) Glacial retreat

5) Decreased snow cover

6) Sea level rise

7) Declining Arctic sea ice

8) Extreme events

9) Ocean acidification

How does the greenhouse effect work? What are some natural processes that affect climate?

The Earth’s surface, warmed by the sun, radiates heat into the atmosphere. The greenhouse gases absorb some of this energy (heat) and radiate much of it back towards the surface whilst the rest is radiated out to space. This is crucial in keeping the Earth's surface warm and able to sustain life.

Natural processes that affect climate:

1) Continental drift

2) Volcanoes

3) The earth's tilt

4) Ocean currents

5) Human causes: The large-scale use of fossil fuels for industrial activities.