Let's explore the effect of aerosols on Earth's albedo by considering the recent eruption of the Icelandic volcano Eyjafjallajökull. Volcanic eruptions release vast amounts of ash. This particulate matter may remain suspended in the atmosphere in the form of atmospheric aerosols.

Aerosols can reflect incoming energy in several ways. Individual suspended particles can reflect incoming photons of light back out of the atmosphere. They can also coalesce into raindrops and become constituents of light-reflecting clouds.

If the Icelandic volcano Katla erupts, the particulate matter released may reflect enough solar energy that Earth's temperature will noticeably cool in the short term. In the long term, the gases it releases, such as SO2 and CO2, may have other climatic effects.

Now that you have explored the meaning of albedo, consider how it affects the overall radiation balance of the earth. Open the Planetary Climates learning tool, navigate to the 'Build A Planet' learning tool, and enter the following conditions to create Earth:

Question: What would happen if Earth's albedo increased to 0.5 (50% of light reflected back into outer space)?

After creating Earth in the Build a Planet simulator (as above), increase the albedo to 0.5 as shown on the right.

Note that the central radiation bars are no longer balanced. We can re-establish a balance by changing the surface temperature of the planet. In what direction must you shift the temperature?

With an increased albedo, more energy will reflect out of the atmosphere. This will cause the surface of the planet to receive less energy and become much cooler. Adjust the temperature until the energy is once again balanced. You will find that Earth's temperature becomes a chilly -2°C.

Question: What would the earth's temperature be if our planet had a lower albedo value of 0.25?