Albedo: What is it and Why is it so Important?

Decreasing the Earth’s temperature with energy efficiency is what many companies, organizations and people are trying to do by fighting the effects of climate change. However, one way of doing this is largely ignored due to a lack of large scale solutions on the topic.  I am referring to efforts of increasing the albedo of our planet. Albedo (also known as the reflection coefficient) is the reflective power of a surface. Therefore, when Earth’s albedo is increased, the global temperature should drop (or rise at a slower rate) and consequently slow climate change.  Since capturing the energy of the sun has proven to be quite costly, perhaps it would be a good idea to reflect it instead.

Ideas including increasing cloud cover, layering huge expanses of ground with white material, placing mirrors or reflective dust into the upper atmosphere, and many others have been proposed in the past by climate change advocates. Similar to wearing black clothing on a sunny day, the goal is to decrease the heat absorbed by the Earth via lighter colored and reflective materials.

A study done by the United Nation's IPCC measured the possible financial and climate change savings for Los Angeles if the albedo was increased. The results showed that a 7.5% increase in albedo would lead to 50-60% reductions in electricity for cooling, 30+% reductions in peak loads for air-conditioners, fewer photochemical smog days with reduced health costs and as much as a 5 degree Fahrenheit drop in temperature. This could be accomplished by simply increasing the albedo of roads, roofs, footpaths, and the walls of many buildings, along with strategic planting of tress and greenery. Not only would this slow climate change, but it would probably clean up and rejuvenate many run down cities around the world.

Also according to the study, potential savings for Los Angeles are estimated to be half a billion dollars annually after such adjustments, when health cost savings are included. Although a timeline for return on investment was not mentioned, it would probably be fairly short relative to many climate change timelines proposed for the next few hundred years.

Buildings with more albedo not only use less energy for heating and cooling, but they also last longer than dark colored structures which are subjected to greater daily extremes of expansion and contraction. The same goes for roads which have historically been paved with black asphalt, but could easily be paved using lighter colored materials and face less torment from the sun’s rays. Over the next few posts, I will go into the more outlandish ideas proposed above in more detail to see which ones are actually viable to slowing future climate change.