CAJ - Albedo enhancement (Surface)

Albedo enhancement (surface)

In order to direct even more solar radiation back towards space, the reflectivity of other surfaces besides clouds should be increased. One of the most widely discussed targets for this project are urban areas. The plan looks like this: Enhanced albedo methods in urban areas could be applied by painting roofs and by paving areas completely white. This method could be highly effective when it is realised on a global basis. It is estimated that surface albedo enhancement would cost several billion dollars for material as well as for labor but would, on the other hand, save a considerable amount of energy costs. For example, the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) succeeded in reducing building heating and cooling costs by approximately 70% annually. How did they manage that? Thanks to new installations of cool roofs, which are specially designed roofs to maintain a lower temperature than traditional roofs, in certain urban areas. Isn’t that incredible?

There are, as always, a few drawbacks when it comes to enhancing the surface albedo of urban areas. Firstly, people are concerned of the aesthetic appeal of such roofs and white paved areas. Should that really be of concern nowadays? Anything that helps to cool the Earth’s temperature should be considered. I actually quite like the look of white roofs. Secondly, a loss of reflectivity benefit of such roofs could be caused if the roofs are not well maintained. And lastly, which is the most understandable concern, the energy costs in colder climates for heating could increase as a consequence.

Apart from painting roofs and paving areas white, there are additional techniques considered for enhancing the surface albedo. One proposal is to modify plants through genetic engineering to highly increase their albedo. Sugar beets with their broad leaves, for example, would actually reflect 26% of solar radiation. Studies showed that an implementation could, in case of doubled CO2 and 3 ºC warming, lead to 0.1 ºC cooling globally. Another study showed that 20% increase in crop albedo could cool  Europe's summertime temperature to 1%. The effect could actually be locally and seasonally even larger. During summer, the enhanced albedo crops would help to keep soil moisture at high levels. This could be, as a result, beneficial to agricultural productivity as well. The implementation costs for this proposed method  is considered relatively low. However, it will take at least one decade for such enhanced albedo plants to be commercially available. The question arises whether it will already be too late at this stage? 

One last proposal for enhancing surface albedo is to cover oceans with reflective surfaces. This project raises the concern about the potential negative impact on aquatic life this reflective surface could have and about where this surface should be placed. 

The conclusion is: Any big surface with a colour can be geoengineered :-)