The albedo effect is the ability that a surface has to reflect light. For example, the average albedo effect of the Earth is 0.3. The number shows that the Earth’s surface reflects about 30 % of the sun’s radiation. More so, a low albedo effect means that a surface absorbs the sun’s heat and contributes to a warmer planet. The albedo effect is crucial for the Earth’s optimal temperature. That is why it is common to hear about it in the ongoing climate crisis.
High albedo effect
Large bright surfaces are needed to maintain a temperature so that planet Earth, and the life that it sustains, can thrive. Therefore, white and snow-covered areas such as the Arctic and the Antarctic are essential – they have a very high albedo effect. These areas are the Earth’s most important cooling mechanisms. Naturally, the effect is highest in wintertime, as fresh snow reflects up to 90 % of the radiation from the sun. Other surfaces with a high albedo are clouds and deserts.
Low albedo effect
In contrast to the above, some areas have a very low albedo effect — for instance, the dark and open oceans. The ocean’s surface has an average impact of only 0.08 (meaning it reflects 8 % of the sun’s radiation). In other words, the oceans absorb the radiation and heat of the sun, contributing to a warmer Earth. Furthermore, the albedo of the oceans varies due to the angle of the sun’s rays. In some places, it can be as low as 0.02, absorbing about 98 % of the light from the sun.
Today, the planet’s ice-covered areas are melting very fast. As a result, the oceans are expanding – meaning more areas absorb heat from the sun. This development creates a “feedback loop” (also known as a feedback mechanism). Since the oceans grow bigger due to ice melting, they contribute to an even faster ice-melting process. Furthermore, this leads to rising sea levels.
The example of the feedback loop can also have the opposite effect. In this case, the icecaps will grow larger as the oceans get smaller. The reduced surface of the ocean then contributes to a colder climate. It allows the ice to spread even further than “normal”. In other words, the albedo effect of the entire Earth would increase. Hence, a feedback mechanism that contributes to the cooling of the planet.
Other parts with significant albedo effects are forests. However, the effect differs greatly depending on which forest it is. For example, a deciduous (broad-leaf) forest has a higher effect than a coniferous forest (e.g. Christmas trees). This difference is because the light leaves in a deciduous forest reflect more light than dark spruce. More so, the leaves of a deciduous forest fall off in the winter. Therefore, many climate researchers have stated that deciduous or mixed forests are best for the climate, which means that these forests would naturally contribute to the cooling of the planet.
Another interesting fact is the ability to use the albedo effect in energy-smart buildings. For example, in construction, one can easily create surfaces that absorb more heat, such as a black roof. This heat source can be wise to consider in countries with colder climates. More so, the shape of the rooftop can matter, as one would want the snow to fall off the roof in wintertime. Similarly, one can choose light colours for a house to gain a cooling effect. In warmer countries, this leads to less consumption of energy, e.g. air conditioning.