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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. This means that about 30 % of the suns radiation is reflected back and away from the planet by the earth’s surface. More so, a low albedo effect means that a surface absorbs the suns heat and contributes to a warmer planet. The albedo effect is crucial for the earth’s optimal temperature. Therefore, 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. In fact, these areas are the earth’s most important cooling mechanisms. Naturally, the effect is at its 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 surface of the ocean has an average effect of only 0.08 (meaning 8 % is reflected). 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 rays. In some places it can be as low as 0.02. This means that it absorbs about 98 % of the light from the sun.

Feedback loops

At present time, the planets ice-covered areas are melting at a very fast rate. As a result, the oceans are expanding – meaning there are more areas that absorb the heat from the sun. This creates something that is called a “feedback loop” (also known as a feedback mechanism). Since the oceans are increasing, due to the melting ice, they contribute to an even faster process of ice-melting. Furthermore, this contributes to rising sea levels.

The example of the feedback loop can also have an opposite effect. In this case, the icecaps will grow larger as the oceans become smaller. The reduced surface of the ocean then contributes to a colder climate and allows the ice to spread even further than “normal”. In other words, the albedo effect of the entire planet earth would increase. Hence, a feedback mechanism that contributes to the cooling of the planet.

More facts

Other parts with significant albedo effects are the forests. However, the effect differs greatly depending on which kind of forest it is. For example, a deciduous forest (broad-leaf forests) , has a higher effect than a coniferous forest (e.g. christmas-trees). This has to do with the fact that 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. Meaning that these forests would naturally contribute to the cooling of the planet.

Another interesting fact is that the albedo effect can be used in energy-smart buildings. In construction, one can easily create surfaces that absorb more heat, such as a black roof. This can be smart to consider in countries with colder climates. More so, the shape of the roof can matter, as one would want the snow to fall off the roof at winter time. In a similar way, one can chose light colors for a house to gain a cooling effect. In warmer countries, this leads to less consumption of energy for air conditioning.

 


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