Physics

#ELI5 - The Earth's High Albedo

The albedo rate is a complicated concept
The albedo rate is a complicated concept

Updated August 01st, 2018

ELI5 is an internet term I first heard on Reddit. It means "Explain Like I'm Five" and is a phenomena that I believed was developed for people like me, whose understanding of certain things outside of their area of expertise is sorely lacking and who find a lot of the academic explanations experts offer to be confusing. ELI5 is layman's terms for millennials. Basically, it's asking questions about something you don't understand and asking for responses that might be given to kids. It comes in handy when you want to learn things, which was me, this summer, with the albedo effect.

Learning Like I'm Five
I truly believe in the methodology of ELI5/layman's terms. As a person who deals with numbers, geographical occurrences like global warming and solar radiation/sunlight are only on my periphery, but I recognize the both of them as being information that I should know.

No matter what POTUS says, global warming is a very real phenomenon - the wheels of which are already in motion toward the decline of our planet. So when I wanted to learn more about global warming and this albedo I'd heard so much about, I decided that I would search for a lesson aimed at school children rather than a scientific journal because those simple terms are helpful, regardless of age. How else can we learn anything worth knowing?

First and foremost, the word albedo comes from the Latin for light, albus.

What is the Earth's Albedo?

Have you ever been playing in the snow for so long that you start to get floaters in your eyes? That's due to the earth's albedo. The higher the level of albedo, the more sunlight will reflect off of the earth and back into the atmosphere.

Snow has a high albedo, and therefore less of the sun's energy is absorbed when it's present. The average albedo of our planet, on the other hand, is between 30-35%. This is much lower than the albedo of snowy surfaces or lands and therefore means that less sunlight is reflected back into space.

What Happens to the Sunlight That Isn't Reflected Back?

If you are to go into the desert, you will probably be told to wear white to repel heat. This is a great example of albedo. White clothing will reflect the sunlight, much like snow (which is cold) and the human body will, therefore, absorb less heat.

Black, on the other hand, will absorb the heat, which is an effect of albedo. Much like the plants, the forests, the earth, and deep oceans absorb the remaining 70-75% of sunlight. This absorption keeps our planet warm and helps sustain all forms of life.

How Does Albedo Affect the Planet?

The earth has many different surfaces, all of which albedo affects differently. If we take snow as an example again, one should expect places like the Arctic or Norway or certain parts of Canada to have a higher albedo/sun repellant than those in South America, Australia, and Asia, where there are a lot of dense woodlands.

This also means that the warmer places with a higher albedo (South America, Australia, Asia) absorb more energy from the sun than those of the former, northernmost locations.

Why Do People Think Albedo Affects Global Warming?

Global warming is a very real situation, and the earth's albedo has a high hand to play in this. We've heard people talking about the polar ice caps melting. If these polar ice caps are, as of now, not reflecting as much energy back into the atmosphere, they are going to melt. As a result, they'll turn to water, absorb more heat due to their lower albedo, and the climate - because of its average - will change across the entire planet. This is the feedback effect.

What is the Feedback Effect?

The earth's climate system is influenced by positive and negative feedback loops. The ice caps melting into water, for example, is far easier explained as thinking of it like the day after a heavy snow day. What causes the sheet of bright white snow to begin to melt? The melting snow exposes more of the ground which lessens the albedo, warms the climate, and then melts more of the snow.

This feedback effect/these loops are constantly changing (as our climate does, as albedo does), creating rapid and vastly occurring changes in climate. You've heard someone say, "it should not be this warm in February!" and responded with, "Global warming", right? This is due to the changes in albedo in the Arctic, that feeds back on the rest of our planet.

Is There a Way We Can Stop Global Warming?

Scientists have been trying to figure out a way to do this for years. In the last twenty years, the rise of solar-powered energy, solar panels, and even solar-powered vehicles has been a good step toward an end product. Most people believe that the earth is too far gone for us to save after hundreds of years of fossil fuels being sent up into the feedback loop of our atmosphere, but that might not be the case.

Could we lay a reflective surface down over all of the polar ice caps so that the albedo goes up again? Sure, if we want to ruin how beautiful the scenery is. Polar bears have adapted to the melting ice because that is what we, as warm-blooded mammals, are built to do!

If we got the albedo to rise again in the Arctic, could it help to reverse the effects of global warming? Sure, if we start to dispose of our trash into bins, replace driving to work with cycling or walking, and cut down on airfare and warfare, but there's only a couple of those things we can actually do personally.