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Albedo is a unitless, non-dimensional metric that measures how well a surface reflects solar radiation. An albedo is a number that ranges from 0 to 1. Albedo is a term used to describe the ‘whiteness’ of a surface, with 0 indicating black and 1 indicating white. A value of 0 indicates that the surface is a ‘perfect absorber’, absorbing all energy. Solar energy can be absorbed and used to heat the surface or, in the case of sea ice, to melt it. A score of 1 indicates that the surface is a ‘perfect reflector’, absorbing all incoming energy and reflecting it.
Albedo is a term that refers to the reflectivity of visible light, though it can also refer to the infrared part of the electromagnetic spectrum. When you stroll on the blacktop on a sunny summer morning, you immediately understand the concept of low albedo. Because the black surface absorbs more energy and reflects significantly less, the blacktop has a substantially lower albedo than concrete.
Albedo Effect
The albedo effect has a tremendous impact on our climate here on Earth. The earth absorbs more solar energy with a reduced albedo, causing temperatures to rise. If the albedo is more than usual and the Earth is more reflective, it would cool the planet.
The snow temperature feedback is one example of this albedo effect. A snow-covered area reflects a large amount of radiation. This is why getting bad sunburns while skiing is so common. However, the albedo decreases when the snow-covered land warms up and melts. Temperatures rise as more sunlight is absorbed in the area. According to climate scientists, global warming is causing the polar ice caps to melt. Dark ocean water will absorb more sunlight when the ice caps melt, contributing even more to global warming.
Global Warming
As can be seen, the albedo of the Earth impacts climate. Changes in one place can affect the entire planet’s environment since the quantity of sunlight reflected by Earth is average. Scientists are concerned that changes in the albedo of the Earth could contribute to global warming. The hypothesis that the Earth’s temperature rises due to increased carbon dioxide and other substances is known as global warming.
Remember how albedo is high in polar ice? The albedo in this area will be lower if much of the ice melts and becomes dark ocean water, contributing to global warming. Some arctic ice has melted, according to scientists.
Earth observation satellites use a variety of sensors to measure the Earth’s albedo continuously, and the planet’s reflectivity may be assessed using Earthshine, which is light from the Earth that reflects off the Moon.
Different sections of the Earth contribute different amounts to our planet’s overall albedo. Because trees are dark and have a poor albedo, removing them may boost an area’s albedo, especially in regions frequently blanketed in snow during the winter.
Climate Change
The Earth’s climate is based on the balance of the incoming and departing sun’s energy balance, determined by albedo. It could be said that the albedo of the Earth, which is 0.30, has a substantial impact on the Earth’s equilibrium temperature because it influences how much solar radiation is reflected rather than absorbed by the Earth. This alters the way the Earth’s energy budget balances and, as a result, the Earth’s heat balance.
The albedo of the Earth changes as the planet warms. As a result of rising temperatures caused by global warming, the amount of ice covering the earth is dwindling. Consequently, the total area of white surfaces diminishes, causing less energy to be reflected and more to be collected. This process causes the Earth to become even warmer. The loss of Arctic ice is particularly problematic because it causes positive feedback (a feedback cycle that drives the climate out of control). The greenhouse effect can change the Earth’s albedo in addition to melting ice, which reduces it.
How to increase the Earth’s Albedo?
The following is a plan of action proposed by geo-engineers to increase the Earth’s Albedo:
- Sulphate aerosols are sprayed into the stratosphere and reflect sunlight to space.
- The use of seawater as a spray.
- Increasing the reflectivity of the world’s roofs by pouring white paint on them.
- Thousands of small mirrors floating in space between the Earth and the Sun
Conclusion
The percentage of the Earth’s surface covered by snow and ice significantly impacts how much solar radiation is reflected or absorbed. Low albedo (dark surfaces) leads to increased energy intake and, as a result, heat. Furthermore, more dark surfaces will emerge when more ice and snowmelt. As a result, this has a self-reinforcing impact. As a result, climatic change in the Arctic has a significant impact on worldwide climate change.
