Albedo: How the World’s Smallest Ocean Reflects Sunlight to Keep Us All Cool
For millions of years, long before humans ever walked the Earth, the Arctic Ocean has been frozen year-round. Its thickest ice withstood the heat of 24-hour summer sunlight, and its thinner ice would solidify again during the dark, cold winter months. But today, the Arctic Ocean is changing from the white of ice to the black of open waters. Its multi-year ice is shrinking, and in just half a century 75 percent of its summer sea ice has disappeared. The loss has profound and far-reaching consequences, because it represents the breakdown of the Earth’s natural cooling system.
“Albedo”, which is derived from the Latin for “whiteness”, is a measure of the reflectivity of a surface. The albedo effect, when applied to the Earth, is a measure of how much of the sun’s energy is deflected back into space. The Earth’s surface is a vast patchwork of colours, ranging from the dark surfaces of oceans and forests to the dazzling white of ice and snow. Each surface has a specific effect on the Earth’s temperature. Snow and ice have the highest albedo, reflecting 50 percent of the sun’s rays. Dark open water has the lowest albedo, absorbing 90 percent.
As the white ice decreases in area, more heat is absorbed into the dark ocean. This triggers a positive feedback loop: Warmer water then melts more ice from underneath, while CO₂ trapped in the atmosphere holds heat in the air and continues to warm the surface ice. Humidity also increases as the temperature rises, and water vapour is a powerful greenhouse gas. More ice therefore melts, which exposes more dark water, which melts more ice from underneath, and so on. Scientists call what is happening in the Arctic Ocean a “death spiral.” The more the Arctic ice melts, the warmer the entire planet gets, which melts even more ice, with catastrophic global results.
The Global Impact of Reduced Albedo Effect
For example, as the ice melts, the world’s weather patterns become unstable. Floods and droughts are on the rise, hitting hardest in already vulnerable areas. A heating planet also means water and hunger crises. Moreover, loss of polar ice also contributes to sea level rise. Hundreds of millions of people live in cities that are susceptible to rising sea levels. On our current trajectory, sea level rise will redraw the map of the world, displacing 2 billion people by the year 2100.
Business activity in the Arctic Ocean further complicates the problem by breaking up the remaining ice, darkening what’s left, and extracting oil and gas reserves which scientists warn are off limits if we want to keep the world from heating up more than 2°C. By transforming the entire Arctic Ocean above the Arctic Circle into the world’s largest preservation area, MAPS, the Marine Arctic Peace Sanctuary, protects remaining sea ice from the break-up and befoulment these activities would cause.
Considering these factors, it is clear that strong, meaningful and large-scale protection of the Arctic Ocean is required in order to stop fueling the “death spiral” and prevent significant global ecological and humanitarian impacts. MAPS, the Marine Arctic Peace Sanctuary, is the swiftest and most comprehensive option available, and we urge all relevant policy-makers to adopt it immediately.