One of the great wonders of the natural world is in hot water . . . literally. Warm ocean temperatures are destroying Australian coral at the Great Barrier Reef. Innovative scientists hope to help by engineering the clouds. They are testing a concept called “cloud brightening” to cool the water and protect the vital marine structure.
Off the coast of Queensland, Australia’s Great Barrier Reef stretches for over 1,400 miles. Billions of tiny soft-bodied animals called coral polyps built the reef, which is home to millions of other sea creatures and plants.
By themselves, coral polyps are clear. But healthy corals aren’t usually alone. Colorful algae live inside their tissues, giving corals their beautiful hues.
God made corals and algae to depend on each other for survival. Corals provide algae a safe home, and algae make food products for corals. As long as the ocean environment stays fairly stable, the two get along just fine.
However, corals under stress sometimes expel the vibrant algae, an event called “coral bleaching.” Without their main food source, bleached corals begin to die. The flora and fauna that depend on reefs also lose habitat and suffer.
Many things can stress corals, including high air and water temperatures, coastal development, chemical runoff, and invasive human activity such as over-fishing.
The Great Barrier Reef has endured four major bleaching events since 1998. Some scientists fear recent coral death rates could be the worst ever. They have been experimenting for years with ways to cool ocean water in hopes of preserving the world’s reefs. Daniel Harrison is part of a team experimenting with cloud brightening. The idea is to alter clouds in Earth’s atmosphere so that they reflect warming sunlight away instead of letting it through.
“We’re trying to look at all the different ways that we could prevent bleaching on the Great Barrier Reef,” Harrison says. “When we did all the analysis, cloud brightening came out as really one of the better ideas.”
The approach involves shooting tiny saltwater droplets into the air using giant boat-mounted blowing machines. When the mist evaporates, tiny salt crystals remain. According to Harrison, “hundreds of trillions” of crystals drift into the atmosphere, “brightening existing clouds and deflecting solar energy away from the reef waters.”
Think of the crystals as tiny mirrors redirecting the Sun’s beams back up into the sky—one minute reflection at a time.
Harrison’s team has tested cloud brightening successfully on a small scale. But no one is sure whether the method is possible to recreate over much larger areas. Where to place the misting machines and how much the concept will cost are unknown also.
O Lord, . . . the Earth is full of your creatures. Here is the sea, great and wide, which teems with creatures innumerable, living things both small and great. — Psalm 104:24-25