From Death Valley Flooding to Space Mirrors: Geoengineering Ideas to Combat Climate Change


Editor’s note: “Doomsday” author and WRAL TechWire contributor Marshall Brain says these eight geoengineering ideas could fight climate change. Here is an overview of each:

Geoengineering Option #1 – Adding Sulfur Dioxide to Earth’s Stratosphere

Scientists have long known that volcanic eruptions can cool the planet. For example, when Mount Pinatubo erupted in 1991, average temperatures around the world dropped by 0.5°C. Why ? Because the eruption sent 20 million tons of sulfur dioxide into the stratosphere. It turns out that sulfur dioxide reflects incoming sunlight back into space, which means less sunlight reaches the Earth’s surface. The entire planet is cooling down after a large volcanic eruption.

Humans could mimic this effect by letting high-altitude planes release sulfur dioxide into the stratosphere. Watch this video for a nice description of the idea and the controversy:

People who don’t like this approach say it’s a bad idea because we don’t know about unintended side effects. The opposite of this argument is that we know things could get catastrophically awful if we allow the planet to continue to warm via fossil fuel emissions. We may have no choice but to cool the planet.

Geoengineering Option #2 – Place Orbiting Mirrors in Space to Block Sunlight

If you don’t like the idea of ​​blocking sunlight with sulfur dioxide in the stratosphere, then how about using mirrors in space to do the blocking? The idea here is to put mirrors into orbit and use them in a controlled way to reduce the amount of sunlight reaching the planet.

This approach would probably be more expensive and more difficult than option 1, but it might give us more control. For example, if we wanted to shade the Arctic and Antarctica to specifically cool them, rather than block out sunlight globally, it might be possible to imagine this using orbiting mirrors. But a lot of research and money would be needed to bring this idea to fruition, as well as to understand/mitigate potential side effects.

Geoengineering Option #3 – Create More Clouds Over Oceans

If we could add more clouds covering the Earth, those clouds would reflect sunlight back into space. Clouds can also have different levels of brightness during this reflection, so we would like to make the clouds brighter if we could. This is where the idea of ​​Marine Cloud Brightening comes in.

This idea is basically simple:

  1. We build large floating machines to spray seawater mist into the air
  2. In the process, a lot of salt gets into the air
  3. Tiny salt particles in the air help form glowing clouds over the oceans

If we did it on a large enough scale, it would help cool the planet. We could also toggle the effect on and off very quickly.

Geoengineering Option #4 – Add Iron to the Ocean to Increase Plankton

This option may seem strange to you at first, but this one has actually been tried many times in the real world on a small scale. It turns out that adding iron to plankton dead zones in the ocean can dramatically increase plankton growth there. This nutrient alone is what stunts the growth of plankton in dead zones. So the idea is to add iron, let the plankton grow and die as they naturally would, and then that dead plankton sinks to the bottom and takes a bunch of carbon with it. In the ideal case, the plankton remains in the sediments at the bottom of the ocean without decomposing, and the carbon stays there for many years.

Early experiments showed that the basic idea works, but also showed that there could be unforeseen side effects and caveats. Therefore, much more research is needed.

Geoengineering Option #5 – Make Arctic Ice More Reflective With Glass Beads

Have you ever looked at a highly reflective road sign or tape at night and wondered what makes it so reflective? In many cases, the reflectivity is caused by tiny glass beads. When light enters one of these beads, it is reflected off the bead quite effectively. And glass beads are very similar to sand, which means they tend to be harmless to the environment.

Therefore, one idea is to use glass marbles in massive quantities to reflect sunlight back into space. And one place where that is being considered is in the Arctic, where the ice is melting rapidly. If we use glass beads to thin the ice, the ice will melt less. More ice in the Arctic is good because it means more sunlight reflecting back into space and less sunlight heating up the Arctic Ocean.

Geoengineering option #6 – Create ponds and lakes in desert areas

The Sahara Desert is gigantic at 3.5 million square miles. What if we flood parts of it with seawater or desalinated water? Or what would happen if we flooded Death Valley in the United States, which is 5,000 square miles and already below sea level? These projects would be expensive, but they would cool things down and give us more space to grow plankton for carbon sequestration. Watch this video for perspective on these ideas –

Geoengineering Option #7 – Adding Yellow Dye to the Arctic Ocean

Kim Stanley Robinson is a popular science fiction author whose book titled “The Ministry of the Future” found a large audience. In this book, he talks about two geoengineering techniques that have become more well known due to the popularity of the book. The first is to add a yellow dye to the Arctic Ocean to cool it.

The problem we face in the Arctic is that the sea ice is melting. With less ice there is more open water. Open water absorbs much more sunlight than ice because white ice is reflective. Consequently, the ocean is warming and melting the ice even faster in a destructive feedback loop.

By regularly adding large amounts of bright yellow dye to seawater, the lighter color means the seawater absorbs far less sunlight and therefore heat, thus keeping more ice around.

Geoengineering option #8 – Slow down glaciers like Thwaites Glacier

In this article, we talked about the gigantic global risk created by the Thwaites Glacier and other nearby glaciers in Antarctica. The problem is that these glaciers are naturally descending towards the sea and their speed is increasing. If the Thwaites Glacier collapses into the ocean, the rate of sea level rise would be catastrophic for beaches and coastal towns.

In his book, Robinson’s fictional scientists hypothesize that a layer of meltwater beneath these glaciers lifts them from their bedrock and lubricates their descent. Therefore, the idea of ​​geoengineering is to drill holes through glaciers and pump out meltwater. The glaciers then reconnect with the rock below them and slow down, preventing sea level rise due to collapsing glaciers.


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