Sweet Shades: Can Geo-Engineering Keep Earth Cool?

Have you seen those aluminum light reflectors that go inside the front windshield of your car to keep the car from getting so hot in the summer? Pretty useful, even if they just keep your car a few degrees cooler. Well, scientists have essentially come up with a way to create something similar for the entire planet.

Scientists believe they have found a way to utilize geo-engineering (basically manipulation of the planet’s environment) to counteract the warming expected if we maintain our current rate of carbon emissions. By injecting very small particles of sulfate into the upper atmosphere, we could deflect some of the sunlight coming towards Earth. Scientists estimate that if we block 2% of the sun’s incoming light, we could counteract the warming expected with the projected rise in atmospheric carbon from 390 parts per million (ppm) today to 560 ppm.

I did a bit of research and found there are a number of different geo-engineering methods that have been suggested to combat climate change, and they fall into two basic categories: deflection of solar energy (for example, the reflective sulfate particles mentioned above) and removal of carbon dioxide. Some alternative geo-engineering methods include:

  1. Ocean iron fertilization: Adding iron to the oceans on a massive scale would promote phytoplankton blooms. These blooms would help to absorb carbon dioxide through photosynthesis and eventually sink to the bottom of the ocean after the plankton dies. (My question: Would more surface plankton reduce sunlight to the upper ocean and have an adverse affect on the populations of other marine species?)
  2. CO2 Capture and Storage: Carbon capture can be done in two ways – 1) Removing the C02 gas after a fossil fuel source is oxidized but before combustion occurs, or 2) Capturing carbon from exhaust gases post-combustion (post-combustion capture can be applied to existing power plants, or it could be performed in an “oxy-firing” environment where fuel is burned in pure oxygen rather than air). After the carbon is captured, it is then stored deep underground. (My question: Could underground carbon storage result in any type of pressure build up or have an effect on tectonic plate movement?)
  3. Reforestation: Rebuilding forests would pull carbon dioxide from the atmosphere through an increased level of photosynthesis. (I love this idea. Plants give us more clean oxygen to breathe, plus they’re nice to look at J.)
  4. Cloud seeding: Spraying ultra-fine droplets of sea water into the air can increase the reflectivity of clouds (called “albedo) by increasing the concentration of water droplets and thus the overall surface area of the cloud. (My question: Would increased reflectivity also allow the clouds to better trap the heat that does enter Earth’s atmosphere?)
  5. Space mirrors: This is exactly what it sounds like; scientists would position one or more large mirrors in the Earth’s orbit in order to deflect some of the sun’s incoming rays. (My question: What happens if something knocks the mirror out of place? Could we get hit with even more concentrated sunlight?)

I would love to do more research on each of these methods to find out the risks and proposed benefits of each. But in the meantime, I found the diagram below, which illustrates the variety of geo-engineering methods scientists are currently considering. I found it informative, so I thought I’d share it with you:


Source: http://swaltersky.files.wordpress.com/2012/02/geo-engineering-challenges.png

Geo-engineering is a very interesting concept. I like that it attempts to proactively address the issue of rising global temperatures. But, it also appears to involve dramatic steps that could have many unknown consequences. We know that human actions can have unintended effects on the environment. We have wiped out species at an alarming rate, contaminated our air and water, and depleted many natural resources. While each of the above geo-engineering methods has the good intention of combating climate change, we do not know what other consequences these methods may have on our ecosystem. One article reports that geo-engineering experiments have resulted in reduced rainfall. I believe we should explore our options for protecting the Earth against excessive warming, but I think that a great deal of additional research and testing is necessary before geo-engineering could be rolled out on any large scale.

One response to “Sweet Shades: Can Geo-Engineering Keep Earth Cool?

  1. Pingback: Let’s Pump Some Iron « greenismything·

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