One method of preventing a climate disaster would be to eliminate the extra CO2 from the atmosphere. This would be a fantastic plan if we could. The big reason that we’re having such an issue is that we’re taking carbon that has been outside of the carbon cycle for the last 300 million years and putting it back into the carbon cycle.
Our carbon cycle, which is pretty much plants take in carbon dioxide and give off oxygen and animals take in oxygen and give off carbon dioxide, just can’t handle the extra 30 billion tons of carbon we’ve been injecting into it for the last few decades.
I should clarify here. There is a lot more to the carbon cycle than that, for example, some of the excess carbon dioxide is dissolved into the ocean, which makes the ocean more acidic, which dissolves calcium carbonate shells in animals. I also need to add that the planet can accept all the extra carbon, but there are some significant consequences to us as a species and the vast majority of other species on this planet.
OK, so, one way of helping out is to prevent carbon dioxide from getting into the atmosphere. Theoretically, we should be able to capture the carbon dioxide emissions of power plants (for example) and then bury the carbon. That’s problematic for a couple of reasons. First, the technology is still in its infancy. As of 2012, there were 75 large scale projects being worked on, about 14 of which were in use (depending on what source you refer to. These 14 projects capture and store about 33 million tons of carbon annually. To put that in perspective, the top 12 US power plants in terms of carbon pollution annually emit over 200 million tons.
Besides which, there’s all that carbon still in the air. What if we could take that carbon out of the air and do something useful with it.
Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley recently announced an artificial photosynthesis system that can generate not just one, but several useful products using nothing but sunlight and atmospheric carbon dioxide.
It works by using silicon and titanium dioxide nanowires. These wires, when hit by photons from the sun, will emit electrons. The electrons are then passed to an anaerobic bacteria living in the nanowires (and protected by them). These bacteria take in carbon dioxide and, using the energy from the nanowire grid, make it into acetate. The acetate is then passed to a genetically modified Escherichia coli bacterium and made into useful compounds.
The efficiency of the light capture is about the same as that of a real leaf, about 0.38%. The conversion of acetate to other chemicals was very efficient.
The yields of target chemical molecules produced from the acetate were also encouraging – as high as 26-percent for butanol, a fuel comparable to gasoline, 25-percent for amorphadiene, a precursor to the antimaleria drug artemisinin, and 52-percent for the renewable and biodegradable plastic PHB.
They anticipate that the 2nd generation system will approach 3% light capture efficiency. And they say that once they reach 10%, the system will be profitable.
Carbon capture is a great idea, but it is expensive and doesn’t produce any return, except for preventing global warming. This system could do that and provide an income. Which is an important point, systems and processes to prevent global warming don’t have to be economically negative.