Image source: Getty Images
Okay so they're not necessarily plastic (though they could be), and they probably won't "solve" climate change, but according to Klaus Lackner, a geophysicist at Columbia University, the concept would give us time to develop alternative energies and slow the damaging effects of CO2 in our atmosphere. The San Diego Union Tribune reported today that both real and fake trees are being explored as options to fight climate change. Researchers are looking at both options to suck up CO2 out of our atmosphere and it looks like the fake trees might be winning.
The idea would be to make tall, fake "trees" that collect CO2; not in the way a normal tree would gather CO2, but rather, by using filters that stick to CO2 as it passes by. The current prototypes are 1,000 times better than real trees at sucking up CO2 and they are not using energy to photosynthesize anything.Scientists at the University of Maryland and the University of Griefswald in Germany, on the other hand, are looking to real trees for the answer. They say that if we could manage all of the forests in the world then we technically could offset all of our fossil fuel emissions. Though there are several problems with this strategy A) thats a lot of management B) you would need a system to bury the trees deep underground when they die otherwise you're still releasing CO2 and C) that assumes no growth in fossil fuel emissions.
How Can We Manage Forests To Capture CO2?
The UM professors suggest thinning forests every 5 years and burying the wood. The possibility even exists to have tree farms strictly for growth, capture of CO2 and burial. The catch: the scientists estimate it would take 2.47 billion acres of forest just to capture annual global carbon dioxide emissions. "Its about 1/4 of all the Earth's land surface currently covered by forest." While you can plant trees just about anywhere, location and type of tree also affects carbon capture.
In addition, huge forests of trees can be heat sinks, thus raising the temperatures around them. There are also questions about how increasing trees would affect the landscape around the area.
How do CO2 filter trees work?
The fake trees are in test phase right now in Arizona. After several trials, they have a version that requires very little energy to operate. Basically, they use "tree trunks" that are multiple filters coated in a plastic resin. When air passes over the filter, the CO2 sticks to the resin and creates sodium carbonate (soda ash). When the filters are exposed to moisture the sodium carbonate is released and can then be stored/buried. The filters are then reusable.
What's even better is that they are so effective. A 20 square inch filter piece can take up the annual carbon emissions of one American in one year. One of these "trees" is 55 feet by 65 feet, and captures 90,000 tons of CO2 each year, equal to 15,000 cars. Now we're talking.
What to Do With the Captured Carbon?
Several options include burying it in underground mines or oil fields or even deep in the ocean. Since its denser than water it would be trapped at the bottom. Down the road it may be possible to turn the CO2 "into a stable, inert, harmless solid." Other options include turning it into a marketable product - its already used in fire extinguishers, as "dry ice" and even to promote growth in green houses. An even better idea - a fuel source - if its converted to liquid hydrogen-carbon. At this time it's still too expensive as a fuel source, but who knows what the future will bring. As for costs, estimates are that the trees could capture CO2 at $30 per ton (25 cents per gallon of gas), but they are still in the research phase.
The beauty behind the fake trees is that technically they could be located anywhere. Since CO2 is distributed globally, we could put them in the middle of nowhere or even right next to power plants with heavy emissions and and they would still do their job. No permitting fiascos (a la offshore wind) and no weird trees in our neighborhoods (a la fake cell phone towers) unless we want them.
Either way, we still need to get our emissions under control. Even if trees (real or fake) can capture our emissions, they are still rising with no stop in sight. According to Lackner, "this is not a scientific question. It's a question of our pain threshold. How long can we go before we all agree that something must be done?"
::San Diego Union Tribune
More on Carbon Sequestration
Carbon Capture and Storage: Now With 40% More Acid Rain
Scientists Develop Low-Cost Version of Carbon Capture and Storage
Important! Why Carbon Sequestration Won't Save Us
Human Brain Enzyme Used for Carbon Capture
Could a Century's Worth of Carbon Emissions Be Stored Within the Juan de Fuca Plate?