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A New Way To Remove CO2 From The Air

December 13, 2019 By EarthWise Leave a Comment

Researchers at MIT have developed a new way of removing carbon dioxide from a stream of air that could be a powerful tool in the battle against climate change. The new system can pull carbon dioxide out of almost any concentration level of the gas, even including the roughly 400 parts per million level currently found in the atmosphere.

The technique is described in a new paper in the journal Energy and Environmental Science and is based on passing air through a stack of electrochemical plates. The device is essentially a large battery that absorbs carbon dioxide from the air passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged.

To use it, the device would simply alternate between charging and discharging. Fresh air or some other feed gas would be blown through the system during the charging cycle and then pure, concentrated carbon dioxide would be blown out during discharging.

The specialized battery uses electrodes coated with a compound called polyanthraquinone, which is composited with carbon nanotubes. These unique electrodes have a binary affinity to carbon dioxide, which means that they either strongly want to capture carbon dioxide or not at all, depending upon whether the device is charging or discharging.

Carbon dioxide is important in many industries such as soft drinks and greenhouse agriculture. With this device, the stuff could literally be pulled out of the air. And, of course, in power plants where exhaust gas is dumped into the air, these novel electrochemical cells could be used to prevent the emission of CO2 into the atmosphere. At the right price, this could be a game changer.

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MIT engineers develop a new way to remove carbon dioxide from air

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

How Much CO2 Can The Oceans Hold?

May 2, 2019 By EarthWise Leave a Comment

The carbon dioxide that enters the atmosphere doesn’t necessarily stay there. As part of the natural carbon cycle, much of it goes into plants, soil and, very significantly, the ocean. In fact, the world’s oceans are a sink for human-generated carbon dioxide without which the extent of global climate change would be far worse.

Oceans takes up CO2 in two steps: first the CO2 dissolves in the surface water. Then, the ocean’s overturning circulation distributes it. Currents and mixing processes transport the dissolved CO2 from the surface deep into the ocean’s interior, where it accumulates over time.

A long-standing priority for climate researchers is to determine how much of the CO2 we produce is being absorbed by the oceans and, ultimately, how much can they hold?

An international team of scientists has recently provided some answers. As reported in Science, the researchers have determined that the oceans have taken up from the atmosphere as much as 37 billion tons of human-made carbon between 1994 and 2007. This figure corresponds to nearly a third of all the anthropogenic CO2 emitted during that time.

Furthermore, they found that the percentage of CO2 taken up by the oceans has remained relatively stable compared to the preceding 200 years even as the absolute quantity has increased. So, evidently, the oceans’ capacity for carbon dioxide has not yet been saturated.

That’s the good news. The bad news is that putting all that CO2 into the oceans has a steep price: the dissolved CO2 acidifies the water. The consequences for a wide range of marine life including coral reefs are serious and getting worse. We need to drastically reduce carbon emissions.

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Ocean sink for human-made carbon dioxide measured

Photo, posted November 5, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Speed Breeding Of Crops

January 4, 2019 By EarthWise Leave a Comment

A technique pioneered by NASA for the purpose of growing plants extra-terrestrially is now being applied here on earth to fast-track improvements in a range of crops. The technique, known as speed breeding, has been adapted for use by British and Australian researchers on a scale ranging from vast greenhouses to desktop growth chambers.

Speed breeding uses enhanced LED lighting and day-long regimes of up to 22 hours to optimize photosynthesis and promote rapid growth of crops. By speeding up the breeding cycle of plants,it is possible, for example, to grow six generations of wheat in a year compared with two generations using traditional breeding methods.

With shortened breeding cycles, genetic improvements such as yield gain, disease resistance and climate resistance can be fast-tracked in crops such as wheat, barley, chickpeas, various Brassica species, oil seed rape and peas.

The ability to do this in compact desktop chambers permits cutting-edge research to be performed inexpensively before being scaled up to large greenhouses.

Crop development is an increasingly important activity and speed breeding is increasingly attractive in light of the opposition in some quarters to modern gene-editing techniques to create GMO crops. Speed breeding allows crop improvements via anon-GMO route.

The new technique is already being applied in Australia, which is experiencing one of the worst droughts on record. It is being used to rapidly cycle genetic improvements to make crops more drought resilient.

Generation time in most plant species is a major bottleneck in applied research programs and breeding. Speed breeding can greatly reduce this bottleneck, allowing scientists to respond more quickly to emerging diseases, the changing climate and increased demand for specific plant traits.

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