How farting cows should become more climate-friendly

All of the climate researchers' scenarios come to the conclusion that it will not be possible to limit the global temperature rise to 1.5 degrees without separating carbon dioxide from the atmosphere. Researchers have been developing technologies that enable the capture of CO2 from the air for years. Pilot systems prove that the thing works in principle.

The systems suck air from the environment and direct it through a filter in which the CO2 molecules are bound. Once the filter has reached its storage capacity for carbon dioxide, it is heated to 100 degrees after the reaction chamber has been sealed airtight. At this temperature, the carbon dioxide is released from the filter so that it can be collected as a concentrated gas.

The filter is then ready to absorb CO2 again. The collector can be opened again and air can be sucked in. The carbon dioxide captured from the air in this way can either be used as a raw material for chemicals or stored underground in a safe geological location (“carbon capture and storage”).

Of course, separating CO2 from the air only makes sense as a climate protection measure if the energy required for such a system, especially for heating the filter, is available in a CO2-neutral manner. The pilot plants are operated with electricity from solar cells.

So could the climate problem be solved with CO2 capture technology? Theoretically yes, but the efficiency of the separation technology is still far too low to remove CO2 from the air in such large quantities to achieve a significant effect.

A team of scientists led by Hao Chen is now reporting in the journal Science Advances on a new material that can be used to almost triple the efficiency of CO2 capture. The researchers from Lehigh University in Bethlehem, USA, and Tianjin University in Shenzhen, China, combined a polyamine resin with a solution containing copper to create a hybrid material that has a high binding capacity for carbon dioxide. In addition to the higher storage capacity, another advantage of the new material is that less thermal energy is required to later release the CO2 from the filter. That also improves the efficiency of the overall process.

In view of the efforts to reduce the CO2 concentration in the air with suitable technologies, it must sound absurd at first glance that researchers elsewhere are also working on using sophisticated technology to introduce additional carbon dioxide into the atmosphere. And yet this can also be a contribution to climate protection.

For example, researchers from the Technical Research Center of Finland (VTT) have developed a technique that converts methane from the ambient air into carbon dioxide. Both gases, both CO2 and methane (CH4), are climate-relevant gases. However, the greenhouse effect of methane is 28 times greater than that of CO2. The bottom line is that it is better to accept additional CO2 if it removes the corresponding amount of methane from the atmosphere. This accelerates a process that takes place naturally anyway: Methane introduced into the atmosphere decomposes into carbon dioxide after ten to twelve years anyway.

The researchers have in mind the use of this technology in cattle sheds. Large amounts of methane are released there by the animals. A cow produces around 15 kilograms of methane per year. The concentration of the gas is therefore significantly higher in stables than elsewhere in the ambient air. The use of the technology can therefore be particularly worthwhile here. An electrically generated, cold plasma splits the methane molecules and binds carbon with atmospheric oxygen to form CO2.

In the European Union, more than a million tons of methane are emitted from cattle stalls every year. In view of these quantities, the fast and efficient conversion of methane into CO2 is definitely in the interests of climate protection.

"Aha! Ten minutes of everyday knowledge" is WELT's knowledge podcast. Every Tuesday and Thursday we answer everyday questions from the field of science. Subscribe to the podcast on Spotify, Apple Podcasts, Deezer, Amazon Music, among others, or directly via RSS feed.