The clash between increasing public awareness about climate change and the political ongoing discussion around this, is manifesting itself more and more. Demonstrators are begging politicians to listen to scientists and the technological solutions they provide. What are scientists saying? Which solutions do they push forward?
The solution seems simple: take the best technology available and invest in it to develop it, scale it and implement it. So, how do we find that ideal technology? No one can crawl through the enormous amount of research papers on CO2 mitigation that have been published. Unless… Artificial intelligence to the rescue!
To provide a digestible overview, the content of more than 50,000 research papers published in the last ten years was extracted through automatic topicing using CRAiN*. An unbiased classification through publication volume and recency allows identifying which technologies are gaining traction and maturity, and which ones are still in an early development stage.
Dots indicated in blue are the industries focused on by researchers. This research can be directed both on their emission as well as possible solutions to decrease or overcome their impact. The size of the dots indicates the amount of scientific papers linked to that industry. Next to the most obvious and most discussed polluters (blue) in the media such as electricity production and transport (aviation, automotive, transport of goods), other domains are being examined by researchers such as the construction, meat, dairy and tourism industry (purple). Looking into these domains may provide solutions that, so far, are not in the mainstream picture against climate change.
For example, the construction industry is a lesser discussed domain in the media, but it has gained a lot of interest in research in recent years. The cement production is one of the largest CO2-emitting industries globally, with the US contributing 64.3 MMT (million metric tons) of CO2 in 2014. The growing interest results from research being performed to decrease this emission and ideally capture and store CO2 in new cement (ecological concrete).
A wide variety of technologies for removal of CO2 from the atmosphere - dots shown in orange and red - have been described in research. Established solutions often mentioned in the media include afforestation & reforestation, photosynthesis as well as carbon capture and storage (orange) (e.g. wherein CO2 is even collected and injected in abandoned oil wells). Less dominant technologies include separation of CO2 from air or other gases (e.g. by cryogenic CO2 separation, membrane separation, calcium looping capture, direct air capture) (red). In a next step, this CO2 can also be stored or converted into valuable products that can contribute to our economy.
Technologies utilizing biomass also show a recent increase in academic literature. Here, CO2 is captured and stored in biochar, oceans and coastal ecosystems by promoting growth of mangroves, seagrass, cyanobacteria, algae, plankton etc. Similarly, chemical means are being developed and optimized for absorbing CO2 in e.g. aqueous ammonia or adsorbing CO2 on metal organic frameworks. Besides taking a lot of CO2 out of the atmosphere, these methods also lead the way for synthetic conversion of CO2, through electroreduction or photocatalytic conversion.
Electroreduction and photocatalytic conversion are two promising technologies that are quite new in the field of CO2 reduction, but that are already heavily studied. Herein, carbon dioxide is converted to more reduced chemical species by using electrical energy. Instead of fixating carbon through plants, electrical energy can be used to transform carbon dioxide to organic products such as formic acid, methanol, ethylene, methane and carbon monoxide. This can be used as fuel or transformed into plastics (e.g. polethylene), hereby recycling the carbon dioxide.
While electroreduction relies on electrical energy, photocatalytic conversion directly utilizes solar energy. Another implementation of photocatalytic conversion, developed by the KU Leuven, is currently being tested. Instead of converting carbon dioxide to reduced species, solar energy is used directly to convert water to hydrogen gas, as an alternative energy source.
Although we are here only covering one aspect to battle climate change, it is already clear that technological advances are diverse and continuously being made. Despite hope, this also adds additional complexity to the equation in a debate where emotional reactions overrule the needed insights and expertise of the scientist. So, next time someone tells you that ‘the solutions are not yet out there’, remember that there is already a broad scope of technologies that can contribute to reduce global warming.
It goes without saying that each technology contains a multitude of variation and sub-problems. For the sake of clarity, these were grouped in a simplified graph. Contact CREAX for more details.
*CRAiN is an in-house developed platform by CREAX, that utilizes natural language artificial intelligence for automatic topicing and clustering.