Carbon storing polymers: gaining time in fighting climate change

To limit global warming to 1.5°C, as defined in the Paris Agreement, we need to cut global annual emissions by some 45% until 2030 and achieve net-zero emissions by 2050. Unfortunately, global emissions have increased year by year ever since this goal was agreed upon. Every year of too little action is going to require a year of extra action to compensate. 

That being the bad news, there is also good news: more and more technologies are being developed and rolled out to reduce greenhouse gas (GHG) emissions. Capacities for renewable electricity are increasing. Businesses are replacing processes based on fossil resources with new technologies using renewable materials. Where emissions can’t be avoided, technologies to capture them and use or store them are being deployed. 

Aside from reducing or avoiding emissions, there are also technologies on the rise that can remove CO₂ from the atmosphere, attempting to reverse the effects of centuries of fossil resource use. Given that the major problem isn't CO₂ emissions per se but the concentration of CO₂ in the atmosphere, these technologies provide intriguing opportunities. The concept of removing CO₂ from the atmosphere becomes especially intriguing when it comes to the years of extra action to compensate for missing the targets in the previous years. 

Vegetation and oceans are the earth’s largest carbon pool. “Carbon pool” refers to a pool that continuously absorbs carbon, while a “carbon storage” maintains a constant amount of carbon for a period of time.

Leveraging natural carbon cycles

The concept of not only stopping the CO₂ concentration from increasing but actually removing CO₂ from the atmosphere is also interesting for the materials sector: polymers for example are made from carbon, and depending on the application, they may store this carbon for years or even decades. One such application would be construction materials, which might serve as parts of a building for very long periods of time. If these construction materials included polymers, and these polymers were made from bio-based materials, they would store carbon that was previously removed from the atmosphere.  

When biomass e.g. a plant grows it absorbs CO₂ from the atmosphere. When the plant dies, the biomass rots and emits the CO₂ back into the atmosphere – the zero sum game of the carbon cycle in nature. With polymers made from bio-based materials, the sum of the game could be changed in our favor, though. 

Instead of leaving it to rot, the biomass can be turned into polymers, which are then used in long-lasting applications like construction materials. As long as the construction materials remain, we have a negative impact on the amount of CO₂ in the atmosphere – assuming of course that the emissions generated by making the polymers and construction materials are not higher then the CO₂ absorbed during biomass growth.

Due to the longevity of buildings and construction materials in buildings, the potential to use these materials as carbon storages is large.

Carbon storages as temporary carbon buffers

At the end of their use-phase, materials may release the carbon stored back into the atmosphere, for example, if the materials are being incinerated at the end of their life. In the case of construction materials, however, this may be several decades in the future. What may sound like a concept that just postpones problems to later generations can actually be a useful addition to attempts of reducing and avoiding emissions right from the beginning: There is a very high chance that we will have an increasing amount of new technologies at our disposal to handle CO₂ emissions in the future. The bigger challenge might, therefore, be reducing emissions right now and in the near and mid-term. 

Renewable carbon storages can help with just that: the technologies are available at scale already right now. We can use them as a buffer buying us time. And who says that the materials are ultimately just incinerated? If we manage to increase recycling of polymers in the next decades, we may very well be able to continue keeping the carbon out of the atmosphere even after the applications have reached the end of their life. It might also be that we use incineration in combination with carbon capture and utilization to keep the carbon in the loop. Hand in hand, renewable and recycled solutions could therefore have a serious contribution to combating climate change. 

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