$100M to whoever invented forests? Why we should not bank on trees exclusively to deal with CO2. 

“Am donating $100M towards a price for best carbon capture technology.” Elon Musk tweeted on January 22. He is obviously aware of the severe damage that too much carbon in our environment can cause. Now and even more in the future.

His tweet provoked some very funny answers. One, for instance, replied that the person who invented forests can consider themselves the lucky winner. Another one suggested the $100M award should be given to a tree itself. Elon replied that “they are part of the solution but require lots of fresh water & land. We may need something that’s ultra-large-scale industrial in 10 to 20 years”.

One tree can bind 48 lbs a year, on an average. Keep it up, buddy. Please!

To evaluate his estimation, let’s take a closer look at trees and their photosynthesis. One tree can bind 48 lbs of CO2 per year. This process is controlled enzymatically. The responsible enzyme is called RuBisCO which is short for Ribulose-1.5-Bisphosphate-Carboxylase-Oxygenase. Don’t worry though, there’s no need to memorize it. What is important to know is that enzymes have activity-maxima, a temperature-optimum at which they work best.

The downside: enzymes are proteins that become less efficient and eventually decompose when temperatures are rising. Therefore, the process of photosynthesis is limited in its function – depending on the temperatures of the environment. Where the photosynthesis of tropical plants functions easily with temperatures around 45 °C, the photosynthesis of evergreen trees in moderate climate zones requires an optimal temperature between 20 - 30 °C.

Plants bind more CO2 than they produce. This might change to the opposite due to global warming.

The photosynthesis happens during the day as it needs light to work. At night, plants start their cellular respiration and they consume oxygen and release CO2. Until now, plants run their photosynthesis longer than their cellular respiration. The result: they bind more CO2 than they produce.

And now think of global warming and its effect on the photosynthesis. This is where the potential nightmare for humankind comes into play. Rising temperatures boost both processes. But as the photosynthesis becomes increasingly less efficient once its optimum temperature  is exceeded, a tipping point might be reached.

At this point, plants might bind less CO2 than they produce. The result: they would no longer help to slow down global warming. In a worst-case scenario, plants would even accelerate global warming.  

Worst-case scenario: global warming accelerates exponentially.

In a study carried out by the Center for Ecosystem Science and Society in Flagstaff, Arizona, scientists estimated that by the middle of the century big CO2-reducers, such as the rain forests, might lose about half their efficiency. And, by the end of the century, half of the terrestrial ecosystems might reach the tipping point. From this moment on global warming would accelerate exponentially.  

Thankfully, science often offers different results, interpretations and estimations. Other researchers, such as Markus Reichstein from the renowned Max-Planck-Institute for Biochemistry in Jena, come to a different conclusion. He believes the study was misinterpreted and predicts a different progress: plants will be able to adapt to changing temperatures and reduce the amount of CO2 released. So can we breathe a sigh of relief?

Innovative technologies could once again save the day – and our air.

Rather not! Whatever may be, we should not bank on plants exclusively when it comes to CO2 and global warming. We need to search for different possibilities and technologies to protect the environment and ourselves. Probably, Elon Musk was heading in the right direction with his $100M incentive.

So looking to the future,, so-called NETs – negative emission technologies – could help to solve the problem. NETs create negative emissions by retrieving CO2 from the atmosphere. Unfortunately though, these technologies are not that successful yet, as they work rather slowly and are incredibly costly. However, three of the most promising NETs are PyCCS, BECCS and DAC. Don’t worry, here comes the explanation:

First three steps into the right direction: PyCCS, BECCS, and DAC.

With the help of the pyrogenic carbon capture and storage technology (PyCCS), biomass is treated thermally and carbonizes. In this process, the so-called pyrolysis, biochar and gas arise. Both can be reused. The CO2 created in this process is stored underground.

A similar technology is bioenergy carbon capture and storage (BECCS). In this process, energy is generated from biomass while revoking CO2 from the atmosphere and storing it. The extracted carbon is incorporated by the biomass during its growth period. In the end the generated energy can be used for electricity, for instance.

Last, but not least, the direct air capture technology (DAC) offers a simple but smart solution. In this case the CO2 is revoked with the help of filters. Afterwards, it can be used in the chemical industry for CO2-neutral fuels or be stored geologically.

It’s amazing what science can do. And even though these incredible technologies are too slow and costly at the moment, it’s a great step into the right direction. And maybe Elon’s $100M offer can help to come up with the next smart solution.  

Any ideas? You can register to take part in the competition starting Earth Day this year – April 22, 2021. The contest will end 4 years later on Earth Day 2025.

▷ https://www.xprize.org/prizes/elonmusk