What Does Carbon Neutrality Mean in Practice?

According to The Summary for Policymakers (SPM), "[…] human activities are estimated to have caused approximately 1.0 °C of global warming above pre-industrial levels. [...] Global warming is likely to reach 1.5 °C between 2030 and 2052, if it continues to increase at the current rate."

20th-century industry, agriculture, and the rampant growth economic model have led us to the point where society cannot avoid taking action in the face of the consequences imposed by Climate Change.

Hansjörg Lerchenmüller continues, "[...] Climate Change has become a reality, and that is clearly caused by the fact that the atmosphere has a too high content of CO2. That is 99.9% scientifically proven. There are no serious scientists who look at it from a different perspective. It is us, it is CO2, it is human-made, and it is really, really bad. It is bad to the extent that the pandemic is almost nothing against it."

Beyond the goals and strategies set by the adoption of the landmark Paris Agreement on Climate Change, the present interview explores the intricacies we will face in the following years in order to reach a carbon-neutral society by 2050. Hansjörg Lerchenmüller helped us analyze closely the opportunities some key emerging technologies provide and the possible challenges for implementation while pursuing carbon neutrality.

You are now invited to explore the insights shared throughout the interview, as well as glimpse emerging technologies included in this article.

What is Meant by Climate Collapse?

Before Lerchenmüller answers, he contextualizes, "in the Paris Agreement, many countries worldwide decided to put a limit to the consequences of Climate Change by lowering down two degrees of Earth's temperature. But that is the average temperature all over the globe; over land, over the sea, over the North and South Hemispheres. People might think two degrees is not so much of a difference, but it actually is."

Every bit of warming matters. The two degrees Celsius limit, often referenced by the scientific community as the “tipping point,” originates from a paper written by the Yale economist Willian Nordhaus. In 1975, he concluded that a fair threshold to keep climatic variations at bay would be twice as much as pre-industrial CO2 levels —a period centered on the mid-19th-century —, which he equated to a temperature increase of 2ºC. Then, the 2ºC limit entered the policy and political world’s dictionaries; from 1996 when it was adopted by the European Union’s Council of Ministers, in 2008 by the G8, in 2010 by the UN, to 2015 by the Paris Agreement. The latter discloses final decisions where negotiations decided to stop the global average temperature increase to below 2ºC above pre-industrial levels and pursue efforts to limit temperature rise to 1.5ºC.

However, temperature increases are not proportionate everywhere in the world. The “mechanics” of ecosystems are dynamic, and biomes from North to South, East to West, do not behave uniformly. This means that the consequences of increased temperatures are different; while in some places limiting the 2ºC above pre-industrial levels will be enough, in others, a 1.5ºC increase will be deemed critical for the survival of species, the future of some crop yields, and the availability of natural resources, such as water. Studies from CarbonBrief forecast that regions such as the Mediterranean may face considerable hurdles in freshwater availability with a 1.5ºC increase in the near future. On the other hand, in West Africa and South-East Asia, a 2ºC temperature increase could mean losses in some crop yields, such as wheat and maize. To many climate experts, this would mean a climate collapse.

By climate collapse, Lerchenmüller defines a scenario where "[...] many people could die because of high temperatures, as well as starve because agriculture would not work as before; there might be no rain in some places. These people would have to become refugees."

How Can We Avoid a Climate Collapse? Is Carbon Offsetting Really an Option?

For those not acquainted with carbon offsetting, it is a method in which companies and individuals emitting CO2 invest in side projects working on reducing carbon emissions and preserving ecosystems. In other words, with the intent to conceal the impact of their activities on the environment, some companies choose to offset their emissions through the investment on green initiatives emitting less CO2. For Lerchenmüller, "carbon offsetting is not necessarily bad; if one person can help another to offset, or reduce emissions by giving them money, yes, it could be an option. But [with carbon offsetting] we will never meet carbon neutrality. It is basically trading."

He explains, "if I pay you to emit less, why would I derive the right to emit instead? We cannot emit any more CO2 into the atmosphere. We need incentives, we need to help people reduce their emissions. The thinking that, by helping someone to reduce their emissions, derives you the right to emit yourself, is not the right thought. This will not lead to carbon neutrality."

"We have to stop emitting CO2. It is as simple as that," says Lerchenmüller. Also, he explains that "[...] cutting down emissions to a fourth or a fifth of current total emissions is relatively quick; it is possible. But any emission is dangerous." He adds, "we need to reach negative emissions, that is the only way to become carbon-neutral. There is too much carbon in the atmosphere, so we need to actively take CO2 out of the atmosphere."

If We Reach Carbon Neutrality by 2050, What Comes After?

By then, Lerchenmüller says that we will "[...] need to reduce the CO2 content in the atmosphere actively. If carbon neutrality is seen as a balance of reduced emissions on one side and taking down CO2 on the other, after 2050, we will need to move this balance to another level; remove more CO2 than what society emits into the atmosphere."

Which Technologies Hold the Best Promise of Reaching Negative Carbon Emissions?

According to Lerchenmüller, "seven solutions are being looked at currently, and the two most spoken of are afforestation and reforestation. Everyone loves trees, therefore, trees are thought to be the solution, but there are some problems. First, when you talk of trees, you also need to think of wood's carbon-preserving application. Planting trees, cutting down, and burning them is not a help. At best, it is carbon-neutral. When you replant, in this case, reforestation, the right way of looking at it is to let the trees grow, and at one point in time, take out the wood and make buildings, or use it in long-term carbon preserving applications. It is fundamentally wrong to think of wood and to build cheap and scrappy furniture. Wood should be seen as a carbon sink, any wooden table, and chair."

Simply put, a carbon sink can be anything that absorbs more carbon from the atmosphere than the amount it releases, such as the soil, plants, and in the example given by Lerchenmüller, wood. He contextualizes his argument, "then only after a hundred years when a house is going to be demolished, the wood could be thermally treated, for example, through Pyrolysis."

Pyrolysis, according to Lerchemüller, is the third of the seven most promising solutions. It is a process that converts biomass into Biochar, a concentrated carbon sink that stores CO2 that was previously sequestered by trees. This technological method works together with nature, where, in Lerchemüller's words, "[...] trees take the CO2 out of the atmosphere, and the Pyrolysis converts the biomass into a stable form of carbon. If used in a carbon preserving manner, in soil and concrete, for example, then it is preserved forever."

The fourth solution is the practice of increasing organic matter in soils. Lerchemüller explains, "[...] leaving soils open, for example, is terrible for the CO2 balance. After harvest, [farmers] need to plant something new immediately, so green things grow and help to maintain organic matter in the soil." Similarly, the soil can work as a great catalyst to sequestering carbon from the atmosphere through other processes, which is the case of the fifth solution mentioned by Lerchenmüller.

According to him, "the fifth one is by crushing silicate rocks, such as Basalt, and placing them in the soil, then exposing the rock to the atmosphere, converting them into carbonates. This technological method is known as Enhanced Weathering." He continues, "it efficiently takes CO2 out of the atmosphere. However, it is still at very early stages of research, so it is not, yet, readily available."

The sixth solution is Bioenergy Carbon Capture and Storage by burning biomass in plants, extracting CO2 from the exhaust gas, pressurizing the CO2, and then sending it via pipelines to geological storage areas. Finally, the seventh technological method, according to Lerchenmüller, is called Direct Air Capture, a technical process that captures CO2 from the ambient air, and in turn, generates a concentrated stream of CO2 for producing carbon-neutral fuel. This method is applied through CO2 Extractor Arrays.

Are These Solutions Feasible?

"When you look at all these solutions, there are synergies between them. It is not that one solution will for the next hundred years be the only one that will help us. We need trees, we need soil organic matter, we will also need Enhanced Weathering, and Direct Air Capture. However, the timelines for technologies such as Direct Air Capture and Enhanced Weathering are much longer because they require a lot of energy to function."

On the other hand, for Bioenergy Carbon Capture and Storage, in his opinion, "[...] it only makes sense when you can use the exhaust heat. Burning biomass without making use of the heat is probably not a good idea. In terms of efficiency, when we burn biomass, we always have to make use of the heat. There should not be any surplus of heat energy." For him, "Biochar is probably the solution that is easiest to scale up. It is ready. There are already four or five serious players in Europe, and if you want to buy the equipment, you call up one of the sales representatives and buy it. " He contextualizes, "It is not rocket science. [Biochar] is quickly scalable because it is not at a nuclear power size, it is something a single company can invest in."

He concludes, "I have much less difficulty imagining a couple of trucks driving around with Biochar as a negative emission material, than having pipelines transporting pressurized CO2 to store it into geological storage. The great thing about Biochar is that it is readily available. It can be used as a feed and soil additive because it is beneficial for animals and the soil."

What Are the Possible Risks and Implementation Challenges Related to Biochar Application?

For Lerchenmüller, "with Biochar there is no real risk, always provided you do it right. If you do it wrong, like using machines that do not separate the air and accumulate the exhaust gas in the Biochar material, it could potentially assemble toxic substances that should otherwise be left out. However, any state-of-the-art equipment has solved this problem”.

In terms of growth and challenges for implementation, Lerchenmüller explains his background "as European biochar consultants; we have an ambitious target of expanding the industry, with a growth rate of 80% for the next 15-20 years. We want to become climate-relevant by 2035. The expected growth rate for 2020-2021 will be 90%. The last three-year average was 60%. The growth rate brings huge challenges to the companies, as they have to change constantly, they have to hire and raise money. Companies will need to invest in new buildings, partnerships, etc."

He adds, "for approximately ten years, there will not be a problem in terms of biomass, because there is a lot of biomass available. I am not suggesting we should collect every leaf; leaves are good for the worms and good for the soil. What I mean is that every combustion of biomass [without pyrolysis] is a missed chance to create a carbon sink. Biomass is carbon, if you burn it, it is not gone; it goes to the atmosphere. We have to rethink the usage of biomass and convert the ever-growing percentage to Biochar, and at the same time, use the energy produced by doing so. Biochar is energy self-containing."

For the Other Solutions You Mentioned, What Are the Main Challenges for Implementation?

In relation to Direct Air Capture and Bioenergy Carbon Capture and Storage, Lerchenmüller explains that, for it to become climate-relevant, it "[...] needs to be further improved and pilot proper implementation. As these technologies need energy and heat, it only makes sense when the energy sector is mostly decarbonized. Cost is a challenge."

He also points out important considerations, "[...] whenever we talk about negative emissions, we always have to talk about reducing emissions first. As all negative emissions technologies are at an early stage today, the cost challenge for the energy sector will take up to 10-15 years to be fully scalable."

For Enhanced Weathering, the rationale is similar. Lerchenmüller explains that "[Enhanced Weathering] is not a bad solution, but science today is not yet quite sure how to quantify the outcomes of its application. It is a special rock, you do not have it everywhere. You need to destroy a lot of rocks, which demands a lot of energy." From his point of view, "it is still on a proof of concept stage, and I doubt it will be very fast to scale up."

However, Lerchemüller refers back to aforestation, saying it is "[...] readily available, and people are doing that, but there are some related risks." He exemplifies, "Climate change destroys entire forests, which demands a political change in many countries. It is not an argument for not doing it, but we should stay realistic [regarding aforestation]. Similarly, increasing the soil organic matter in agricultural land is important, and it has to be done. The question we should ask ourselves is: how much can it really contribute? Historically, if you look over time, it is not one solution, but many solutions combined."

Do You Think the Challenges for Implementation are the Same for Developing and Developed Countries?

According to Lerchemüller, "for Biochar, we have to go to places where biomass is found abundantly, for instance, where there is a lot of rain. Generally speaking, the growth of biomass is distributed, therefore, solutions will have to be distributed too."

In terms of low-tech development, Lerchenmüller exemplifies, "there are low-tech solutions for Biochar, such as Kon-Tiki, but it is still a field that needs to be pushed for and further developed." This initiative is a Pyrolysis kiln developed by the Swiss Ithaka Institute, which combines ancient techniques with modern thermodynamics to produce Biochar with low emissions. Current Kon-Tiki experiments utilize centuries-old practices, such as the construction of a bed of flaming embers at the ground. By gradually adding, layer by layer, combustible material to the bed on the ground, such as food scraps, bones, and wood, it maintains a smoke-consuming fire that sinks the carbon into these materials. Lerchenmüller continues, "this solution can help everyone produce Biochar."

What Would be a Crazy Futuristic Scenario for 2050 Having These Techs in Mind?

"Everyone that has dry solid biomass, be it, rest biomass from nutshells, wood processing like old pallets, furniture, would be thermally converted in Pyrolysis and making biochar. What is very important in this scenario is that the applications of Biochar are not limited to soil applications. Biochar is pure carbon; an element, a material."

He illustrates, "I can picture a world where people are converting old furniture into carbon and to concrete as well. It would go beyond the application of carbon into the soil. We are in a position where we can manage to reach this point without having to look for more dramatic alternatives, such as manipulating the weather, for instance."

According to a Biochar Report, Biochar can also insulate buildings and regulate humidity, allowing Biochar “[...] to be used in textiles as a way to provide thermal insulation as well as reduce odors produced by sweat.” Pyrolysis can also be a source of energy for cooking, where biomass is burned in pyrolytic stoves for home cooking, becoming an affordable alternative to reduce wood consumption in indoor cooking.

He concludes,