Look around you. You’ll see stuff. In fact, everywhere we look there’s stuff. While physical structures don’t receive the same amount of attention as transportation and energy sectors in terms of decarbonising the economy, their production results in the emission of greenhouse gases such as carbon dioxide that exacerbate the climate crisis. Buildings, roads, and factories require a lot of materials to build.
We should offset the greenhouse gas emissions that result from carbon capture and storage. (AFP)
In his book How to Avoid a Climate Disaster, Bill Gates notes that the world is expected to build the equivalent of a New York City every month for 40 years. All of that construction will require cement sand, steel, and glass. And the bad news only gets worse. The ways we make things are extremely hard to decarbonise.
Affluent countries already have a lot of built-up infrastructure. On the other hand, low- and middle-income countries have an opportunity to grow their economies rapidly by building. China’s economic growth has been fuelled in large part through building projects on a grand scale. Today, China has more skyscrapers than any other country in the world.
As we found out in the most recent budget, India also plans to spur economic growth through massive infrastructure projects. Increasing GDP and growing economically are both excellent goals, but they come at a cost to the environment because of greenhouse gas emissions.
Cement is, in fact, the most widely used construction material on the planet after water. The world needs a lot of cement and most of it is produced locally. And cement is incredibly difficult to decarbonise because the emission of carbon dioxide is part of the process of making this durable construction material.
A lot of carbon dioxide escapes as a byproduct of steel production too. Around 8% of emissions are the result of cement production and around 7-8% come from the steel-making process. The production of cement and steel results in about the same quantity of emissions that come from some of the largest countries.
New technologies that allow carbon dioxide to be embedded in concrete made with cement are being tested out, but they’re not at the scale of development to be able to supply building materials to most of the world.
The production of steel in ways that burn fewer fossil fuels and release less carbon dioxide as a byproduct is also gaining traction. However, it’s going to be impossible to decarbonise these sectors of the global economy especially when much of the world is growing at a fast pace. These technologies just can’t keep up.
The world is making great strides in shifting from fossil fuels to other sources of energy in the home and for transportation. However, petroleum is also the source material for an incredible number of chemicals that are used every day, including plastics which are found in everyday objects such as packages, electronics, and clothes. In addition, petrochemicals include paints, explosives, and solvents.
Plastics are different from steel and cement because a lot of the carbon is embedded in the product itself. This explains why the chemical industry, which is the most energy-intensive industrial sector, is the third-largest source of emissions (after cement and steel). However, since plastics are carbon-based materials, they’re often burned instead of being recycled at the end of their useful life cycles releasing greenhouse gases.
Cement, steel, and plastic production will always be net positive carbon emitters on a global scale. And they highlight the need to capture carbon and reuse it or store it in a way that is carbon negative. Otherwise, the world will never achieve the goal of net-zero carbon emissions.
Here’s where trees come in. Green plants such as trees pull carbon dioxide naturally through the process of carbon fixation by photosynthesis. That’s one of the reasons why major tree-planting initiatives are popular today. However, it’s not enough to just plant saplings and forget about them. Tree-planting doesn’t work if the right trees are not planted or taken care of.
There are also innovative technologies that can pull carbon dioxide from the air and store it underground or under the sea. However, the costs of these technologies are (so far) too prohibitive to allow their global scale use in the absence of financial incentives.
Then there’s the idea of making useful chemicals at an industrial scale by reusing carbon dioxide that would otherwise escape into the atmosphere. One such example is demonstrated in a research paper published in Nature Biotechnology on February 21. The strategy in the paper is ingenious because it takes carbon dioxide that’s a byproduct of steel production and converts it into acetone and isopropanol. These chemicals are precursors of other commercially important products, which are usually made from fresh fossil fuels.
The process employs bacteria that naturally grow in low to no oxygen environments and take up carbon dioxide to make more complex carbon-containing compounds. But what the authors have done is they’ve genetically engineered these bacteria to produce commercially useful chemicals. Here, carbon dioxide is recycled to make new stuff on an industrial scale. This is an elegant solution to a pressing problem and the basic principles can be used to make other chemicals from greenhouse gases too.
The world is not going to get away from making stuff. But we should offset the greenhouse gas emissions that result from carbon capture and storage. We should also reuse greenhouse gases to create a circular economy that doesn’t add more emissions to a heating planet.
Anirban Mahapatra, a scientist by training, is the author of COVID-19: Separating Fact From Fiction
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