From deserts and soil to oceans and skies: The innovations changing the way we think about carbon

Posted: December 06, 2024

In 2023, global levels of fossil-fuel carbon emissions reached an all-time high, despite falling in some regions, including the U.S. and Europe. To avoid the worst impacts of climate change, we need to limit global temperature increase to 1.5°C above pre-industrial levels. As the Earth is already about 1.1°C warmer than it was in the late 1800s, time is of the essence. Governments and businesses are striving to reach net zero by 2050, working to reduce emissions through innovative technologies that increase efficiencies and decrease wastage.

Understanding the carbon emissions challenge

While reducing emissions at source is the most important part of the picture, innovators are also looking for ways to mitigate and capture the carbon that is already in the atmosphere. This isn’t an alternative to reducing emissions—in fact, some climate experts say tech solutions are simply a distraction from reducing emissions. In Canada in 2023 however, wildfires caused more carbon dioxide emissions than all global aviation did in 2022. Even if we do manage to reduce emissions from human activities and industry, mitigating emissions from natural disasters will still require another approach.

Land and ocean “sinks” naturally absorb about half of all CO₂ emitted, while the rest remains in the atmosphere. There are conventional, nature-based carbon capture methods, such as reforestation, afforestation (planting new trees), and soil carbon sequestration. Soil naturally contains a lot of carbon from broken-down plant matter. Soil-based carbon sequestration involves farmers planting specific crops to store more carbon or planting additional crops after their main crop is harvested.

Carbon capture can help us reduce emissions in energy-intensive sectors. It can also help us deal with the unavoidable emissions from events like wildfires. The Intergovernmental Panel on Climate Change highlighted that “negative emissions” technologies are likely to be a necessary part of the transition to net zero. Between 2000 and 2022, research grants into novel carbon capture technologies were estimated to be worth $2.6 billion. The United Nations Framework Convention on Climate Change believes carbon capture and storage has “tremendous potential”, which could be further enhanced with the use of AI. So what do these technologies look like?

Novel emissions technologies

In 2022, carbon capture research grant funding was fairly evenly split between conventional methods, such as soil carbon sequestration (22%), novel methods such, as direct air carbon capture and storage (21%), and bioenergy with carbon capture and storage (BECCS) (18%).

Direct air carbon capture uses fans to capture CO₂ from the air, catching the carbon dioxide with either a physical filter or a chemical reaction. In August 2023, the U.S. announced it was spending $1.2 billion on two direct air capture facilities. The program aims to kickstart a nationwide network of large-scale carbon removal sites. In Canada, the U.S. and Europe, 18 direct air capture facilities were operating in 2022.

BECCS helps to decarbonize industries that are reliant on bioenergy by capturing the carbon that is released when bioenergy is burnt or converted into fuels. Bioethanol is the leading BECCS application, and around 70 additional bioethanol facilities are planned to be in use before 2030.

These more established methods sit alongside exciting innovations that are using engineering and technology to advance and scale up carbon capture, often taking inspiration from nature itself. Like soil, the ocean naturally acts as a huge carbon sink. It’s responsible for absorbing around 30% of our carbon emissions, but doing so makes the ocean more acidic, damaging the environment for marine life.

Capturing seawater

Researchers at the University of Exeter have developed SeaCURE, a technology that removes CO₂ from seawater. As the natural concentration of CO₂ is much higher in seawater than in air, carbon capture from the sea is more scalable and affordable than direct air capture techniques. Removing CO₂ from one cubic meter of seawater is equivalent to CO₂ removal from 150 cubic meters of air. After carbon is removed from seawater and stored, the sea can then absorb more carbon.

In the SeaCURE plant, researchers drop the pH of seawater, rapidly removing 90% of the stored carbon. The CO₂ is then purified, where it can either be used or geologically stored. As the purified seawater is returned to the sea, it automatically retakes carbon from the atmosphere. The team hopes to create offshore plants to decarbonize the ocean at scale.

Marine algae

London-based Brilliant Planet is also making use of the ocean, using marine algae to capture and store carbon. Like forests and the sea, coastal algal blooms are already making a huge contribution to carbon capture—they contribute 20% to photosynthesis-based global atmospheric CO₂ reduction every year. Brilliant Planet replicates this natural process in the desert to capture carbon without displacing agricultural land or resources.

The company starts by carefully growing an algal starter in a lab, before moving it to a greenhouse, which allows the algae to acclimate. Next, the algal bloom is moved to large outdoor ponds, where it rapidly grows, absorbing carbon as it does so. The algae is then filtered from the pond, which captures the biomass and lets filtered, de-acidified seawater back into the ocean. The captured biomass is dried into a salty powder, collected, and stored in special landfill sites, which should remain stable for thousands of years. Brilliant Planet currently has pilot sites in Morocco, South Africa and Oman, and is building a new demonstration facility in Morocco.

What’s next for carbon capture technologies?

Carbon dioxide removal is already happening at scale, but it needs to dramatically increase to enable us to reach net zero by 2050. The State of Carbon Dioxide Removal report states that in the last decade, the gross amount of carbon dioxide humans are moving from the atmosphere into durable carbon storage is around 2,200 million tons per year, of which only an estimated 1.35 million tons per year is from the kinds of novel methods discussed.

Novel carbon removal methods are increasing in popularity and efficacy though, with double the amount of carbon captured via novel methods in 2023 compared to 2021. The BECCS project pipeline is diversifying from primarily bioethanol-based projects to include more capture projects in heat, power, hydrogen and cement. In the UK, the East Coast Cluster stands ready to remove 50% of the UK’s industrial cluster CO₂ emissions by 2035. With exciting pilot projects proving new methods of capture are possible, we can begin to see a road to net-zero and negative emissions.