What Are Negative Emissions Technologies? Pull To Refresh

What Are Negative Emissions Technologies?

By Rachel Jaeger

What are Negative Emissions Technologies?

In 2015, the United Nations created the Paris Climate Agreement, which set a goal for countries to address global warming and climate change. In order to complete this goal, it is necessary for humanity to not only emit less carbon dioxide into the atmosphere, but also to remove the greenhouse gas emissions that are already there.

There are many methods and technologies that are being developed to achieve this goal. Since these technologies are removing CO2 emissions, they are called Negative Emissions technologies. They are also referred to as Carbon Removal, Emission Reversal, Greenhouse Gas Removal, and Carbon Dioxide Removal.

Negative Emissions technologies are a major part of the effort to mitigate climate change and bring atmospheric carbon back towards pre-industrial levels. In this article, we will discuss in detail why everyone should know what they are and how they can change our world for the better.

Why do we need to go beyond zero emissions?

While it is important to reduce emissions, it is still important that we remove carbon from the atmosphere as well. This is partially due to the fact that there is so much carbon in the atmosphere currently that it is impossible to rely on only emission reduction. In order to avoid catastrophic climate change, we should target four or more gigatons of carbon removal per year. The current global capacity to capture CO2 is only .7% of the four gigatons that are needed. To reach this goal, companies need to increase their use of negative emissions technologies both quickly and significantly.

Types of Negative Emissions

Through their work with negative emissions, scientists have succeeded in developing several different types of negative emissions technologies. These technologies can be divided into three groups: biological, geochemical, and technological.


Biological negative emission technology consists of adding back plants into the earth that naturally store carbon. For example, reforestation—replanting forests that had been destroyed—and afforestation—adding forests where there previously had not been any—are both biological forms of negative emission. This technology is simpler and cheaper than other options, but it also is not the most conducive to our needs. Forests take a lot of land, land that we sometimes do not have available, and they also store carbon for only a limited time.


Geochemical negative emission technology manipulates natural resources within the earth to store carbon for long periods of time. Enhanced weathering is one of these processes. When rocks break down by wind or rain, they release particles that bind to CO2, thus catching it and storing it.

One way to speed up this process is by spreading crushed silicate minerals on the rocks and the soil, helping them to break down faster and capture more carbon. While there are still uncertainties with this technology, like how much carbon it will capture and the potential for carbon rerelease, it offers promise and is relatively cheap and simple to use.


Bioenergy with carbon capture and storage (BECCS) is one of the most common forms of technological negative emissions technologies. However, it’s important to note the difference between carbon capture and carbon removal. Carbon capture prevents emissions from going into the air by capturing them at the source, and carbon removal which removes CO2 that has already made it into the air. BECCS allows for the capture and storage of CO2 in places where biomass is used to generate electricity.

Since biomass absorbs CO2 naturally, it can be captured and stored underground as the biomass burns, thus removing it from the carbon cycle. BECCS is one of the most promising negative emission technologies, as it can be low-cost and many companies have begun to use it. In the United States, the Illinois Industrial Carbon Capture and Storage Project captures nearly one million metric tons of CO2 each year using BECCS. There are still some concerns with it, like whether biomass will continue to be available in the coming years, but for the most part, BECCS continues to be a mature and sustainable negative emissions technology.

Emerging Negative Emissions Technologies

Since negative emissions technology as a whole is a recent concept, there are few that are fully developed yet, but one of the most recent is direct air capture. Direct air capture involves using a chemical process to extract the carbon—as the name indicates—directly from the air and storing it. This process actually allows the captured CO2 to be sold, often used in carbonated drinks or to make synthetic fuel. Currently, this process is very expensive, and there are only ten direct air capture plants throughout all of the United States, Canada, and Europe.

However, the United States is currently developing a large-scale plant, with hopes to capture up to one million metric tons of CO2 a year. If work continues at a steady pace, it may become operational in 2023. There is a new direct air capture project in Iceland as well, called the CarbFix project. The goal of this project is to capture the CO2 and store it in basalt rock formations. While direct air capture is currently underdeveloped and expensive, these new plants may lead to a breakthrough in the technology and more negative emissions.

The Importance of employing both Negative Emissions Technology and Reducing Emissions

Reducing emissions is not just a good thing to do, it is urgently  required if we want to avoid drastic climate change. In any areas where it is possible, emissions should be eliminated entirely. However, this isn’t always the case. There are some areas where it is impossible for carbon emission to be eliminated entirely—steel and cement making, but also many other major sectors, including farming and aviation. We need negative emission technology in order to make up for these areas, and to remove the emissions that are already in the air and oceans.

The main goal for negative emission technology is to reach net zero and then go beyond it to reduce the overall ppm of CO2 in the carbon cycle. When companies reduce their emissions as much as possible and also use negative emissions technologies, this goal is achievable.

The Takeaway

With all these different types of negative emissions technologies, it is possible to reach net zero, and perhaps go even farther. We can’t reach this goal, however, unless we both continue to reduce negative emissions and build and use better negative emissions technologies. Both are needed in order to fully realize the goal outlined in the Paris Agreement. 

Pull To Refresh is working hard to reach this goal as well. We are working on a different type of negative emission technology that involves sinking Sargassum macroalgae–a type of seaweed–into the ocean. Seaweed soaks up emissions from the atmosphere, and when it washes up on shore, it releases those emissions back into the air. We use our own vessels to sink this algae over 1000 meters deep. This is a beneficial and stable solution that stores the carbon in the seaweed deep at the bottom of the ocean, where it will stay for up to 1000 years.

If you are interested in helping us reach our goal in achieving net zero, you can buy into this negative emission technology! There is a long road yet to net zero, but negative emissions technologies are helping us to move towards a carbon negative future.

By Rachel Jaeger

Rachel is a third-year undergrad student at the University of Northwestern-St. Paul studying Professional Writing. She currently works as a Blog and Content Writing intern at Pull to Refresh, Inc.