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Climate Engineering & Negative Emissions Technology

There’s no question that the Earth’s climate is changing at a rapid rate. Climate change is having a major impact on the environment, human health, and more. To combat climate change, governments and businesses around the world are searching for ways to mitigate the changes happening right now to our climate. One such method is […]

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PlanetMark
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There’s no question that the Earth’s climate is changing at a rapid rate. Climate change is having a major impact on the environment, human health, and more. To combat climate change, governments and businesses around the world are searching for ways to mitigate the changes happening right now to our climate. One such method is climate engineering.

In this article, we’ll take a look at what climate engineering is and the different negative emissions technologies that can work to reduce or stop climate change.

What is Climate Engineering?

Climate engineering can be loosely defined as a broad set of methods that aim to deliberately alter the climate system in order to limit the impact of climate change on the entire planet. You may hear this sometimes referred to as geoengineering; however, most experts recognize the term “climate engineering” as the official climate intervention term.

Climate engineering encompasses several different proposed strategies that are designed to slow or prevent climate change by directly removing CO2 from the atmosphere through the use of negative emissions technology or by limiting the amount of solar energy absorbed by the planet (called solar radiation management).

Sucking CO2 from the Atmosphere

Next on our list of negative emissions technology is the process of sucking CO2 from the atmosphere.

Now that you understand the basic definition of climate engineering, we’ll take a look at different technologies being considered to remove CO2 from the atmosphere.

1. Enhanced Weathering

Enhanced weathering is under consideration as a way to speed up the slow carbon cycle. Under this process, rock will be used to absorb CO2 from the atmosphere and transport it to the bottom of the ocean. This is a naturally occurring process that takes thousands of years. However, enhanced weathering can make the process much faster.

The process involves crushing silicate rock (such as basalt) and spreading the rocky powder onto deserts, farmer’s fields, and coastal areas to speed up the weathering process. Studies have shown that the rate of weathering is between 5-50 tonnes of CO2 per square km/year. Warm, wet areas are best for enhanced weathering.

2. Ocean Nutrition

Ocean nutrition is a strategy that works to accelerate the rate at which algae in the ocean sequester carbon dioxide from the atmosphere. This process is meant to increase the rate at which the ocean is able to absorb carbon.

Algae absorb about 36 billion tonnes of CO2 through photosynthesis each year. Some experts believe that artificially adding fertiliser (such as iron, phosphate, or nitrogen) to the ocean could encourage algae growth and increase carbon absorption, where the carbon is deposited on the ocean floor.

However, there’s a major drawback to this process. Experiments have shown that using iron fertilisers brings about large algae blooms. The algae grew so quickly that they depleted the surrounding water of oxygen, leading to the death of other aquatic life, killing the algae, and releasing all the carbon back into the atmosphere.

3. Reducing Deforestation, Reforestation, or Afforestation

This process requires stopping the destruction of the forests on our planet, restoring forests of the past, or growing new forests to speed up the land-based biological carbon cycle. Trees absorb carbon dioxide through the process of photosynthesis by day and expel about half as much CO2 through respiration at night when they grow.

The average tree absorbs about half a tonne of CO@ from the atmosphere over the course of its life (about 25-75 years). The carbon is locked in the trunk, branches, and root systems of the trees.

If each country planted cheese, full forests could be reached in the coming decades. What’s more, planting trees is fairly inexpensive, effective, and low risk. There are also added benefits to this model, including flood control, soil preservation, and water retention. However, this process only does enough to offset a fraction of the world’s emissions.

4. Direct Air Carbon Capture (DAC) & Storage

Direct air carbon capture & storage involves technology that filters CO2 right out of the air. The process uses large fans and chemical reactions that create a process similar to trees. The CO2 is either stored deep underground or turned into other products.

However, there is a major challenge DAC. The process is quite costly and not entirely effective. There are many costs involved, including equipment, storage, and labour costs.

5. Biomass with Carbon Capture and Storage (BECCS)

BECCS is another process that involves growing biomass like trees or crops for fuel. The resulting fuel would then be used to provide heat or electricity while capturing CO2 emissions in the process. The CO2 is then stored underground.

The overall effect would be a continuous CO2 drawdown from the atmosphere while creating a source of energy. The technology already exists and there are plants already operating in several places around the world.

Pros & Cons of Climate Engineering

DAC processes remove carbon from the air to sequester and store it. But are these methods truly feasible?

Pros

Scope & Reach

DAC systems have an advantage over scrubbers in that DAC can effectively mitigate CO2 emissions from multiple sources, including homes, vehicles, and more, that are difficult or impossible to use single-source level CO2 removal methods.

Mobility

DAC can be built anywhere in the world and stay effective. They can be built in areas where the environment isn’t suitable for farming, human habitation, or where reforestation and afforestation are not feasible.

Technologically Feasible & Accessible

DAC systems are also technologically feasible with the current knowledge and technology currently available. The plants could be built and start operating in less time than it takes other solutions.

Cons

Build & Operation Costs

DAC systems tend to be large projects that require the design and construction of roads, building facilities, equipment, and machinery. This requires a huge investment and international/governmental cooperation, which are not easy to arrange.

Storage & Post-Processing

Another concern with the installation and operation of DAC systems is what to do with the CO2 once it’s been removed from the air. Underground storage is concerning because of possible leaks and environmental damage/contamination. There are also questions about the long-term operation and monitoring of these sites.

Overall Energy Use

DAC facilities require so much energy that some believe the CO2 produced by these facilities will outpace their CO2 removal.

Summing It Up

More research is needed to find feasible ways to control and remove CO2 from the atmosphere. Negative emissions technologies are available on a limited scale, such as tree planting. However, large-scale projects mean large expenses and uncertain results.

Negative emissions technologies may have a place in response to climate change, but they will most likely need to be combined with other options to create a cost-effective method to remove CO2 from the atmosphere.

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