As the world begins to emerge from blockages and secondary and tertiary waves, the temporary lull in emissions caused by aviation is expected to come back in force. Before the pandemic, sustainability was the industry’s biggest challenge. The standard way to go green has been to purchase carbon offset credits. However, with United Airlines claiming to invest millions of dollars in carbon capture technology, how do these solutions stack up?

Carbon offsetting and carbon capture are two different things, and both will help reduce the impact of aviation on climate change. Photo: Getty Images

Carbon offsetting alone is not enough, says Kirby

Thusday, United Airlines announced an ambitious new plan reduce its emissions by at least 100% by 2050. aGlobal Alliance has made similar statements, United is the first carrier to proclaim that beyond sustainable aviation fuels and carbon offsetting, it will invest in a technology known as direct carbon capture in the air. .

We have been hearing about carbon offset programs for years in connection with aviation sustainability efforts. However, investing in carbon capture is an entirely new initiative for an airline. United Airlines CEO Scott Kirby hopes this will prompt other carriers to follow suit, as “buying carbon offsets alone is just not enough.”

So what exactly is the difference between carbon offsets and carbon capture? Let’s take a closer look at each concept.

Boeing 787-10, operators, United Airlines
United Airlines on Thursday announced its intention to be 100% green by 2050 by investing in sustainable fuels and direct carbon capture from the air. Photo: Getty Images

Compensation in exchange for credits

Carbon offset programs allow individuals and businesses to invest in environmental projects around the world to “offset” the greenhouse gas emissions they themselves produce.

Organizations that will make our consciousness feel a little lighter are aimed at specific industries and activities. They bet on events and daily commutes to appliances and heating and, of course, air travel.

The projects invested aim either to prevent (like renewable energy sources) or to reduce (like reforestation) greenhouse gas emissions. Offsets are measured in metric tons of carbon dioxide equivalent, and the buyer then receives credits that “offset” their own contribution to the pollution.

BA flies with contrails
Carbon offsets give the buyer credits in carbon dioxide equivalents. Photo: Getty Images


The United Nations Carbon Offsetting and Reduction Program for International Aviation (CORSIA) aims to ensure that aviation emissions above 2020 levels are offset elsewhere. The Paris Agreement covers domestic aviation for countries that have ratified (not withdrawn) it. However, international flights are placed under the auspices of the UN’s International Civil Aviation Organization (ICAO).

CORSIA will start operating in January 2021. A voluntary pilot phase will last two years. All airlines operating on routes between two participating states will have to meet the compensation requirements for their flights. So far, 78 countries have volunteered to participate in the pilot project.

KLM Boeing 737-700
Several airlines, such as KLM, already offer voluntary compensation programs, but how effective are they? Photo: KLM

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Voluntary diets are ineffective, reports say

Many airlines already operate their own voluntary carbon offset programs for passengers. SAS, Delta, KLM and Qantas, among others, all offer travelers to pay extra to fly a little greener. Qatar Airways and Wizz both have recently launched their own versions, while British Airways and JetBlue themselves bear the compensation costs for all domestic flights.

However, according to a BBC Last year’s report, less than half of the world’s largest airlines offered carbon offsetting opportunities to their customers. And, perhaps even sadder, only about 1% of passengers choose to take the airline on offer.

Qatar is back to serve 100 destinations this week
Qatar Airways has just launched its carbon offset program. Photo: Getty Images

Ethical concerns and term credit

In the meantime, this is not the only problem with carbon offset programs. They are often marketed as a quick fix, an easy way to pass the problem on to someone else; out of sight out of mind. There have also been ethical issues regarding reforestation programs where entire populations have been arbitrarily evicted from land. The financial incentives offered by such programs can also lead to other problematic behaviors.

Of course, there is also a delay. While an airline or passenger may offer to offset their carbon emissions today, a newly planted tree will take years to absorb carbon in significant amounts. This means that compensation is bought and paid long before it is certain that it will be achieved, often referred to as “term credit”. Thus, the carbon offsetting equation is somewhat avoided and highly dependent on unknown assumptions.

Air pollution at China airport
It will take more than a term loan for aviation to offset its contribution to pollution. Photo: Getty Images

That being said, some projects invest both socially and environmentally or encourage forestry companies to let their trees grow longer. It is important to research and ensure that the companies we choose to sponsor are legitimate and really make a difference, especially in a largely unregulated field. Hope we can also trust the airlines to have done this for us.

Direct carbon capture

Another technology that works with what’s going on in the atmosphere right now is the direct capture of carbon in the air. As its name suggests, it involves taking CO2 directly from the air. It can then be stored in the ground or used to produce new fuels, chemicals or other materials containing carbon dioxide.

When stored, it is permanently removed from the atmosphere. This translates into zero emissions. According to the intergovernmental International Energy Agency (IEA), there are currently 15 direct air carbon capture plants around the world (although this may have increased slightly since the agency’s last publication). Together, they capture more than 9,000 tonnes of CO2 per year.

While more than 30 installations are in the planning stages, the technology is still incredibly expensive. It needs political incentives and investment in research to develop and significantly reduce the repayment of our carbon debt.

Local and general CSC

There are two forms of carbon capture. One is a localized version that can be used for specific companies in their production facilities, trapping CO2 directly at its emission source. It’s actually been around much longer than we realize, as oil and gas companies have used it as a way to improve recovery.

In the other version, the plant sucks carbon directly from the general atmosphere. In either case, the carbon capture and storage (CSS) process has three main stages. First, the carbon must be trapped and separated from other gases. It must then be transported to a storage location. The next step is to store it away from the atmosphere, which means a deep subsoil known as geological sequestration, or, potentially, submarine.

Climate justice
While offsetting is a good start, scaling up carbon capture would have a much more direct impact. Photo: Getty Images

Combined efforts for the sixth largest polluter in the world

In 2018, flights were responsible for 2.4% of global energy-related carbon dioxide emissions. If aviation were a country, it would be in sixth place for total emissions. While other industries are also major contributors to pollution, reducing the impact of aviation is paramount for, without being too dramatic about it, future life on earth.

While carbon offsetting is an important step towards climate change mitigation, if commercial aviation increases according to pre-pandemic projections, larger efforts such as carbon capture will be essential to achieve zero emissions by the year. mid-century.

What do you think of carbon offsetting versus carbon capture? Do you think airlines should invest in either or both? Let us know in the comments.

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