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Delta And The World Need Carbon Offsets To Stop Global Warming

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Delta Air Lines’ announcement on Valentine's Day that it will go carbon neutral is a move in the right direction. Travelers who want to address the climate impact of their flying can only buy carbon offsets now. And they are the only current option for airlines as well.

We can't fly on battery power or hydrogen fuel cells. Aircraft are already relatively efficient in part because the single greatest cost for an airline is fuel.

It is not clear if consumers would make different choices even if they could compare flight carbon emissions while buying tickets. Would you switch to less convenient departure times or higher-priced tickets for a trip that saves carbon? If you leave your sports equipment at home for your next golf or ski vacation, you'll save more CO2 than choosing the most efficient carrier on the planet.

Commercial aircraft require energy in liquid form. Sustainable aviation fuel (SAF) is a proven way to reduce emissions, but there is not enough SAF available today. Lower carbon fuels produced from waste-based feedstock can dramatically reduce life cycle carbon. Taking used cooking oil or tallow from livestock does not require any petroleum. Solar and wind can provide the power to make green hydrogen and renewable electricity to process and refine the waste oil feedstock and eventually to transport it to airports via zero-carbon supply chains. Lipid (or fat) based conversion technology is the most commercially mature SAF option.

However, even if every drop of used cooking oil and animal rendering is collected, it will represent less than 10 percent of global aviation demand. Additional sustainable feedstock-based refineries are pending. Forestry residue and municipal solid waste plants can prove viable but are still a few years from operating. The total available supply in 2019 could power a round trips flight from London to New York on every third day.

Even if magically an unlimited SAF supply materialized, economics are a barrier. If Delta were willing to pay the premium on the lowest-priced sustainable jet fuel of at least $2/gallon, it would cost them over 6x the bonus that they paid their workers this year or a premium equivalent to their total annual payroll. No airline can take on this expenditure and expect to stay in business.

Will carbon offsets be necessary for a long time? As we are increasingly realizing, reducing our emissions alone likely will not be enough. If the goal is keeping global warming below 1.5C, we'll need to pull CO2 out of the atmosphere. That means there will be a meaningful role for carbon offsets in almost any climate scenario. And burning fuel in the Stratosphere generates clouds. The contrails and cloud cover produce a short-term warming effect that is greater than a plane's carbon emissions. SAF provides fewer aerosols that form the water vapor droplets. But even with a 100% carbon-free fuel, the atmospheric impacts must be addressed.

Several NGOs are skeptical of using carbon offsets. WWF recommends that they are the measure of last resort and direct emissions reductions as strongly preferable. The Science Based Targets institute (SBTi) does not recognize offsets to achieve firm-wide emissions reductions aligned with climate stability. And WRI and CDP do not incentivize the use of purchased carbon reduction within their industry-standard greenhouse gas accounting framework. Given the range of non-profit views regarding carbon offsets it is natural that companies and consumers have questions about their use.

In reality, carbon offsets are a robust climate solution. Credible carbon registries such as Gold Standard, Verra, American Carbon Registry and Climate Action Reserve verify that projects produce carbon reduction. Each carbon offset developer must prove "additionality" that the revenue from the project makes the emission reduction financially possible. Projects must demonstrate "permanence," which is

equated with removing carbon for at least the next 100 years. Virtual tracking capabilities are mature, and consumers can view official "retirements," ensuring that offsets are sold and counted only a single time. Furthermore, projects often deliver additional co-benefits, such as improving habitat or air quality.

There is little danger of exhausting carbon project supply. As demand grows the price for offsets will increase. It will become worthwhile for project developers to pursue more costly options like soil sequestration and tree planting. The private sector has proposed audacious programs such as Indigo Ag's Terraton Initiative and Salesforce backing the UN's Trillion Tree Campaign. Companies and governments willing to pay upwards of $20 metric ton will catalyze millions of new projects and hundreds of gigatons of CO2 removal. Mechanical carbon capture from the air is another viable but expensive option on the horizon.

Can we do better? Yes, aircraft can be powered by 100% SAF with a zero-carbon footprint to produce and supply. Aviation needs to reduce carbon directly, and that requires a fuel solution. But even once conventional fossil jet production is wholly replaced, contrail warming effects will have to be mitigated. And we need to remove our historical carbon emissions from the atmosphere. So there is a critical role for offsets. Let's also make sure that we also invest in SAF as the long-term aviation climate solution.

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