The DfT did, having said that, say the government was “exploring no matter if and how non-CO2 impacts could be incorporated in the scope of the UK ETS (emissions trading scheme)”.

Professor Piers Forster, an atmospheric physicist and member of the independent Climate Transform Committee, told openDemocracy it was “completely wrong” for the aviation market to claim the science on aviation’s non-CO2 effects was also uncertain to address them.

He mentioned: “It’s a bit of a joke to say the effects are also uncertain to do something about. We see their contrails and we’ve identified for more than 20 years that they are warming the planet. The market ought to not hide behind uncertainty.”

He added that “the non-CO2 effects definitely have to be accounted for in some way and action ought to be taken to lower them”.

Milan Klöwer, a climate physicist at Massachusetts Institute of Technologies, mentioned airlines have been adopting a “typical climate denialist strategy” by overstating the level of uncertainty about non-CO2 effects.

“Even in the greatest case they roughly double the impact of CO2 emissions on the climate,” he mentioned.

He known as on airlines to begin accounting for their non CO2 effects and invest extra in options, such as option fuels, which decreased these effects.

Rob Bryher, aviation campaigner at climate charity Attainable, mentioned: “These documents show that airlines can not be trusted to decarbonise on their personal. Demand management options like a frequent flyer levy, introducing fuel duty, carbon pricing, or management of airport capacity are going to be important.”

Matt Finch, UK policy manager of campaign group Transport &amp Atmosphere, mentioned: “Aviation’s non-CO2 impacts are someplace among large and definitely huge. But the market does not want you to know that. Alternatively of confronting its environmental challenges head-on, the market copies the tobacco market of the ’50s and the oil market of the ’70s in casting doubt and disbelief about the science.”

BA mentioned it was operating with academics and professionals on non-CO2 impacts of flying though Sustainable Aviation, an market group that consists of airlines, mentioned it was committing to addressing them but reiterated extra investigation was necessary. Wizz Air mentioned it was currently addressing the impacts by way of a variety of measures.

Some airlines ignore non-CO2 effects in schemes they assistance to assistance passengers calculate and offset the emissions of their flights.

BA’s emissions calculator states a one particular way flight from London Heathrow to New York emits 348kg CO2E (carbon dioxide equivalent) and charges £3.97 for offsetting.

Atmosfair, a German non-profit organisation which supports the decarbonisation of flying, calculates the exact same journey on a Boeing 777-200 – an aircraft sort applied by BA – emits 896kg and charges 21 euros (£18.37) for offsetting. Atmosfair’s emissions total comprises 308kg of CO2 emissions and 587 kg equivalent for “climate influence of contrails, ozone formation etc”.

Even though the DfT has so far failed to act on non-CO2 effects, they are talked about in official tips to corporations from the Division for Business enterprise Power and Industrial Method on how to report their emissions.

It says: “Organisations ought to involve the indirect effects of non-CO2 emissions when reporting air travel emissions to capture the complete climate influence of their travel.”

A DfT spokesperson mentioned: “Our Jet Zero Method confirmed our aim of addressing the non-CO2 impacts of aviation, by building our understanding of their influence and probable options, and the UK is one particular of the top nations operating to address this problem.”

Sustainable Aviation Fuel

International Airlines Group (IAG), which owns BA, Vueling and Aer Lingus, told DfT’s Jet Zero consultation it could address non-CO2 emissions by supporting “sustainable aviation fuel” (SAF).

SAF is a jet fuel produced from sources which the market claims are sustainable, like cooking oil and animal fat. It performs in a comparable way to kerosene but can make up to 80% much less CO2 based on how it is produced. It potentially also reduces contrails.

IAG told the Jet Zero consultation SAF was “the only viable remedy for decarbonising medium and lengthy haul flights”, which account for about 70% of international aviation emissions.

But additional documents obtained by openDemocracy reveal IAG then lobbied the DfT to water down its SAF mandate.

In response to a separate consultation, IAG argued the SAF mandate ought to only cover flights inside the UK or to the EU, and not the lengthy haul flights on which British Airways tends to make most of its income.

IAG also lobbied against a proposal to ban airlines from dodging the mandate by filling their tanks with inexpensive kerosene at overseas airports – a practice identified as “tankering”.

A BBC Panorama investigation in 2019 revealed tankering by BA and other airlines was generating smaller monetary savings but unnecessary carbon emissions.

IAG also argued against a proposal aimed at creating demand for “power-to-liquid” jet fuel, which is made by combining hydrogen produced by renewable power with carbon captured from the atmosphere.

In contrast to other so-known as sustainable jet fuels, energy-to-liquid fuel does not involve a feedstock necessary by other industries to decarbonise, such as applied cooking oil or animal fat.

IAG known as it “a pretty high-priced pathway to straight decarbonise aviation”.

Sustainable Aviation, an market group that consists of airlines, mentioned: “We are committed to addressing [non-CO2] impacts primarily based on the scientific proof, but additional investigation is essential to building helpful mitigation options, for instance the use of sustainable aviation fuels (which include decrease contrail forming particulates), alongside actions such as optimising flight routes to stay clear of contrail formation.”

BA, IAG’s principal airline, mentioned: “We are actively engaging with academics, professionals inside the market and the government’s Jet Zero Council to take proactive actions to appear into non-CO2 influence.”

Wizz Air mentioned it was mitigating non-CO2 effects “through route optimisation and jet fuel improvements” and by utilizing Airbus A321neo aircraft which decreased NOx emissions by 50%.

Ryanair did not respond to a request for comment.