A United Nations panel has proposed the first global greenhouse-gas emissions standard for aircraft.

The draft rule, released by the International Civil Aviation Organization (ICAO) on February 8, applies to most commercial and business aircraft, including designs already in production. It would require minimal changes to aviation design over the next 12 years, and many environmentalists say that the proposal is inadequate to combat climate change.

The plan—which would take full effect in 2028—could decrease fuel consumption in new aircraft at cruising speed by an average of 4% compared to the current level, according to the International Council on Clean Transportation (ICCT), a non-profit research group based in Washington DC. The ICAO is expected to adopt the CO2 standard later this year.

Many environmental groups found the UN panel's action wanting. ”We think that this is just woefully insufficient,” says Vera Pardee, an attorney with the Center for Biological Diversity in Oakland, California. She calls the requirements for new aircraft weak, and notes that the plan would not require any changes to aircraft that are already flying. “ICAO is not proposing to do anything about the existing fleet, and it could,” she says.

Daniel Rutherford, programme director for marine and aviation at the ICCT in San Francisco, agrees that the ICAO could have been much more aggressive. An ICCT study released in December found that manufacturers could reduce fuel consumption in new aircraft by 24% in 2024 and 40% in 2034 in a cost-effective manner. These efficiency gains would come from improvements in engine technologies and aerodynamics as well as reductions in aircraft weight.

Nonetheless, Rutherford says, the new ICAO standard is a step forward. “These standards do tend to matter over time as you update them and make them more stringent,” he adds.

Looking ahead
The ICAO process was designed to plug a gap in the United Nations climate agreement signed in Paris in December. That agreement did not address growing emissions from international aviationor shipping, which together account for more than 3% of humanity's carbon dioxide output. In addition to the CO2 standard, ICAO is working on a market-based offset mechanism that would levy a fee on international flights to pay for emissions reductions in other sectors.

In the meantime, individual countries are free to implement more stringent standards for aircraft emissions, and environmentalists are gearing up for a fight. For instance, lawsuits from environmental groups helped to push the US Environmental Protection Agency (EPA) to begin developing its own greenhouse-gas standards for aircraft.

Although the EPA has said it is waiting to see what the ICAO's final rule looks like, Pardee notes that the United States did push for a stricter standard when the UN panel met this week in Montreal. That could be a sign that the US agency will pursue regulations that are tougher than the ICAO plan. If the EPA fails to do so, environmentalists could sue the agency once again. 

Meanwhile, the ICAO is also developing a market-based offset mechanism to cap international aviation emissions by raising money to reduce emissions in other sectors, beginning in 2021. The discussions build on the European Union's decision in 2012 to include domestic aviation emissions in its Emissions Trading Scheme. The EU plan initially included international flights, too, but bloc officials backed off to give ICAO time to develop its own offset scheme.

International aviation produced more than 492 million tonnes of carbon dioxide in 2014—making its output larger than that of the United Kingdom. And that number is projected to skyrocket in coming years, with more than 56,000 new aircraft projected to hit the skies by 2040, according to the Environmental Defense Fund (EDF), an environmental group based in New York. EDF calculates that carbon dioxide emissions from air travel and transport could increase by a factor of three or four over that period.

With that in mind, EDF attorney Annie Petsonk argues that the ICAO's proposed emissions standard sets an important precedent—and could create momentum for the panel's nascent market-based emissions measure, which could achieve larger reductions in greenhouse-gas output.

“It’s going to be a tough negotiation, but the global spotlight is now on ICAO to deliver,” Petsonk says.

This article is reproduced with permission and was first published on February 9, 2016.

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