The global carbon offseting system created by the International Civil Aviation Organization (ICAO) is the first of its kind for the aviation industry. It is expected to help slow the growth of emissions from commercial flights and will cost the industry less than 2 percent of revenues. Although governments must still take action to implement the agreement's limits, the system will become mandatory for states with larger aviation industries starting in 2027. Airlines will need to purchase carbon credits from specific environmental projects worldwide in order to offset the increase in emissions. According to Olumuyiwa Benard Aliu, president of ICAO's governing council, the system is the result of compromises and consensus. Aliu stated that despite objections from a few countries, the plan would not be derailed. He mentioned that 65 countries, accounting for over 80 percent of aviation activity in the initial phases, had exceeded the agency's expectations in terms of participation and that this number would continue to increase. The main point of tension was between developed nations, who historically have been responsible for most greenhouse gas emissions, and emerging and developing countries who are concerned about increased costs affecting growth. Russia and India have announced they will not take part in the initial phases, citing unfair burdens on emerging economies. In contrast, China has expressed its intention to participate in the voluntary phase. Brazil has previously expressed concerns about a deal but now supports it without committing to participating in the initial phases. According to ICAO estimates, the deal could cost airlines between $1.5 billion and $6.2 billion in 2025, potentially reaching up to 1.8 percent of industry revenues by 2035. Despite slim profit margins for airlines, the deal is seen as more cost-effective than various national and regional climate agreements. Paul Steele, a vice president at IATA, believes the costs associated with the deal are manageable for the industry. The US Department of State, which has been advocating for a deal, stated that it will lead the industry towards sustainable, carbon-neutral growth. However, environmentalists believe that due to the voluntary phase and exceptions for smaller markets, the scheme will not achieve its intended goals. According to the International Council on Clean Transportation, the agreement will only require airlines to offset around three-quarters of growth after 2021, which is equivalent to one-quarter of total international traffic. Some critics are concerned about the deal's reliance on offsets, with Transport and Environment director Bill Hemmings stating that it will not reduce demand for jet fuel and will not effectively combat the environmental impact of air travel. Discussions will now focus on the specific technical aspects of the agreement, particularly regarding the types of offset credits that will be considered acceptable. The deal, approved by an assembly of ICAO's 191 member states in Montreal, will impact international passenger and cargo flights, as well as business jets that produce over 10,000 tonnes of emissions per year. Previous negotiations led to tensions prior to the 2013 ICAO assembly, with the European Union directing foreign airlines to purchase credits under its program due to slow progress. This move was met with resistance from China and other nations who felt it infringed on their sovereignty. The agreement follows the recent implementation of the Paris accord to combat climate change. Aviation was not included in the agreement, even though the sector is responsible for around 2 percent of carbon dioxide emissions, which is more than some industrialized countries. With the industry anticipating a doubling of passenger numbers to 7 billion by 2034, it is crucial to reduce aircraft pollution in order to meet the temperature goals set in Paris, according to Lou Leonard, a vice president at the World Wildlife Fund.