An aeroplane flies underneath the jet stream of another aircraft above the Italian city of Padova September 18, 2013. REUTERS/David Gray

MONTREAL (Reuters) - A deal this fall to cap carbon emissions from global aviation at 2020 levels must be enforceable and set long-term goals in line with the 2015 Paris agreement on climate change, a coalition of environmental groups said on Monday.

Aviation was excluded from the landmark climate accord in Paris in December. But carbon emissions from the sector could triple by 2050 if left unchecked, the International Coalition for Sustainable Aviation, which represents a half dozen non-profit groups, warned in a statement.

In Paris, countries agreed to limit the rise in global temperatures to “well below” 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels.

“Now, countries need to fulfill their Paris promises by ensuring that the aviation industry does its fair share,” Brad Schallert, a senior program officer at the World Wildlife Fund, said in the statement.

While other transportation modes, such as the maritime industry, are also discussing ways to limit emissions, the world’s attention is centered on aviation - a sector that would be the world’s seventh-largest carbon emitter if it were a country.

The International Civil Aviation Organization has until October to finalize a deal that would cap and cut the carbon pollution of all international flights. The market-based plan must win the support of the International Civil Aviation Organization’s 190 member countries at its Montreal assembly, or risk the EU breaking off talks and imposing its own emissions trading plan on international airlines.

The International Coalition for Sustainable Aviation, which is closely following the ICAO talks, said any deal must have clear compliance requirements that are enforceable and include accurate flight-by-flight emissions monitoring.

The coalition also said a deal should be subject to review to help the aviation industry meet its more ambitious goal of cutting carbon emissions by 50 percent in 2050 from 2005 levels.