Some of the world's largest airlines called on Tuesday for the industry to set global emissions targets as part of efforts to include aviation in a broader climate agreement at the end of the year.

The seven airlines, including Air France/KLM and British Airways, along with international NGO The Climate Group, have backed a range of emissions reduction targets for negotiators involved in UN-backed climate talks to consider.

Aviation is responsible for about 2 percent of global greenhouse gas pollution and that share is expected to rise.

The sector is under pressure from green groups, the European Union and other governments to clean up its act, leading to the airlines to try to craft a deal to tackle emissions, or risk having a deal imposed on them.

The proposals, from carbon-neutral growth, a 5 percent reduction and a 20 percent reduction in emissions through to 2020, using a 2005 base-year, will be presented to negotiators at the latest round of climate talks being held this week in Bonn, Germany.

The carriers, part of the Aviation Global Deal Group, said in a statement that participation in an international carbon trading market would be crucial to meeting their goals.

Under the group's proposal, a proportion of the sector's emission allowances would be auctioned to generate revenues for climate change initiatives in developing countries.

"Based on the scenarios assessed, auction revenues of up to $5-billion per annum could be generated to support activities such as climate adaptation programmes and initiatives to combat tropical deforestation," the group said in the statement.

The group also proposed that airlines' carbon dioxide (CO2) emissions are based on the carbon content of their annual fuel purchases and that CO2 pollution should be addressed through a global sectoral agreement, rather than a patchwork of regional schemes.

"The AGD Group believes that negotiators should set a target for the international aviation sector as part of a broader global climate agreement that would cover all international flights," the statement said.

Other members of the group are Cathay Pacific, Virgin Atlantic, airport operator BAA, Finnair, Qatar Airways and Virgin Blue Airlines.

Delegates from nearly 200 countries meet at the end of the year in the Danish capital Copenhagen to try to agree on the shape of a broader climate pact to replace the UN's Kyoto Protocol, whose first phases ends in 2012. (Reporting by David Fogarty; Editing by Lincoln Feast) - Reuters