MONTREAL, June 3 (Reuters) - Airlines need to reach

long-term agreements to buy bigger quantities of sustainable

aviation fuel if they want to boost global volumes of the

lower-emission fuel required for industry climate targets, a

Bayer executive said on Tuesday.

Airline members of the International Air Transport

Association are sticking to a target of net zero emissions by

2050 despite warnings that carriers will struggle to meet such

sustainability goals due to low production of SAF, which is more

expensive than conventional jet fuel.

IATA, which wrapped up a summit in India on Tuesday, expects

the amount of sustainable aviation fuel produced to double in

2025 to reach 2 million tonnes, representing 0.7% of airlines'

fuel consumption.

While airlines have called for greater action by energy

companies and other partners to boost SAF volumes, Matthias

Berninger, a Bayer executive vice president and sustainability

head, said in Montreal there needs to be more long-term

purchases of the fuel, similar to some commitments in the

renewable energy sector.

Bayer, which acquired Monsanto in 2018, said its crop

science unit sells seeds and pesticides to farmers who produce

crops for biomass-based feedstocks used to develop biofuels.

"If they (airlines) commit to buy a certain amount over a

certain period of time, we can guarantee that farmers will grow

it and processors will process it," Berninger told Reuters on

the sidelines of the International Civil Aviation Organization's

aviation climate week.

"And the question whether or not that supply meets the

market (demand) depends on long-term purchasing contracts of the

airline industry sending a very clear demand signal comparable

to what we have in the renewable space."

SAF can be produced from plants, used cooking oil or wastes,

among other products. ICAO's Carbon Offsetting and Reduction

Scheme for International Aviation (CORSIA), seeks to cap

emissions from international flights at 85% of 2019 levels.

(Allison Lampert in Montreal; Editing by David Gregorio and

Michael Perry)