A COP26 declaration to cut aviation emissions is “full of scams”, environmental campaigners have warned.

The International Aviation ­Climate Ambition Coalition agreed to ­support measures to reduce the sector’s ­carbon emissions.

These included promoting the ­development of low-carbon aircraft, sustainable aviation fuels and carbon offsetting. It was signed by 20 countries ­including the UK, the US, France and Spain.

But Greenpeace is calling on ­European leaders not to support it, and urged them to ban short-haul flights and “massively invest” in rail instead.

Doug Parr, chief scientist for Greenpeace UK, said: “This announcement is full of scams like offsetting, and excessive optimism on so-called ­‘sustainable aviation fuels’ and future aircraft designs.

“But it lacks the one thing that’s needed to deliver the goal of ­limiting temperature rise to 1.5C, which is tangible action to prioritise green travel and reduce flights.

“At COP, the final decision must commit to phase out fossil fuels, which means reducing demand for those fuels from industries like ­aviation.

“Policymakers and countries should ban short-haul flights ­wherever a ­viable alternative already exists, and invest in rail to create a transport system that’s good for the planet while also being affordable and accessible to all.”

Meanwhile, campaigners have ­rallied to call for better public ­transport in Scotland, saying the free travel pass given to COP26 delegates shows the need for a fully integrated system.

Those attending the climate change summit are given a travel pass which can be used on buses, trains and the Glasgow underground for free travel.

While parts of Scottish public ­transport have smartcard systems, there is no integrated card for all ­public ­transport users across the whole network.

A demonstration organised by Friends of the Earth Scotland and Get Glasgow Moving was held in George Square yesterday morning.

It comes amid COP26’s Transport Day, where the summit discusses how to make travel greener.

Ellie Harrison, of Get Glasgow Moving, said the travel pass for COP26 attendees showed a similar system could be used across Scotland.

She said: “With political will and funding you can do anything.

“It’s disgraceful that Glasgow city council and the Scottish Government have presided over such a diabolical system for so long.

“Now, when the eyes of the world are on them, they’ve pulled this out the bag to say, ‘we’ve got an ­integrated public transport system’.”

The Scottish Government ­recently extended free bus travel to ­everyone under the age of 22 and is ­currently commissioning a “fair fares ­review” which will take an integrated ­approach to public transport.

Harrison said: “We don’t need any more reviews, we’ve been banging on about this for years, what we need is action.”

Gavin Thomson, a transport ­campaigner with Friends of the Earth Scotland, said delegates ­coming to Scotland would be “shocked at how disjointed our public transport ­system is”.

He said: “We’ve been told for years it’s too difficult to implement a card like the one the delegates have.”

Separately, Scottish ­Labour leader, Anas Sarwar, joined ­councillors in Glasgow to back plans for a publicly-controlled bus network in the city.

He said: “We cannot achieve net-zero with rocketing fares on public transport and bus services in decline.

“It is time for transformational change.”