Royal family events, major UK sporting occasions, airlines and English councils have used Scottish land to clean up their carbon emissions, despite claims such 'offsets' are a "greenwashing scam" and harm land reform efforts.

Analysis by The Ferret has found carbon credits, or 'offsets', produced by trees planted in Scotland have been bought by events including motorsport rallies, the Queen's state funeral and her Platinum Jubilee.

Other buyers include British Airways, councils in Devon and Norwich and luxury fashion brand Burberry.

Buying carbon credits theoretically 'offsets' carbon emissions created by events and companies by funding tree planting and peatland projects that absorb CO2 from the atmosphere. The credits are supposed to be used to mop up an organisation's unavoidable emissions.

However an MSP and a former boss of Scotland's environment watchdog said buying carbon credits was the "easy, short-term option" for organisations, unless they had "exhausted all possibility of reducing their own emissions".

The use of carbon credits is "a greenwashing scam" that "does nothing to cut carbon pollution," one green campaigner argued.

Companies do not have to buy the credits and some do so because of a genuine commitment to protecting the environment. The firms and events who bought Scotland-generated credits told The Ferret offsets were only a small part of the actions they were taking to reduce their climate impacts.

We found that Ascot racecourse, in Berkshire, bought Scottish credits to compensate for emissions produced by a 'net zero enclosure' at its famous Royal Ascot event. The London Marathon purchased them to make up for pollution produced by international travel to the race.

Upmarket pizza oven company Ooni also bought credits, partly to make up for emissions produced by its own anniversary celebrations.

Once redeemed, each credit permits its owner to emit one tonne of CO2, because the equivalent amount has been absorbed. Some believe carbon credits will play an important role in tackling the climate crisis, by attracting money into projects to revive nature and capture carbon.

But in Scotland, there are also concerns about how competition for sites to produce the credits is driving up rural land prices, potentially shutting out local communities from owning land. A 2023 study found that ownership of Scotland's forests is becoming increasingly dominated by wealthy estates, investors and absentee owners who live outside Scotland.

Swathes of land across the country are currently earmarked for tree planting and peatland restoration projects which will generate offsets. Some landowners who sell carbon credits do so with the aid of millions of pounds of taxpayer subsidies and a wide range of tax relief, as we detailed in February.

Revealed: Politicians, billionaires and offshore firms' taxpayer forestry handouts

Our new findings come from analysis of a public register of carbon credits assigned to organisations in the last three years.

The Ferret's previous research, in 2022, found weapons manufacturers, the Labour Party, and financial institutions that poured billions of pounds into fossil fuels were among those buying Scottish carbon credits. They were generated on land owned by Scotland's richest man, private equity companies and property firms.

That followed the revelation in 2020 that senior Scottish Government forestry officials feared that a £5m tree-planting deal with Shell - which earns carbon credits for the oil giant - could be viewed as "greenwashing".

Most of the credits sold over the last few years are known as 'pending issuance units' (PIUs), which cannot be used to offset emissions immediately because planted trees are not yet mature. In fact, some might not be ready until the early 22nd century. The average PIU was estimated to cost £23.30, according to the Woodland Carbon Code.

The register only includes the sale of credits to companies who agree to be named publicly, so some buyers may remain secr...