SCOTLAND’S carbon footprint fell to its lowest level on record and by 20 per cent over a 20-year period – amid a warning from a top adviser that a flagship 2030 target “is on the fringes of credibility”.

New research released by the Scottish Government chief statistician, Roger Halliday, has revealed that the country’s carbon footprint dropped to the lowest levels ever recorded in 2017 – while the figure was cut by one fifth between 1998 and 2017.

After hitting a high of 101.1 MtCO2e in 2007 when the SNP came to power, the overall carbon footprint reduction between the 2007 peak and 2017 was 30%.

The figures looked at the environmental impact of goods and services purchased by Scots, wherever in the world the impact may be, as well as the direct effect from things like heating and driving within Scotland.

In 1998, Scotland’s carbon footprint was 89.6 million tonnes of carbon dioxide equivalent, but by 2017, the figure fell to 70.7 million, the lowest recorded amount.

Over the same 19-year period, the emissions produced within Scotland dropped by 45.8%, from 75.6 million tonnes to 41 million. The output fell by 3.5% between 2016 and 2017.

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Despite the record drop, the middle of the 2000s saw a marked increase in Scotland’s carbon footprint, coinciding with period of economic boom.

However, a sharp drop was felt as the banking crisis of 2008 took hold.

As well as the Scottish Government’s commitment for the nation to become carbon neutral by 2045, MSPs have pledged for Scotland to cut 1990 levels of carbon emissions by a staggering 75% by 2030.

By the end of 2018, Scotland was unable to reduce its emissions by the 54 per cent requirement from levels in 1990 - partly blamed on the weather.

The commitment forced ministers to update their climate change plan which was published in December.

But Chris Stark, the chief executive of the Committee on Climate Change (CCC) an independent body that advises UK governments on policy, has raised concerns about how difficult the 2030 pledge will be to achieve, warning none of the organisation’s modelling scenarios included the target being hit.

Speaking to Holyrood’s Environment, Climate Change and Land use Committee, Mr Stark was asked how credible the Scottish Government’s updated climate change plan was.

He said: “In terms of the credibility of the plan, I think it’s on the fringes of credibility but so to is the Scottish 2030 target itself.

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“The work that we’ve done in the CCC, we’ve built five separate scenarios for achieving net zero – none of them achieves the Scottish 2030 target, even one we deliberately constructed to get to net zero sooner than the statutory dates.

“That troubles me – that means that the 2030 target is very, very stretching. It’s not my position that it’s the wrong target, it’s just going to be very hard to meet.”

As part of the climate change plan update, ministers have committed to "phasing out the need for new petrol and diesel light commercial vehicles by 2025”.

Mr Stark, the Scottish Government's former director of energy and climate change, told MSPs that the modelling work done by the CCC tried to minimse highly polluting items being scrapped “because that means the transition tends to be easier and cheaper and has greater support”.

Instead, he said there was a focus on “replacing high carbon assets with a low carbon asset as much as possible at the end of its useful life”.

He added: “You could flex that as something meaning you could go faster in Scotland.

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“Even with the flex to do more of those things in Scotland and to do more of those things earlier, I think this is right on the edge of what you might consider to be achievable strategy – without doing more punitive things which tend to carry much less public support.”

But he warned that the strategy appears to be “a process that has struggled to meet the exam question that parliament set for it in 2030”.

He said: “That’s going to be very difficult.

“It took 30 years to half Scottish emissions from 1990 to where we are today. We’re going to have to do that again in the next 10 (years). That is a huge challenge.

“It may be possible to do that but it’s going to be very hard.”