Scotland may not be able to meet ambitious climate change targets following cuts to windfarm subsidies, energy minister Fergus Ewing has warned.

He said the Scottish Government's target for cutting greenhouse gas emissions was "extremely challenging" after the UK Government brought forward plans to axe the main subsidy for onshore wind power generators.

The decision last week was criticised by industry leaders, environmental campaigners and politicians.

UK Energy and Climate Change Secretary Amber Rudd announced that new onshore wind projects would not qualify for subsidies from from the Renewables Obligation, which is levied on conventional energy generation and passed on to consumers, from next April.

Industry body Scottish Renewables said the move, a year earlier than expected, could deprive Scotland of £3billion of investment.

Interviewed on the BBC's Sunday Politics Scotland, Mr Ewing said it could also wreck the government's climate change targets.

Ministers have an ambitious medium term target to reduce CO2 and other harmful emissions by 42 per cent by 2020, compared with 1990.

Up to now they have insisted they are on to course to achieve the goal despite missing interim targets for the past four years.

But asked if the 2020 target was in jeopardy, he said: "I think it will be extremely difficult and that is absolutely disappointing.

"The 2020 target will be extremely challenging."

Ministers said they were three quarters of the way towards meeting the 2020 target when they latest figures were published earlier this month.

However the annual limit was missed for the fourth year running as the figures showed Scotland produced 53 million tonnes of carbon dioxide equivalent in 2013 compared with the target of 48 million tonnes.

It emerged yesterday that some wind power projects could face the axe despite already having planning permission.

The UK Government granted a grace period for schemes with planning permission but Scottish Secretary David Mundell said they must also have secured a connection to the national grid to qualify for subsidies.

Defending the decision, he told the BBC: "I think the decision has been made on the right grounds.

"We have reached the level of onshore wind that needed to be subject to subsidy."

He dismissed criticisms from First Minister Nicola Sturgeon, who had described the decision as "wrong headed, perverse and downright outrageous".

The Conservatives promised to cut wind power subsidies in their election manifesto.

They are also planning to give communities in England the final say on proposed new developments, a move Mr Ewing rejected for Scotland,

He cited a survey showing seven out 10 Scots backed the expansion of onshore wind schemes and insisted existing planning procedures allowed people to give their views.

He repeated his warning that energy companies set to lose out from the ending of subsidies could take the UK Government to court.

Ministers want the equivalent of Scotland's total energy consumption to be generated from renewable sources by 2020.

They are confident an interim target to generate 50 per cent of energy demand from renewables by the end of this year will be met.

According to the most recent figures from the Department of Energy and Climate Change, renewables made up 46.4 per cent of total electricity generation in Scotland in 2013, up from 39.9 per cent the previous year.