Nicola Sturgeon has confirmed the Scottish government will rethink plans to cut air travel taxes after agreeing to reduce carbon emissions to zero by 2045.

The first minister said Scotland needed to dramatically step up its efforts after she accepted a target from the UK Committee on Climate Change (CCC) to set a tougher goal of net-zero emissions over the next 25 years.

Sturgeon told the Scottish National party conference on Sunday that she accepted the world faced a climate emergency, and on Thursday her government tabled amendments to its environment bill that will set legally binding targets to reach the target.

Chris Stark, the chief executive of the CCC, said Sturgeon needed to drop her plan to cut and then eventually abolish air departure tax from Scottish airports, because it would drive up emissions from aviation.

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During first minister’s questions Sturgeon was pressed by Richard Leonard, the Scottish Labour leader, Alison Johnstone from the Scottish Greens, and several other MSPs on whether she would abandon the policy entirely.

Johnstone said reducing aviation duty would be a “climate-busting tax cut”. Leonard said it would reduce tax income by £150m and mostly benefit the richest, since it would cut the cost of long-haul air fares the most, and would drive up emissions.

The first minister had deflected criticisms of the aviation tax last week but told MSPs the policy would now be reviewed. “The increase in our scale of ambition today means we will need to reconsider policies across the whole range of our responsibilities,” she said. “All of us recognise we have to do more and we have to do it quickly.”

She challenged Leonard and other Holyrood parties to stop their “kneejerk opposition” to policies designed to cut emissions. Scottish Labour and the Tories are blocking proposals from the Scottish Green party for new taxes on private parking at workplaces.

Scotland’s carbon emissions have fallen by nearly 50% since 1990, driven chiefly by the closure of coal-fired power stations and a concerted drive by Scottish ministers to support windfarms, paid for partly by a levy on household energy bills across the UK.

Rail travel has also increased, with the Scottish government investing heavily in electrification and new trains, and initiatives to promote electric car use. Sturgeon has set a target of phasing out all new petrol and diesel car sales by 2032, eight years ahead of the rest of the UK.

However, environmental campaigners and opposition MSPs accuse the SNP of failing to tackle a steep fall in bus travel and a steady increase in private car use; a failure to adopt Scotland-wide 20mph zones in urban areas; a lack of opposition in Westminster to the expansion of Heathrow airport; and of delaying an outright ban on fracking in Scotland.

Sturgeon’s government remains wedded to a strategy of maximising North Sea oil and gas production, producing 74m tonnes of oil in 2018, and Scotland has seven open-cast coal mines, which in 2017 produced 800,000 tonnes, more than a quarter of the UK’s coal. The CCC said on Thursday that the UK would continue to use fossil fuels well into the future; as a result, Scotland must dramatically increase forest cover and store excess CO2 underground to offset that.

Environmental campaigners believe ministers covering farming, finance and transport have been blocking or watering down policies that could be politically or electorally unpopular, and protecting those seen as vote winners.

Roseanna Cunningham, Scotland’s environment and climate secretary, said she intended to press other Scottish ministers to reassess their priorities, as well as plan public information campaigns on food waste, green travel and home energy use.

“One of the things I need to do now is have quite urgent conversations with some of my colleagues about the implications of this and thinking very carefully about what they can up the pace on,” she said on Thursday.

Getting to net zero was an overriding priority, she said. “Yes this is challenging but there’s no alternative; the alternative is going to be much worse.”

Cunningham agreed Scottish ministers needed to do more on decarbonising transport but confirmed she too opposed the Greens’ proposal for mandatory 20mph speed limits in urban areas. The Scottish government has full control over all speed limits in Scotland, but has never reduced them.

“As I understand it, there are issues in a large number of urban areas which would make [20mph zones] extremely difficult,” Cunningham said. “I live in an urban area where, I’m sorry, that would be extremely problematic.

“We live in a democracy, and we have to be able to persuade people that this is the right thing to do and take them with us.”