A coalition of climate campaigners and business groups have called for a ban on all petrol and diesel vehicles in Scottish cities as part of a multibillion-pound strategy to cut carbon emissions.

The climate emergency response group, a coalition of 19 environment groups, civic institutions, companies and business groups, said the Scottish government had to significantly speed up and strengthen its responses to the threats posed by global heating.

That includes focusing the £11bn spent by the Scottish government every year on buying goods and services that reduce carbon emissions.

Nicola Sturgeon, the first minister, has agreed 2045 will be Scotland’s new net-zero target for CO 2 emissions, with ministers due to set out more detailed proposals in coming weeks.

Claire Mack, the chief executive of Scottish Renewables, an industry body for energy companies, said: “We are already witnessing the effects of climate change, and now is the moment when we must accelerate our response if we are to avoid the worst effects and secure the many social and economic benefits of moving to a climate neutral economy.”

The group, which includes the University of Edinburgh, the Energy Saving Trust and the landowners’ body Scottish Land and Estates, has produced a 12-point plan that recommends:

• A ban on petrol and diesel-powered cars in all city centres by 2030

• Establishing four green, low-carbon city investment deals

• A £100m fund to decarbonise farming

• Regional land use plans to maximise the countryside’s role in cutting CO 2 emissions

• A public information campaign to promote climate-friendly, lower meat and dairy diets

The UK government expects to be chosen as a co-host of next year’s COP26 global climate talks. It has recommended Glasgow hosts the summit later in the year, adding to pressure on both the Scottish and UK governments to intensify their efforts on the climate crisis.

The Scottish government is spending tens of millions of pounds on various road and rail electrification projects, and on energy efficiency, but has yet to deliver any cuts in CO 2 emissions from transport or farming, while bus use is falling.

Its ministers have refused to support calls from the Scottish Green party for urban speed limits to be cut to 20mph across Scotland, claiming it was not electorally popular. Sturgeon has, however, abandoned plans to cut aviation taxes and her government’s support for wind power has resulted in Scotland becoming a net exporter of zero carbon electricity.

The climate emergency response group also includes companies and organisations with a business interest in promoting low-carbon energy, such as the forestry industry body Confor, and Star Renewable Energy, which makes heat pumps.