Pump prices have become as fickle as the weather as of late, but there is one certainty: on Sunday, the price per litre goes up another cent, the third consecutive carbon-tax hike in B.C.

Motorists are being reminded — by the Canadian Taxpayers’ Federation and the B.C. Conservatives — to gas up early. Not that they can steer around the price hike past Saturday night. Sunday morning, the tax rises to 6.67 cents a litre from 5.56 cents a litre.

“In B.C., July 1 has become synonymous with gas-tax increases,” said Jordan Bateman, B.C. director of the taxpayers’ federation. “This is the third straight year the carbon tax has increased and taxpayers are struggling under the weight of B.C.’s massive gas tax burden.”

B.C. motorists will pay a record $1.8 billion in gas taxes this year.

British Columbia was the first jurisdiction to introduce a carbon tax when the Liberal government enacted it in 2008. The premise for the tax is to use revenues to offset the environmental impacts of burning hydrocarbons and build incentive for alternatives.

“Everyone will pay more for gas on Sunday, so fill up your tank before then,” said John Cummins, B.C. Conservative leader. “Both the Liberals and the NDP support this latest carbon tax hike. We already pay the highest gas taxes in North America and they want us to pay more.”

Cummins said his party would scrap the carbon tax if elected to government, which would save drivers seven cents a litre.

To drive home the message, the party is sending a voice message to thousands of households, reminding people to gas up early.

The provincial government introduced the tax with the promise that it would be, technically at least, revenue-neutral for government. In other words, tax credits would compensate for the increased cost. Bateman argues those credits mean little to the average citizen.

The credits include the small business venture capital tax credit, a corporate income tax cut, an industrial property tax credit, interactive digital media tax credit, scientific research tax break and film industry tax break as offsetting the carbon tax.

“These offsetting tax cuts don’t do much to help drivers and families straining to make ends meet,” Bateman said. “Most of the families I know fill up their cars with gas, but very few of them engage in scientific research, film production or own industrial property.”

The federation plans to tell the provincial government’s current review of the carbon tax that the levy should be scrapped.

Environment Minister Terry Lake said Premier Christy Clark has made it clear the province has no intention of scrapping the tax. If that were to happen, the $1.2 billion in revenue would have to be found to replace the revenues.

This will be the last legislated increase in the tax, which put B.C. at the forefront of jurisdictions around the world wrestling with the prospect of greenhouse warming, he said.

“We are seeing other jurisdictions around the world follow our lead,” Lake said, noting that Alberta has a carbon tax for heavy emitters.

It’s untrue that ordinary citizens don’t share in tax-relief measures, since low-income earners receive a carbon-tax rebate, he said. He also cited the $200 credit tied to the homeowner grant available to rural residents.

As for economic impact, Lake cited a recent report indicating that B.C.’s GDP and population grew between 2007-2010 while the province cut emissions.