Calls for a higher B.C. carbon tax received a bump today.

More than 130 businesses have signed a letter asking Premier Christy Clark for a round of increases beginning in July 2018.

The tax has remained at $30 per tonne since 2012. Environmental organizations have proposed a slow but gradual increase to as much as $150 per tonne over the long term.

The group of businesses have suggested B.C. begin with increases modestly. Their open letter dated March 29 states companies could benefit from annual increases of $10.

“In 2008, the Climate Action Plan—with the carbon tax as its central pillar—helped move the province’s economy ahead, it helped boost the province’s reputation and it helped the environment,” the letter reads. “Taking the next steps on the carbon tax as part of the Climate Leadership Plan is an opportunity to build on those initial successes, and it is an opportunity we must seize as a province.”

Signatories to the letter include Mountain Equipment Co-op (MEC), Modo Car Coop, NEI Investments, False Creek Collision, and SFU Community Trust (view the complete list). The letter was initiated by a group of B.C.-based environmental organizations consisting of Board of Change, Clean Energy BC, Climate Smart Businesses Inc., the Pembina Institute, and Clean Energy Canada.

Matt Horne, the Pembina Institute’s associate director for B.C., argued that regular increases to the carbon tax should be incorporated into the provincial government’s plan to minimize the effects of climate change.

“B.C.’s carbon pollution is going up and new policies have lagged behind progress in other provinces,” he said quoted in a media release. “If the Climate Leadership Plan is to live up to its name, it must include a strengthened carbon tax.”

On March 2, the Straight reported Clark had signalled it might not be long before the government breaks from a freeze on the province’s carbon tax.

“We are considering raising the carbon tax,” Clark said on March 2. Speaking at the Globe 2016 Leadership Summit where Prime Minister Justin Trudeau was in attendance, Clark added that B.C. would also “protect competitiveness and communities”.