The former head of one of Canada’s largest pension plans is calling for patience when it comes to Canada’s transition to a greener economy.

In an interview Thursday, Jim Leech, a former president and chief executive officer of the Ontario Teachers’ Pension Plan, said the shift away from fossil fuels in favour of renewable energy will be a complex process that will take decades.

“The reality is, you can’t just flip a switch and change from our current use of carbon-intensive energy to totally green. It just won’t happen that quickly,” he said.

“We still need fossil fuels for the next couple decades. The question is how do we make them cleaner, number one; and number two, how do we start the transition without destroying the jobs and the companies, etcetera?”

Leech’s comments come on the heels of a new energy industry initiative, as some of the nation’s largest oil sands players formed a pact to reach net zero greenhouse gas emissions by 2050. Suncor Energy Inc., Canadian Natural Resources Ltd. and Cenovus Energy Inc. are among the heavy hitters to form the alliance, with members of the pact accounting for approximately 90 per cent of Canadian oil sands production.

It’s not just the Canadian energy industry that is looking to make strides in reducing its carbon footprint. Prominent energy supermajors including Royal Dutch Shell Plc, Chevron Corp. and Exxon Mobil Corp. have all come under activist pressure to clean up their environmental footprints amid mounting concerns about climate change.

Leech said that, ultimately, industry and investors will have to take the lead on climate initiatives, and that those stakeholders will ultimately determine the timeline for reaching those lofty climate goals.

“It certainly is being driven by the providers of capital, and it will be the providers of capital that determine how quickly this transition is made.”