TORONTO - An environmental analyst says a new report revealing that oil and gas production has become the single biggest source of greenhouse gas emissions adds further weight to calls for Ottawa to regulate the sector.

An Environment Canada summary report released quietly Friday shows that energy production has now surpassed the transportation sector as the largest generator of the climate-change causing gases.

Analyst P.J. Partington with eco think tank the Pembina Institute says the change further underlines the need for the Harper government to bring in long-delayed regulations for the oil patch.

The report covers the period from 1990 to 2012, and states that crude oil production and the oilsands were behind the energy sector's 70 per cent emissions jump in that time span.

Oil and gas is now responsible for one-quarter of Canada's greenhouse emissions, narrowly edging out transportation, while reductions in electricity and manufacturing cut overall emissions by under one per cent between 2011 and 2012.

The report shows that Canada's emissions have dropped five per sent since 2005, meaning the country still remains far off from meeting its Copenhagen accord commitment of a 17 per cent reduction by 2020.