Former President George W. Bush said building the Keystone XL oil sands pipeline is a "no-brainer" for economic growth.

"I think the goal of the country ought to be, 'How do we grow the private sector?' " Bush said at a Pittsburgh luncheon with energy executives, according to DeSmog Blog.

"If private-sector growth is the goal and Keystone pipeline creates 20,000 new private-sector jobs, build the damn thing," Bush said.

The State Department says the proposed Canada-to-Texas pipeline would create 42,100 direct and indirect positions — about 3,900 of them being construction jobs — during the two-year construction phase. The agency says it would contribute 35 permanent jobs after construction.

President Obama, who has questioned Keystone's jobs potential, has said he won't approve the pipeline if it "significantly exacerbates" carbon emissions.

State is reviewing the project as it's in the process of finalizing an environmental assessment. The draft assessment said the pipeline wouldn't significantly exacerbate carbon emissions, though Keystone's opponents have charged that the review was flawed because of possible bias. The State Department's internal watchdog is looking into whether the contractor that performed the draft evaluation had a conflict of interest, as it had previously consulted for Keystone builder TransCanada.

Keystone's detractors say the pipeline is needed to accelerate production of Canada's oil sands, a dense, carbon-intensive form of crude.

They seized on comments in an International Energy Agency report released last week that said new pipeline capacity is required to bring oil sands to market — a blow to the oil industry, which has said demand for oil sands is strong enough to bring the crude to market by rail.

But Fatih Birol, the IEA's chief economist, said in an interview published Monday in Canada's The Globe and Mail, that the impact of oil sands on global greenhouse gas emissions wouldn't be as severe as critics say.

"The oil sands definitely makes a contribution to the increase in CO2 emissions,” Birol said. “But the difference in getting oil from oil sands when compared to conventional oil, it is such a small contribution that it will be definitely wrong to highlight this as a major source of carbon dioxide emissions worldwide."