Wilkinson, who represents North Vancouver, told the Green Jobs BC conference last week:

What we call a climate lens and green lens will affect decisions with respect to how projects are selected going forward. Certainly the focus for infrastructure spending going forward is going to be much more on matters that are consistent with the climate agenda. … There definitely is a strong preference for public transit over building of new highways, there is no question about that.

But on the question of funding for Via Rail, Wilkinson admitted he didn’t know if improved passenger rail would be part of the government’s climate agenda.

This change does not come out of the blue. The NDP and Greens helped pass Liberal MP Andy Fillmore’s motion to the same effect in September. M-45 calls for analysis of the greenhouse gas impact of every infrastructure funding proposal over half a million dollars, and for giving funding priority to projects that reduce climate pollution.

If Trudeau’s Liberals follow through on this new commitment in a serious way, it will mean billions more for public transit and billions less for urban roadway expansion every year. Freeway loving premiers, such as Christy Clark of British Columbia, will be sorely disappointed. But most mayors of cities with public transit will likely applaud the move. If M-45 is implemented, it could free up substantial funds for improved Via Rail passenger service in rural areas in addition to urban transit.

The federal Liberals’ 2015 infrastructure plan acknowledged that infrastructure will need to be beefed up to deal with climate impacts such as flooding from more intense storms and rising sea levels. But it was strangely silent on the carbon pollution that Trudeau enthusiastically committed to cut in the UN’s Paris climate agreement.

In B.C., Premier Clark returned from the Paris climate talks and then went cap in hand looking for freeway expansion funding from Ottawa. Clark denies that her freeway expansions schemes, such as the 10-lane $3.5 billion Massey Tunnel replacement in Metro Vancouver, would increase climate pollution. Wilkinson’s statement suggests that Clark and other premiers won’t have much luck with similar requests.

The cliché “you can’t build your way out of congestion” is well supported by experience and studies. In a 2007 study, Clark Williams-Derry, research director of the SightLine Institute, found that “considering the increased emissions from highway construction and additional vehicle travel, adding one mile of new highway lane will increase CO2 emissions by more than 100,000 tons over 50 years.”

It is possible for provincial governments to fund major urban road expansion programs without federal help. But if federal money is available for transit but not roads, it becomes much easier to do the right thing for the climate.

A climate test for government spending in Canada is a big deal. But if the idea was adopted and applied rigorously in India, China and other countries the effect would be enormous. Without the tens of billions of public dollars poured into freeways every year, the already shaky business case for oil sands expansion and new pipelines would collapse.

Oil executives will likely be lobbying behind the scenes against a climate test for infrastructure funding, not so much for fear of lost markets in Canada but for fear that the idea might spread.

Every billion dollars of public money spent on roadway expansion is a billion spent to sabotage the Paris Agreement. And a climate test would result in billions more for better public transit every year in Canada. This is the kind of good idea that should, and might well, spread around the world.

Eric Doherty is a Victoria-based transportation planning consultant. Find him on twitter at @Eric_Doherty