OTTAWA - Prime Minister Justin Trudeau is getting a lot of love from climate change campaigners these days simply because he doesn't insult them.

The last prime minister -- that would be Stephen Harper, of course -- had a natural resources minister that talked about "environmentalists and other radical groups" who would "hijack our regulatory system." One of Harper's public safety ministers tabled anti-terrorism legislation that specifically identified environmentalists as a threat.

It was all part of a clear-as-a-bell strategy by the Harper Conservatives to demonize anyone and everyone who opposed continued development of Canada's energy resources and the oil pipelines urgently needed to diversify Canada's energy market.

Trudeau, on the other hand, loves these "environmentalists and other radical groups." His principal secretary, Gerald Butts, used to be the Canadian boss at the World Wildlife Federation. The chief of staff to his environment and climate change minister is Marlo Raynolds, who used to be the boss of the "green" advocacy group The Pembina Institute.

One of Trudeau's MPs, Will Amos, was one of the leading lawyers in EcoJustice, a charity which whose lawyers, including Amos, would show up in any court, anywhere, anytime -- including the Supreme Court -- to advance the cause of "environmental justice."

There is no doubt that the so-called 'green lobby' is massively behind the Trudeau government.

And yet, even as Trudeau prepares to speak Monday to the global climate change conference in Paris, his government is offering gruel as thin as Harper's when it comes to actually doing anything about the problem. It's a classic bait-and-switch.

What is the problem?

The problem is that if the world does not figure out a way to prevent average global temperature from rising 2C beyond what it was in our pre-industrial era, the planet and its inhabitants are in for some kind of trouble.

Now some columnists in this paper will howl and argue that science to support that claim is wrong or incomplete.

Fair enough. Let that debate continue.

But I'm a political reporter. And there is no mainstream political party anywhere in the country which now challenges the science of climate change. The last who tried was Danielle Smith, the former leader of Alberta's Wildrose Party, who, in the 2012 provincial election suggested the science was "not settled." She got a lot of grief -- in Alberta -- for that comment.

Harper's Conservatives would be and continue to be denounced by their political opponents as knuckle-dragging anti-science climate change deniers. And yet, it was the Harper government that put its name on the 2009 Copenhagen Accord that agreed with, supported, and endorsed the idea that climate change and global warming is real, that humans are responsible, and that we can and ought to do something about it.

That last bit is the tricky part. What to do about it.

Experts say we ought to have a global "carbon budget" that, if we held to that budget, would see greenhouse gas emissions drop to a level that saves the planet.

Each country would be allocated a certain amount of space in that "carbon budget" and each country would have to meet their commitments.

But such an agreement to stick to a carbon budget only works if it is a binding target, a target where, if you foul up and break your word, you will face some sort of penalty.

The big Paris conference this week and next will not come anywhere close to setting binding targets for emissions cuts.

Trudeau's environment and climate change minister Catherine McKenna conceded as much in a Sunday press conference in Paris with reporters. What we might get after all the yakking in Paris is a binding agreement on how to report your emissions.

But that won't cut it. I've seen no brief from any climate change campaigner which suggests cutting emissions is possible without the world's biggest emitters committing to a legally binding target to do so.

And for the Trudeau government to fail to commit to this basic principle in its international diplomacy is surely to fail the trust and admiration of the climate change campaigners who had so much hope that there really would be "real change" in Ottawa.