In less than two months, the two political leaders named by New Statesman as the “world’s worst climate change villains” have been tossed out of power: Australia’s Tony Abbott by his own party, and Canada’s Stephen Harper in a national poll.

It is good news for the upcoming Paris climate change talks. Both countries, under their former leaders, ranked at the bottom of the 34 countries in the Organisation for Economic Co-operation and Development (OECD) for their efforts on climate change. Among G20 countries, only Saudi Arabia ranked lower than them.

Since their elections – Harper in 2006, and Abbott in 2013 – they had applied the brakes on climate change and renewable energy policy, despite some strong efforts at sub-national levels (the provinces in Canada and states and territories in Australia).

During a visit to Canada last year, Abbott and Harper decided to create a “conservative alliance among ‘like-minded’ countries” to try to dismantle global efforts on climate change.

At a press conference, Harper applauded Abbott’s efforts to dump Australia’s carbon tax. Indeed, Abbott had borrowed the “axe the tax” slogan from an earlier Canadian campaign.

Now, both have gone. Abbott became a victim of his own poor polling and a push to replace him with the more moderate Turnbull. Harper’s Conservative Party has been stunned by the revival of the Liberals, led by Justin Trudeau, the son of former prime minister Pierre Trudeau.

Both new leaders promise more on climate change. Turnbull does not believe the climate science is crap, and the Liberals have vowed to take action. But what will they change in the form of policies?

Turnbull – barely credibly, but because of unstated commitments to the conservative rump in his party – has said that Australia’s 2030 emissions reduction targets will not change. He even defends Direct Action, a policy he once lampooned.

And, on Tuesday, he questioned whether Australia needed an institution such as the Clean Energy Finance Corporation, the institution that Abbott vowed to dismantle, but couldn’t. The CEFC has been at the heart of all major initiatives on large scale renewables and financing for rooftop solar and energy efficiency in the last two years.

Trudeau has promised to tackle climate change as one of three big priorities of his new government – along with repairing relationships with Barack Obama and ending bombing runs on Islamic State, and focusing instead on humanitarian interventions. But there are few details.

He has promised to attend the Paris climate conference, along with provincial leaders, and within 90 days, hold a meeting with these First Ministers “to work together on a framework for combating climate change.” Central to this would be the creation of national emissions reduction targets.

But not everyone is impressed, because Trudeau has not stated what his targets will be. As one columnist in the Toronto Start lamented, Canada has a history of promising big on climate but delivering little.

“If past practice is the best indicator of future conduct, it won’t matter what target Trudeau sets because the Liberals will miss it as they’ve missed every other target they’ve ever announced going back 22 years,” Lorrie Goldstein wrote.

“The Liberals never implemented Jean Chretien’s 1993 promise to reduce Canada’s GHG emissions to 20% below 1988 levels by 2005.

“Subsequently, Chretien promised in 1997 under the UN’s Kyoto accord, to reduce Canada’s emissions by a less ambitious average of 6% below 1990 levels between 2006 and 2012.

“By the time Chretien’s successor, Paul Martin, lost power to the Conservatives in 2006, the Liberals were 30% over that target.

“That isn’t surprising given that top Chretien aide Eddie Goldenberg admitted in 2007 the Liberals knew they couldn’t meet their Kyoto target when they agreed to it.

“Ironically, that’s the real reason Canada today is viewed, as Trudeau repeats ad nauseam, as an international climate pariah.”

Harper tore up Canada’s Kyoto targets, but while he promised to reduce Canada’s GHG emissions to 30% below 2005 levels by 2030, few expected him to actually achieve it.