Justin Trudeau, Canada's new prime minister, unveiled a cabinet Wednesday (05.11.2015) that left climate campaigners across the world smiling. As he was sworn in, Trudeau reassured Canadians that the days of "dirty Canada" under his predecessor, Stephen Harper, were over.

Meanwhile, on the other side of the planet, a leadership change in Australia has ushered in a similar wave of climate optimism just ahead of a pivotal United Nations climate summit in Paris this December.

Although not top emitters in absolute terms, the two countries have among the highest per-capita emissions in the world, due to heavy resource extraction. They have also been among the most uncooperative developed countries on climate change in recent years.

Confident Canadians

On the day he was sworn in, Trudeau announced that for the first time, Canada will have a minister for climate change. Additionally, the country's new foreign minister, Stephane Dion, is a former environment minister, and will head a new special cabinet committee on environment, climate change and energy.

"Canada is going to be a strong and positive actor on the world stage, including in Paris," Trudeau said.

Such moves have fueled optimism. "These signals, setting up the climate ministry and the cabinet committee, are important," says Ed Whittingham, executive director of the Canadian think tank the Pembina Institute.

"Canada still has a tough job ahead of it, because [under Harper] it has become an economy based on resource extraction," Whittingham told DW. "But we're hopeful, because the last government was so antagonistic, that things can only get better."

Harper, from the Conservative Party, had pulled Canada out of the Kyoto Protocol, the predecessor to the "Paris protocol" hoped to be agreed this December, which would take effect in 2020.

Harper had encouraged increased extraction of the country's heavy-emitting tar sands oil, and did not support creation of any national program to reduce the country's emissions.

Although Canada had pledged in 2009 to reduce its emissions 17 percent from 2005 levels by 2020, Harper's full-throttle embrace of tar sands has meant that Canada will actually have more emissions in 2020, and not fewer.

While Harper wholeheartedly endorsed new pipelines such as Energy East and Keystone XL, Trudeau has said such pipelines should only go forward if they can demonstrate improved environmental performance from existing pipelines.

Assuaged Aussies

Harper's defeat comes just a month after Australia's Tony Abbott, also a noted climate skeptic, was unseated as prime minister by a leadership challenge within his party.

These two men were seen as a "dastardly duo" by climate campaigners. The European Union, which is pushing for an ambitious global agreement to cap emissions growth the COP21 summit in Paris, in particular had expressed frustration because these two commonwealth realms not long ago had center-left governments that cooperated closely with Brussels on climate.

At a joint press conference last year, Harper and Abbott together lashed out at international efforts to fight climate change, with Harper saying that a systematic carbon tax would be "job-killing."

Abbott's rhetoric against climate action had been far harsher than Harper's. The Australian prime minister once called the idea of human-caused climate change "crap," and said that "coal is good for humanity."

Abbott had crusaded against renewable energy - deriding wind farms as loud and ugly - and been a strong proponent of the massive Carmichael coal mine. The administration recently gave the mine a green light, despite a federal court having blocked the project due to environmental concerns.

Abbott also pulled the plug on Australia's emissions trading scheme last year, only two years in. The scheme was supposed to be the first one to partner with the EU's emissions trading scheme.

Abbott's replacement, Malcolm Turnbull, had attacked Abbott's climate policy, or lack thereof, and he supported the country's emissions trading system. So far, Turnbull hasn't offered any new climate policies, and he says that for now, he will stick to his predecessor's plan.

But the change in tone has already had an effect.

"We haven't seen much change by way of substance, but we've certainly seen a significant change in the atmospherics," says John Connor, CEO of the Climate Institute in Sydney. "I've described it as a fatwa being lifted on the public discourse."

New leaders, same offers

Key to those atmospherics is that both Trudeau and Turnbull will be attending next month's climate summit in Paris. Their predecessors had not planned to come.

However, Trudeau and Turnbull will still be bringing the previous leaders' emissions reduction offers. Canada and Australia have announced they will reduce emissions by 30 percent and 26 percent, respectively, from 2005 levels by 2020.

Those offers, made earlier this year, were heavily criticized by climate protection advocates, and compare for example to a 40 percent reduction commitment by the EU.

Due to time constraints, it's unlikely that these pledges will be changed before the Paris summit. But both leaders have hinted that they will make major announcements in Paris about establishing more ambitious tools for achieving the targets.

And if the Paris protocol includes a hoped-for "ratchet-up mechanism," these pledges could always be revised.

Regardless of what action is taken, the change in tone means that climate protection advocates will have two less "climate villains" to worry about.

"I think some who were having to watch closely negative moves from Australia and Canada can now probably put that effort into watching other countries blocking progress," says Connor.

The COP21 summit begins in Paris on November 30.