Britain’s PM says countries that have ‘done the least’ need to lift their game if agreement is to be reached on post-2020 emissions

British prime minister David Cameron has joined calls for Tony Abbott to do more to tackle climate change, saying “countries that have so far done the least have to think about what more they can do”.

Cameron told Britain’s Sky News that every nation needed to “put more on the table” if the world was to reach a successful agreement in Paris next year on reducing greenhouse emissions after 2020.

“Countries that have so far done the least have to think about what more they can do. I’ve had good and friendly discussions with prime minister Abbott about that,” he said, adding that even those unsure of climate science should regard action as a form of “insurance”.

“I hope [Australia will] do everything they can in the coming months to look at what more they can deliver, because when it comes to Paris if we want to get a global agreement everyone is going to have to bring something to the table.”

On Saturday US president Barack Obama dramatically forced climate on the G20 agenda - against the wishes of the Australian hosts - with a hard-hitting speech urging the world to rally behind a new global agreement, pledging $3bn to the green climate fund and pointing out that countries such as Australia had the most to lose from global warming.

The surprise announcement from Obama and Chinese president Xi Jinping on the eve of the summit of post-2020 greenhouse reduction targets also increased pressure on Australia to unveil its own promise for deeper longer term emission cuts.

Abbott downplayed the significance of that agreement at the time, saying it was welcome because US and China were the two biggest emitters in the world, whereas Australia’s emissions accounted for only “about 1%”. He insisted Australia was “not focusing on the far distant future” but “actually cutting our emissions … as a result of the Direct Action policy.

And he still insisted that the G20 was not an appropriate gathering to discuss climate because there were plenty of other United Nations meetings to do that.

Cameron said Abbott had told him Australia was meeting its pre-2020 target of a 5% emissions cut, but he said it made sense for governments to insure against climate change even if they weren’t sure it was happening.

“I always say, think about it like insurance, even if you don’t believe in the nature of this threat, isn’t it better to insure against it? You might think there’s only a 10% chance of your house burning down, but even if it’s that percentage chance wouldn’t you do something to try and make sure you can save your world, your environment for your children and your grandchildren?”

Abbott has argued climate discussions would distract from the G20’s economic policy focus and should be left to other UN-led meetings.

In the backrooms of the G20 on Saturday, Australian negotiators were continuing to resist language in the official communique encouraging countries to make pledges to the Green Climate Fund - to which Obama had just pledged $3bn - prompting environmental and aid groups to warn the host nation was appearing like a “blocker”.

Australian ministers have said they will unveil a post-2020 climate pledge well ahead of the Paris meeting, but it is not clear how it will be calculated, and deeper cuts would be extremely expensive under the Direct Action policy in its current form.

On Saturday, the United Nations secretary-general, Ban Ki-moon, also insisted the G20 had to discuss climate change because it was “the defining issue of our times”.

with agencies