Prime Minister Scott Morrison will take part in a session on climate at the G7-plus meeting in Cornwall this weekend.

A number of countries want to lift global ambition on cutting emissions, with America, the United Kingdom and European Union all targeting net zero emissions by 2050.

Mr Morrison is expected to tell leaders at the summit and on its sidelines Australia wants to reach zero net emissions by mid-century or earlier if possible, but on its own terms.

Australian National University vice-chancellor Brian Schmidt is one of the 126 Nobel laureates who signed the joint statement, which states: "Time is running out to prevent irreversible changes."

"Without transformational action this decade, humanity is taking colossal risks with our common future. Societies risk large-scale, irreversible changes to Earth's biosphere."

Professor Schmidt said for many people, heading off cataclysmic climate change appeared so huge and difficult it may seem futile.

"But I honestly believe any sense of despair can be overcome by hope - the hope is global action," he said.

"By tackling COVID-19, science undertaken with urgency, scale and international cooperation has proven its undeniable value to humanity.

"The goodwill science has generated must now be harnessed for our biggest challenge."

ANU itself has committed to net negative carbon emissions by 2030 - one of the first universities in the world to set such a target.

In a speech ahead of the G7 meeting, Mr Morrison will say it is in Australia's interest to cut emissions, but only in a way that does not put at risk manufacturing and heavy industries, threaten jobs or push up power prices.

"It's not an argument about climate change," he will say.

"It's about how Australia best advances our interests as part of a world that is dealing with climate change."

Australian Associated Press