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."