Australia has become even more isolated on climate change after the heads of the world's largest economies agreed to end government support for coal-fired power stations by the end of the year.
A said continued global investment in unabated coal power generation was incompatible with keeping global warming to 1.5 degrees Celsius.
The statement was not designed to single out Australia but highlighted Scott Morrison's outsider status on climate change.
It also made it more difficult for the prime minister to continue resisting calls to commit to achieving net-zero carbon emissions by 2050.
The climate statement is likely to enrage strident coal supporters in the Liberal and National parties.
Labor leader Anthony Albanese said the summit showed Australia was increasingly falling behind the rest of the world.
Prime Minister Boris Johnson greets Australian Prime Minister Scott Morrison during the G7 summit in Cornwall. Source: AAP
"Here we have all the world's major powers, the G7, all committing to net zero emissions by 2050 and Australia being isolated in our opposition to that," he told reporters.
He said the prime minister needed to explain why money was being spent on a feasibility study for a new coal-fired power station in Queensland.
Deputy Prime Minister Michael McCormack said while Australia was not a signatory to the G7 communique, it was committed to lowering emissions and keeping power prices affordable.
"We will decide what's best for Australia in Australia's national interest," he said.
Mr McCormack said the coal industry employed 55,000 people and produced $66 billion in exports.
"It pays for a lot of hospitals. It pays for a lot of schools. It pays for a lot of barista machines that produces the coffee inner city types sit around drink and talk about the death of coal."
The G7 leaders backed calls from the United States and Australia for a new investigation into the origins of coronavirus, following renewed speculation the deadly virus escaped from a lab in China.
Mr Morrison said a fresh inquiry was vital to preventing future pandemics.
The leaders proposed a new scheme to force countries to declare outbreaks much sooner.
They also vowed to boost global access to coronavirus vaccines and agreed to challenge China's economic coercion and human rights violations.
The prime minister's key meeting at the G7 summit was with US President Joe Biden.
The three-way meeting has perplexed political pundits.
The leaders issued a joint statement after their meeting that highlighted a changing strategic context in the Indo-Pacific and the need for deeper cooperation between the three countries.
Mr Morrison also held one-on-one meetings with the leaders of Japan, Germany and South Korea while in Cornwall for the summit.
After the weekend conference, he travelled to London for trade talks with Mr Johnson.
