Leaders hope the Cornwall meeting will energise the global economy with plans to formally embrace a universal minimum tax of at least 15 percent on corporations, following an agreement reached a week ago.
G7 leaders have gathered for their first in-person talks in nearly two years, with an expected pledge to donate one billion Covid vaccine doses to poor countries on the agenda in a show of Western democratic cohesion.
The club of leading economies - Britain, Canada, France, Germany, Italy, Japan and United States - say a joint approach is the world's best chance for recovering from the global health crisis, and tackling climate change.
President Joe Biden has set the tone, ditching former US President Donald Trump's isolationist stance to ram home a message of resolve by the G7 and NATO against both Beijing and Moscow, as he heads into his first sit-down with Russian President Vladimir Putin next week in Geneva.
Campaigners say the G7's vaccine donations pledge for this year and next – including 500 million US doses – is far too little, too late to end a pandemic that has claimed over 3.7 million lives worldwide.
"If the best G7 leaders can manage is to donate one billion vaccine doses then this summit will have been a failure," Oxfam said, insisting the world needs 11 billion doses.
The leaders hope the meeting will also energise the global economy. On Friday, they are set to formally embrace a global minimum tax of at least 15 percent on corporations, following an agreement reached a week ago by their finance ministers. The minimum is meant to stop companies from using tax havens and other tools to avoid taxes.
READ MORE: G7 nations set minimum global corporate tax rate at 15 percent
Group seeking to counter China's influence
But the G7 has recognised it needs to rise to competing "vaccine diplomacy" efforts launched by China and Russia, with the Biden administration stressing it expects nothing in return for its donated jabs.
G7 leaders meeting at the seaside resort of Carbis Bay in Cornwall, southwest England, are also expected to outline more help for developing nations to build up infrastructure, as a counterpoint to the debt-fuelled spending by China in Africa, Asia and Latin America.
The initiative "will embrace a high standards, transparent, climate friendly, non-corrupt mechanism" for infrastructure investment in the developing world, the US official said.
"It will be an alternative to that which other countries, including China, are offering."
Underpinning the US-led diplomatic revival, Biden and British Prime Minister Boris Johnson on Thursday adopted a new "Atlantic Charter", modeled on the pact signed by their World War II predecessors to help build a new world order.
Johnson dislikes the decades-old phrase "special relationship", arguing it makes Britain look subservient to Washington, telling the BBC instead that it should be viewed as "indestructible".
He also played down any differences with Biden over the restive British province of Northern Ireland, ahead of showdown talks between Johnson and EU chiefs on Saturday to tackle deep fissures opened up by Brexit.
British Foreign Secretary Dominic Raab hit back Friday after French President Emmanuel Macron launched a broadside over UK backpedalling regarding special post-Brexit arrangements for Northern Ireland.
Raab told Sky News that "change must come from the European Commission side" and that "we are not negotiating or haggling the integrity of the United Kingdom".
Late Thursday, more than 3,000 pro-UK loyalists staged a protest in Belfast against the "protocol" that effectively keeps Northern Ireland in the EU customs union and single market.
Johnson will hope to lighten the mood at a beach barbecue on Saturday, joined by his new wife Carrie and other G7 spouses, with a sea shanty band and toasted marshmallows around fire pits.
That will follow a reception for the G7 leaders Friday evening hosted by Queen Elizabeth II at Cornwall's Eden Project, an exhibition that showcases the world's ecological riches.
READ MORE: All smiles as Biden, Johnson meet for first time ahead of G7 summit
Biodiversity agreement expected
Safeguarding global biodiversity is another G7 theme this weekend, with the leaders set on an agreement to protect at least 30 percent of the world's land and oceans by 2030.
They will also debate aiding poorer nations to transition out of fossil fuels, in the build-up to the UN's COP26 climate summit in November in Scotland.
Like the G7, Britain wants COP26 to be held in-person, and announced that it plans to offer vaccinations to delegates from poorer nations if they cannot get them otherwise.
Greenpeace UK released a video shot with 300 illuminated drones over Cornwall, creating a startling display of endangered animals, to urge G7 leaders to stop mass extinctions.
"We need to see action, not just warm words, to tackle the climate and nature emergency," Rebecca Newsom, head of politics for the environmental group, told AFP.
"We need to see those tangible commitments this weekend -- otherwise our world leaders are failing us," she said.
READ MORE: Competing agendas on Covid, Brexit threaten real gains at G7
Plan to boost girls education
The G7 is also expected to adopt a UK plan to ensure schooling for another 40 million girls by 2025, after the pandemic destroyed educational opportunities for many around the world.
The G7 chiefs will be joined over the weekend by the leaders of Australia, South Africa, South Korea, the United Nations and European Union, with India joining remotely.
"This is a compelling agenda for global recovery, ambitious yet achievable, provided we summon the will and the ingenuity," Johnson said in an appeal to "kindred democracies".