Climate change and the relaunch of the global economy will top the G20 agenda as leaders of the world's most advanced nations meet Saturday, the first in-person gathering since the pandemic.

The U.N.'s top human rights official and U.S. President Joe Biden's climate envoy called Thursday for countries to step up the fight against global warming, describing it as an issue of sheer survival for humankind.

In a statement ahead of the U.N. climate summit in Glasgow, the global body's High Commissioner for Human Rights said "only urgent, priority action can mitigate or avert disasters that will have huge — and in some cases lethal — impacts on all of us, especially our children and grandchildren."

Protesters started gathering Friday in the heart of London's historic financial district to lobby against the use of fossil fuels ahead of the start of the U.N. climate summit in the Scottish city of Glasgow.

The protests in London, which were to be joined by Swedish climate activist Greta Thunberg, are part of a worldwide day of action before leaders head to Glasgow for the U.N. Climate Change Conference, known as COP26. Many environmentalists are calling the Oct. 31-Nov. 12 gathering the world's last chance to turn the tide in the battle against climate change.

More than one world leader says humanity's future, even survival, hangs in the balance when international officials meet in Scotland to try to accelerate efforts to curb climate change. Temperatures, tempers and hyperbole have all ratcheted up ahead of the United Nations summit.

And the risk of failure looms large for all participants at the 26th U.N. Climate Change Conference, known as COP26.

The European Union's chief executive called Thursday for a show of climate leadership ahead of two major international meetings focused on curbing global warming, warning that world leaders face "a moment of truth."

"What we need is, first of all, leadership," European Commission President Ursula von der Leyen said before she heads to a weekend summit in Rome of the Group of 20 most developed nations. The 26th U.N. Climate Change Conference, known as COP26, starts Sunday in Glasgow, Scotland.

Australia on Thursday ruled out promising to cut methane emissions by 30% by the end of the decade in a stance that will add to criticism that the country is a laggard in addressing climate change.

Minister for Industry, Energy and Emissions Reduction Angus Taylor announced his government's decision before he was to fly with Prime Minister Scott Morrison to a U.N. climate summit in Glasgow, Scotland.

A nor'easter that battered the Atlantic coast with hurricane-force wind gusts left more than a half-million homes and businesses without power in New England and forced the closure of bridges, ferries and schools in the region.

Utility workers labored to restore power as the storm's winds and rain, which were felt as far north as Nova Scotia, diminished throughout the day. Restoring power in the hardest-hit areas in southeastern Massachusetts will take days, the utility Eversource told the Cape Cod Times.

For centuries, Lake Tuz in central Turkey has hosted huge colonies of flamingos that migrate and breed there when the weather is warm, feeding on algae in the lake's shallow waters.

This summer, however, a heart-wrenching scene replaced the usual splendid sunset images of the birds captured by wildlife photographer Fahri Tunc. Carcasses of flamingo hatchlings and adults scattered across the cracked, dried-up lake bed.

Climate protesters sought to block two major roads into London on Wednesday, despite court injunctions banning them from disrupting traffic.

Activists from the group Insulate Britain, which wants the government to better insulate homes in the country to cut carbon emissions, targeted two busy roads leading into the capital during the morning rush hour.

A study commissioned by the environmental group Greenpeace shows that over one-third of the busiest short-haul flights in Europe have viable train alternatives which are far less polluting.

The group called on European governments Wednesday to boost train travel so fewer polluting planes are flying over the continent. The study by OBC Transeuropa showed that 34% of the 150 busiest short-haul flights have train trip alternatives of less than 6 hours.