More than 50 world leaders are gathering in Paris for a summit that President Emmanuel Macron hopes will give new momentum to the fight against global warming, despite U.S. President Donald Trump's rejection of the Paris climate accord.

Some 3,100 security personnel are fanned out around Paris for Tuesday's event, including extra patrol boats along the Seine River. Macron will accompany the visiting leaders to the summit site on a river island by boat.

Snow and wintry weather are still wreaking havoc on travelers in Britain, with flights cancelled, roads sheathed in ice and rail travel disrupted.

With temperatures dropping overnight as low as minus 11.6 Celsius (11 degrees Fahrenheit), hundreds of schools were closed Monday. Europe's largest airport, Heathrow, warned Monday that some flights would be cancelled as it cleared the backlog of flights delayed by Sunday's snowfall.

Firefighters on Thursday battled raging wildfires across southern California that have forced tens of thousands of people to flee their homes, including residents on the outskirts of Los Angeles, America's second-largest city.

Winds with hurricane-force gusts of up to 80 miles per hour (130 kilometers per hour) fueled the blazes, creating apocalyptic scenes of hillsides engulfed in billowing smoke and towering plumes of flame.

The U.N.'s forecast for global warming is about 15 percent too low, which means end-of-century temperatures could be 0.5 degrees Celsius higher than currently predicted, a study has said.

As New Delhi and other major cities hit new toxic smog peaks, the United Nations sounded the alarm Wednesday over the damage that pollution is doing to babies' developing brains.

Gently, Kenzo the sea turtle is lowered onto a beach where a scattering of bottle caps, candy wrappers, yoghurt cups and discarded flipflops scar an otherwise idyllic setting.

As its human handlers step aside, Kenzo struggles out of the harness, pushes hard with its flippers on the sand, and slides into small waves specked with bits of plastic trash.

Pollution stopped play Sunday in the third Test between India and Sri Lanka, and visiting coach Nic Pothas said the smog was so extreme that his players -- who took the extraordinary step of wearing face masks -- were "coming off the field and vomiting."

Former US president Barack Obama launched a veiled barb at his successor Donald Trump on Friday, saying there is "a pause in American leadership" on climate change.

The open burning of waste in Lebanon poses serious health risks, Human Rights Watch warned in a report released on Friday, blaming decades-old, across the board government failure.

The New York-based watchdog said the crisis, which escalated in 2015 when waste management largely collapsed across Lebanon, was a particular threat for children and old people, and constituted a rights violation.

Burkina Faso and France on Wednesday launched West Africa's biggest solar farm, a 33-megawatt facility designed to power tens of thousands of households and ease dependence on imported energy.