The Philippines' most active volcano was gently spewing lava down its slopes Monday, alerting tens of thousands of people they may have to quickly flee a violent and life-threatening explosion.

More than 12,600 people have left the mostly poor farming communities within a 6-kilometer (3.7-mile) radius of Mayon Volcano's crater in mandatory evacuations since volcanic activity increased last week. But thousands more remain within the permanent danger zone below Mayon, an area long declared off-limits to people but where generations have lived and farmed because they have nowhere else to go.

President Joe Biden has called the smoke from Canadian wildfires in the eastern U.S. "another stark reminder of the impacts of climate change" and said cabinet officials are monitoring the impact on travel and air quality.

More than 600 firefighters and other personnel from the U.S. have been deployed to Canada to respond to the wildfires there, Biden said in a statement Thursday, adding that he offered additional help to Canadian Prime Minister Justin Trudeau.

Swedish environmental activist Greta Thunberg said Friday she will no longer be able to skip classes as a way to draw attention to climate change because she is graduating from high school.

Thunberg, 20, started staging Friday protests outside the Swedish parliament building during school hours in 2018. Teenagers from around the world followed her lead, leading to an international student movement called Fridays for Future.

On a boat off the coast of an island near Abu Dhabi, marine scientist Hamad al-Jailani feels the corals, picked from the reef nursery and packed in a box of seawater, and studies them carefully, making sure they haven't lost their color.

The corals were once bleached. Now they're big, healthy and ready to be moved back to their original reefs in the hope they'll thrive once more.

Philippine troops, police and rescue workers began forcibly evacuating residents near Mayon Volcano on Friday as its increasing unrest indicated a violent eruption of one of the country's most active volcanoes is possible within weeks or days.

The area within a 6-kilometer (3.7-mile) radius of Mayon's crater is supposed to be off-limits due to possible volcanic emissions, lava flows, rockfalls and other hazards. But many poor villagers have built houses and tended farms in Mayon's danger zone over the years.

Kilauea, one of the most active volcanoes in the world, began erupting on Wednesday after a three-month pause, displaying spectacular fountains of mesmerizing, glowing lava that's a safe distance from people and structures in a national park on the Big Island.

A glow was detected in webcam images from Kilauea's summit early in the morning, indicating that an eruption was occurring within the Halemaumau crater in the summit caldera, the U.S. Geological Survey's Hawaiian Volcano Observatory said.

When Pam Knox walked into the peach orchard at the University of Georgia horticulture farm this spring, there was nothing on the trees except leaves and a couple of brown fruits — the result of one of the state's warmest winters ever followed by two nights of freezing weather in March.

"It's just really odd, because over the course of one night, they lost their entire crop and their entire production here," said Knox, an agricultural climatologist with the University of Georgia Cooperative Extension, which shares research and expertise with farmers and others. Commercial peach farmers in the state lost as much as 95% of their yield, she estimated.

On air quality maps, purple signifies the worst of it. In reality, it's a thick, hazardous haze that's disrupting daily life for millions of people across the U.S. and Canada, blotting out skylines and turning skies orange.

And with weather systems expected to hardly budge, the smoky blanket billowing from wildfires in Quebec and Nova Scotia and sending plumes of fine particulate matter as far away as North Carolina and northern Europe should persist into Thursday and possibly the weekend.

An early bird El Nino has officially formed, likely to be strong, warp weather worldwide and give an already warming Earth an extra kick of natural heat, meteorologists announced.

The National Oceanic and Atmospheric Administration Thursday issued an El Nino advisory, announcing the arrival of the climatic condition. It may not quite be like the others.

Intense Canadian wildfires are blanketing the northeastern U.S. in a dystopian haze, turning the air acrid, the sky yellowish gray and prompting warnings for vulnerable populations to stay inside.