More than a thousand people are feared to have died in a cyclone that smashed into Mozambique last week, while scores have been killed and more than 150 are missing in neighboring Zimbabwe.

The city of Beira in central Mozambique bore Cyclone Idai's full wrath on Thursday before the storm barreled on to neighboring Zimbabwe, unleashing fierce winds and flash floods and washing away roads and houses.

As much of Asia wheezes, coughs and sniffles its way through another smog season, one isolated and windswept corner of Australia is serving as the global standard for clean air.

More than 100 people have died and many more are missing in Mozambique and neighboring Zimbabwe on Sunday after tropical cyclone Idai barreled across the southern African nations with flash floods and ferocious winds.

Dozens of young climate change activists staged a "die-in" in front of the United Nations on Friday, lying sprawled on the pavement to draw attention to the lethal consequences of global warming.

"Today, the young people of the U.S. are declaring the era of American climate change denialism over," said Alexandria Villasenor, a 13-year-old who has been staging a climate strike outside the U.N. headquarters every Friday since December.

Tens of thousands of young people took part in the Paris edition of Friday's global student climate demonstration, according to the police and the rally's organizers.

Nations on Friday were expected to commit to "significantly reduce" single-use plastics over the next decade, in a series of voluntary pledges that green groups warned fell short of tackling Earth's pollution crisis.

Extracting and processing materials, fuel and food contributes as much as half of the world's greenhouse gas emissions, the UN said Tuesday, as experts gathered in Kenya to find ways to rein in exploding global consumption.

Using dozens of data sources, the authors of a major new report presented lawmakers and businesses with a stark choice: drastically reform the global economy to get more from less, or risk the collapse of global infrastructure. 

Countries from around the world set their sights Monday on a pivotal deal to curb plastic waste, a source of long-term pollution and worsening contamination of the ocean's food chain.

Leaving the EU could cause "untold damage" to Britain's ecosystems and undermine its attempts to curb greenhouse gas emissions, green groups warned Friday, calling on the government to prioritise the environment after Brexit.

The United States overtook Europe to become the world's second largest market for electric cars last year, according to a report Wednesday that accused EU carmakers of holding back sales ahead of new emissions rules.