Heatwaves hit and other environment stories you need to read this week

Some 100 million Americans from New York City to Las Vegas were under heat warnings this week as temperatures rose well above 100 Fahrenheit (38 Celsius), part of a trend of extreme weather made worse by climate change. Several cities in the country's northeast broke daily temperature records on Sunday.

It comes as US President Joe Biden said that climate change is an emergency but stopped short of a formal declaration, announcing a modest package of executive actions and promising more aggressive efforts.

China will see more heatwaves in the coming week from east to west, with some coastal cities already on their highest alert level and inland regions warning of dam failure risks because of melting glaciers. Saturday 24 July was the day of the "big heat" in the Chinese Almanac based on the lunar calendar. Xinjiang province has warned of flash flooding, mudslides and risks to agriculture.

Electric buses built by a Chilean company are now operating in the world's top copper-producing nation, as the country seeks ways to reduce its use of fossil fuels and achieve its environmental goals.

Pope Francis on 21 July called on world leaders to heed the Earth's 'chorus of cries of anguish' stemming from climate change, extreme weather and loss of biodiversity. In a message for the World Day of Prayer for the Care of Creation, he urged nations to confront climate change with the same attention as global challenges like wars and health crises, saying global warming hurts poor and indigenous populations the most.

War in Ukraine will in the longer term accelerate Europe's shift to renewable energy from fossil fuel, Britain's climate envoy said on 21 July, even as it prompts nations to burn more coal over the coming months to offset reduced Russian gas supplies.

A new assessment has found that there might be 40% more tigers globally than previously thought.

Emergency services battled wildfires across swathes of southern Europe amid mass evacuations on 20 July, as warnings sounded in London after Britain's hottest day that the fight against climate change needed to be stepped up.

The London Fire Brigade endured its busiest day since World War Two on 19 July when temperatures topped 40C (104 Fahrenheit) for the first time, igniting fires that destroyed dozens of properties in the capital and torched tinderbox-dry grassland at the sides of railway tracks and roads.

The death of a Madrid street-sweeper from heat stroke has prompted companies providing the service in the Spanish capital to adopt measures including halting work during heatwaves, the Madrid mayor announced.

Wildfires in Spain and Morocco have produced more carbon emissions in June and July this year than in the same period of any year since 2003, the European Union's Copernicus Atmosphere Monitoring Service (CAMS) said.

CAMS scientists also warned air pollution is spiking across Britain, France, and southern Europe amid record-breaking temperatures and scorching wildfires.

Portugal has reported more than 1,000 deaths due to the current heat wave, with the health chief warning on 19 July that the country must gear up to cope with the effects of climate change as temperatures continue to rise.

Greek firefighters have also been fighting wildfires over the weekend as temperatures hit 40C (104 Fahrenheit) in parts of the country on Sunday (24 July).

Hungry polar bears are turning to garbage dumps to fill their stomachs as their icy habitat disappears.

On 20 July, a team of Canadian and US scientists warned that trash poses an emerging threat to already-vulnerable polar bear populations as the animals become more reliant on landfills near northern communities. This is leading to deadly conflicts with people, the report published in the journal Oryx said.

Polar bears rely on sea ice to hunt seals. But with the Arctic warming four times faster than the rest of the world, sea ice is melting out earlier in the summer and freezing up later in the fall. This forces bears to spend more time ashore, away from their natural prey.

The report came as a polar bear roaming around an Arctic outpost in northern Russia was rescued after getting its tongue caught in a can of condensed milk.

Residents of the remote settlement of Dikson sounded the alarm when the stricken 2-year-old female was seen wandering up to huts in the village.

A team from Moscow Zoo flew out to tranquillize the animal with a dart, remove the sharp metal from its mouth and treat the cuts to its tongue.

Australia has lost more mammal species than any other continent and has one of the worst rates of species decline among the world's richest countries, a five-yearly environmental report card released by the government on 19 July said.

Some animals such as the blue-tailed skink are now only known to exist in captivity, while the central rock-rat and Christmas Island flying fox are among mammals considered most at risk of extinction in the next 20 years, largely due to introduced predator species.

The sandalwood tree is also in decline.

The report, which comes after drought, bushfires and floods ravaged Australia over the past five years, said increasing temperatures, changing fire and rainfall trends, rising sea levels and ocean acidification were all having significant impacts that would persist.

"The State of the Environment Report is a shocking document - it tells a story of crisis and decline in Australia's environment," Environment Minister Tanya Plibersek said in a statement, adding that the new Labor government would make the environment a priority.