UN chief's warning on Pakistan floods - and other environment stories you need to read this week

The cost of meeting global targets to fight issues such as hunger, poverty and climate change rose 25% to $176 trillion over the last year, with performance on several measures reversing, according to a report.

Climate change could have a devastating effect on the lives of millions in the East Mediterranean and Middle East, where temperatures are rising nearly twice as fast as the global average, an international team of scientists has warned.

Tackling inequality is key to securing the public support needed to overhaul the global economy and reverse climate change, an update to the 1972 'Limits to Growth' climate model - a landmark computer simulation of environmental stress - has found.

Australia's parliament has passed government legislation enshrining a pledge to cut carbon emissions by 43% by 2030 and to net zero by 2050, with the support of the Greens party and independents.

The US National Weather Service issued a flash flood warning for part of northeastern Illinois including Chicago's northern metro area on 11 September, after heavy rains flooded viaducts, stranded cars, and sent water surging into basements.

A rocky Alpine path between two glaciers in Switzerland is emerging for what a local ski resort says is the first time in at least 2,000 years after the hottest European summer on record.

African ministers meeting in Cairo two months ahead of the COP27 climate summit called on 9 September for a sharp expansion of climate financing for their continent while pushing back against an abrupt move away from fossil fuels.

Chad's heaviest seasonal rainfall in over 30 years has left parts of the capital N'Djamena navigable only by boat and forced thousands to flee their flooded homes over the past month, according to aid groups and the state weather agency.

Deforestation in Colombia's Amazon rose to 52,460 hectares (129,631 acres) in the first half of the year and could finish close to 11% higher in 2022, the environment ministry said on 7 September.

Authorities in the Indian city of Bengaluru used tractors on 6 September to rescue residents of affluent housing estates marooned by floods as army teams were sent in after two days of torrential rain in the technology hub.

Green hydrogen will remain scarce in the short term and its supply uncertain in the longer term without a decisive policy push, an analysis published on 8 September concluded. Enthusiasm for green hydrogen, produced using renewable energy, has grown in recent years because of its advantages over other methods of manufacturing the clean-burning fuel.

Companies in the G7 economies are failing to meet Paris Climate Agreement objectives, according to non-profit disclosure platform CDP and global management consultancy Oliver Wyman, based on current corporate pledges to cut emissions.

UN Secretary-General Antonio Guterres on 10 September visited several areas of Pakistan ravaged by floods, calling for increased global financial support at the end of a two-day trip aimed at raising awareness of the disaster.

Record monsoon rains and glacier melt in northern mountains have triggered floods that have killed more than 1,391 people, sweeping away houses, roads, railway tracks, bridges, livestock and crops.

Pakistan estimates the damage at $30 billion, and both the government and Guterres have blamed the flooding on climate change.

"Today it's Pakistan, tomorrow it could be your country, wherever you live. This is a global crisis ... it requires a global response," Guterres told a news conference at the end of his visit.

On 12 September, authorities were scrambling to protect a vital power station supplying electricity to millions of people against a growing threat of flooding, taking steps such as building a dike in front of it.

Five "tipping points" - environmental thresholds beyond which the global climate system could spiral toward a dangerous state - could happen now, according to new research.

The analysis of more than 200 research papers on the 16 tipping points climate scientists monitor finds it is possible the world could hit some of these thresholds at the current level of warming - 1.1C.

These are: the disintegration of the West Antarctic and Greenland ice sheets, coral reef die-offs, collapse of the Labrador-Irminger Seas convection and abrupt permafrost thaw.

"We can see some potential early warning signals," said climate scientist David Armstrong McKay, a co-author of the study published on 8 September in the journal Proceedings of the National Academy of Sciences.

Already, "the Greenland Ice Sheet is showing signs of destabilization with lots of melt and there are potentially early warnings that the Atlantic circulation might be slowing down", said McKay, who works at the University of Exeter, in Britain.