Climate graphic of the week: Record lows for rivers across China, US and Europe sap economies

Factories grinding to a halt, crops devastated, cargo ships forced to carry smaller loads and millions facing a risk of blackouts — these are just some of the drastic consequences of record low river levels during droughts that are gripping the US, Europe and now China.

In the US, the historic lows in water levels in the critical Colorado Basin as a result of the southwestern ‘megadrought’ prompted a federal demand for the states of Arizona and Nevada to cut their water allocations by 21 and 8 per cent respectively in the year ahead, in an order from the Bureau of Reclamation last week.

China saw companies such as Foxconn, Toyota and Foxconn stop production for at most a week due to worsening hydropower shortages. The province of Sichuan is heavily dependent on hydropower. In August, the Yangtze, Asia’s longest river, fell to its lowest ever recorded level. Shipping along the nation’s most important waterway was also affected.

Europe suffered further as unusually hot, dry weather caused the Rhine to drop, a major artery which is used by industry in Germany and Switzerland. Cargo ships had to reduce their cargo, which has caused higher transport costs as well as delays in supply chains. On the weekend, there was only limited relief with rain expected in some areas.

“Flowing from the Swiss Alps to the North Sea, the Rhine River is an important shipping route for many products from grains to chemicals to coal,” said the European Space Agency. “When water levels drop, cargo vessels need to sail with reduced load, so they don’t run aground.”

A severe drought in Italy has hit the agricultural sector, as the economically-important Po has reached unusually low levels.

There are many types of droughts, including agricultural and hydrological. These are complex events that cannot always definitively be linked to climate change. However, their effects are becoming more severe with prolonged periods in unusually hot and dry conditions and associated low water level, which were recorded in many parts of the world this year.

In Alpine regions, as glaciers melt the warming effect is magnified as the darker arid rock that is exposed absorbs the sun’s heat, rather than reflecting it.

“Droughts are not very easy to define and not every drought is the same,” said Liz Bentley, chief executive of the UK’s Royal Meteorological Society. “A changing climate is likely to bring greater variability in rainfall and higher temperatures, meaning that water management may become more of a challenge.”

California, for example, has struggled to reduce water usage over the past several years due to the US’s decades-long drought. Authorities are warning about the possibility of blackouts due to hydroelectricity shortages this year because of the low water levels in Colorado Basin.

“The prolonged drought afflicting the west is one of the most significant challenges facing our communities and our country,” said Tommy Beaudreau, deputy secretary of the US Department of the Interior, in a briefing last week.

“The growing drought crisis is driven by the effects of climate change, including extreme heat and extreme precipitation,” he said, adding that around 93 per cent of the western US was experiencing drought or abnormally dry conditions.

Camille Calimlim Touton, the Bureau of Reclamation commissioner, said the system was “approaching a tipping point,” which required states reliant on the Basin to significantly reduce the amount of water they used.

According to the US National Oceanic and Atmospheric Administration, the first six months of 2022 were the sixth-hottest January-June period ever recorded. The seven years to 2021 were the hottest on record, according to Copernicus, the EU’s Earth monitoring programme.

According to a UN-report, the world has already warmed by around 1.1C in comparison to preindustrial times. This warming will continue for some time even if each country achieves net zero greenhouse gases emissions tomorrow.

Scientists predict that extreme weather will continue to have devastating consequences for national economies and global infrastructure.

Shifts observed in the jet stream have contributed to heatwaves, wildfires and drought in the northern hemisphere, while the unusual phenomenon of back-to-back La Niña weather patterns has resulted in flooding and unseasonably cold weather in the south, with floods in Australia and South Africa. According to estimates, 1200 people were forced from their homes in New Zealand by torrential rainfall last week.

Global estimates of insured losses from natural disasters in the first half 2022 were $35bn. This figure is 22 percent higher than the average for the past ten year, Swiss Re reported earlier in this month. According to the group, climate change was causing more extreme weather events.

“The severe weather events of the past six months once again highlight that natural catastrophes . . . are increasing in frequency and severity in all regions,” Martin Bertogg, head of catastrophe perils at Swiss Re concluded.