Monday, August 23, 2021

A THIRSTY PLANET

 


70% of our planet is covered in water —  more than one billion trillion litres.  Just 1% is accessible fresh water usable for drinking and growing food. Much of that water is increasingly being polluted by fertilizers and factory effluent or is simply being overused — causing aquifer levels to plummet.

"For years wars were fought over oil," said US Vice President Kamala Harris earlier this year. "In a short time they will be fought over water."

In Africa, one in three people are already dealing with extreme water insecurity as the South African city of Cape Town knows too well. It was on the brink of running out of water in 2018, and had to resort to  cutting down hundreds of thousands of trees to help its water supply. 

The Paraná River on the border of Argentina and Paraguay, the second-longest river in South America, has reached its lowest level in decades. the Argentine government declared a state of "water emergency" for 180 days in the provinces that the Paraná runs through.

While some US states like Tennesee are flooding, others are in near-permanent drought — 85% of California is currently in extreme or "exceptional" drought and towns and agricultural areas are running out of water. Tens of millions of people in the Western US have recently been told they will have to reduce their water use next year due to low levels in the country's largest artificial reservoir.

Desalination comes with its own set of problems. First up, extracting salt from water is energy-intensive, which means the process adds to the CO2 emissions that helped fuel water scarcity in the first place.  Expensive desalination plants are unevenly distributed. Of  20,000 installations globally, around half are located in oil-rich Gulf nations. And overall, the vast majority serve high-income countries. Desalinated water is very limited especially in poor, under-resourced countries  hit with variable rainfall and crippling drought. The other problem with desalination is brine. Once the fresh water has been acquired, the heavily salty leftovers are returned to the ocean, where they deplete oxygen and suffocate organisms. 

The  leaked report by UN climate scientists  predicts that 350 million more people living in cities will suffer water scarcity from severe droughts at 1.5 degrees Celsius of warming — which the Intergovernmental Panel on Climate Change recently said could happen next decade. Unless we start cutting our greenhouse gas emissions now, warming and related water stress will be much worse.

One kilo of beef needs 15,000 liters of water.  Meanwhile, a kilo of vegetables like carrots and tomatoes only uses around 200 liters. Even juicy grapefruits require a relatively minor 500 liters of water per kilo. 

Water scarcity: What′s the big deal? | Environment | All topics from climate change to conservation | DW | 23.08.2021

No comments: