Ozone in danger anew

Chemical delays layer recovery

PARIS, June 27, (AFP): Earth’s protective ozone layer, on a slow path to recovery since the 1987 Montreal Protocol banned chemicals that erode it, may be in danger anew, scientists warned Tuesday.

Levels in the stratosphere of dichloromethane, a chemical not covered by the ozone rescue pact, are increasing rapidly and could delay the layer’s recovery, they said. Although “currently modest, the impact of dichloromethane on ozone has increased markedly in recent years,” a team reported in the journal Nature Communications.

“Sustained growth in dichloromethane would ... offset some of the gains achieved by the Montreal Protocol, further delaying recovery of Earth’s ozone layer.”

The layer sits in the stratosphere at 10 to 50 kms (six to 30 miles) above the Earth’s surface, where it filters out harmful ultraviolet light that can cause cancer and damage crops.

The Montreal accord phased out production of chlorofluorocarbons (CFCs) in refrigerators, aerosols, airconditioners and foam insulation when

remains undetermined.

The National Marine Fisheries Service and US Fish and Wildlife Service gave their green light by finding that the project would not mean extinction for endangered and threatened native species of salmon and other fish. The project, which would tap part of the flow of California’s largest river, the Sacramento, would change the way the San Francisco Bay Area, the farm-rich Central Valley and populous Southern California get their water from what is the West Coast’s

Brown

Reed

it was discovered they were responsible for the so-called ozone “hole”.

CFCs were replaced in the 1990s by hydrofluorocarbons (HFCs), which were safe for the now-healing ozone but also highly effective at trapping heat in the atmosphere, contributing to global warming. An amendment to the pact, to phase out HFCs, was signed in Kigali in February.

Scientists have already raised concern about the potential ozone impact of manmade chemicals called “very short-lived substances” or VSLS, such as dichloromethane.

VSLS gases usually break down in less than six months.

The new study sought to quantify the harm threatened by dichloromethane, which is used as a solvent in paint strippers and as a degreaser, and also to decaffeinate coffee.

The researchers found that dichloromethane levels in the stratosphere have nearly doubled since 2004.

Further growth could delay the ozone recovery over Antarctica, where the depletion was most severe, by more than a decade.

largest estuary. The twin tunnels, both four stories high and 35 miles long, would be California’s most ambitious water project since the 1950s and 1960s. Then, Brown’s father, the late Gov Pat Brown, helped oversee building of the pumps, dams, and aqueducts that move water from the green north to more arid south. (AP)

SpaceX delivers satellites:

The American company SpaceX on Sunday successfully placed 10 satellites for the communications company Iridium into orbit using a Falcon 9 rocket.

After launching as scheduled from the Vandenberg Air Force Base in California at 1:25 pm local time (2025 GMT), the Falcon 9’s first stage returned less than eight minutes after taking off.

As planned, it landed on a barge floating in the Pacific Ocean. SpaceX has successfully landed multiple rockets on both land and water, as part of its effort to bring down the cost of space flight by re-using multimillion dollar components instead of jettisoning them in the ocean after launch. (AFP)