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  • As of 2019, the earth is facing rising temperatures, severe storms, and were all pretty much

  • eating microplastics.

  • The last thing anyone wants to hear right now is that our ozone, the gas that protects

  • us from the hazardous UV radiation, is still being destroyed.

  • In the last few years, scientists have seen a recent spike in ozone destroying chemicals,

  • that technically the world banned.

  • It’s been a mystery as to where they were coming from until now.

  • When we talk about thehole in the ozone,” what we actually mean is there’s a roughly

  • 23-million-square-kilometer area that’s much thinner than it should be, and this is

  • mostly due its destruction from chlorofluorocarbons, or CFCs.

  • Now quickly, if youre unfamiliar, the ozone is a very thin layer to begin with.

  • While around 90% of it sits in the stratosphere, it contributes a very small percentage to

  • the overall atmosphere.

  • It’s created when the sun’s rays hit O2 molecules, the kind of oxygen we breathe,

  • and splits them into individual oxygen atoms.

  • This gives them the opportunity to cling to other O2 molecules, creating O3: the ozone.

  • And if you haven’t already guessed, we like the ozone, like a lot.

  • That thin layer of O3 molecules soak up to 99% of UV light that would otherwise penetrate

  • the planet and make the earth uninhabitable.

  • CFC’s are man-made chemicals that come from things like refrigeration systems, propellant

  • devices, or insulation processes and when they escape into our atmosphere, they wreak

  • havoc on the ozone.

  • When sunlight breaks chlorine atoms off the CFC molecule, the chlorine jumps from O3 molecule

  • to O3 molecule, unscathed and destroying ozone in the process.

  • It only takes one chlorine atom to destroy over one hundred thousand ozone molecules

  • before it leaves our atmosphere.

  • But none of this new to scientists. In fact, weve known about it for decades, and the

  • UN made an international treaty back in 1987 called theMontreal Protocolto completely

  • eliminate and stop the manufacturing of these chemicals.

  • It was the first universally ratified treaty and it received signatures from one hundred

  • and ninety-seven member states.

  • We even did a whole video breaking down this historical effort.

  • So what’s happening now?

  • Well, everything was looking pretty good, the ozone was recovering at the predicted

  • pace, that is, until a few years ago.

  • It was then, scientists noticed that the ozone’s recovery was more delayed than projections

  • suggested.

  • There was a spike of the chemical called, CFC-11, also known as, trichlorofluoromethane,

  • which is commonly found in spray foam insulation.

  • Oh, and it’s also one of the most potent chemicals in destroying the ozone. Basically

  • the worst one that could be making a comeback right now.

  • Before 2012, CFC-11’s concentration was dropping by about 0.8% per year, but that rate

  • slowed by half in 2013.

  • By 2018, a study out of Nature had scientists estimate that this could only happen with

  • a new source of emissions.

  • Although they weren’t quite sure exactly where, they identified a region in East Asia.

  • In the latest study from May 2019, scientists used air samples from the international monitoring

  • network called Advanced Global Atmospheric Gases Experiment.

  • The two stations were from South Korea and Japan, which reported that the new emissions

  • are from two provinces in China.

  • Both of which have contributed to some 7,000 metric tonnes annually since the beginning

  • of 2013.

  • This is the first time anyone has broken the international treaty and it doesn’t seem

  • like China has taken the issue lightly.

  • They sent out a public letter last year addressing their zero tolerance policy on the matter

  • of CFC’s and cracked down on companies using the product. But that’s only a fraction of

  • what could account to what the researchers callrogue emissions.”

  • So there’s still a mystery as to where the rest of these CFC-11 spikes are coming from.

  • The emissions in China account for at least 40%, but what theyve collected doesn’t

  • match up to even that.

  • Plus, there’s the possible extra 60% they can’t locate at all.

  • With the current 13,000 metric tonnes of chemicals in our atmosphere, scientists predict there’s

  • already been a setback of a decade before the ozone truly recovers.

  • A question you might have is why anyone would still want to make CFC’s in the first place?

  • Well researchers from the Environmental Investigation Agency speculate CFC-11 is

  • cheap to make and a more efficient product to the alternatives.

  • As it stands right now, we monitor the atmosphere with the Advanced Global Atmospheric Gases

  • Experiment.

  • They have 15 monitoring stations based on islands and mountain tops worldwide.

  • But 15 stations is not enough to cover the entire planet, and it makes our overall monitoring

  • system patchy at best.

  • Let alone the expense and commitment it takes to collecting samples multiple times a day for

  • 30+ years is a hard task to keep.

  • But this spike in CFC-11 just might be what scientists needed to see a bigger concern

  • at play; locating where these rogue emissions are coming from, and stopping them at the

  • source before it’s too late.

  • If you want to know more about the feats were taking in environmental protection, subscribe,

  • and check our video on what happens if the world warms by just a couple degrees Celsius.

  • Thanks for watching, and I’ll see you next time on Seeker.

As of 2019, the earth is facing rising temperatures, severe storms, and were all pretty much

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臭氧層空洞的修復為何要延後十年? (Here’s Why Repairing the Hole in the Ozone Layer Is Delayed by a Decade)

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    林宜悉 發佈於 2021 年 01 月 14 日
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