Whatever happened to the hole in the ozone layer? - Stephanie Honchell Smith

Translator: Emilija Kabanica Reviewer: Nika Kotnik

In the 1980s, the world faced a huge problem:

V 90. se je svet spopadal z veliko težavo:

there was a rapidly expanding hole in the ozone layer.

hitro rastoča luknja v ozonski plasti.

So, what happened? And is it still there?

Kaj se je torej zgodilo? Je še vedno tam?

Let’s go back to the beginning.

Vrnimo se na začetek.

The Sun makes life on Earth possible,

Sonce omogoča življenje na Zemlji,

but too much exposure to its UV radiation damages plant and animal DNA.

a prevelika izpostavljenost UV-žarkom škodi rastlinskemu in živalskemu DNK-ju.

Thankfully, about 98% of that radiation is absorbed by ozone molecules

K sreči približno 98% sevanja absorbirajo molekule ozona

dispersed in the stratosphere,

razpršene v stratosferi,

which are continuously broken apart and reformed in this process,

ki se v tem procesu nenehno razgrajujejo in preoblikujejo

maintaining a delicate equilibrium.

ter tako ohranjajo občutljivo ravnovesje.

But in the early 1970s, two chemists— Mario Molina and Sherwood Rowland—

A v zgodnjih 70. letih sta kemika Mario Molina in Sherwood Rowland dokazala,

demonstrated that widely used chemicals called chlorofluorocarbons, or CFCs,

da bi pogosto uporabljene kemikalije imenovane klorofluoroogljikovodiki ali CFC

could upset this balance.

lahko porušile to ravnovesje.

CFCs were developed in the 1920s by three US-based corporations

CFC-je so razvila v 20. letih tri podjetja s sedežem v Ameriki

as coolants for refrigerators.

kot hladilna sredstva za hladilnike.

Unlike existing alternatives— such as ammonia or methyl chloride—

Za razliko od obstoječih alternativ kot so amonijak ali metilklorid,

CFCs were non-flammable and non-toxic—

so CFC-ji bili nevnetljivi in nestrupeni

meaning they wouldn't burst into flames or cause deadly gas leaks.

kar pomeni, da ne vzplamenijo ali povzročajo smrtonosno uhajanje plinov.

They also made great propellants, foaming agents, and fire-retardants.

Bili so tudi odlično pogonsko sredstvo, penilo in zaviralci ognja.

CFCs soon found their way into a variety of everyday items

CFC-ji so kmalu našli pot do različnih vsakodnevnih izdelkov

and became a multi-billion dollar per year industry.

in postali industrija vredna več milijard dolarjev na leto.

In the lower atmosphere, CFCs don’t break down or react with other molecules.

V spodnji atmosferi se CFC-ji ne razpadejo ali reagirajo z drugimi molekulami.

But Molina and Rowland showed that in the stratosphere,

A Molina in Rowland sta dokazala, da jih v stratosferi

they're broken apart by UV light, releasing chlorine atoms.

UV-žarki razgradijo in začnejo sproščati atome klora.

These then react with ozone,

Ti nato reagirajo z ozonom

destroying it faster than it can be replenished.

ter ga tako uničijo hitreje kot pa se le-ta obnovi.

A single chlorine atom can destroy thousands of ozone molecules

En sam atom klora lahko uniči na tisoče ozonskih molekul

before finally reacting with something else and forming a stable molecule.

preden reagira z nečim drugim in tvori stabilno molekulo.

Seeing the threat to their bottom line,

Ko je to ogrožalo finančne rezultate,

CFC producers pushed back to discredit the scientists,

so proizvajalci CFC-jev udarili nazaj in poskušali diskreditirati znanstvenike

even accusing them of working for the KGB.

ter jih celo obtožili, da delajo za KGB.

Initial estimates showed that within 60 years,

Začetne ocene so pokazale, da bi v roku 60-ih let

CFCs could reduce ozone concentrations by 7%.

CFC-ji lahko zmanjšali koncentracijo ozona za 7%.

But by 1985, it became clear that ozone depletion, especially over Antarctica,

A je do leta 1985 postalo jasno, da se je tanjšanje ozona,

predvsem nad Antartiko, odvijalo veliko hitreje.

was happening much faster.

Here, the extremely cold temperatures and unique structure of Antarctic clouds

Tu so izjemno mrzle temperature in unikatna struktura antarktičnih oblakov

accelerated ozone loss.

pospešile tanjšanje ozona.

Scientists stationed in Antarctica noticed a massive drop

Znanstveniki nastanjeni v Antarktiki so opazili velik upad

in overhead ozone occurring every spring.

prizemnega ozona vsako pomlad.

Satellite data revealed the vast extent of these losses

Satelitski podatki so razkrili velik obseg teh izgub,

and chemical tests confirmed that the cause was unquestionably CFCs.

kemični testi pa so potrdili, da so vzrok nedvomno CFC-ji.

NASA soon released visualizations, which were broadcast around the world

NASA je kmalu objavila podatke, ki so bili prikazani po celem svetu

and captured public attention.

in so pritegnili pozornost javnosti.

If ozone depletion continued, rates of skin cancer would skyrocket.

Če bi se tanjšanje ozona nadaljevalo, bi delež kožnega raka skokovito narasel.

Photosynthesis would be impaired, making plants—

To bi oslabilo fotosintezo, zaradi česar bi bile rastline,

including rice, wheat, and corn—

vključno z rižem, pšenico in koruzo,

less productive and more susceptible to disease.

manj produktivne in bolj dovzetne za bolezni.

Global agricultural production would plummet,

Svetonovna kmetijska proizvodnja bi upadla

and entire ecosystems would collapse.

in celotni ekosistemi bi se zrušili.

But many politicians— weighing immediate economic concerns over long-term ones—

A mnogi politiki se pri tehtanju o kratko- in dolgoročnih gospodarskih razmerah

disagreed about what to do.

niso strinjali glede rešitve.

The fight to ban CFCs found two unlikely allies

Boj za prepoved CFC-jev je naletel na dva nenavadna zaveznika

in US President Ronald Reagan and UK Prime Minister Margaret Thatcher.

v ameriškem predsedniku Ronaldu Reaganu in britanski premierki Margaret Thatcher.

Despite their general opposition to government regulation,

Kljub splošnemu nasprotovanju vladni ureditvi

Reagan, who had undergone treatment for skin cancer,

sta Reagan, ki se je zdravil kožnega raka,

and Thatcher, who was trained as a chemist,

in Thatcher, ki je bila izšolana kemičarka,

recognized the need for immediate action.

priznala potrebo po takojšnjem ukrepu.

The US and UK, along with Canada, Norway, Sweden, and Finland,

Amerika, Velika Britanija, Kanada, Norveška, Švedska in Finska

led calls for an international ban on CFCs.

so pozivale svet k prepovedi CFC-jev.

In 1987, representatives signed the Montreal Protocol,

Leta 1987 so predstavniki podpisali Montrealski protokol,

requiring the rapid phasing out of CFCs

ki je zahteval hitro postopno opuščanje CFC-jev

and creating a fund to assist Global South countries

in ustanovitev sklada za pomoč državam svetnovnega juga

in obtaining affordable, non-ozone depleting alternatives.

pri pridobivanju dostopnih alternativ, ki ne tanjšajo ozonskega plašča.

It was later ratified by every country on Earth—

Kasneje so jo ratificirale vse države na Zemlji.

the only treaty in history to achieve this.

To je edina pogodba, ki je to dosegla.

In 1995, Molina, Rowland, and their Dutch colleague Paul Crutzen,

Leta 1995 so Molina, Rowland in njun nizozemski sodelavec Paul Crutzen,

were jointly awarded the Nobel Prize in Chemistry.

prejeli Nobelovo nagrado za kemijo.

As the use of CFCs declined,

Ker se je uporaba CFC-jev zmanjšala,

the ozone hole began shrinking,

se je ozonska luknja začela krčiti

and is predicted to disappear entirely by 2070.

in predvideva se, da bo do leta 2070 popolnoma izginila.

But we’re not out of the woods yet.

A nismo še na varnem.

While the ban was a win for the climate, as CFCs are potent greenhouse gases,

Čeprav je bila prepoved zmaga za podnebje, ker so CFC-ji močni toplogredni plini,

the alternatives that replaced them— hydrofluorocarbons, or HFCs— are too.

so tudi njihove alternative takšne – hidrofluoroogljikovodiki ali HFC-ji.

While generally less potent than CFCs,

Čeprav so na splošno šibkejši od CFC-jev.

HFCs still trap more heat than carbon dioxide

HFC-ji še vedno zadržijo več toplote kot ogljikov dioksid

and are contributing to climate change.

in prispevajo k podnebnim spremembam.

To address this, in 2016, the Kigali Amendment

Pri reševanju tega, se je leta 2016, Montrealskemu protokolu

was added to the Montreal Protocol,

dodala še kigalijska sprememba,

calling for an 85% cut in global HFCs by 2047.

ki je zahtevala 85-odstotno zmanjšanje HFC-jev na svetu do leta 2047.

This alone could avoid up to 0.5°C of global warming by the end of the century.

Samo s tem bi se lahko izognili do 0.5°C globalnega segrevanja do konca stoletja.

Today, as we face the existential threat of climate change,

Danes, ko se soočamo z eksistencialno grožnjo podnebnih sprememb,

the Montreal Protocol serves as a model for the decisive global cooperation

Montrealski protokol služi kot model za odločilno globalno sodelovanje,

we need to combat it.

ki ga potrebujemo za zmago.

The question is, what will it take for us to come together again?

Vprašanje je, kaj potrebujemo, da bi se ponovno združili?