From 2016 to 2019, meteorologists saw record-breaking heat waves around the globe, rampant wildfires in California and Australia, and the longest run of category 5 tropical cyclones on record. The number of extreme weather events has been increasing for the last 40 years, and current predictions suggest that trend will continue. But are these natural disasters simply bad weather? Or are they due to our changing climate? To answer this question we need to understand the differences between weather and climate— what they are, how we predict them, and what those predictions can tell us.
Od 2016. do 2019. godine, meteorolozi su zapazili rekordni broj toplotnih talasa širom sveta, nezaustavljivih šumskih požara u Kaliforniji i Australiji i najduži zabeleženi tropski ciklon pete kategorije. Broj ekstremnih vremenskih neprilika povećava se poslednjih 40 godina, a trenutna predviđanja sugerišu da će se ovaj trend nastaviti. Nego, da li su ove prirodne nepogode prosto samo loše vremenske prilike? Ili su one posledica menjanja klime? Kako bismo odgovorili na ovo pitanje moramo da razumemo razlike između vremenskih prilika i klime, šta su, kako ih predviđamo, i šta nam ta predviđanja mogu pokazati.
Meteorologists define weather as the conditions of the atmosphere at a particular time and place. Currently, researchers can predict a region’s weather for the next week with roughly 80% accuracy. Climate describes a region’s average atmospheric conditions over periods of a month or more. Climate predictions can forecast average temperatures for decades to come, but they can’t tell us what specific weather events to expect.
Meteorolozi opisuju vremenske prilike kao uslove atmosfere u određeno vreme i na određenom mestu. Trenutno, istraživači mogu da predvide vremenske prilike neke regije za sledeću nedelju sa 80 posto preciznosti. Klima opisuje prosečne atmosferske uslove neke regije tokom perioda od mesec dana ili više. Predviđanja klime mogu da prognoziraju prosečne temperature decenije unapred, ali ne mogu nam kazati koje vremenske okolnosti da očekujemo.
These two types of predictions give us such different information because they’re based on different data.
Ova dva tipa predviđanja nam daju tako različite informacije jer su zasnovana na različitim podacima.
To forecast weather, meteorologists need to measure the atmosphere’s initial conditions. These are the current levels of precipitation, air pressure, humidity, wind speed and wind direction that determine a region’s weather. Twice every day, meteorologists from over 800 stations around the globe release balloons into the atmosphere. These balloons carry instruments called radiosondes, which measure initial conditions and transmit their findings to international weather centers. Meteorologists then run the data through predictive physics models that generate the final weather forecast.
Da bi prognozirali vremenske prilike, meteorolozi treba da izmere početne atmosferske uslove. To su trenutni nivoi padavina, vazdušnog pritiska, vlažnosti, brzine i smera vetra koji određuju vremenske prilike regije. Dvaput dnevno, meteorolozi iz preko 800 stanica širom sveta puštaju balone u atmosferu. Ti baloni prenose opremu koja se zove radiosonda, koja meri početne uslove i prenosi rezultate do internacionalnih hidrometeoroloških centara. Meteorolozi onda ubacuju podatke u predvidive fizičke modele koji generišu konačnu vremesku prognozu.
Unfortunately, there’s something stopping this global web of data from producing a perfect prediction: weather is a fundamentally chaotic system. This means it’s incredibly sensitive and impossible to perfectly forecast without absolute knowledge of all the system’s elements. In a period of just ten days, even incredibly small disturbances can massively impact atmospheric conditions— making it impossible to reliably predict weather beyond two weeks.
Nažalost, postoji nešto što sprečava ovu globalnu mrežu podataka da proizvede perfektnu prognozu. Vremenske prilike fundamelntalno su haotičan sistem. To znači da su neverovatno osetljive i da ih je nemoguće perfetkno prognozirati bez potpunog znanja svih elemenata sistema. U periodu od samo deset dana, čak i neverovatno male smetnje mogu mnogo da utiču na atmosferske uslove, čineći nemogućim da se pouzdano predvide vremenske prilike preko dve nedelje.
Climate prediction, on the other hand, is far less turbulent. This is partly because a region’s climate is, by definition, the average of all its weather data. But also because climate forecasts ignore what’s currently happening in the atmosphere, and focus on the range of what could happen. These parameters are known as boundary conditions, and as their name suggests, they act as constraints on climate and weather.
Predviđanje klime, sa druge strane, je daleko manje turbulentno. Zbog toga što je klima neke regije, po definiciji, prosek svih njenih podataka o vremenskim uslovima. Ali i takođe zbog toga što prognoziranje klime ignoriše šta se trenutno dešava u atmosferi, i fokusira se na opseg onoga što bi moglo da se desi. Ovi parametri su poznati kao granični uslovi, a kao što ime sugeriše, ponašaju se kao prepreke klimi i vremenskim prilikama.
One example of a boundary condition is solar radiation. By analyzing the precise distance and angle between a location and the sun, we can determine the amount of heat that area will receive. And since we know how the sun behaves throughout the year, we can accurately predict its effects on temperature. Averaged across years of data, this reveals periodic patterns, including seasons.
Jedan primer graničnog uslova je solarna radijacija. Analizirajući tačnu razdaljinu i ugao između neke lokacije i Sunca, možemo odrediti količinu toplote koja će zadesiti neku oblast. S obzirom da znamo kako se Sunce ponaša tokom cele godine, možemo precizno predvideti njegove efekte na temperaturu. U proseku mnogogodišnjih podataka, ovo otkriva periodične šablone, uključujući i godišnja doba.
Most boundary conditions have well-defined values that change slowly, if at all. This allows researchers to reliably predict climate years into the future. But here’s where it gets tricky. Even the slightest change in these boundary conditions represents a much larger shift for the chaotic weather system. For example, Earth’s surface temperature has warmed by almost 1 degree Celsius over the last 150 years. This might seem like a minor shift, but this 1-degree change has added the energy equivalent of roughly one million nuclear warheads into the atmosphere. This massive surge of energy has already led to a dramatic increase in the number of heatwaves, droughts, and storm surges.
Većina graničnih uslova ima dobro definisane vrednosti koje se polako menjaju, ako i uopšte. Ovo omogućava istraživačima da pouzdano predvide klimu u budućnosti. Nego, ovde postaje nepouzdano. Čak i najmanja promena ovih graničnih uslova predstavlja mnogo veći preokret za haotični sistem vremeskih prilika. Na primer, temperatura Zemljine površine uvećala se za skoro jedan stepen Celzijusa u poslednjih 150 godina. Ovo može da izgleda kao mala promena, ali ova promena jednog stepena dodala je energiju u atmosferu ekvivalentnu otprilike milionu bojnih glava. Ovaj jak talas energije već je doveo do velikog povećanja broja toplotnih talasa, suša i naleta oluja.
So, is the increase in extreme weather due to random chance, or changing climate? The answer is that— while weather will always be a chaotic system— shifts in our climate do increase the likelihood of extreme weather events.
Da li se povećao broj ekstremnih vremenskih prilika zbog slučajnosti ili promene klime? Odgovor je da, iako će vremenske prilike uvek biti haotičan sistem,
Scientists are in near universal agreement that our climate is changing and that human activity is accelerating those changes. But fortunately, we can identify what human behaviors are impacting the climate most by tracking which boundary conditions are shifting. So even though next month’s weather might always be a mystery, we can work together to protect the climate for centuries to come.
promene klime povećavaju verovatnoću za ekstremnim vremenskim neprilikama. Naučnici su gotovo saglasni da se klima menja i da ljudske aktivnosti ubrzavaju te promene. Ali na sreću, možemo da utvrdimo koja ljudska ponašanja najviše utiču na klimu prateći koji granični uslovi se menjaju. Iako vremenske prilike narednog meseca uvek mogu biti misterija,