Why was summer 2018 so hot??

Why was summer 2018 so hot??

This video was made possible by Brilliant.org If you live in the Northern Hemisphere right now, you might have noticed that it’s really rather hot in the UK. We’re experiencing a weeks long heat wave so severe that when it rained recently it was greeted with jubilation. In England! In Sweden, a surge of wildfires has occurred, including more than a dozen inside the Arctic Circle, where temperatures have topped 30 degrees and in Japan, an unprecedented heatwave has killed more than 65 people in a single week. It’s all but impossible to sleep, horrible to work outside and the land itself is shrivelling up. So, why is this happening? Well as always seems to be the case, there are 3 main causes WAIT! NO NO NO NO NO NOT YET! Cause Number 1: The Atlantic. More specifically, the oceans surface temperature. The surface temperature in the North Atlantic varies in a complex fashion every day. But underneath that variability there’s a see-saw pattern. If you look at the average monthly temperature of the Atlantic over several decades, you see this oscillation between warmer than average and colder than average temperatures. This is called the It’s caused by the huge ocean circulation known as the AMOC – as well as, surprisingly, clouds. I’ll leave a link below to a paper if you’re interested. In fact, every time you see a number on the screen, that’s a reference in the description. Whether the Atlantic is in a warm or a cool phase has a huge impact on parts of the climate like hurricane formation, Arctic sea-ice cover, and global temperatures. And right now, the AMO is in the very positive phase, meaning that the Atlantic is really warm compared to normal. That has a direct effect on the continents surrounding the Atlantic, with lots more thermal energy in the Northern Hemisphere, warming Europe and North America, and making Africa and Europe wetter, while making North America drier. Wait what? The UK resembles Tatooine right now? (Incidentally, you might like the video I did about the planets in Star Wars) While the relationships presented in these papers show what happens on average – so, on average, in the past, when the Atlantic has been warmer than normal, Europe has been wetter than normal. What that average response doesn’t account for is the effect of other climate phenomena and variability on the weather, such as Cause Number 2: The jet stream being particularly weak. The jet stream is a narrow band of fast-moving air that circles the North Pole about ten kilometres up – typically, between about 50 – 60 degrees North. It’s caused by the temperature difference between the pole and the equator, combined with the rotation of the Earth. And, it’s a major factor in what weather we get in the mid-latitudes. At the moment, the jet stream is particularly weak, meaning that the air in the jet is moving slower than normal, but also, that the meanders we see in the jet stream aren’t moving from West to East as fast as normal. Because the jet stream marks a boundary between colder polar air and warmer, temperer air, if meanders in the jet stream stay put for a while, that means that regions south of the jet stream experience warmer than average temperatures for a long time. And conversely, regions north of the jet experience colder than average temperatures for a long time. The UK and Scandinavia, as well as lots of other places I didn’t mention, are all south of the jet stream, and have been for a while. High pressure systems have been sat on top of these places and refused to budge. That means that colder and moisture struggles to get in and alleviate the hot, dry conditions. On the flipside, Iceland for example, has had it’s greyest, wettest summer since 1914. And that’s because Iceland’s been on the other side of the jet stream, sitting further north amongst the persistently cold temperatures. So, Iceland has been cold and wet. The lucky bastards. So what caused the jet stream to be so weak and stationary? Well, that’s quite possible reason number 3: Global Warming. The world is warmer now than it was before the Industrial Revolution, warming faster than any natural cycle allows for, and that warming is directly attributable to human activities – notably, the release of gases like Carbon Dioxide into the atmosphere. There is no debate – the science is unequivocal. If you dispute any of those facts, then, you are wrong. Well, the comments on this video are going to be fun. The globe isn’t warming evenly however. Due to a phenomenon known as the poles are warming faster than the rest of the planet, which reduces the equator to pole temperature gradient. And because the jet stream is fed by that temperature gradient, this results in a weaker jet stream, with bigger meanders. And the bigger the meanders in the jet stream, theory tells us, the more slowly they’re going to move around the Earth. So we get persistent weather patterns, like Japan, and the UK, and Iceland are experiencing. As with all weather events, it is nigh-on impossible to directly attribute a particular event to global warming. These conditions could well have occurred in an atmosphere without a single molecule of anthropogenic origin. But, what we’re observing at the moment certainly matches what we would expect to see in a planet that has undergone global warming. And apart from the weaker jet stream, and persistant associated high pressure systems, the warming caused by these local, short term weather systems gets added on top of the decades-long pattern of global warming we’ve seen, to give record temperatures. In fact, the weak jet stream and warm Atlantic also occurred together in 1976, when the UK had a record-breaking heatwave, which is now regarded as a “yardstick” event This current weather is the most severe heatwave the UK has seen since then, and monthly average temperatures are higher in some parts of the country now than they were in 1976. So thanks to global warming, extreme events are getting that bit more extreme – and research indicates that they’ll be more frequent too. This summer in the Northern Hemisphere is a good example of what climate change is probably going to look like this century. When factors come together such as a warm Atlantic and a weak jet stream, the additional heat trapped in the Earth’s system by anthropogenic emissions will take what would have been a big weather event, and make it an extreme one. Highs will get higher, and as we saw this winter with “The Beast from the East”, (You might want to watch my video about that) the lows will get lower in some places too. But the net effect will be trending towards a warmer on average climate. So when will this current heatwave end in the UK? Well, weather is notoriously difficult to predict! Long range forecasts from the UK Met office indicate that the summer isn’t going to cool off significantly by mid to late August. The high pressure system just isn’t budging. Most likely, it’s going to be uncomfortably warm, with a few cooler days, until September. And then of course, the weather will have to change. Because, you know – Seasons, But weather prediction is incredibly difficult, especially when looking more than about a week ahead. So, this may well turn out to be wrong! For the time being, keep hydrated, avoid the central line, check on elderly neighbours, and if you can, enjoy the sun! Responsibly. This video was sponsored by Brilliant.org. If you’re interested in how the world works, you should check out their expertly curated courses on Science and Maths – including the physics of the everyday. In this course, you’ll get hands on with problems about Nuclear Power, the Coriolis Effect in hurricanes, and, high pressure systems like we’ve been talking about in this video. Brilliant is so well put together, and I’ve recently had some subscribers get back to me saying they’ve really enjoyed doing their courses – as have I. So, if you’d like to join them and the Brilliant community worldwide, then hit the link in the description! That’s Brilliant.org/SimonClark And if you’re one of the first 200 people to do so, then you’ll get 20% off your premium annual subscription. Thanks to Brilliant for sponsoring this video, and thank you for watching it. I hope I was able to provide a little bit more detail than just “It was the jet stream that did it LOL” If you did enjoy it, please do leave a comment down there in the comments section. I would love to do more videos on atmospheric topics, and I basically just don’t know if people would watch them. It’s my forte, it’s what I know the most about, I’d like to make more videos about it, but I could do with a bit of feedback on this. So, if you enjoyed the video, do drop it a like, leave a comment, check out the references in the description, and I’ll see you in the next one. Thank you again for watching.

100 thoughts on “Why was summer 2018 so hot??

  1. Hi Simon,
    Nice video as always, including a reference to our attribution study from last week 🙂
    That said, I do have to take serious issue with the AMO influence. First, it's highly disputed in the first place and the mainstream view has certainly shifted away from it being internally forced alone. It's increasingly viewed as an amplification of the external forcing via AMOC feedbacks. Thing is, if you regress the SSTs over the AMO region with NH temperatures, you find that this region actually cools in comparison to the hemispheric mean. Which makes sense given the long-term AMOC slow-down. If anything, we AMO could be seen as the horseshoe SST-anomaly pattern that it really is. Cold SPG and tropical Atlantic with warm tongue in between as current would correspond to AMO+ and the reverse would correspond to AMO- (e.g. in 1997). But the total temperature effect is rather limited as the whole North Atlantic (NH Atlantic that is) is currently certainly not particularly warm. Try the GISTEMP tool if you find the time: data.giss.nasa.gov/gistemp/maps/
    The most interesting question is to what extent a certain NA SST setup (established via the atmosphere in the preceding winter) can influence the summer circulation in the Atlantic region and hence the adjacent downstream continent, which happens to be Europe. In other words, is it the horseshoe pattern that sets the jet anomalies, or could the jet "override" the SST anomalies in summer (which seems hard given it's reduced strength compared to winter).
    Anyways, just some technical feedback. I'm leading a paper on the very subject matter in which we show that the AMO does not influence NH temperatures (let alone GMST). Still in review, but I thought I bring it up here 😉
    Cheers, KarSteN

  2. Im sorry global warming is a lie. If global warming was true than all our seasons would be warmer but its only summer. But where i live this years winter has been record breaking cold. Wheres the global warming during the other seasons besides summer?

  3. Seattle summers also have been very hot the past few years and even drier than usual. Not to mention the awful wildfire smoke that stuck around during the past 2 summers.
    Nearly every day in the month of July it was near or above 90 degrees (32C). Our A/C is broken and staying inside the house anytime from May-August was unbearable this past year especially. It could still be 100 degrees (38C) and humid inside the house even with the doors and windows open late in the day. I really hope this isn't gonna be a trend that continues.

  4. Just watching this now, couldn't really remember the summer really. Then you said 'avoid the central line' and I remembered the absolute hell of getting to work! It was actually like an oven on the central line


    Brazilians: wtf 20 c is cold espeially in the ne of brazil are you fucking retarded or what?

  6. And in the summer of 2016 rio de janeiro in brazil reached FUCKING 40 C WTF WHY WAS IT SO FUCKING HOT HOLY SHIT

  7. After the really hot summer in 2018, a really warm autumn followed. This winter, I haven’t seen one snowflake fall from the sky and I’m from the northwest where it snows a lot every winter. This winter was basically an extended autumn. Wet, Windy and Mild

  8. In chile it was winter in August,or better said… summer in August? Well it was winter but sometimes the temperatures were so hot that I even used shorts

  9. -UK, Ireland, New Zealand: Can't handle +30 or -0
    -Australians and Americans from the south: Can handle +30 but not -0
    -Canadians: Can handle any kind of weather

  10. OK, let's dig in temperature history, other july 6:
    And you call that hot year?

    ARE YOU FUCKING SHITTING ME !? MOTHERFUCKER !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  11. Here in the Tropics of North Queensland Australia, this summer 2018/2019 we had 8 days above 40C. This has never happened since records began in the 1800's. I grow Vanilla beans and I lost 50% of my crop due to the heat. This event and the constant energy sapping humidity has made me want to sell up and move to a cooler climate. No real action is being taken on climate change and the future of the biodiversity of this planet seems very bleak indeed.

  12. Very well done; easy to understand. Can you dumb it down so the trump lemmings can grasp it?! ? To our British cousins. BTW… always use the metric system in these vidios; if the people who haven't taken the 10 minutes to learn metric don't get it… Too bad!!!

  13. A quick warming factoid. The units are Zettajoules / year:

    warm the melt the

    ocean ice

    Deglaciation: 1.6 1.3

    2000-2018 AD: 13.7 0.18

    "Deglaciation" is the annual average over 12,500 years of significant sea level rise 20,200 to 7,500 years ago, averaging 10.5 mm / year and always >2.7 mm / year.

    "2000-2018 AD" is the annual average over 19 years of 2000-2018 AD.

    One conclusion is that the ocean has already started warming but the ice hasn't started melting yet.

    Incidentally, the 13.7+0.18=13.88 / year is the precise measure of what's referred to as "climate lag" or "in the pipeline" for future increase of Global Mean Surface Temperature (GMST) right now.

  14. Global warming is good because it will melt ice and open up vast areas to exploration for oil and natural gas.

  15. you were doing well until "Reason #3".

    The Sun is the factor that controls the rest. The Sun cycles are the reason the Earth warms and cools.

    Pity, I thought it was going to be a rational video.

  16. This is AWESOME! The plants are growing well. It will be a shame when the banks decide there property investments are at risk and property becomes expensive. And when the corrupt governments start putting fees on food in order to create a manditory contribution against global warming. I'll be sat here watching the worlds funds getting even more concentrated in the hands of the 0.1% whilst trying to convince people the crisis of rainforest destruction and ocean acidification could be solved for under half a trillion dollars one off payment. Anyone with a physics a-level could tell you this if they had enough time to spend a few hours reading up on pricing of ocean liming and earth shading etc

  17. old australian people smashing their keyboards as they listen to Australia average summer temperature be a heat wave in the uk



  20. How about we address the Corporations responsible for destroying all the trees for greed. The polluters of the seas. And the polluters of the sky.
    There is cleaner energy, that can be used, but greed, selfishness, and profiteering by those who have grown senile from their own ignorance and poison preventing the cleaner more efficient energy. Cities have changed the airflow, factories have affected the atmosphere, radiation plagues the oceans and lands. Mining and fracking have disrupted the land, and oil being drawn has affected lubrication of the plates. Earthquakes have gotten stronger, volcanic activity has risen to try to shroud us to cool us down. But earth is sick, and getting angry. If we dont help earth, she will purge this infection as our bodies do with heat when we are sick…

  21. #globalwarming #climatechange no rain, droughts. C02 Ch4 Heat trapping gases, loss of ozone layer. Sun brighter and hotter than ever. Gonna kill us all. God Bless ✝

  22. You Aussies are so used to got tempretures..but in Canada, 13°C is very hot for us, basically sweating every second..

  23. It wasn't hot for the whole of the summer ovrr the whole of the UK.

    It never really got going until after the solstice which is usually when the warm summers usually get going in the UK anyway. And for most of the UK the trally warm weather was over a 5 or 6 week period between 21st June and the end of July. Not for the whole 12 weeks. August was not particularly wonderful for the vast majority of the UK. 1976 had more 32C days than 2018 and far more widespread too.

    And the UK didn't exactly experience one of the hottest summers of the northern hemispherre last summer from 40 North last summer. Anyehere else last summer in the UK wouldn't be deemed spectscular the way it was perceived in the UK press. Canada and Russia below 60 North was hotter for longer last summer, we weren't exactly rivalling Madtid, Cslifornis and Washington for the hottest summer last year.

  24. Currently June 2019 and it literally feels like January. It’s like 9 degrees at 3pm with rain and wind. This time last yr, it was about 21 degrees

  25. All I heard last year was global warming this global warming that. And now it’s June 2019 and anything but hot ! All it proves is that climate change is real – that climate constantly changes is a fact ; that’s what it does. But anthropogenic climate change to the point that we are facing extinction ? Give me a break.

  26. Looking back at summer 2018, my observations in germany were less about heat but more about dryness. The years before, we never had blue skies, we had air traffic con trails that covered the sky by 10 o'clock in the morning. Suddenly in 2018, we saw none of this. We saw a clear blue sky! Why is that? Naturally, a dryer air allows more sunlight to reach the surface, heating the air. But heat is not the primary cause. It is the dryness of the air. Wildfires in all parts of the world confirm that this is not a local event. A very simple but logical explanation for this dryness is that less ocean water evaporated. Why could that be? Again, a simple explanation would be that the sea surface temperatures cooled down. You see the contradiction???

  27. The 1936 North American heat wave was one of the most severe heat waves in the modern history of North America. It took place in the middle of the Great Depression and Dust Bowl of the 1930s and caused catastrophic human suffering and an enormous economic toll. The death toll exceeded 5,000, and huge numbers of crops were destroyed by the heat and lack of moisture.

  28. June 2019 and this summer is going to be a lot worse. And the tea in your glass does not warm up until the ice cubes melt, g'day!

  29. Interesting theory what is the weather is being controlled by the government if they want hot weather they decide to have hot weather if they want cold weather they decided have cold weather if they want train they just wanted to have it is tightly onto their decision what they choose to have just to make news now you're giving out massive amounts of information where it is right but also wrong

    As she need to fill in the gaps and you give us a map which the map is completely wrong because there are more deserts

  30. The global temperature is less than it was in 1998 which was the peak of SC# 23. Now cooler by 0.40 C . No warming the next mini ice age is knocking at your door. Hail storms as exprienced in Mexico and Frqnce haven't happened since the Maunder Minimum. Check out Dr. Zharkova, she knows whqt she talking about. Everyone especially the agricultural industry should be thinking about how to grow crops to feed seven billion people . Brillent is living in the past.

  31. Oh, and I live in the USA, one of the Southern states, and the summer of 2018 was cooler than normal, and wetter than normal!!!

  32. You British are a bunch of limey scumbags your overpopulated little island is a huge problem for the rest of the world, you started the industrial revolution enslaved as many countries as you could, destroyed the environment now you are complaining its hot!! Im just a troll trolling it took a long time to think up this comment so let the comments fly!!!!

  33. Check your history! England had vineyards during the Mideavil Warm period. temperature were much warmer than now. Nothing you are describing is "abnormal". More fear mongering.

  34. not funny now…is it ohhh great all mighty species…….
    i was waiting for it for a long time.
    judgement will be upon us soon

  35. Black people: this is my kind of weather
    Brown people: This is nothing compared to home
    Far East Asians: hot but not that hot


  36. 8 weeks of no rain. it is ridiculous. now we have 2 days without clouds and i am burning…

    the last time i saw clouds it was only because of planes spraying chemtrails.

  37. Slower solarwinds and less cosmic rays account for Less clouds and also has other effects on the weather but I'm not that well versed on it yet

  38. Interesting stumbling across this video after the 2019 summer in Europe (as I continue my relentless addiction to consuming climate change information and getting incredibly depressed).

    Whilst the UK didn't see, on average, the same summer heat as 2018, Europe really copped it. Over here in blighty, we had a few incidents of extreme temperatures for a few days. Our friends in Europe (hopefully they remain that way … pun intended), were not as lucky. The jet stream meandered far enough south to spare most of the country what Europe endured.

    When you consume a vast amount of data over many months and years – in my case, mostly video, because I'm a lazy git – if you have a reasonable level of intellect, the conclusions drawn start to become glaringly obvious. The same conclusions that were drawn back in the 1980's … by scientists working for fossil fuel companies, with a collective intellect that far outstrips a sad old geek in his shed.

    Yet the world sat on its collective hands, at the behest of some unbelievably stupid and greedy people, for almost 40 years.

    Mind boggled. I will go sit in a dark room again and scream for a while. It helps. Sometimes beer does too. But not in a dark room.

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