not saying there’s not a climate change disaster happening, but some of these analyses are a little misleading.
Except that to only say “…since 1979” is to comment in either ignorance or bad faith (your pick). We maintained record breaking temps ALL above the prior record for 36 is the damn point, and to miss that is to miss the entire thing.
There have been 44 years since 1979. Lets say the probability of getting 1 day above the 1979 record in a given year is 1/44 (uniform). The probability of even getting a week of the hottest days in one year would be (1/44)^7, would be a one in 300 billion chance. There are some issues and some assumptions I’m making for convenience, but its not ok to make idle comments with no comprehension of the scale of extremity this event represents.
As in, do you have any fucking idea how unlikely that is? This isn’t an ‘oopsie poopsie’ funny record event.
Not to be too pedantic but your back of the envelope probabilities are based on inaccurate assumptions and probably several orders of magnitude off. Specifically, your not just assuming uniform but also independent from one day to the next. A more accurate treatment would be to assume conditional dependence from one day to the next (the Markov property). Once you have a record hot day, you are significantly more likely to have another record hot day following it.
That said, it’s still low probability, just not as low as what you’re saying.
If we stick with your 1/44 assumption, we can then assume 50% chance that the following day will also be a record setting day (probably too low still but the math is easier). Your one week estimate would be (1/44)*(1/2)^6.
If we stick with your 1/44 assumption, we can then assume 50% chance that the following day will also be a record setting day (probably too low still but the math is easier). Your one week estimate would be (1/44)*(1/2)^6.
While @bloodfoot@programming.dev is right about me not being right, I’m not sure their implementation is correct either. I grabbed the data sheet from here, and have calculated the following probabilities. Now that I’m invested I really want to get this ‘right’.
I think its most fair to calculate this using the marginal probability of the next day being warmer for a given month. Some months are generally warming, some generally cooling, so it makes sense to base the marginal probability of the next day being warmer for a specific month (rather than all months). The probability of a given day in July being warmer than the previous day is 0.615. So pretty close to 50/50, but better to be precise. I think if we’re going to go this way, we can also give ourselves the liberty of not starting on July first, but rather then trend can start any time in July.
So now the math becomes:
State one is defined as the probability of having a record warm day in July: 1/44 *days in July
State two is defined as the probability the next day being warmer than the previous in July : 0.615
Which when I put it into this calculator, we get… .9981? This seems extremely low. So much so, I think either the markov chain is implemented wrong, or that the markov principal doesn’t apply here.
This would put the probability of a summer like the one as a one in 500-ish year occurrence. My understanding and read of the news is that this is an event that is on the scale of ‘has never happened before’.
Update:
So I am still not confident in the markov implementation but I put together another approach. I did a one sided T-test of this July versus all the previous Julys.
Here is a plot of that (month is on the X).
T-statistic came in too low to calculate a p-value.
While the data presented here only goes back to 1979, I seem to recall that some scientists worked out global average temperatures based on coral reef core samples and ice core samples. I think there were some other samples too but I can’t remember what they were. So they are the hottest ever
Not terribly significant. The length, number of heat records broken, and sheer catastrophic scale of this heatwave is unprecedented. We don’t have any reason to think anything remotely like this has happened in human history, and the fact that we didn’t have the means to track the entire planet’s average temperature prior to 1979 doesn’t negate that.
Hawaii is on fire. Oregon is on fire. Canada is on fire. California is on fire. The winter in the southern hemisphere is unprecedentedly warm, and much of Australia burned over their summer. It’s going to burn again.
For the hell of it, I checked the list of hottest temperatures recorded and the top for the US was in 1913, Sweeden 1933, Russia 2010, and Germany/France 2019 (for just a small selection of countries). Very few were from this year and many weren’t even in the last half century.
Much of eastern North America is having a relatively cool summer thanks to the smoke from the Canadian wildfires. Temps in my area have barely broken 85F/30C all summer
…since 1979
Edit: not saying there’s not a climate change disaster happening, but some of these analyses are a little misleading.
Except that to only say “…since 1979” is to comment in either ignorance or bad faith (your pick). We maintained record breaking temps ALL above the prior record for 36 is the damn point, and to miss that is to miss the entire thing.
There have been 44 years since 1979. Lets say the probability of getting 1 day above the 1979 record in a given year is 1/44 (uniform). The probability of even getting a week of the hottest days in one year would be (1/44)^7, would be a one in 300 billion chance. There are some issues and some assumptions I’m making for convenience, but its not ok to make idle comments with no comprehension of the scale of extremity this event represents.
As in, do you have any fucking idea how unlikely that is? This isn’t an ‘oopsie poopsie’ funny record event.
Not to be too pedantic but your back of the envelope probabilities are based on inaccurate assumptions and probably several orders of magnitude off. Specifically, your not just assuming uniform but also independent from one day to the next. A more accurate treatment would be to assume conditional dependence from one day to the next (the Markov property). Once you have a record hot day, you are significantly more likely to have another record hot day following it.
That said, it’s still low probability, just not as low as what you’re saying.
Any thoughts on how I could incorporate that for a better back of the napkin?
(Also, that number is only consider that the number presented was based on 7 independent events, not 34)
If we stick with your 1/44 assumption, we can then assume 50% chance that the following day will also be a record setting day (probably too low still but the math is easier). Your one week estimate would be (1/44)*(1/2)^6.
So the 36-day would just have a ^35 on the end instead 6, if I’m following?
While @bloodfoot@programming.dev is right about me not being right, I’m not sure their implementation is correct either. I grabbed the data sheet from here, and have calculated the following probabilities. Now that I’m invested I really want to get this ‘right’.
This the work book I’m in.
I think its most fair to calculate this using the marginal probability of the next day being warmer for a given month. Some months are generally warming, some generally cooling, so it makes sense to base the marginal probability of the next day being warmer for a specific month (rather than all months). The probability of a given day in July being warmer than the previous day is 0.615. So pretty close to 50/50, but better to be precise. I think if we’re going to go this way, we can also give ourselves the liberty of not starting on July first, but rather then trend can start any time in July.
So now the math becomes: State one is defined as the probability of having a record warm day in July: 1/44 *days in July State two is defined as the probability the next day being warmer than the previous in July : 0.615
Which when I put it into this calculator, we get… .9981? This seems extremely low. So much so, I think either the markov chain is implemented wrong, or that the markov principal doesn’t apply here.
This would put the probability of a summer like the one as a one in 500-ish year occurrence. My understanding and read of the news is that this is an event that is on the scale of ‘has never happened before’.
Update:
So I am still not confident in the markov implementation but I put together another approach. I did a one sided T-test of this July versus all the previous Julys.
Here is a plot of that (month is on the X).
T-statistic came in too low to calculate a p-value.
While the data presented here only goes back to 1979, I seem to recall that some scientists worked out global average temperatures based on coral reef core samples and ice core samples. I think there were some other samples too but I can’t remember what they were. So they are the hottest ever
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I can’t find any indication that 1979 had a 36-day heatwave with anything approaching the temperatures we’re seeing.
I think the significance of 1979 is that’s when we started keeping track of an overall global temperature day by day…
Not terribly significant. The length, number of heat records broken, and sheer catastrophic scale of this heatwave is unprecedented. We don’t have any reason to think anything remotely like this has happened in human history, and the fact that we didn’t have the means to track the entire planet’s average temperature prior to 1979 doesn’t negate that.
Hawaii is on fire. Oregon is on fire. Canada is on fire. California is on fire. The winter in the southern hemisphere is unprecedentedly warm, and much of Australia burned over their summer. It’s going to burn again.
This is an emergency.
For the hell of it, I checked the list of hottest temperatures recorded and the top for the US was in 1913, Sweeden 1933, Russia 2010, and Germany/France 2019 (for just a small selection of countries). Very few were from this year and many weren’t even in the last half century.
https://en.wikipedia.org//wiki/List_of_weather_records#Highest_temperatures_ever_recorded
You’re downvoted because you’re comparing one day record temp to a full month of record highs.
Also, a large part of the reason the global average temperature is high is because the Southern hemisphere is having a very warm winter.
Comparing global average to local max temperatures is also wrong.
Much of eastern North America is having a relatively cool summer thanks to the smoke from the Canadian wildfires. Temps in my area have barely broken 85F/30C all summer
Oh good, maybe the smoke from everything being on fire will cool us down!
/s