16 ms·

Do climate models predict extreme weather?

135 points by nsoonhui 5y ago

mc32 5y ago
Basically she's saying the current models would be poor tools to use for deciding what to do about climate change and moreover the media is too simplistic and confident when they make extreme weather attribution. But that is nothing new --hence Gell-Mann amnesia effect. >"And that is what I think is the biggest problem. The way that extreme event attributions are presented in the media conveys a false sense of accuracy. The probabilities that they quote could be orders of magnitude too small. The current climate models just aren’t good enough to give accurate estimates."
- icegreentea2 5y ago
  I think Sabine's point is more limited than "current models would be poor tools to use for deciding what to do about climate change", and more like "current models would be poor tools for extreme weather attribution". Of course, if your threshold for action on climate change is strong extreme weather attribution, then ok. But I think it's reasonable to also have lower or different thresholds for planning nad action. I do feel queasy about the current phrasing of extreme weather attribution, especially as portrayed in the media.
simonh 5y ago
Another great video and article from Sabine. So it seems like yes they do, and they can give us useful indicative estimates like lower bounds for the increased likelihood of extreme events, but there are still huge unknowns. Honestly I’m amazed we can get the estimates we do, given that this particular field of analysis is so young. I’m not as pessimistic about the usefulness of this data though. Knowing that these events are becoming much more likely and having an understanding of why is useful work. There are always unknowns, and now there are fewer of them. That’s good. Take the estimate that bush fires in Australia are now at least twice as likely than they were. Sure it would be better to know if they are twice, three times or 10x as likely, but knowing they are at least twice as likely and why that is the case is still useful data.
PaulDavisThe1st 5y ago
I don't really understand the conflict that seems to exist between the title of the article ("Do Climate Models predict Extreme Weather? ") and the body of the article, which argues that event attribution can't be done with much accuracy. So ... "Do Climate Models predict Extreme Weather? ": yes, yes they do. But .... "how much impact does climate change have on extreme weather?": hard to say with much accuracy, but the factor isn't negative! How useful is it to note that the factor might 2 or 200 or 2 million?
- mhh__ 5y ago
  Sabine plays a mean game when it comes to marketing her work, i.e. slightly reductive titles and a vaguely countercultural spin in her prose.
- matthewdgreen 5y ago
  There is a difference between asking “is it a good idea to play in the casino with the loaded dice” and “can that one particular loss be attributed to the loaded dice.” I think the second question is interesting, but it’s not really that important compared to the first question. Naturally the second question is the one that’s getting all the attention from people who want to keep playing in this particular casino. I guess that’s better than just outright climate denial, but aim not sure how much better it is.
timmg 5y ago
One of the things about "extreme weather attribution" that makes me uncomfortable is the asymmetry of it. To be clear: I'm in no way an expert (or even educated) in the area. To give an example. Let's say there's a 1% chance every year that there will be a catastrophic wildfire in some particular area. Now let's say climate change increases a chance of drought in that area. Then we get a wildfire one year and the attribution is (say) "20% due to climate change" -- which I guess means there is now a 1.2% annual chance of a catastrophic fire. But what if climate change causes more rain in the area? And, for the sake of argument, that causes the change of catastrophic fire to go down to say 0.8%. Then, in a given year, there is no fire. No one is going to bother doing an attribution study to say, "Climate change is 20% responsible for the fact that we didn't have a fire this year."
- divbzero 5y ago
  Extreme weather can occur in both directions. A year with more rain may be less prone to fire but more prone to flooding. It also does not take natural disaster to notice extremes. People who have lived in the same area awhile will know if there is an unusually wet, dry, hot, or cold year.
  - jjulius 5y ago
    >... more prone to flooding. Or mudslides.
  - timmg 5y ago
    > Extreme weather can occur in both directions. Of course that's true. What I guess I was trying to say is that a change in climate doesn't necessarily mean more extreme weather (in every instance, I mean). A change in climate could cause something to happen more or happen less. But no one is going to study a given year and a given place that doesn't have an extreme weather event.
    - hedgehog 5y ago
      Discrete events are a human construct but the underlying data is continuous. I'm not sure the attribution of individual events is that meaningful and the article suggests for a variety of reasons the models aren't really built for that purpose anyway. So I think in a sense you are right, but this doesn't necessarily imply any problem for the predictive value of the models or research going into them.
tokamak 5y ago
tldr; No
fasteddie31003 5y ago
I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.
- joe_the_user 5y ago
  This is a pretty extreme claim to make without references. Have you looked at climate change computer models? Which ones what are your credentials in making this sort of "code review"? Etc.
  - masteranza 5y ago
    It is not extreme at all. Sabina is using Luboš Motl wisdom as her own for some time now anyway.
  - deleted 5y ago
    [deleted]
- WoahNoun 5y ago
  Examples? This is a pretty dubious claim.
  - fasteddie31003 5y ago
    Just simple extrapolating logic. Climate is chaotic. Chaotic systems cannot be forecasted years out. Therefor a computer model for climate forecasting is not going to be accurate.
    - yed 5y ago
      Climate is not chaotic, weather is chaotic. Without any models at all we can predict that the Sahara desert will be hot and dry many many years out.
- 5y ago
pmjones 5y ago
Models say only what the modeler tells them to say.
- nabla9 5y ago
  That's not true. Climate models model and simulate physical and chemical condition on Earth. Modellers don't know what they say beforehand. Offhandedly portraying scientists and researchers as dishonest and conspirators in every opportunity possible seems the default here.
  - refurb 5y ago
    Models are constantly tweaked to make them more accurate. How do you do that without looking at output and then going back to tweak it?
    - magicalhippo 5y ago
      One way is to verify them. Run multiple variations on data from the 1950's and see how they compare to measured values up to today. Throw away the models that don't fit the measured values. Then you have some confidence that the remaining variations may be representative when run into the future. This is also done in weather forecasting, though maybe they run the model in reverse, I can't recall. Same idea though, verify with existing data before predicting.
      - sanxiyn 5y ago
        Yes this happens, but it is very controversial. To quote from the article I linked above: > The question of whether the twentieth-century warming should be considered a target of model development or an emergent property is polarizing the climate modeling community, with 35% of modelers stating that twentieth-century warming was rated very important to decisive, whereas 30% would not consider it at all during development. Some view the temperature record as an independent evaluation dataset not to be used, while others view it as a valuable observational constraint on the model development. Likewise, opinions diverge as to which measures, either forcing or ECS, are legitimate means for improving the model match to observed warming. The question of developing toward the twentieth-century warming therefore is an area of vigorous debate within the community.
Proven 5y ago
whatever1 5y ago
We are taking a system that was in equilibrium and we introduce a huge disturbance (+ multiple degrees C). Hell yes it will be unstable until it reaches the new equilibrium (whatever that equilibrium will look like - catastrophic for life or not).
- nlitened 5y ago
  From what I know about climate on Earth, it has literally never been in equilibrium — see periodic ice ages with glaciers up to 3—4 km thick, or periods of warmer climates when plants grew in huge amounts at latitudes where we have now vast oil reserves in Siberia.
  - whatever1 5y ago
    You are talking about changes over millions of years, not changes that happened within 100 years.
chiefalchemist 5y ago
I believe the climate it changing. I believe human activity has contributed to these changes. However, I do not believe _every_ "extreme event" belongs in that category. For example, the recent fires in the Denver / Boulder. Have you been there? It's effectively a desert. Dry, very dry. Open. There are few natural barriers once a fire starts. Based on what I know of the area, those homes - God bless those families - were built in harm's way. That disaster - regardless of climate change - was inevitable. To suggest otherwise is simply irresponsible.
- dragonwriter 5y ago
  > For example, the recent fires in the Denver / Boulder. Have you been there? It's effectively a desert. Dry, very dry. Not normally, so much, but yes, when the entire state ranges between “abnormally dry” and “extreme drought” [0], it probably seems desert-like. But...how are those unusual and extreme conditions an argument against the events being a product of anthropogenic climate change? [0] https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?CO https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonito...
  - chiefalchemist 5y ago
    Against? The point is, the state of that state in that area is naturally a fire hazard. Toss in some wind - which is as old as the earth itself - and POOF! disaster happens. Humans love to build homes and structures where they probably should not. We have this false ideal that we're bigger, stronger, and faster than Mother Nature. And then when it goes sideways we blame MN. That's not working out well.
fubarr 5y ago
Climate is a ~30yr moving average of weather. Climate models cannot attempt to model weather events. Such events can rarely be predicted more than a week or two out. The above should tell you that using a climate model to predict anything about weather events is a pointless exercise. Particularly trying to derive the statistics of weather events. The stats are built in to the models!
- viraptor 5y ago
  This can be easily shown to be false. I can't tell you if it's going to rain next week in most cases, but I can easily tell you about how many days in a year it's going to rain over a large area. Same applies to how many floods we're going to have and bushfires. We've been doing that for a very long time now.
  - fubarr 5y ago
    Telling me about averages deduced from past behavior? Great, you've read the statistic that's built into a model. Telling me what way that statistic will behave in future? Especially at extremes? Not a chance.
    - viraptor 5y ago
      We're commenting on an article pretty much saying we have models which estimate in the right directing, but don't go far enough. Now we can learn from the changes and improve the models. If you're discounting a whole field of research, can you provide more reasoning for why it can't be improved from the current results?
dnautics 5y ago
It bothers me that the A/B in these models is between "pre-industrial" and now, seems like a better comparison over the timescales people are expecting to match up with their "perceived experiences of increased climate disasters" should be "20 years ago vs now" e.g.
tasty_freeze 5y ago
Statistics are tricky to think about, even for people with technical educations. Something that was a lightbulb moment when someone was discussing professional baseball players. I forget the exact point the blog was making, but it came down to this: many things in life, like the ability to throw or hit a baseball, falls on a distribution that is close enough to a gaussian distribution. But when talking about professional baseball players, they represent just the very right hand tip of that distribution. Whatever intuitions you might have about gaussian distributions needs to be thought about in light of that. The same applies with extreme weather events. It is easy to look at articles and headlines describing an exponential increase in the frequency of extreme weather events. But think for a second about the equation of a gaussian distribution. When you shift the offset by a small, fixed amount, the area under that right hand tip goes up exponentially. No, one cannot point to climate change as the cause of any individual weather event. But it is a measured certainty that the warming is happening; the number of record high temperatures are a multiple higher than the number of record low temperatures every year for the past couple of decades. It would be weird if the temperature rose and the number of extreme events went up, say, linearly.
- onos 5y ago
  If this logic applies here then the increase in “extreme events” almost seems like a non statement. The distribution has shifted (as everyone agrees, though some debate cause) and consequently we will get more extreme events.
  - tasty_freeze 5y ago
    The point is it isn't just an increase -- it is an exponential increase. I myself have seen people claim that an author of an article citing an exponential increase in weather disasters is just hyperbolic, when (if the math of the distribution is to be believed) is literally true.
credit_guy 5y ago
Looks to me Sabine made a fairly elementary mistake towards the end. She mentions 3 probability distribution curves, 2 model produced (blue and red) and one empirical (green). She forgot to mention a fourth one, the empirical-preindustrial. In any case, you'd like to be able to measure the ratio of empirical distributions, but let's say that's difficult because of data retention. So, instead of having the actual ratio x/y you have a ratio of proxies, x'/y'. This ratio could be both higher and lower than x/y. She claimed it can only be lower, and that's not quite true.
- stkdump 5y ago
  I also thought that. But on second thought I agree with her analysis. The reason that y and y' are different is the same that x and x' are different. It is a problem of lacking resolution, so it will always underestimate more on the higher value, at least if you do enough simulations to get enough samples.
lisper 5y ago
It's not just the frequency of extreme events that is going up, but the intensity of the most extreme events. That is a function of the shape of the tail of the distribution. A very small change in the mean or median, or even just the standard deviation, can result in a huge increase in the expected value of the extremes. Combine this with human psychology and you have a recipe for catastrophe -- literally. You get an extreme event, and then everything reverts to the mean and things seem normal for a while, and people assume that the extreme event was a fluke. It wasn't. It's the new normal, and the next extreme event will be even worse. You see this playing out in California right now. Everyone thinks the drought is over because it rained last month. It's not over. It's just getting started.
d--b 5y ago
The point is that warning about extreme weather events is the only narrative that got people to consider global warming a problem at all. A 2 degree change in average temperature doesn’t change how people live. A heat wave does. Now I don’t know if it’s actually true or not but it feels like the frequency of extreme weather event has increased. It’s difficult to say because that’s something our grandparents already said 50 years ago. But then there are 2 possibilities: 1. Either the frequency of extreme events has actually increased and it would be hard not to pin it down on climate change (despite our inability to do it scientifically). 2. Or it hasn’t changed significantly (statistically speaking), and it’s all a bit of mass hysteria. Either way doesn’t actually matter. I personally don’t care if people are scared about the acidification of oceans or about rain for their next barbecue. As long as they vote for people who want to do something about it. I personally have been criticized by friends for saying that we don’t know what the impact of climate change is on the weather. I don’t care anymore. It’s all about narrative. That one works, let’s not poke holes in it. It only benefits people running polluting industries.
- LudwigNagasena 5y ago
  This attitude exemplifies the problem with the public discourse. The public discourse isn’t about finding out truth and forming actionable democratic consensus, it is about duping “stupid people” into supporting “good things”™.
  - nefitty 5y ago
    By the time Machiavelli wrote The Prince, the very act of writing the book was a tracer round to rampant political cynicism. Once an attitude or ideology is the target of satire, it has already bcome interwoven into a society. I presume that to be even moreso in eras where publishing had high cost. There's also this naive commitment to truth. Yes, we want our mental models to be more accurate and predictive. What if a model results in an increase of net suffering? What is the role of a democratic government, to provide services to a society to lessen individual offering, or to pursue truth and align legislation at all costs?
    - 5y ago
mbfg 5y ago
My understanding from the video is: the climate models stink, and everyone in the science understands this but has difficulty communicating this. The real world is more extreme than the models. But we have no way to extend the models to cover the seen extremes, nor do we know how to cap the possible extremities in any model. Do i have that right?
- matthewdgreen 5y ago
  We’ve terraformed the crap out of the world in ways that are guaranteed to have massive and significant effects, and climate scientists are racing to try to predict where the worst impacts will fall. This is an incredibly difficult thing to do because while in the aggregate the damage we’ve done is visible, weather is chaotic and the problem is near impossible. Instead of seeing modelers as our best, if highly imperfect, guides to weathering this storm we are (predictably) using the imperfection of their models as an excuse to do nothing about the problem, even though the overall effect of our actions is extremely obvious.
  - mythrwy 5y ago
    There are things we can reasonably do something about in a reasonable time period. There are things we cannot (as it sits right now) without killing large numbers of people and possibly ending civilization as we know it. What might happen isn't as important as what will happen. This isn't necessarily evading the problem but it's also inexcusable to not make the changes we can. Wasting non renewable fossil fuels and the amount of litter and pollution we are producing are horrible no matter the ultimate reality of climate change (which I maintain is poorly understood and over-hyped right now). There are real problems that are well understood we aren't doing anything about while wringing our hands about that which we practically can't at this juncture.
yongjik 5y ago
FWIW, I think it's quickly becoming an academic question. Last year had an extreme heat wave in Canada (worst in record) and a cold wave in Texas. Sure, last year might have been a freak year, but the thing with unmitigated climate change is that a "freak year" quickly becomes a "normal year" which then becomes a thing of the past. For example, see the graph in [1], and imagine we only have data up to 1999. The year 1998 sticks out like a sore thumb - it was a freak hot year. Except that it became the new normal temperature in the 2000s, and then the most recent six or seven years have handily beat it. It will be an unusually cool year if it happened now. We are transitioning into a world where "worst since weather records began" is a regular phrase at evening news. When a town burns down, will its residents even care if the particular fire was linked to climate change or not? [1] https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature https://www.climate.gov/news-features/understanding-climate/...
lngnmn2 5y ago
Obviously no, because the factors that would cause extreme weather events are not yet there. In general, any abstract model has the same relationships to actual reality as cartoons - they look sort of plausible and even convincing, even when a cat or a mouse speaks perfect English. There should be a clear warning statement, like with GMO labeling, that models are astrology with numbers instead of planets and stars. And no, no matter how sophisticated, a model will never be more than a cartoon, in the same way that a map would never be a territory.
ddddfdohvsyknn 5y ago
To borrow a phrase, one temperature reading is weather, a million is climate. While it seems difficult to attribute any given extreme or uncharacteristic weather event to climate change, the fact that average temperature is increasing means a larger average kinetic energy in the atmosphere, which in the aggregate should lead to more extremes. Of course there is more to it than that, since the Earth's albedo and atmospheric composition is also changing. Even more worrisome the ph of the ocean is changing, which could have profound consequences for oxygen producing phytoplankton, which again affects all of the above and us. Not a mathematician but I wonder can these discrete perturbed and repeated simulations approximate some well defined probability measure over the actual system?

135 points by nsoonhui 5y ago

mc32 5y ago

Basically she's saying the current models would be poor tools to use for deciding what to do about climate change and moreover the media is too simplistic and confident when they make extreme weather attribution. But that is nothing new --hence Gell-Mann amnesia effect. >"And that is what I think is the biggest problem. The way that extreme event attributions are presented in the media conveys a false sense of accuracy. The probabilities that they quote could be orders of magnitude too small. The current climate models just aren’t good enough to give accurate estimates."

icegreentea2 5y ago
I think Sabine's point is more limited than "current models would be poor tools to use for deciding what to do about climate change", and more like "current models would be poor tools for extreme weather attribution". Of course, if your threshold for action on climate change is strong extreme weather attribution, then ok. But I think it's reasonable to also have lower or different thresholds for planning nad action. I do feel queasy about the current phrasing of extreme weather attribution, especially as portrayed in the media.

simonh 5y ago

Another great video and article from Sabine. So it seems like yes they do, and they can give us useful indicative estimates like lower bounds for the increased likelihood of extreme events, but there are still huge unknowns. Honestly I’m amazed we can get the estimates we do, given that this particular field of analysis is so young. I’m not as pessimistic about the usefulness of this data though. Knowing that these events are becoming much more likely and having an understanding of why is useful work. There are always unknowns, and now there are fewer of them. That’s good. Take the estimate that bush fires in Australia are now at least twice as likely than they were. Sure it would be better to know if they are twice, three times or 10x as likely, but knowing they are at least twice as likely and why that is the case is still useful data.

PaulDavisThe1st 5y ago

I don't really understand the conflict that seems to exist between the title of the article ("Do Climate Models predict Extreme Weather? ") and the body of the article, which argues that event attribution can't be done with much accuracy. So ... "Do Climate Models predict Extreme Weather? ": yes, yes they do. But .... "how much impact does climate change have on extreme weather?": hard to say with much accuracy, but the factor isn't negative! How useful is it to note that the factor might 2 or 200 or 2 million?

mhh__ 5y ago
Sabine plays a mean game when it comes to marketing her work, i.e. slightly reductive titles and a vaguely countercultural spin in her prose.
matthewdgreen 5y ago
There is a difference between asking “is it a good idea to play in the casino with the loaded dice” and “can that one particular loss be attributed to the loaded dice.” I think the second question is interesting, but it’s not really that important compared to the first question. Naturally the second question is the one that’s getting all the attention from people who want to keep playing in this particular casino. I guess that’s better than just outright climate denial, but aim not sure how much better it is.

timmg 5y ago

One of the things about "extreme weather attribution" that makes me uncomfortable is the asymmetry of it. To be clear: I'm in no way an expert (or even educated) in the area. To give an example. Let's say there's a 1% chance every year that there will be a catastrophic wildfire in some particular area. Now let's say climate change increases a chance of drought in that area. Then we get a wildfire one year and the attribution is (say) "20% due to climate change" -- which I guess means there is now a 1.2% annual chance of a catastrophic fire. But what if climate change causes more rain in the area? And, for the sake of argument, that causes the change of catastrophic fire to go down to say 0.8%. Then, in a given year, there is no fire. No one is going to bother doing an attribution study to say, "Climate change is 20% responsible for the fact that we didn't have a fire this year."

divbzero 5y ago
Extreme weather can occur in both directions. A year with more rain may be less prone to fire but more prone to flooding. It also does not take natural disaster to notice extremes. People who have lived in the same area awhile will know if there is an unusually wet, dry, hot, or cold year.
- jjulius 5y ago
  >... more prone to flooding. Or mudslides.
- timmg 5y ago
  > Extreme weather can occur in both directions. Of course that's true. What I guess I was trying to say is that a change in climate doesn't necessarily mean more extreme weather (in every instance, I mean). A change in climate could cause something to happen more or happen less. But no one is going to study a given year and a given place that doesn't have an extreme weather event.
  - hedgehog 5y ago
    Discrete events are a human construct but the underlying data is continuous. I'm not sure the attribution of individual events is that meaningful and the article suggests for a variety of reasons the models aren't really built for that purpose anyway. So I think in a sense you are right, but this doesn't necessarily imply any problem for the predictive value of the models or research going into them.

tokamak 5y ago

tldr; No

fasteddie31003 5y ago

I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.

joe_the_user 5y ago
This is a pretty extreme claim to make without references. Have you looked at climate change computer models? Which ones what are your credentials in making this sort of "code review"? Etc.
- masteranza 5y ago
  It is not extreme at all. Sabina is using Luboš Motl wisdom as her own for some time now anyway.
- deleted 5y ago
  [deleted]
WoahNoun 5y ago
Examples? This is a pretty dubious claim.
- fasteddie31003 5y ago
  Just simple extrapolating logic. Climate is chaotic. Chaotic systems cannot be forecasted years out. Therefor a computer model for climate forecasting is not going to be accurate.
  - yed 5y ago
    Climate is not chaotic, weather is chaotic. Without any models at all we can predict that the Sahara desert will be hot and dry many many years out.
5y ago

pmjones 5y ago

Models say only what the modeler tells them to say.

nabla9 5y ago
That's not true. Climate models model and simulate physical and chemical condition on Earth. Modellers don't know what they say beforehand. Offhandedly portraying scientists and researchers as dishonest and conspirators in every opportunity possible seems the default here.
- refurb 5y ago
  Models are constantly tweaked to make them more accurate. How do you do that without looking at output and then going back to tweak it?
  - magicalhippo 5y ago
    One way is to verify them. Run multiple variations on data from the 1950's and see how they compare to measured values up to today. Throw away the models that don't fit the measured values. Then you have some confidence that the remaining variations may be representative when run into the future. This is also done in weather forecasting, though maybe they run the model in reverse, I can't recall. Same idea though, verify with existing data before predicting.
    - sanxiyn 5y ago
      Yes this happens, but it is very controversial. To quote from the article I linked above: > The question of whether the twentieth-century warming should be considered a target of model development or an emergent property is polarizing the climate modeling community, with 35% of modelers stating that twentieth-century warming was rated very important to decisive, whereas 30% would not consider it at all during development. Some view the temperature record as an independent evaluation dataset not to be used, while others view it as a valuable observational constraint on the model development. Likewise, opinions diverge as to which measures, either forcing or ECS, are legitimate means for improving the model match to observed warming. The question of developing toward the twentieth-century warming therefore is an area of vigorous debate within the community.

Proven 5y ago

whatever1 5y ago

We are taking a system that was in equilibrium and we introduce a huge disturbance (+ multiple degrees C). Hell yes it will be unstable until it reaches the new equilibrium (whatever that equilibrium will look like - catastrophic for life or not).

nlitened 5y ago
From what I know about climate on Earth, it has literally never been in equilibrium — see periodic ice ages with glaciers up to 3—4 km thick, or periods of warmer climates when plants grew in huge amounts at latitudes where we have now vast oil reserves in Siberia.
- whatever1 5y ago
  You are talking about changes over millions of years, not changes that happened within 100 years.

chiefalchemist 5y ago

I believe the climate it changing. I believe human activity has contributed to these changes. However, I do not believe _every_ "extreme event" belongs in that category. For example, the recent fires in the Denver / Boulder. Have you been there? It's effectively a desert. Dry, very dry. Open. There are few natural barriers once a fire starts. Based on what I know of the area, those homes - God bless those families - were built in harm's way. That disaster - regardless of climate change - was inevitable. To suggest otherwise is simply irresponsible.

dragonwriter 5y ago
> For example, the recent fires in the Denver / Boulder. Have you been there? It's effectively a desert. Dry, very dry. Not normally, so much, but yes, when the entire state ranges between “abnormally dry” and “extreme drought” [0], it probably seems desert-like. But...how are those unusual and extreme conditions an argument against the events being a product of anthropogenic climate change? [0] https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?CO https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonito...
- chiefalchemist 5y ago
  Against? The point is, the state of that state in that area is naturally a fire hazard. Toss in some wind - which is as old as the earth itself - and POOF! disaster happens. Humans love to build homes and structures where they probably should not. We have this false ideal that we're bigger, stronger, and faster than Mother Nature. And then when it goes sideways we blame MN. That's not working out well.

fubarr 5y ago

Climate is a ~30yr moving average of weather. Climate models cannot attempt to model weather events. Such events can rarely be predicted more than a week or two out. The above should tell you that using a climate model to predict anything about weather events is a pointless exercise. Particularly trying to derive the statistics of weather events. The stats are built in to the models!

viraptor 5y ago
This can be easily shown to be false. I can't tell you if it's going to rain next week in most cases, but I can easily tell you about how many days in a year it's going to rain over a large area. Same applies to how many floods we're going to have and bushfires. We've been doing that for a very long time now.
- fubarr 5y ago
  Telling me about averages deduced from past behavior? Great, you've read the statistic that's built into a model. Telling me what way that statistic will behave in future? Especially at extremes? Not a chance.
  - viraptor 5y ago
    We're commenting on an article pretty much saying we have models which estimate in the right directing, but don't go far enough. Now we can learn from the changes and improve the models. If you're discounting a whole field of research, can you provide more reasoning for why it can't be improved from the current results?

dnautics 5y ago

It bothers me that the A/B in these models is between "pre-industrial" and now, seems like a better comparison over the timescales people are expecting to match up with their "perceived experiences of increased climate disasters" should be "20 years ago vs now" e.g.

tasty_freeze 5y ago

Statistics are tricky to think about, even for people with technical educations. Something that was a lightbulb moment when someone was discussing professional baseball players. I forget the exact point the blog was making, but it came down to this: many things in life, like the ability to throw or hit a baseball, falls on a distribution that is close enough to a gaussian distribution. But when talking about professional baseball players, they represent just the very right hand tip of that distribution. Whatever intuitions you might have about gaussian distributions needs to be thought about in light of that. The same applies with extreme weather events. It is easy to look at articles and headlines describing an exponential increase in the frequency of extreme weather events. But think for a second about the equation of a gaussian distribution. When you shift the offset by a small, fixed amount, the area under that right hand tip goes up exponentially. No, one cannot point to climate change as the cause of any individual weather event. But it is a measured certainty that the warming is happening; the number of record high temperatures are a multiple higher than the number of record low temperatures every year for the past couple of decades. It would be weird if the temperature rose and the number of extreme events went up, say, linearly.

onos 5y ago
If this logic applies here then the increase in “extreme events” almost seems like a non statement. The distribution has shifted (as everyone agrees, though some debate cause) and consequently we will get more extreme events.
- tasty_freeze 5y ago
  The point is it isn't just an increase -- it is an exponential increase. I myself have seen people claim that an author of an article citing an exponential increase in weather disasters is just hyperbolic, when (if the math of the distribution is to be believed) is literally true.

credit_guy 5y ago

Looks to me Sabine made a fairly elementary mistake towards the end. She mentions 3 probability distribution curves, 2 model produced (blue and red) and one empirical (green). She forgot to mention a fourth one, the empirical-preindustrial. In any case, you'd like to be able to measure the ratio of empirical distributions, but let's say that's difficult because of data retention. So, instead of having the actual ratio x/y you have a ratio of proxies, x'/y'. This ratio could be both higher and lower than x/y. She claimed it can only be lower, and that's not quite true.

stkdump 5y ago
I also thought that. But on second thought I agree with her analysis. The reason that y and y' are different is the same that x and x' are different. It is a problem of lacking resolution, so it will always underestimate more on the higher value, at least if you do enough simulations to get enough samples.

lisper 5y ago

It's not just the frequency of extreme events that is going up, but the intensity of the most extreme events. That is a function of the shape of the tail of the distribution. A very small change in the mean or median, or even just the standard deviation, can result in a huge increase in the expected value of the extremes. Combine this with human psychology and you have a recipe for catastrophe -- literally. You get an extreme event, and then everything reverts to the mean and things seem normal for a while, and people assume that the extreme event was a fluke. It wasn't. It's the new normal, and the next extreme event will be even worse. You see this playing out in California right now. Everyone thinks the drought is over because it rained last month. It's not over. It's just getting started.

d--b 5y ago

The point is that warning about extreme weather events is the only narrative that got people to consider global warming a problem at all. A 2 degree change in average temperature doesn’t change how people live. A heat wave does. Now I don’t know if it’s actually true or not but it feels like the frequency of extreme weather event has increased. It’s difficult to say because that’s something our grandparents already said 50 years ago. But then there are 2 possibilities: 1. Either the frequency of extreme events has actually increased and it would be hard not to pin it down on climate change (despite our inability to do it scientifically). 2. Or it hasn’t changed significantly (statistically speaking), and it’s all a bit of mass hysteria. Either way doesn’t actually matter. I personally don’t care if people are scared about the acidification of oceans or about rain for their next barbecue. As long as they vote for people who want to do something about it. I personally have been criticized by friends for saying that we don’t know what the impact of climate change is on the weather. I don’t care anymore. It’s all about narrative. That one works, let’s not poke holes in it. It only benefits people running polluting industries.

LudwigNagasena 5y ago
This attitude exemplifies the problem with the public discourse. The public discourse isn’t about finding out truth and forming actionable democratic consensus, it is about duping “stupid people” into supporting “good things”™.
- nefitty 5y ago
  By the time Machiavelli wrote The Prince, the very act of writing the book was a tracer round to rampant political cynicism. Once an attitude or ideology is the target of satire, it has already bcome interwoven into a society. I presume that to be even moreso in eras where publishing had high cost. There's also this naive commitment to truth. Yes, we want our mental models to be more accurate and predictive. What if a model results in an increase of net suffering? What is the role of a democratic government, to provide services to a society to lessen individual offering, or to pursue truth and align legislation at all costs?
  - 5y ago

mbfg 5y ago

My understanding from the video is: the climate models stink, and everyone in the science understands this but has difficulty communicating this. The real world is more extreme than the models. But we have no way to extend the models to cover the seen extremes, nor do we know how to cap the possible extremities in any model. Do i have that right?

matthewdgreen 5y ago
We’ve terraformed the crap out of the world in ways that are guaranteed to have massive and significant effects, and climate scientists are racing to try to predict where the worst impacts will fall. This is an incredibly difficult thing to do because while in the aggregate the damage we’ve done is visible, weather is chaotic and the problem is near impossible. Instead of seeing modelers as our best, if highly imperfect, guides to weathering this storm we are (predictably) using the imperfection of their models as an excuse to do nothing about the problem, even though the overall effect of our actions is extremely obvious.
- mythrwy 5y ago
  There are things we can reasonably do something about in a reasonable time period. There are things we cannot (as it sits right now) without killing large numbers of people and possibly ending civilization as we know it. What might happen isn't as important as what will happen. This isn't necessarily evading the problem but it's also inexcusable to not make the changes we can. Wasting non renewable fossil fuels and the amount of litter and pollution we are producing are horrible no matter the ultimate reality of climate change (which I maintain is poorly understood and over-hyped right now). There are real problems that are well understood we aren't doing anything about while wringing our hands about that which we practically can't at this juncture.

yongjik 5y ago

FWIW, I think it's quickly becoming an academic question. Last year had an extreme heat wave in Canada (worst in record) and a cold wave in Texas. Sure, last year might have been a freak year, but the thing with unmitigated climate change is that a "freak year" quickly becomes a "normal year" which then becomes a thing of the past. For example, see the graph in [1], and imagine we only have data up to 1999. The year 1998 sticks out like a sore thumb - it was a freak hot year. Except that it became the new normal temperature in the 2000s, and then the most recent six or seven years have handily beat it. It will be an unusually cool year if it happened now. We are transitioning into a world where "worst since weather records began" is a regular phrase at evening news. When a town burns down, will its residents even care if the particular fire was linked to climate change or not? [1] https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature https://www.climate.gov/news-features/understanding-climate/...

lngnmn2 5y ago

Obviously no, because the factors that would cause extreme weather events are not yet there. In general, any abstract model has the same relationships to actual reality as cartoons - they look sort of plausible and even convincing, even when a cat or a mouse speaks perfect English. There should be a clear warning statement, like with GMO labeling, that models are astrology with numbers instead of planets and stars. And no, no matter how sophisticated, a model will never be more than a cartoon, in the same way that a map would never be a territory.

ddddfdohvsyknn 5y ago

To borrow a phrase, one temperature reading is weather, a million is climate. While it seems difficult to attribute any given extreme or uncharacteristic weather event to climate change, the fact that average temperature is increasing means a larger average kinetic energy in the atmosphere, which in the aggregate should lead to more extremes. Of course there is more to it than that, since the Earth's albedo and atmospheric composition is also changing. Even more worrisome the ph of the ocean is changing, which could have profound consequences for oxygen producing phytoplankton, which again affects all of the above and us. Not a mathematician but I wonder can these discrete perturbed and repeated simulations approximate some well defined probability measure over the actual system?