4 ms·

Good call out. Not just a disservice and unscientific, it’s just plain wrong. An observed variance in weather over one day or even a few days isn’t even climate

by dvtrn 6y ago

Good call out. Not just a disservice and unscientific, it’s just plain wrong. An observed variance in weather over one day or even a few days isn’t even climate. It’s just weather activity.

titzer 6y ago
Sorry, but increased variance is very much in line with systemic climate change. In fact, it's one of the main predictions as climate change means disruption of the normal distribution, not just pushing the median but increasing the standard deviation.
- dvtrn 6y ago
  Please re-read what I posted more closely. > An observed variance in weather *over one day or even a few days* https://www.ncei.noaa.gov/news/weather-vs-climate https://www.ncei.noaa.gov/news/weather-vs-climate If you observe a few days of severe weather, you've observed severe weather. Taking a mere observation over one week of weather activity cannot be looked at in isolation and simply called "climate change, tada!" FTA: >When scientists talk about climate, they're often looking at averages of precipitation, temperature, humidity, sunshine, wind, and other measures of weather that occur over a long period in a particular place. In some instances, they might look at these averages over 30 years. And, we refer to these three-decade averages of weather observations as Climate Normals.
- tomp 6y ago
  > increased variance is very much in line with systemic climate change Not really, it's also in line with the limited amount of high-quality data we have. E.g. viewed in isolation, recent Gulf of Mexico hurricanes were pretty bad (2019 in particular, IIRC). But if you look into history, 1932,1933 was also pretty bad. Arguably, if we had even more recorded history, such outliers wouldn't seem that exceptional - there still is a possiblity that climate change is affecting hurricanes (making them worse) but you can't just look at the variance (outliers) - trend is also (more?) important. https://en.wikipedia.org/wiki/Atlantic_hurricane_season https://en.wikipedia.org/wiki/Atlantic_hurricane_season
  - titzer 6y ago
    Let's use math and statistics, not anecdotes. If an increase in variance means that you get a +5 outlier 10x more often, then looking at a 10x longer timescale will mean that you see the +5 outlier roughly as often, making it seem "less exceptional". The problem is that the exceptional thing is now happening 10x more often. For example, Texas getting three "500 year" floods in 3 years. These were floods that were estimated to be a 0.2% probability in any given year. The fact that they are happening at much higher frequency is because the entire probability distribution has shifted (and expanded). Now if you improved your ability to peer into the past and found another "500 year flood" a few hundred years back, you'd be tempted to think everything is fine, when everything is decidedly not fine.
    - koheripbal 6y ago
      You cannot take prove a global phenomenon with local data, unless you compare global occurrences of local events. Taking only Texas as an "example" means you're cherry picking data. I'm sure we could find other parts of the world that had multiple rare events in every decade of the last century as well.
      - titzer 6y ago
        It was just an example. If you look at all the data together, the trend is clear. Both median temperatures and variance are increasing. Same for other extreme weather events like hurricanes, wildfires, and droughts.
        koheripbal 6y ago
        Is there a data source that says that temperature variances have increased? I have never seen meaningful evidence of this. > Same for other extreme weather events like hurricanes, wildfires, and droughts. Extreme weather events are extremely hard to define, and have such a low occurrence rate that you cannot extrapolate an increase in the timeframe we're discussing on a global level.
  - 6y ago

by dvtrn 6y ago

Good call out. Not just a disservice and unscientific, it’s just plain wrong. An observed variance in weather over one day or even a few days isn’t even climate. It’s just weather activity.

titzer 6y ago

Sorry, but increased variance is very much in line with systemic climate change. In fact, it's one of the main predictions as climate change means disruption of the normal distribution, not just pushing the median but increasing the standard deviation.

dvtrn 6y ago
Please re-read what I posted more closely. > An observed variance in weather *over one day or even a few days* https://www.ncei.noaa.gov/news/weather-vs-climate https://www.ncei.noaa.gov/news/weather-vs-climate If you observe a few days of severe weather, you've observed severe weather. Taking a mere observation over one week of weather activity cannot be looked at in isolation and simply called "climate change, tada!" FTA: >When scientists talk about climate, they're often looking at averages of precipitation, temperature, humidity, sunshine, wind, and other measures of weather that occur over a long period in a particular place. In some instances, they might look at these averages over 30 years. And, we refer to these three-decade averages of weather observations as Climate Normals.
tomp 6y ago
> increased variance is very much in line with systemic climate change Not really, it's also in line with the limited amount of high-quality data we have. E.g. viewed in isolation, recent Gulf of Mexico hurricanes were pretty bad (2019 in particular, IIRC). But if you look into history, 1932,1933 was also pretty bad. Arguably, if we had even more recorded history, such outliers wouldn't seem that exceptional - there still is a possiblity that climate change is affecting hurricanes (making them worse) but you can't just look at the variance (outliers) - trend is also (more?) important. https://en.wikipedia.org/wiki/Atlantic_hurricane_season https://en.wikipedia.org/wiki/Atlantic_hurricane_season
- titzer 6y ago
  Let's use math and statistics, not anecdotes. If an increase in variance means that you get a +5 outlier 10x more often, then looking at a 10x longer timescale will mean that you see the +5 outlier roughly as often, making it seem "less exceptional". The problem is that the exceptional thing is now happening 10x more often. For example, Texas getting three "500 year" floods in 3 years. These were floods that were estimated to be a 0.2% probability in any given year. The fact that they are happening at much higher frequency is because the entire probability distribution has shifted (and expanded). Now if you improved your ability to peer into the past and found another "500 year flood" a few hundred years back, you'd be tempted to think everything is fine, when everything is decidedly not fine.
  - koheripbal 6y ago
    You cannot take prove a global phenomenon with local data, unless you compare global occurrences of local events. Taking only Texas as an "example" means you're cherry picking data. I'm sure we could find other parts of the world that had multiple rare events in every decade of the last century as well.
    - titzer 6y ago
      It was just an example. If you look at all the data together, the trend is clear. Both median temperatures and variance are increasing. Same for other extreme weather events like hurricanes, wildfires, and droughts.
      - koheripbal 6y ago
        Is there a data source that says that temperature variances have increased? I have never seen meaningful evidence of this. > Same for other extreme weather events like hurricanes, wildfires, and droughts. Extreme weather events are extremely hard to define, and have such a low occurrence rate that you cannot extrapolate an increase in the timeframe we're discussing on a global level.
- 6y ago