15 ms·

Climate change and the 1991-2020 U.S. Climate Normals

133 points by ctk_brian 5y ago

robomartin 5y ago
There's a lot that bothers me about this chart. If you want numbers that sound large, use a scale that's numerically larger for the same dimension. The interval shown goes from -1 degree F to +1 degree F. 1.8 degrees F = 1 degree C. In other words, the same scale in C would go from -0.56 C to +0.56 C. In other words, the entire range is about 1 C. The other issue is that the color representation of the maps grotesquely exaggerate the magnitude. The visual impact from deep blue to dark brown is far greater than the 1 C range it represents. Such color range would be more accurately used to represent the delta in temperature between, say, deep winter at the cold end and a very hot summer at the hot end. I other words, it visually represents a difference that could easily be 50 C, rather than 1 C. An honest scale would represent the range of temperatures (minima and maxima) across the US from winter to summer in a scale from, say, -30 F to +120 F and present maps colored using this scale. The problem with doing this is that this +/- 1 F delta across 120 years would be just-about imperceptible. In addition to this, the image has no information whatsoever on what the color coding truly represents. One legend reads "Difference from average" while another says "30 year normal compared to 1901-2000". If you look at the website, they have graphs that compare the "global temperature anomaly compared to 1901-2000". In other words, they average some temperatures (undisclosed) over that period of time, this becomes "zero" and everything is compared to this artificial zero. The temperature over this period averages out to some number and everything before a certain year looks colder than this average while everything past a certain point looks hotter. Huh? What am I actually looking at? Where is the map/data with absolute measurements, not this weird averaging over a period that stops twenty years ago. Why does the reference average stop in 2000, twenty one years ago and does not include the last twenty years? Do these measurements correspond to exactly the same date and location each year? Average of what? When? How? What was the tolerance, error, reliability of the measurements? They are comparing measurements made 120 years ago on a scale with a full range of 1 C. Let's put these numbers into context: Hot day in Las Vegas: 48 degrees C. Let's say we have a measurement error of +/-1%. What would that range be? Well, that's + or - 0.48 degrees C from true temperature. And this graph is showing a range of +/- 0.56 degrees C over a period of 120 years? An measurement error of 1% across such a vast number of measurement sites, with different instruments, people and systems recording them isn't only plausible, it is very likely. In fact the error could be significantly greater than that. Read a thermometer, not a digital one, a mercury thermometer of the kind they used to use for much of the last century. Can you read that thermometer to an accuracy/reliability of 1%? Likely not. The thing would have to be massively large for you to be able to visually interpolate that scale to such accuracy. Where are you reading it? Top of the meniscus? Bottom? Middle? How did the guy in New York read it? The one in Dallas? How was it read in years 1, 5, 10, 20, 30, etc.? Same instrument for over a century? Likely not. How were they calibrated, if at all? Who calibrated them? How often? To what standard? Etc. I don't have a problem for making a case for environmental awareness and more responsible behavior. However, proponents need to understand that extreme honesty and accuracy in every statement being made is of paramount importance. Graphically distorted and numerically exaggerated graphs such as this one only serve to feed deniers and those who aim to increase their numbers. In other words, the reaction could be "I got you! You are lying to me!". Not a very useful outcome. Either we are doing science or marketing. I propose only one of those will result in changing hearts and minds. Don't lie. Don't manipulate. Be accurate, precise, accountable, transparent and backup your data.
- allturtles 5y ago
  > 1.8 degrees F = 1 degree C. In other words, the same scale in C would go from -0.56 C to +0.56 C. In other words, the entire range is about 1 C. F is the standard measurement that most people in the U.S. understand intuitively. > An honest scale would represent the range of temperatures (minima and maxima) across the US from winter to summer in a scale from, say, -30 F to +120 F and present maps colored using this scale. The problem with doing this is that this +/- 1 F delta across 120 years would be just-about imperceptible. Why would you want to do that with this data set? The point of the data is to show deltas in temperature over a long period of time. It's not a weather map to help people figure out whether they should wear a t-shirt today or not. > Where is the map/data with absolute measurements, not this weird averaging over a period that stops twenty years ago. Why does the reference average stop in 2000, twenty one years ago and does not include the last twenty years? Again, if you want to show deltas, you have to chose some fixed point and normalize against it. This is common in all sorts of data visualizations, e.g. charts of inflation that choose some arbitrary point in the past as '100'. > And this graph is showing a range of +/- 0.56 degrees C over a period of 120 years? An measurement error of 1% across such a vast number of measurement sites, with different instruments, people and systems recording them isn't only plausible, it is very likely. In fact the error could be significantly greater than that. With a large # of measurements over a large period of time, you would expect cancelling errors, not a secular trend in one direction over time. It also doesn't require fractional precision in individual measurements to create fractional differences in averages. e.g. if I have one set of people that are 50, 51, 52, and 53 inches tall, and another who are 51, 51, 52, and 53 inches tall, I can say that the second set is on average 0.25 inches taller than the first. > Do these measurements correspond to exactly the same date and location each year? Average of what? When? How? What was the tolerance, error, reliability of the measurements? They are comparing measurements made 120 years ago on a scale with a full range of 1 C. You're basically asking for a full explication of decades of work to build a global temperature record data set. It's not feasible to recapitulate that in every discussion of global temperature changes. To get an idea of how the temperature record was constructed, you could start with Paul Edwards, A Vast Machine. (edit: here's a fairly succinct summary of how the raw data is adjusted - https://www.carbonbrief.org/explainer-how-data-adjustments-affect-global-temperature-records https://www.carbonbrief.org/explainer-how-data-adjustments-a...)
Hammershaft 5y ago
Interesting... judging from this pic the 1960s seemed to be unusually cool. I wonder why. https://www.climate.gov/sites/default/files/30yrNormal_Temp_1901-2000_620.png https://www.climate.gov/sites/default/files/30yrNormal_Temp_...
- Diederich 5y ago
  Only slightly educated guess forthcoming. Air pollution was pretty bad in the United States from the 1950s through the late 1980s, and we know that https://en.wikipedia.org/wiki/Global_dimming https://en.wikipedia.org/wiki/Global_dimming has kept temperatures down a bit. So basically from the early 1970s through the 1990s in the United States, the amount of 'global dimming' type air pollution decreased tremendously, because of a number of factors, including all sorts of clean air mandates and regulation.
  - kossTKR 5y ago
    The dimming factor seems a bit frightening. I don't know how sound the theory is, but i remember listening to the climate podcast Radio Ecoshock where a scientist talked about aerosols in general and that there could be a negative feedback loop that would disappear if we stop polluting heavily, ironically then raising temperatures significantly - this could mean that an extremely agressive decrease towards 2030 could increase temperature weirdly enough. The effect was seen over the US after 9/11 as far as i remember. A damned if you do and don't situation.
    - pedrocr 5y ago
      > The effect was seen over the US after 9/11 as far as i remember. There was a study that claimed that but there's a second study that claims general cloud cover was a confounding factor not controlled for that explains the actual result: https://en.wikipedia.org/wiki/Global_dimming#Contrails_and_clouds https://en.wikipedia.org/wiki/Global_dimming#Contrails_and_c... Even with a full set of airplanes in the air contrails are a tiny minority of the cloud cover. Seems pretty hard for them to have any visible impact. Aerosols in general are another matter all together. Those are all over the atmosphere and it wouldn't be surprising if they had a large effect as they accumulate.
deleted 5y ago
[deleted]
potatoman22 5y ago
Is 0.16 F increase in average temperature per decade a legitimate cause for concern? From my (unlearned) perspective, It seems barely statistically significant.
- Afforess 5y ago
  > average temperature It's not the average temperature change that is significant, its the effect of the temperature that is significant. For example, 33F vs 32F is very significant... If there are more days above freezing, which leads to extra ice melt, it doesn't matter if the average is up only a tiny bit.
  - potatoman22 5y ago
    That makes a lot of sense, thanks.
- melling 5y ago
  When there were only 22 American Coronavirus deaths on March 9, 2020, was there a cause for concern? Many people said no.
  - Pyramus 5y ago
    Your comment may sound unrelated - but it's exactly at the heart of the problem. Both climate change and viral growth increase exponentially. Not only do we release more CO2 into the atmosphere every year, but also the growth rate accelerates.
    - potatoman22 5y ago
      Why does climate change increase exponentially? For reasons other than our collective output increasing exponentially?
      - deleted 5y ago
        [deleted]
learn_more 5y ago
I wonder how much warming and change in precipitation is related to greening of the country from additional CO2 in the atmosphere and resulting changes in the albedo.
tryonenow 5y ago
In my day to day work, if you showed me a noisy graph of a periodic signal measured over some 1/10th to 1/10000th of a typical cycle period, I would tell you that you don't have nearly enough data to establish a trend. Especially when the underlying phenomena are chaotic, complex, impossible to model accurately, and incompletely understood. I also believe that the orthodoxy is overly negative. Who's to say that earth won't be better off with the newly arable northern latitudes? The OP seems to indicate a trend toward increasing rainfall as well - and plants thrive in increased CO2 environments. Then there is the supposed looming socioeconomic catastrophy as sea levels rise and displace coastal inhabitants. That also sounds like positive economic churn to me, especially if you go by the metric of GDP. This will be a gradual migration over 50-100 years and potentially a boon for various economies - jobs for infrastructure and construction. I'm just not sold on the idea that the world is ending (literally or figuratively) if we don't act.
- nerdponx 5y ago
  This will be a gradual migration over 50-100 years This is wishful thinking. potentially a boon for various economies - jobs for infrastructure and construction. This is the broken window fallacy.
  - betwixthewires 5y ago
    Is it wishful thinking though? How exactly? Also how is the idea that this may be good for some economies a broken window fallacy?
    - allturtles 5y ago
      You seem to be imagining that the sea level will smoothly rise mm by mm over a century and that people will gradually and peacefully abandon the shoreline and move inland. It seems to me that a more likely outcome is that people will build defenses to protect existing cities (which are after all massive investments) and and that those defenses will work well right up until they catastrophically fail in a major storm (e.g. see Katrina).
deleted 5y ago
[deleted]
betwixthewires 5y ago
So one thing to keep in mind, showing 20 year averages every 10 years and comparing them to century long averages for the same time period is a really good idea, it shows that there is a trend and it can show shorter temporal anomalies. One thing I found very interesting is the information on precipitation. I've heard it said "a warmer world is a wetter world" and that would appear to be supported by this data.
- chrisco255 5y ago
  We don't have a century of homogenous temperature data. We didn't have weather satellites until the late 70s, early 80s. And temps were only recorded in some cities and some towns, with uneven coverage, with inconsistent global quality practices. Sea temps were also inconsistently recorded.
  - shoto_io 5y ago
    This should be the top comment. The images suggest a level of detail and accuracy that can’t be correct.
  - newacct583 5y ago
    So... we have a half century of homogenous high quality temperature then. Does the good data we do have not support the same conclusion? Seems like it does to me.
crispyporkbites 5y ago
This is a bit misleading as the data is US only but the climate and weather doesn’t care about our made up borders. So to get a real picture of climate change you need to look at global weather patterns and temperature changes.
- exporectomy 5y ago
  So? Isn't its purpose it to show American farmers what the climate is like to help them plan their planting?
NotChina 5y ago
The universal constant of climate is what?
thanatos519 5y ago
I'm happy to see unmuzzled reporting from US government funded scientists again. Welcome back!

133 points by ctk_brian 5y ago

There's a lot that bothers me about this chart. If you want numbers that sound large, use a scale that's numerically larger for the same dimension. The interval shown goes from -1 degree F to +1 degree F. 1.8 degrees F = 1 degree C. In other words, the same scale in C would go from -0.56 C to +0.56 C. In other words, the entire range is about 1 C. The other issue is that the color representation of the maps grotesquely exaggerate the magnitude. The visual impact from deep blue to dark brown is far greater than the 1 C range it represents. Such color range would be more accurately used to represent the delta in temperature between, say, deep winter at the cold end and a very hot summer at the hot end. I other words, it visually represents a difference that could easily be 50 C, rather than 1 C. An honest scale would represent the range of temperatures (minima and maxima) across the US from winter to summer in a scale from, say, -30 F to +120 F and present maps colored using this scale. The problem with doing this is that this +/- 1 F delta across 120 years would be just-about imperceptible. In addition to this, the image has no information whatsoever on what the color coding truly represents. One legend reads "Difference from average" while another says "30 year normal compared to 1901-2000". If you look at the website, they have graphs that compare the "global temperature anomaly compared to 1901-2000". In other words, they average some temperatures (undisclosed) over that period of time, this becomes "zero" and everything is compared to this artificial zero. The temperature over this period averages out to some number and everything before a certain year looks colder than this average while everything past a certain point looks hotter. Huh? What am I actually looking at? Where is the map/data with absolute measurements, not this weird averaging over a period that stops twenty years ago. Why does the reference average stop in 2000, twenty one years ago and does not include the last twenty years? Do these measurements correspond to exactly the same date and location each year? Average of what? When? How? What was the tolerance, error, reliability of the measurements? They are comparing measurements made 120 years ago on a scale with a full range of 1 C. Let's put these numbers into context: Hot day in Las Vegas: 48 degrees C. Let's say we have a measurement error of +/-1%. What would that range be? Well, that's + or - 0.48 degrees C from true temperature. And this graph is showing a range of +/- 0.56 degrees C over a period of 120 years? An measurement error of 1% across such a vast number of measurement sites, with different instruments, people and systems recording them isn't only plausible, it is very likely. In fact the error could be significantly greater than that. Read a thermometer, not a digital one, a mercury thermometer of the kind they used to use for much of the last century. Can you read that thermometer to an accuracy/reliability of 1%? Likely not. The thing would have to be massively large for you to be able to visually interpolate that scale to such accuracy. Where are you reading it? Top of the meniscus? Bottom? Middle? How did the guy in New York read it? The one in Dallas? How was it read in years 1, 5, 10, 20, 30, etc.? Same instrument for over a century? Likely not. How were they calibrated, if at all? Who calibrated them? How often? To what standard? Etc. I don't have a problem for making a case for environmental awareness and more responsible behavior. However, proponents need to understand that extreme honesty and accuracy in every statement being made is of paramount importance. Graphically distorted and numerically exaggerated graphs such as this one only serve to feed deniers and those who aim to increase their numbers. In other words, the reaction could be "I got you! You are lying to me!". Not a very useful outcome. Either we are doing science or marketing. I propose only one of those will result in changing hearts and minds. Don't lie. Don't manipulate. Be accurate, precise, accountable, transparent and backup your data.

allturtles 5y ago
> 1.8 degrees F = 1 degree C. In other words, the same scale in C would go from -0.56 C to +0.56 C. In other words, the entire range is about 1 C. F is the standard measurement that most people in the U.S. understand intuitively. > An honest scale would represent the range of temperatures (minima and maxima) across the US from winter to summer in a scale from, say, -30 F to +120 F and present maps colored using this scale. The problem with doing this is that this +/- 1 F delta across 120 years would be just-about imperceptible. Why would you want to do that with this data set? The point of the data is to show deltas in temperature over a long period of time. It's not a weather map to help people figure out whether they should wear a t-shirt today or not. > Where is the map/data with absolute measurements, not this weird averaging over a period that stops twenty years ago. Why does the reference average stop in 2000, twenty one years ago and does not include the last twenty years? Again, if you want to show deltas, you have to chose some fixed point and normalize against it. This is common in all sorts of data visualizations, e.g. charts of inflation that choose some arbitrary point in the past as '100'. > And this graph is showing a range of +/- 0.56 degrees C over a period of 120 years? An measurement error of 1% across such a vast number of measurement sites, with different instruments, people and systems recording them isn't only plausible, it is very likely. In fact the error could be significantly greater than that. With a large # of measurements over a large period of time, you would expect cancelling errors, not a secular trend in one direction over time. It also doesn't require fractional precision in individual measurements to create fractional differences in averages. e.g. if I have one set of people that are 50, 51, 52, and 53 inches tall, and another who are 51, 51, 52, and 53 inches tall, I can say that the second set is on average 0.25 inches taller than the first. > Do these measurements correspond to exactly the same date and location each year? Average of what? When? How? What was the tolerance, error, reliability of the measurements? They are comparing measurements made 120 years ago on a scale with a full range of 1 C. You're basically asking for a full explication of decades of work to build a global temperature record data set. It's not feasible to recapitulate that in every discussion of global temperature changes. To get an idea of how the temperature record was constructed, you could start with Paul Edwards, A Vast Machine. (edit: here's a fairly succinct summary of how the raw data is adjusted - https://www.carbonbrief.org/explainer-how-data-adjustments-affect-global-temperature-records https://www.carbonbrief.org/explainer-how-data-adjustments-a...)

Hammershaft 5y ago

Interesting... judging from this pic the 1960s seemed to be unusually cool. I wonder why. https://www.climate.gov/sites/default/files/30yrNormal_Temp_1901-2000_620.png https://www.climate.gov/sites/default/files/30yrNormal_Temp_...

Diederich 5y ago
Only slightly educated guess forthcoming. Air pollution was pretty bad in the United States from the 1950s through the late 1980s, and we know that https://en.wikipedia.org/wiki/Global_dimming https://en.wikipedia.org/wiki/Global_dimming has kept temperatures down a bit. So basically from the early 1970s through the 1990s in the United States, the amount of 'global dimming' type air pollution decreased tremendously, because of a number of factors, including all sorts of clean air mandates and regulation.
- kossTKR 5y ago
  The dimming factor seems a bit frightening. I don't know how sound the theory is, but i remember listening to the climate podcast Radio Ecoshock where a scientist talked about aerosols in general and that there could be a negative feedback loop that would disappear if we stop polluting heavily, ironically then raising temperatures significantly - this could mean that an extremely agressive decrease towards 2030 could increase temperature weirdly enough. The effect was seen over the US after 9/11 as far as i remember. A damned if you do and don't situation.
  - pedrocr 5y ago
    > The effect was seen over the US after 9/11 as far as i remember. There was a study that claimed that but there's a second study that claims general cloud cover was a confounding factor not controlled for that explains the actual result: https://en.wikipedia.org/wiki/Global_dimming#Contrails_and_clouds https://en.wikipedia.org/wiki/Global_dimming#Contrails_and_c... Even with a full set of airplanes in the air contrails are a tiny minority of the cloud cover. Seems pretty hard for them to have any visible impact. Aerosols in general are another matter all together. Those are all over the atmosphere and it wouldn't be surprising if they had a large effect as they accumulate.

deleted 5y ago

[deleted]

potatoman22 5y ago

Is 0.16 F increase in average temperature per decade a legitimate cause for concern? From my (unlearned) perspective, It seems barely statistically significant.

Afforess 5y ago
> average temperature It's not the average temperature change that is significant, its the effect of the temperature that is significant. For example, 33F vs 32F is very significant... If there are more days above freezing, which leads to extra ice melt, it doesn't matter if the average is up only a tiny bit.
- potatoman22 5y ago
  That makes a lot of sense, thanks.
melling 5y ago
When there were only 22 American Coronavirus deaths on March 9, 2020, was there a cause for concern? Many people said no.
- Pyramus 5y ago
  Your comment may sound unrelated - but it's exactly at the heart of the problem. Both climate change and viral growth increase exponentially. Not only do we release more CO2 into the atmosphere every year, but also the growth rate accelerates.
  - potatoman22 5y ago
    Why does climate change increase exponentially? For reasons other than our collective output increasing exponentially?
    - deleted 5y ago
      [deleted]

learn_more 5y ago

I wonder how much warming and change in precipitation is related to greening of the country from additional CO2 in the atmosphere and resulting changes in the albedo.

tryonenow 5y ago

In my day to day work, if you showed me a noisy graph of a periodic signal measured over some 1/10th to 1/10000th of a typical cycle period, I would tell you that you don't have nearly enough data to establish a trend. Especially when the underlying phenomena are chaotic, complex, impossible to model accurately, and incompletely understood. I also believe that the orthodoxy is overly negative. Who's to say that earth won't be better off with the newly arable northern latitudes? The OP seems to indicate a trend toward increasing rainfall as well - and plants thrive in increased CO2 environments. Then there is the supposed looming socioeconomic catastrophy as sea levels rise and displace coastal inhabitants. That also sounds like positive economic churn to me, especially if you go by the metric of GDP. This will be a gradual migration over 50-100 years and potentially a boon for various economies - jobs for infrastructure and construction. I'm just not sold on the idea that the world is ending (literally or figuratively) if we don't act.

nerdponx 5y ago
This will be a gradual migration over 50-100 years This is wishful thinking. potentially a boon for various economies - jobs for infrastructure and construction. This is the broken window fallacy.
- betwixthewires 5y ago
  Is it wishful thinking though? How exactly? Also how is the idea that this may be good for some economies a broken window fallacy?
  - allturtles 5y ago
    You seem to be imagining that the sea level will smoothly rise mm by mm over a century and that people will gradually and peacefully abandon the shoreline and move inland. It seems to me that a more likely outcome is that people will build defenses to protect existing cities (which are after all massive investments) and and that those defenses will work well right up until they catastrophically fail in a major storm (e.g. see Katrina).

deleted 5y ago

[deleted]

betwixthewires 5y ago

So one thing to keep in mind, showing 20 year averages every 10 years and comparing them to century long averages for the same time period is a really good idea, it shows that there is a trend and it can show shorter temporal anomalies. One thing I found very interesting is the information on precipitation. I've heard it said "a warmer world is a wetter world" and that would appear to be supported by this data.

chrisco255 5y ago
We don't have a century of homogenous temperature data. We didn't have weather satellites until the late 70s, early 80s. And temps were only recorded in some cities and some towns, with uneven coverage, with inconsistent global quality practices. Sea temps were also inconsistently recorded.
- shoto_io 5y ago
  This should be the top comment. The images suggest a level of detail and accuracy that can’t be correct.
- newacct583 5y ago
  So... we have a half century of homogenous high quality temperature then. Does the good data we do have not support the same conclusion? Seems like it does to me.

crispyporkbites 5y ago

This is a bit misleading as the data is US only but the climate and weather doesn’t care about our made up borders. So to get a real picture of climate change you need to look at global weather patterns and temperature changes.

exporectomy 5y ago
So? Isn't its purpose it to show American farmers what the climate is like to help them plan their planting?

NotChina 5y ago

The universal constant of climate is what?

thanatos519 5y ago

I'm happy to see unmuzzled reporting from US government funded scientists again. Welcome back!