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This is why I'm a skeptic, change my mind: Let's say we have 150 years of accurate temperature data, and it shows an increase of a few degrees. What is the sta

This is why I'm a skeptic, change my mind: Let's say we have 150 years of accurate temperature data, and it shows an increase of a few degrees. What is the standard deviation in global temperature for 150 year periods for the last 100K or 1M years? How do we know what is significant change? Any data gathered from models (ice core, tree rings, ...) just doesn't have the resolution to answer these questions.

Malarkey73 12y ago
Lets say we have my blood alcohol level measured in the last 5 mins. It's 0.2g/dL. Whats my blood alcohol level throughout my lifetime though - i reckon it goes up and down quite a bit? How do i know I'm drunk or that it was caused by this keg I just drank? Any data gathered from physiological models I will just arbitrarily ignore... just because...[waves hands]
- kbd 12y ago
  That's a terrible analogy. Blood alcohol level only rises upon consumption of alcohol. Temperature rises and falls due to tons of external (not fully understood) factors.
  - unabridged 12y ago
    Not to mention BAC has a known baseline of 0. What is the known baseline for mean global surface temperature? Why is 1951-1980 a good choice for a base period?
  - Malarkey73 12y ago
    well I was trying to be funny.. but blood alcohol does indeed have a physical model that relates consumption to levels in the blood. And atmospheric temperature has a simple physical model that relates it to C02 levels. And I use the term "simple" deliberately because whilst the short term fluctuations of climate are indeed vey complex - on geological time we have always seen rising temperatures with rising CO2 and have a simple compelling atmospheric model to explain it. Without arguing over the resolution of the historical scientific data or how fast global warming will happen - it seems inevitable that with the current CO2 levels it will happen.
mkhaytman 12y ago
What difference does it make if the cause is entirely man made or not. Should we let 80% of worlds population who live on the coast just deal with rising sea levels, because it natural? Do you really need to know it's causing a rise in temperature to want less trucks and cars polluting the air in your city? Or does the fact that we will never have the historic data to know for sure if humans are causing global warming, make it okay to ignore the issue entirely, forever?
- unabridged 12y ago
  I agree that I want humans to stop fucking up the earth and I want less pollution. But those feelings do not prove climate change exists. Science doesn't work this way.
- triangleman 12y ago
  >What difference does it make if the cause is entirely man made or not. If it's not entirely man made, it would mean that efforts to curtail emissions (and consequently economic output) would be pointless and unnecessary. >Should we let 80% of worlds population who live on the coast just deal with rising sea levels, because it natural? It's not like the sea will simply rise several meters overnight, if it does actually rise. And again, if it's natural, then wouldn't that mean that we must, in fact, "deal with it"? >Do you really need to know it's causing a rise in temperature to want less trucks and cars polluting the air in your city? The air pollution you are concerned about here is sulfur, particulates, and other things unrelated to the CO2 debated over by politicians currently. >Or does the fact that we will never have the historic data to know for sure if humans are causing global warming, make it okay to ignore the issue entirely, forever? It certainly moves one's focus of concern to more pressing environmental and social issues.
_archon_ 12y ago
This is a fair perspective. I propose that the scientific community's collective stance is not that this is a wild deviation from typical variations, but that a significant change will result in unfavorable consequences for humanity as a species. Such change is occurring based on the data we have available to us. If we can mitigate or delay such change, we will be better off for it. This leads to emission controls, etc. I believe the cause for concern among the proponents of awareness and regulation is that a notable change is happening, and we desperately want the status quo. Whether or not this change falls within normal variations is irrelevant to this argument.
- belovedeagle 12y ago
  This is a refreshingly honest analysis. Personally I'm not convinced by the need to maintain the status quo, however. We can read all about 'X species going extinct in Y years', 'Average temperatures will go up by .X degrees in Y years', and 'X miles of coastline will be destroyed in Y years', and yet none of this explains /why/ these are undesirable outcomes. The unstated premise is that "change is bad", which is a strange position to take, to say the least.
  - dirktheman 12y ago
    Living in a country where a large part is located below sea level, I can assure you that a rising water level concerns me. But you're right, in the grander scheme of things global warming isn't necessarily a good or a bad thing, it just is.
facepalm 12y ago
I don't understand why that line of thought makes you a skeptic. Apparently you found something the current data can not answer. But why do you think your question is even relevant - more important than, say, average temperature? Just because there are questions a model can't answer, the model isn't proven wrong. It just shows that there are things we don't know yet, not that everything we know is wrong. (I am not a climate scientist so I don't know what the main data points are that are employed in the arguments. I also don't know if your claim that your question can not be answered is correct or not)
- unabridged 12y ago
  My point is that you cannot even begin to ask what humans are doing to the global temperature if you do not even have an idea what it would look like without humans.
  - facepalm 12y ago
    But why do you say "we have no idea"? Lots of things are known, like temperature averages and trends. As I said, I am not a climatologist myself. I am a bit surprised that tree rings are supposedly not accurate enough to say things about a 150 year interval. I was under the impression tree rings develop on a yearly basis? I suppose there are other factors besides temperature that affect their growth. Then again, for standard derivation as you desire, those factors might be easy to cancel out?
    - glenra 12y ago
      For tree rings to tell you what you want, trees would need to have a linear growth-response pattern with respect to temperature, and they don't. It's more of an inverse U-shaped pattern. Trees in temperature-limited areas do tend to grow better if it gets a little warmer, but if it gets a LOT warmer they'd grow worse again. The rings get smaller if it gets too cold, but they also get smaller if it gets too warm. For this reason, it's essentially impossible to tell based on tree rings if it was warmer than today in times past. Another thing to keep in mind is "the divergence problem" - several tree ring series right now suggest it's been getting "colder" for the last 50 years. This might be due to that U-shaped response kicking in, or it might be for various other reasons - some hypothesize it's due to changes in air pollution. It's a known issue, but not a solved issue. Here's a good paper on the subject: http://icecap.us/images/uploads/Loehle_Divergence_CC.pdf http://icecap.us/images/uploads/Loehle_Divergence_CC.pdf
asgard1024 12y ago
The problem is you're focusing only on one part of the evidence. The other part is the law of conservation of energy, the fact from which follows (after some modeling) that atmosphere will heat up when you add greenhouse gases. And, quite interestingly, these two independent lines of evidence, match. (There are several others.) In other words, you doubt the relevance of historical data. But the evidence is not just historical, it's also based on our understanding of the underlying physical mechanism.
DCKing 12y ago
You appear to be saying that you think this could be explained by some natural variation. That seems plausible, but is not supported by scientific evidence. The term "man-made climate change" is a term for the truth of these three claims: 1. Human activity has increased the concentration of CO2 (and other green-house gases) in the atmosphere. 2. The global temperature has risen over the last 150 years. 3. An increase in the concentration of CO2 in the atmosphere is the cause of the rise in global temperature over the last 150 years. Point 2 is simple scientific fact by now. Measurements show that this is the case, despite being critically revised and corrected for sampling biases over the years. Point 3 is also scientific fact; the theoretical effect has been shown to be true in simple laboratory expirements (it has been known for over 100 years) and the strong correlation of CO2 concentration and temperature over the last 150 years overwhelmingly implies that this laboratory effect applies for the atmosphere as well. That could still mean that the source of all of this greenhouse gas is natural. Still seems plausible, but again scientific evidence shows that the large majority of this "new CO2" is sourced by human activity [1]. Various sources of evidence exist; the isotopic signature of CO2 in the atmosphere is atypical for natural sources, the concentration of CO2 in the oceans is rising fastest near the surface, and there are many more pieces of evidence. It is true that there is still a large degree of ignorance on how global temperature varies "naturally" over long periods of time. However, we can show that this specific warming we're observing today is not just a natural variation. It is caused by humans. [1] http://www.skepticalscience.com/co2-increase-is-natural-not-human-caused.htm http://www.skepticalscience.com/co2-increase-is-natural-not-...

Malarkey73 12y ago

Lets say we have my blood alcohol level measured in the last 5 mins. It's 0.2g/dL. Whats my blood alcohol level throughout my lifetime though - i reckon it goes up and down quite a bit? How do i know I'm drunk or that it was caused by this keg I just drank? Any data gathered from physiological models I will just arbitrarily ignore... just because...[waves hands]

kbd 12y ago
That's a terrible analogy. Blood alcohol level only rises upon consumption of alcohol. Temperature rises and falls due to tons of external (not fully understood) factors.
- unabridged 12y ago
  Not to mention BAC has a known baseline of 0. What is the known baseline for mean global surface temperature? Why is 1951-1980 a good choice for a base period?
- Malarkey73 12y ago
  well I was trying to be funny.. but blood alcohol does indeed have a physical model that relates consumption to levels in the blood. And atmospheric temperature has a simple physical model that relates it to C02 levels. And I use the term "simple" deliberately because whilst the short term fluctuations of climate are indeed vey complex - on geological time we have always seen rising temperatures with rising CO2 and have a simple compelling atmospheric model to explain it. Without arguing over the resolution of the historical scientific data or how fast global warming will happen - it seems inevitable that with the current CO2 levels it will happen.

mkhaytman 12y ago

What difference does it make if the cause is entirely man made or not. Should we let 80% of worlds population who live on the coast just deal with rising sea levels, because it natural? Do you really need to know it's causing a rise in temperature to want less trucks and cars polluting the air in your city? Or does the fact that we will never have the historic data to know for sure if humans are causing global warming, make it okay to ignore the issue entirely, forever?

unabridged 12y ago
I agree that I want humans to stop fucking up the earth and I want less pollution. But those feelings do not prove climate change exists. Science doesn't work this way.
triangleman 12y ago
>What difference does it make if the cause is entirely man made or not. If it's not entirely man made, it would mean that efforts to curtail emissions (and consequently economic output) would be pointless and unnecessary. >Should we let 80% of worlds population who live on the coast just deal with rising sea levels, because it natural? It's not like the sea will simply rise several meters overnight, if it does actually rise. And again, if it's natural, then wouldn't that mean that we must, in fact, "deal with it"? >Do you really need to know it's causing a rise in temperature to want less trucks and cars polluting the air in your city? The air pollution you are concerned about here is sulfur, particulates, and other things unrelated to the CO2 debated over by politicians currently. >Or does the fact that we will never have the historic data to know for sure if humans are causing global warming, make it okay to ignore the issue entirely, forever? It certainly moves one's focus of concern to more pressing environmental and social issues.

_archon_ 12y ago

This is a fair perspective. I propose that the scientific community's collective stance is not that this is a wild deviation from typical variations, but that a significant change will result in unfavorable consequences for humanity as a species. Such change is occurring based on the data we have available to us. If we can mitigate or delay such change, we will be better off for it. This leads to emission controls, etc. I believe the cause for concern among the proponents of awareness and regulation is that a notable change is happening, and we desperately want the status quo. Whether or not this change falls within normal variations is irrelevant to this argument.

belovedeagle 12y ago
This is a refreshingly honest analysis. Personally I'm not convinced by the need to maintain the status quo, however. We can read all about 'X species going extinct in Y years', 'Average temperatures will go up by .X degrees in Y years', and 'X miles of coastline will be destroyed in Y years', and yet none of this explains /why/ these are undesirable outcomes. The unstated premise is that "change is bad", which is a strange position to take, to say the least.
- dirktheman 12y ago
  Living in a country where a large part is located below sea level, I can assure you that a rising water level concerns me. But you're right, in the grander scheme of things global warming isn't necessarily a good or a bad thing, it just is.

facepalm 12y ago

I don't understand why that line of thought makes you a skeptic. Apparently you found something the current data can not answer. But why do you think your question is even relevant - more important than, say, average temperature? Just because there are questions a model can't answer, the model isn't proven wrong. It just shows that there are things we don't know yet, not that everything we know is wrong. (I am not a climate scientist so I don't know what the main data points are that are employed in the arguments. I also don't know if your claim that your question can not be answered is correct or not)

unabridged 12y ago
My point is that you cannot even begin to ask what humans are doing to the global temperature if you do not even have an idea what it would look like without humans.
- facepalm 12y ago
  But why do you say "we have no idea"? Lots of things are known, like temperature averages and trends. As I said, I am not a climatologist myself. I am a bit surprised that tree rings are supposedly not accurate enough to say things about a 150 year interval. I was under the impression tree rings develop on a yearly basis? I suppose there are other factors besides temperature that affect their growth. Then again, for standard derivation as you desire, those factors might be easy to cancel out?
  - glenra 12y ago
    For tree rings to tell you what you want, trees would need to have a linear growth-response pattern with respect to temperature, and they don't. It's more of an inverse U-shaped pattern. Trees in temperature-limited areas do tend to grow better if it gets a little warmer, but if it gets a LOT warmer they'd grow worse again. The rings get smaller if it gets too cold, but they also get smaller if it gets too warm. For this reason, it's essentially impossible to tell based on tree rings if it was warmer than today in times past. Another thing to keep in mind is "the divergence problem" - several tree ring series right now suggest it's been getting "colder" for the last 50 years. This might be due to that U-shaped response kicking in, or it might be for various other reasons - some hypothesize it's due to changes in air pollution. It's a known issue, but not a solved issue. Here's a good paper on the subject: http://icecap.us/images/uploads/Loehle_Divergence_CC.pdf http://icecap.us/images/uploads/Loehle_Divergence_CC.pdf

asgard1024 12y ago

The problem is you're focusing only on one part of the evidence. The other part is the law of conservation of energy, the fact from which follows (after some modeling) that atmosphere will heat up when you add greenhouse gases. And, quite interestingly, these two independent lines of evidence, match. (There are several others.) In other words, you doubt the relevance of historical data. But the evidence is not just historical, it's also based on our understanding of the underlying physical mechanism.

DCKing 12y ago

You appear to be saying that you think this could be explained by some natural variation. That seems plausible, but is not supported by scientific evidence. The term "man-made climate change" is a term for the truth of these three claims: 1. Human activity has increased the concentration of CO2 (and other green-house gases) in the atmosphere. 2. The global temperature has risen over the last 150 years. 3. An increase in the concentration of CO2 in the atmosphere is the cause of the rise in global temperature over the last 150 years. Point 2 is simple scientific fact by now. Measurements show that this is the case, despite being critically revised and corrected for sampling biases over the years. Point 3 is also scientific fact; the theoretical effect has been shown to be true in simple laboratory expirements (it has been known for over 100 years) and the strong correlation of CO2 concentration and temperature over the last 150 years overwhelmingly implies that this laboratory effect applies for the atmosphere as well. That could still mean that the source of all of this greenhouse gas is natural. Still seems plausible, but again scientific evidence shows that the large majority of this "new CO2" is sourced by human activity [1]. Various sources of evidence exist; the isotopic signature of CO2 in the atmosphere is atypical for natural sources, the concentration of CO2 in the oceans is rising fastest near the surface, and there are many more pieces of evidence. It is true that there is still a large degree of ignorance on how global temperature varies "naturally" over long periods of time. However, we can show that this specific warming we're observing today is not just a natural variation. It is caused by humans. [1] http://www.skepticalscience.com/co2-increase-is-natural-not-human-caused.htm http://www.skepticalscience.com/co2-increase-is-natural-not-...