8 ms·

You're right. However, it's hard to argue with the speed at which this warming occurs. It's never seen before if you look at all the records we have. That's wha

You're right. However, it's hard to argue with the speed at which this warming occurs. It's never seen before if you look at all the records we have. That's what's worrying.

karl11 10y ago
The sample size of our records is incredibly small when stacked against the history of the earth and all the records we're missing.
- euyyn 10y ago
  What makes you think so? There's plenty of ways to indirectly know past temperatures, even if there wasn't a human writing it down.
  - Udik 10y ago
    Not with the accuracy and resolution of the data we have since last century. When you compare the current time series with the reconstructed ones from the past, you're comparing a day by day thermometric reading with the assembled averages of multiple, very noisy and extremely low frequency samples. Very tricky to say from those what might have been the actual speed of change in the past.
    - euyyn 10y ago
      Tricky for sure, as in it requires scientists to understand statistics and probability. Thankfully, many do, and many university departments hire mathematicians to keep the quality there high.
    - deleted 10y ago
      [deleted]
    - mememachine 10y ago
      With the quality of data we have from the past your reconstruction can only be so accurate. Its not a stretch to say our reconstructions cant really predict the short term spikes were trying to compare against.
- corradio 10y ago
  We'd be incredibly unlucky to have missed a temperature change as fast as the one we're measuring now, if it indeed would have been caused by a small sample size of past measurements.
  - mememachine 10y ago
    How unlucky we would have to be sounds like something you can calculate rather than just claim off hand.
    - euyyn 10y ago
      That's what's called a "p-value", and as you guessed it is indeed calculated. It's a basic tool of science, to the point that even better probabilistic tools have been advocated for years, and it's one of the first things you check when you're reviewing a paper.
      - mememachine 10y ago
        I'm aware of what a "p-value" is but what were talking about is reconstruction from historical samples and its perfectly calculable what kind of events wouldnt show up in that reconstruction (and p-values have almost nothing to do with it). Your attitude is obnoxious.
        euyyn 10y ago
        You say it's calculable and I agree. What's make you think it isn't calculated? Sorry if I came out as obnoxious, but "you should be able to calculate that" is a veiled accusation that it is in fact not calculated, as if no scientists take this seriously. "How unlucky we would have been to see this data of the past, if a spike in temperatures had actually happened then" is P(data|hypothesis), the frequentist argument for or against a hypothesis. It's what a p-value is, but arguing what to call it is pointless anyway.
        mememachine 10y ago
- briandear 10y ago
  In addition, the quality of our data is subject to debate. For example, using ship-water inflow temperature measurements which are warmer than buoy-measured temperatures as well as using models of suspicious provenance to extrapolate data where none exists. NOAA researchers corrected for the "cold bias" from buoy measurements compared to measurements made in ship engine rooms. My point isn't to deny the climate is changing but to call into question the quality of the data being used to create models and formulate policy. Each source of measurement has inherent bias and error -- that's the nature of scientific measurement -- especially measurements that often occur in the hulls of a ship. Who calibrates the measurement devices? Who calibrated them 50 years ago?
  - euyyn 10y ago
    > using models of suspicious provenance As in "I learned this model in a dark alley in Stalingrad, and I won't defend it in my paper"? Good luck trying to publish a paper if your model isn't well known and you don't explain it.
izend 10y ago
The end of the last ice age had much faster warming, see: http://www.nature.com/scitable/knowledge/library/abrupt-climate-change-during-the-last-ice-24288097 http://www.nature.com/scitable/knowledge/library/abrupt-clim...
- acqq 10y ago
  It wasn't "much faster" then at all. First, the work you've sent doesn't have the temperature graph, it's the "oxygen isotope record" on the y axis. Second, it's true that the last glacial period had much colder climate, but the changes were across a thousand of years for a few degrees, now we can have that amount of changes over a hundred years if nothing is done -- some ten times faster! And at that time there were no 7 billion people and no world economy that would be affected. Also, the temperatures that we can reach are going in the direction that can be higher than those recorded in the last 5 million years! If we "do something" we can stay at one or two degrees, not crossing that target. If we "don't do anything" it can be 4 (or even 6) degrees warming, 2 (or 4) degrees more than the maximum(!) in the last 5 million years. https://en.wikipedia.org/wiki/Temperature_record#/media/File:Five_Myr_Climate_Change.png https://en.wikipedia.org/wiki/Temperature_record#/media/File... That's why there's so much worry.

You're right. However, it's hard to argue with the speed at which this warming occurs. It's never seen before if you look at all the records we have. That's what's worrying.

karl11 10y ago

The sample size of our records is incredibly small when stacked against the history of the earth and all the records we're missing.

euyyn 10y ago
What makes you think so? There's plenty of ways to indirectly know past temperatures, even if there wasn't a human writing it down.
- Udik 10y ago
  Not with the accuracy and resolution of the data we have since last century. When you compare the current time series with the reconstructed ones from the past, you're comparing a day by day thermometric reading with the assembled averages of multiple, very noisy and extremely low frequency samples. Very tricky to say from those what might have been the actual speed of change in the past.
  - euyyn 10y ago
    Tricky for sure, as in it requires scientists to understand statistics and probability. Thankfully, many do, and many university departments hire mathematicians to keep the quality there high.
  - deleted 10y ago
    [deleted]
  - mememachine 10y ago
    With the quality of data we have from the past your reconstruction can only be so accurate. Its not a stretch to say our reconstructions cant really predict the short term spikes were trying to compare against.
corradio 10y ago
We'd be incredibly unlucky to have missed a temperature change as fast as the one we're measuring now, if it indeed would have been caused by a small sample size of past measurements.
- mememachine 10y ago
  How unlucky we would have to be sounds like something you can calculate rather than just claim off hand.
  - euyyn 10y ago
    That's what's called a "p-value", and as you guessed it is indeed calculated. It's a basic tool of science, to the point that even better probabilistic tools have been advocated for years, and it's one of the first things you check when you're reviewing a paper.
    - mememachine 10y ago
      I'm aware of what a "p-value" is but what were talking about is reconstruction from historical samples and its perfectly calculable what kind of events wouldnt show up in that reconstruction (and p-values have almost nothing to do with it). Your attitude is obnoxious.
      - euyyn 10y ago
        You say it's calculable and I agree. What's make you think it isn't calculated? Sorry if I came out as obnoxious, but "you should be able to calculate that" is a veiled accusation that it is in fact not calculated, as if no scientists take this seriously. "How unlucky we would have been to see this data of the past, if a spike in temperatures had actually happened then" is P(data|hypothesis), the frequentist argument for or against a hypothesis. It's what a p-value is, but arguing what to call it is pointless anyway.
        mememachine 10y ago
briandear 10y ago
In addition, the quality of our data is subject to debate. For example, using ship-water inflow temperature measurements which are warmer than buoy-measured temperatures as well as using models of suspicious provenance to extrapolate data where none exists. NOAA researchers corrected for the "cold bias" from buoy measurements compared to measurements made in ship engine rooms. My point isn't to deny the climate is changing but to call into question the quality of the data being used to create models and formulate policy. Each source of measurement has inherent bias and error -- that's the nature of scientific measurement -- especially measurements that often occur in the hulls of a ship. Who calibrates the measurement devices? Who calibrated them 50 years ago?
- euyyn 10y ago
  > using models of suspicious provenance As in "I learned this model in a dark alley in Stalingrad, and I won't defend it in my paper"? Good luck trying to publish a paper if your model isn't well known and you don't explain it.

izend 10y ago

The end of the last ice age had much faster warming, see: http://www.nature.com/scitable/knowledge/library/abrupt-climate-change-during-the-last-ice-24288097 http://www.nature.com/scitable/knowledge/library/abrupt-clim...

acqq 10y ago
It wasn't "much faster" then at all. First, the work you've sent doesn't have the temperature graph, it's the "oxygen isotope record" on the y axis. Second, it's true that the last glacial period had much colder climate, but the changes were across a thousand of years for a few degrees, now we can have that amount of changes over a hundred years if nothing is done -- some ten times faster! And at that time there were no 7 billion people and no world economy that would be affected. Also, the temperatures that we can reach are going in the direction that can be higher than those recorded in the last 5 million years! If we "do something" we can stay at one or two degrees, not crossing that target. If we "don't do anything" it can be 4 (or even 6) degrees warming, 2 (or 4) degrees more than the maximum(!) in the last 5 million years. https://en.wikipedia.org/wiki/Temperature_record#/media/File:Five_Myr_Climate_Change.png https://en.wikipedia.org/wiki/Temperature_record#/media/File... That's why there's so much worry.