4 ms·
The sample size of our records is incredibly small when stacked against the history of the earth and all the records we're missing.
by 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 agoWhat 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 agoNot 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 agoTricky 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 agoWith 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 agoWe'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 agoHow unlucky we would have to be sounds like something you can calculate rather than just claim off hand.
- euyyn 10y agoThat'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 agoI'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 agoYou 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 agoIm not making an accusation that climate scientists wouldnt calculate this, because its not something thats in the content of the paper were discussing. My accusation is that you (or whoever i replied to) didnt have that data. At the same time I wouldn't be surprised if there were climate scientists who chose to avoid these sorts of calculations. Also, the p-value might tell you whether or not an event like this would literally be one of your samples, but its not whats going to tell you whether or not a reconstruction from these samples contains information about these events. Although I guess its not much of a distinction.
- briandear 10y agoIn 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.