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No, nobody is making accurate predictions right now and that's the fundamental problem. We want to enact change on future predictions, but the models we're usin

by rjf72 7y ago

No, nobody is making accurate predictions right now and that's the fundamental problem. We want to enact change on future predictions, but the models we're using to predict things have a history that's shown them to be unreliable. Each time a prediction fails to pass it ends up undermining the entire system of climate modeling more and more. We can't expect national bodies to engage in anything other convenient changes based on predictions with a poor track record. This is why you need accuracy above all. As for the temperature increase, I don't picture things in such a polarized fashion. I think there's little doubt that humans are contributing to climate change. But what really confounds this issue is that climate, even absent humanity, is a very unstable system. These [1] are the data from the ice cores over the past 800k years, so literally before humanity existed. And you'll note a regular and often quite extreme shift in temperatures. For instance check out the end of the ice age before our most recent one - about 130k years ago. In an extremely brief period of time the temperatures skyrocketed something like 14 degrees celcius. We then gradually made our way out of that ice age hitting unprecedented lows dropping some 15 degrees celcius before once again starting an extremely rapid rise about 12,000 years ago which we are now in. And we've yet to hit the 'normal' highs of times past. So even if humans did not exist, we would almost certainly be seeing rapid warming. As for his comments referencing temperature, I'm also not entirely sure. His comment was somewhat unusual since the last ice age obviously did not only last 8,000 years. It also didn't end 10,000 years ago (though that's not too far off). And it would also be quite unusual for a UN speaker to use Fahrenheit. In this case, I think we can dodge this issue since 0.68C = 1.2F and that's given not only a failure to reverse carbon emissions but an unprecedented spike in them, so the point holds true in either case. Extreme CO2 increase = bottom or below the bottom of "most conservative scientific estimates" in temperature increases? We can't expect nations to engage in urgent action based on data like this. [1] - https://en.wikipedia.org/wiki/Global_temperature_record#/media/File:EPICA_temperature_plot.svg https://en.wikipedia.org/wiki/Global_temperature_record#/med... [2] - https://en.wikipedia.org/wiki/4.2_kiloyear_event https://en.wikipedia.org/wiki/4.2_kiloyear_event

martinpw 7y ago
I don't understand why you are doubling down on your misunderstandings here. The actual increase that you yourself quoted falls entirely within the error bounds of the IPCC estimates. It doesn't matter that it is towards the bottom of those error bounds - the whole point of an error bound is that it is a range that captures the uncertainty. To argue about where in the range it falls is to fundamentally misunderstand the purpose of an error bound in the first place. And the 'conservative estimate' is again a quote from the same person who made the dubious unverifiable 1-7F claim, so is also not relevant compared to the IPCC data. The IPCC range is their best estimate, so it is not a conservative range according to the IPCC report, which is what matters here. It is sad that you are focusing on the words of one person who was not even directly involved in the study, while ignoring or misunderstanding the published work of hundreds of climate scientists who contributed to the actual numbers which have proved 30 years later to be accurate predictions.
- rjf72 7y ago
  This is a misunderstanding of ranges. Imagine you flip a coin 100 times and you only get 41 heads. Is this coin fair? 41 heads falls just within the 95% confidence interval for a fair coin over 100 flips, so you can answer yes in that regard. But things are not binary. It's all probabilistic. In other words, it's not like 40 heads = rigged coin, 41 = legit. Your assumed interval is going to be a normal distribution. That means, if your assumption of it being a fair coin is correct, that you'll hit close to the perfect spot (50 in this case) disproportionately more often than you'll hit at the tails ends of your distribution. By contrast, now let's assume the coin was rigged to hit tails about 60% of the time. Now you'd be hitting extremely near that 41 constantly. Climate predictions are annoying because we can only get one sample at a time on a time frame that generally requires years to decades, so it's really really hard to determine whether we're right or wrong. But what you can safely say is that the further you fall away from your expected value - the less probable it becomes that your hypothesis (of said expected value being true) was accurate. In other words hitting 1 on e.g. a range of 1 to 7 with an expected value of 3.5 is a much less likely scenario than hitting 1 on a range of 0.5 to 1.5 with an expected value of 1.
  - citrablue 7y ago
    Dumb question, but how can you assume the ranges offered are a normal distribution?
  - martinpw 7y ago
    Having spent several years doing a PhD that was primarily statistical analysis, I can assure you I understand ranges very well. I certainly did not assume it is a normal distribution. There are going to be multiple sources of uncertainty including statistical and systematic errors which have different distributions. Taking all that into account they came up with an overall bound, and the actual number is within that range. That means the data are consistent with the prediction. And you need to stop quoting that 7F number. That number is not in the IPCC report, which is the thing we need to be comparing against - it is an unverifiable number quoted from one person who appears to have made multiple other errors, as you yourself pointed out (eg ice ages timeframes).
richardhod 7y ago
He was definitely using Fahrenheit because he was talking in New York, and most of the conversations on global warming in the American sphere was conducted in Fahrenheit until about 10 years ago.
bdamm 7y ago
We don't have time machines. Predictions can only be made with models, and the models aren't perfect.

by rjf72 7y ago

martinpw 7y ago

I don't understand why you are doubling down on your misunderstandings here. The actual increase that you yourself quoted falls entirely within the error bounds of the IPCC estimates. It doesn't matter that it is towards the bottom of those error bounds - the whole point of an error bound is that it is a range that captures the uncertainty. To argue about where in the range it falls is to fundamentally misunderstand the purpose of an error bound in the first place. And the 'conservative estimate' is again a quote from the same person who made the dubious unverifiable 1-7F claim, so is also not relevant compared to the IPCC data. The IPCC range is their best estimate, so it is not a conservative range according to the IPCC report, which is what matters here. It is sad that you are focusing on the words of one person who was not even directly involved in the study, while ignoring or misunderstanding the published work of hundreds of climate scientists who contributed to the actual numbers which have proved 30 years later to be accurate predictions.

rjf72 7y ago
This is a misunderstanding of ranges. Imagine you flip a coin 100 times and you only get 41 heads. Is this coin fair? 41 heads falls just within the 95% confidence interval for a fair coin over 100 flips, so you can answer yes in that regard. But things are not binary. It's all probabilistic. In other words, it's not like 40 heads = rigged coin, 41 = legit. Your assumed interval is going to be a normal distribution. That means, if your assumption of it being a fair coin is correct, that you'll hit close to the perfect spot (50 in this case) disproportionately more often than you'll hit at the tails ends of your distribution. By contrast, now let's assume the coin was rigged to hit tails about 60% of the time. Now you'd be hitting extremely near that 41 constantly. Climate predictions are annoying because we can only get one sample at a time on a time frame that generally requires years to decades, so it's really really hard to determine whether we're right or wrong. But what you can safely say is that the further you fall away from your expected value - the less probable it becomes that your hypothesis (of said expected value being true) was accurate. In other words hitting 1 on e.g. a range of 1 to 7 with an expected value of 3.5 is a much less likely scenario than hitting 1 on a range of 0.5 to 1.5 with an expected value of 1.
- citrablue 7y ago
  Dumb question, but how can you assume the ranges offered are a normal distribution?
- martinpw 7y ago
  Having spent several years doing a PhD that was primarily statistical analysis, I can assure you I understand ranges very well. I certainly did not assume it is a normal distribution. There are going to be multiple sources of uncertainty including statistical and systematic errors which have different distributions. Taking all that into account they came up with an overall bound, and the actual number is within that range. That means the data are consistent with the prediction. And you need to stop quoting that 7F number. That number is not in the IPCC report, which is the thing we need to be comparing against - it is an unverifiable number quoted from one person who appears to have made multiple other errors, as you yourself pointed out (eg ice ages timeframes).

richardhod 7y ago

He was definitely using Fahrenheit because he was talking in New York, and most of the conversations on global warming in the American sphere was conducted in Fahrenheit until about 10 years ago.

bdamm 7y ago

We don't have time machines. Predictions can only be made with models, and the models aren't perfect.