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The IPCC has historically released "worst case scenarios" that line up with the worst case that all of the people in the room can agree with. Because of this, "
by deftnerd 7y ago
The IPCC has historically released "worst case scenarios" that line up with the worst case that all of the people in the room can agree with. Because of this, "worst case" often ends up being "likely outcome" while worst case is exponentially worse.
We've been seeing events happen more and more with quotes from scientists saying "This wasn't expected to happen for another 50 years" [according to the IPCC reports].
Additionally, the IPCC notoriously makes their predictions algorithmically based purely on existing observations and doesn't take feedback loops into account. Those feedback loops are nearly guaranteed, but since they haven't been triggered yet, the extent of the feedback is hard to predict and thus is ignored.
It's because of these things that I tend to think that the IPCC reports are milquetoast. Even though they shock the public, they're actually doing a disservice by making people think they have more time than they actually have.
Plus, even if it was correct, most people will see this headline and think that we have 80 years to fix the problem and not realize that the bulk of the melting will take place before the 80 years is up.
My non-scientific rule-of-thumb with IPCC reports is to take the time and divide it by 10 as the lower boundary and by 5 as the upper boundary. This is to take into account the "1 in a 1000 year events" that seem to occur every few years now.
I personally expect the Kush-Himalaya ice sheet melt to be complete between 8 and 16 years from now because of a drastic and "unforeseen" weather event that accelerates it one year, like a stalled heat "blob" that camps over it for a season or a season of above-freezing rain that carves up the ice and carries it as melt-water downriver.
- merpnderp 7y ago"Additionally, the IPCC notoriously makes their predictions algorithmically based purely on existing observations and doesn't take feedback loops into account." This is not even close to true. The UAH and RSS global temperature sets have shown rock solid rates of change of around ~.13C/decade for 40 years. Yet the IPCC predicts much higher rates of change in the near future (the only possible way to get to >+2C/century). You can't just wave your hands and say the IPCC hasn't considered all the possible outcomes better than you. What you're doing is FUD, what they're doing is science.
- chrisco255 7y agoSort of. Modeling and predictions are just part of science. The IPCC never throws out bad models, they just average all the models together.
- merpnderp 7y agoIt's nothing like that awful. Like I couldn't just come up with a model tomorrow and have it approved and averaged - there are absolutely standards to be met. And the IPCC reports go into great detail on the differences in the models and why they predict different outcomes.
- chrisco255 7y agoA model is a hypothesis. It doesn't matter how much work goes into an incorrect hypothesis. If it doesn't align with reality, then it must be thrown out. The scientific method demands this. But the IPCC continues to use an average of dozens of models.
- merpnderp 7y agoCan you point out which models which have been shown to be provably false are still being averaged? I think the answer is far more complicated than you're making it.
- noiv 7y agoWell, how many humans live at the altitude measured by UAH and RSS?
- jcranberry 7y agoWhen I was in university and had access to scientific papers, I would often read papers on AGW. I remember reading several times that IPCC models were conservative and the msot bullish models in their assessment reports hadn't predicted the rate at which the north pole is melting.
- chrisco255 7y agoCurrently the Arctic is sitting at about 2007 levels: https://neptune.gsfc.nasa.gov/csb/index.php?section=234 https://neptune.gsfc.nasa.gov/csb/index.php?section=234
- perfunctory 7y agoComparing two random years is one way to look at it. Another is to look at the trend: https://climate.nasa.gov/vital-signs/arctic-sea-ice/ https://climate.nasa.gov/vital-signs/arctic-sea-ice/
- chrisco255 7y agoAll the trends start in the 70s, which was the coldest decade of the 20th century. That doesn't say much at all.
- jcranberry 7y agoDoesn't seem to be that way according to the global temperature tab one click away. https://climate.nasa.gov/vital-signs/global-temperature/ https://climate.nasa.gov/vital-signs/global-temperature/
- chrisco255 7y agohttps://youtu.be/8455KEDitpU https://youtu.be/8455KEDitpU you should watch this
- graeme 7y ago
- perfunctory 7y agoHere is a good read on IPCC conservatism http://climateextremes.org.au/wp-content/uploads/2018/08/What-Lies-Beneath-V3-LR-Blank5b15d.pdf http://climateextremes.org.au/wp-content/uploads/2018/08/Wha... The sea level chart on page 31 is quite interesting.