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>The IPCC reports have consistently predicted more warming than has actually occurred; by now the actual warming is outside the lower end of the IPCC's confiden

>The IPCC reports have consistently predicted more warming than has actually occurred; by now the actual warming is outside the lower end of the IPCC's confidence interval. What confidence interval is that? What prediction was much higher than the +1C that has occurred? Looking up the 1990 IPCC report I see +1.5 to +4.5 between 2025 and 2050. We seem to be within that prediction. http://www.ipcc.ch/ipccreports/1992%20IPCC%20Supplement/IPCC_1990_and_1992_Assessments/English/ipcc_90_92_assessments_far_overview.pdf http://www.ipcc.ch/ipccreports/1992%20IPCC%20Supplement/IPCC...

pdonis 8y ago
> What prediction was much higher than the +1C that has occurred? +1 C from 1990 to now? It's not +1C, it's +0.61C, according to NASA's smoothed data: https://climate.nasa.gov/vital-signs/global-temperature/ https://climate.nasa.gov/vital-signs/global-temperature/ The temperature anomaly (quoted on that page as 0.9C) is not based on 1990 as the zero point, so that's not the relevant number. The actual numbers are in the data behind the smoothed curve shown on the right of the page (click the "HTTP" link next to "Get Data"). > Looking up the 1990 IPCC report... The relevant prediction in that report is for the "business as usual" scenario for CO2 increase, since that matches pretty closely how CO2 has actually increased since 1990. The prediction for that scenario is +0.3C per decade. However, there are other comparisons that can be made, which make the models look even worse. See, for example, here: https://judithcurry.com/2015/12/17/climate-models-versus-climate-reality/ https://judithcurry.com/2015/12/17/climate-models-versus-cli... This is comparing the IPCC AR5 model runs with balloon and satellite data. (And note that, unlike the comparison I did above, the "model runs" curve in this graph averages models for all of the CO2 increase scenarios, not just the "business as usual" one; just showing the "business as usual" model prediction curve would increase the gap between the models and the data.
- pedrocr 8y ago
  >+1 C from 1990 to now? +1C from pre-industrial times. Apparently we are at +0.8-1.2 in that measure. >The prediction for that scenario is +0.3C per decade. The report says 0.2-0.5. The +0.6 from 1990 to today is at the lower end of that range. It seems to me you're splitting hairs when the models are doing alright.
  - pdonis 8y ago
    > +1C from pre-industrial times. Apparently we are at +0.8-1.2 in that measure. Which all depends on how you choose "pre-industrial times" and how accurate you think temperature readings from those times are. Since even today's thermometers are only accurate to within half a degree or so, I'm not sure how we can even know the change from "pre-industrial times" to within less than half a degree (four tenths of a degree according to your statement). > The report says 0.2-0.5. The +0.6 from 1990 to today is at the lower end of that range. Yes, that's true. But as I noted, that's not the only comparison between models and data. Looking at comparisons overall, the statement I made, that the data is outside the lower end of the models' confidence interval, is correct.

pdonis 8y ago

> What prediction was much higher than the +1C that has occurred? +1 C from 1990 to now? It's not +1C, it's +0.61C, according to NASA's smoothed data: https://climate.nasa.gov/vital-signs/global-temperature/ https://climate.nasa.gov/vital-signs/global-temperature/ The temperature anomaly (quoted on that page as 0.9C) is not based on 1990 as the zero point, so that's not the relevant number. The actual numbers are in the data behind the smoothed curve shown on the right of the page (click the "HTTP" link next to "Get Data"). > Looking up the 1990 IPCC report... The relevant prediction in that report is for the "business as usual" scenario for CO2 increase, since that matches pretty closely how CO2 has actually increased since 1990. The prediction for that scenario is +0.3C per decade. However, there are other comparisons that can be made, which make the models look even worse. See, for example, here: https://judithcurry.com/2015/12/17/climate-models-versus-climate-reality/ https://judithcurry.com/2015/12/17/climate-models-versus-cli... This is comparing the IPCC AR5 model runs with balloon and satellite data. (And note that, unlike the comparison I did above, the "model runs" curve in this graph averages models for all of the CO2 increase scenarios, not just the "business as usual" one; just showing the "business as usual" model prediction curve would increase the gap between the models and the data.

pedrocr 8y ago
>+1 C from 1990 to now? +1C from pre-industrial times. Apparently we are at +0.8-1.2 in that measure. >The prediction for that scenario is +0.3C per decade. The report says 0.2-0.5. The +0.6 from 1990 to today is at the lower end of that range. It seems to me you're splitting hairs when the models are doing alright.
- pdonis 8y ago
  > +1C from pre-industrial times. Apparently we are at +0.8-1.2 in that measure. Which all depends on how you choose "pre-industrial times" and how accurate you think temperature readings from those times are. Since even today's thermometers are only accurate to within half a degree or so, I'm not sure how we can even know the change from "pre-industrial times" to within less than half a degree (four tenths of a degree according to your statement). > The report says 0.2-0.5. The +0.6 from 1990 to today is at the lower end of that range. Yes, that's true. But as I noted, that's not the only comparison between models and data. Looking at comparisons overall, the statement I made, that the data is outside the lower end of the models' confidence interval, is correct.