tag:blogger.com,1999:blog-19727420.post7698772362671569761..comments2024-03-23T12:05:13.464-07:00Comments on Ideas: Have Past IPCC Temperature Projections/Predictions Been Accurate?David Friedmanhttp://www.blogger.com/profile/06543763515095867595noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-19727420.post-23709747685305583952021-11-02T07:59:50.927-07:002021-11-02T07:59:50.927-07:00David, thanks for your effort, in particular, the ...David, thanks for your effort, in particular, the zero and trend following alternatives. In terms of falsification, there would be even more to verify: 1. alternative prediction questions which establish the true causality: e.g. why CO2 and not plain land usage or population growth? 2. Verifications of fear-inducing impact forecasts. We can always enter a bunch of long-term impact predictions for automatic reality checks. Cheers, HubertusHubertushttps://www.blogger.com/profile/06821767723525452608noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-9848438085513986332021-11-02T07:56:01.733-07:002021-11-02T07:56:01.733-07:00David, thanks for your effort, in particular, the ...David, thanks for your effort, in particular, the zero and trend following alternatives. In terms of falsification, there would be even more to verify: 1. alrenative prediction questions to establish the causality: e.g. why CO2 and not plain land usage or population growth? 2. The fear-inducing impact forecasts. We can always enter a bunch of long-term impact predictions for automatic verification. Cheers, HubertusAnonymoushttps://www.blogger.com/profile/15405415272413002650noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-55675165897452151272021-10-26T19:02:47.421-07:002021-10-26T19:02:47.421-07:00Consider the record-obliterating heat waves that h...Consider the record-obliterating heat waves that have taken place around the globe for the last 10-20 years. Those have occurred with only ~1ºC warming, and haven't been only about 1 1/2ºC warmer than previous high extremes. The old trope about cold killing more than heat was never really proven and by now is a sad joke.<br /><br />NYC Battery Park has observed nearly a foot of SLR rise since pre-industrial times. That foot was the critical difference - and noting that the magnitude is smaller is irrelevant. Find the videos of the 11'8" bridge - a two-inch lack of clearance opens a panel truck like a sardine can.<br /><br />What other events have caused a global average temperature rise of the same magnitude that was permanent?<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-85326917458334989852021-10-26T11:02:41.683-07:002021-10-26T11:02:41.683-07:00@anonymous:
Which changes in extremes are you des...@anonymous:<br /><br />Which changes in extremes are you describing? Table 11.SM.2 of the sixth report shows the projected effect on the hottest day of various levels of warming. Typically it goes up by between a degree and a degree and a half for every degree of warming. Figure 11.SM.1 shows the effect on minimum temperature, with the temperature of the coldest day typically going up by two to three degrees for each degree of warming, although less in (typically) warmer climates. Given that both heat and cold kill, with cold apparently killing considerably more than heat, that looks like a gain for humans.<br /><br />So far as Sandy, are you saying that eight inches of sea level rise (A.1.7 gives .2 meters from 1902 to 2018) were responsible for flooding subways? I thought the problem was that it hit at high tide, which is about a six foot difference.<br /><br />By what standard is 2° in a century incredibly rapid? That's equivalent to moving from Iowa to Indiana.<br /> David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-47115240104505294632021-10-25T20:49:53.992-07:002021-10-25T20:49:53.992-07:00A global mean temperature increase of 2 to 3 degre...A global mean temperature increase of 2 to 3 degrees C (which is where we’re headed; we’ve already baked in 1 degree C) in a century so is incredibly rapid, David.<br /><br />You’re still missing the changes in extremes caused by a shift in the mean. Why is that?<br /><br />A meter of sea level rise beyond the highest tide is a big deal. Sandy wouldn’t have flooded the NYC subways if not for the sea level rise already in place.<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19727420.post-38100848723724513922021-10-25T19:05:51.905-07:002021-10-25T19:05:51.905-07:00@SB:
A sufficiently rapid change would be a proble...@SB:<br />A sufficiently rapid change would be a problem, but a degree or two in a century is not rapid. Take a look at a list of average temperatures by U.S. state to see how small a difference that is. It doesn't require mass migration.<br /><br />Note also that, as per the latest IPCC report, warming is lower in hot areas. Warming in India is projected as lower than the average, in the arctic as much higher. <br /><br />Sea level rise of a meter or so doesn't require mass migration either — that's about half the difference between high tide and low.David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-29721440202254900182021-10-25T04:41:03.791-07:002021-10-25T04:41:03.791-07:00The projections you quote from the 1990 report are...The projections you quote from the 1990 report are "business-as-usual emissions scenario"; if the world actually <i>has</i> taken some emission-reduction actions over the past thirty years, that would explain why those projections are more dramatic than actually happened. Are the projections you quote from subsequent reports likewise based on "business-as-usual emissions scenarios"?<br /><br />On the question of positive and negative impacts... it's certainly possible that a planet a degree or two warmer would be just as habitable as the one we grew up with, albeit with more people living in Canada and Siberia and fewer in the tropics. But it's the <i>rapid transition</i> that worries me: a degree-or-two change over the course of a century will be a substantial geopolitical and economic challenge, forcing many millions of (mostly-poor) people to migrate, all in the same direction at the same time, and a much greater challenge for non-human species, many of which will go extinct because this is a faster change than they can adapt to.SBhttps://www.blogger.com/profile/09786720503589745463noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-44582821337395844002021-10-24T13:38:35.128-07:002021-10-24T13:38:35.128-07:00Climate models aren't exercises in curve-fitti...Climate models aren't exercises in curve-fitting. For example, the presence of ENSO is an emergent phenomena in GCMs - they're not tuned to create ENSO specifically.<br /><br />The change in the mean creates a change in the extremes - and that's where the pain hits. A small change in the mean can change the frequency/intensity of a mean by a far greater amount. Hence the off-the-charts Pacific NW heat wave this summer. Record highs weren't just barely passed, they were obliterated. <br /><br />You're also ignoring shifts in circulation patterns and in precipitation - anthropogenic climate change isn't just warming temperatures. Minnesota may only get as warm as Iowa, but if its precipitation becomes more like New Mexico, that's a bigger problem.<br /><br />There is no good reason to expect the net effect to be positive, either. Erring on the side of optimism comes off as naive.<br />Anonymoushttps://www.blogger.com/profile/09615584493250954273noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-46777723572746420402021-10-23T07:28:25.444-07:002021-10-23T07:28:25.444-07:00I'm somehow reminded of the old story, "T...I'm somehow reminded of the old story, "The boy who cried Wolf."<br />G. Gary Y.https://www.blogger.com/profile/09137482435966442566noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-53326105597094981682021-10-22T18:00:09.364-07:002021-10-22T18:00:09.364-07:00It doesn't much worry me. Their predictions fo...It doesn't much worry me. Their predictions for the end of the century involve considerably less change in temperature than the current range of climates that people live and function over — by the end of the century Minnesota may be as warm as Iowa is now. I think the future is sufficiently uncertain, due mostly to technological progress, that taking actions now on the basis of what we think will happen more than a century out is almost always a mistake. <br /><br />As I have argued at length on this blog, climate change has positive and negative effects uncertain in size and there is no good reason to expect the net effect to be negative, although it could be. There is no reason I can see to expect the net to be not only negative but catastrophic, a position many people hold although it is not supported by the most recent IPCC report.David Friedmanhttps://www.blogger.com/profile/06543763515095867595noreply@blogger.comtag:blogger.com,1999:blog-19727420.post-33247256173150162292021-10-22T09:58:50.467-07:002021-10-22T09:58:50.467-07:00If their predictions might be getting more accurat...If their predictions might be getting more accurate if yet a bit too warm, are you worried about the implications? In other words, if they are roughly correct, does that worry you (assuming current trends of economic growth)? Or is there an extra premise needed of some sort of "escape velocity" of temperature growth that would lead to existential crisis?A Country Framernoreply@blogger.com