the Air Vent

Because the world needs another opinion


Posted by Jeff Id on December 15, 2010

I wonder what readers really think.  What is the amount of warming you expect for the next 100 years?

Do you have any opinions on this?

62 Responses to “Question”

  1. Jeff Id said

    Yup, it’s lazy but I’m curious.

  2. Bad Andrew said


    Actual warming in an actual place?

    Or imaginary warming that occurs on a graph, but never in an actual place?


  3. John_L said

    -2.0 vs trend

  4. curious said

    Nothing wrong with being curious…

    By what measure are you going? Do you think GISStemp etc will still be around in 100 years?? 🙂

  5. TimG said

    CO2 will peak around 600-700ppm as population declines and fossil fuel price increases.
    Warming will peak around 1degC above today.

  6. Andre said

    It’s so hard to know anything about the future. It’s the hardest thing I know to know anything about. In a 100 years? Hmm … I realy don’t know, but probably it will not be deemed important, – the global average temp. I mean.

  7. Mark T said

    The question presumes the concept of a global temperature has meaning. Sorry, I just don’t buy it.

  8. agesilaus said

    Lets see 50 years of Dalton minimum brings up up to 2065, so how were the temps around 1910 or so?

  9. Frank K. said

    The problem with this question is that the “global average temperature” is a meaningless metric, thermodynamically speaking. Better to cast this in terms of total energy increase/decrease of the ocean/atmosphere in mega-Joules. In any case, the answer is impossible for our current crop of numerical models to predict with any accuracy…

  10. Rick Bradford said

    Within 1degC (either side) of where we are today.

    Depending on the temperature trend at the time, the e-newspapers will be shouting “World faces global warming crisis” or “World faces global cooling crisis.”

  11. timetochooseagain said

    1.5 ± .5 Degrees Celsius. On the basis of of the trend in about the last thirty years and allowing for some uncertainty.

    I’ll grant you there are a lot of assumptions I am making and I’ll grant people most of the objections they raise. But I think this estimate at least has plausibility which is more than I can say for “official” estimates.

  12. Joel Upchurch said

    I expect somewhere between 1 and 2 degrees centigrade. The problem is that this is more of an economic forecast than a climate forecast and an economic forecast for a century is pretty much horse shit. I don’t expect practical fusion power in the next century, but cheap fission breeder reactors could drastically reduce carbon emissions. We also need to look at the world population leveling out at 9-10 billion around 2050 and also at the transition of China and India from developing countries into developed countries.

    This doesn’t even account for possible radical changes in our economy caused by biotechnology, which could displace most conventional manufacturing.

  13. RickA said

    My guess is cooling for 50 years, to about -1.5C (2060), then warming for 30 years to -0.5C, then cooling for the next 10 (to get to 2100) to -.75C. Further cooling for the next 20 years, to round out the 30 year cycle, to -1.5C by 2120.

    All temperatures relative to todays global average temperature GISS index.

  14. Mark T said

    Dang, forgot about China. When China wipes the rest of us out, a global average temperature will still be meaningless.


  15. Stephen Singer said

    A range of +- 1.0c.

  16. […] This post was mentioned on Twitter by C Jenkins, Science Blog News. Science Blog News said: Question: I wonder what readers really think. What is the amount of warming you expect for the next 100 ye… […]

  17. don said

    Actually, the question caused me to think what is the amount of cooling I can expect in the next 100 years since, all things being equal, I’ll be dead.

  18. MDJackson said

    I don’t expect any amount of warming. I figure the party’s over as far as a warmer Earth is concerned. I base this on two factors. A:) Nothing good lasts forever and B:) I only just noticed it and was actually enjoying it.

    In Canada, particularly further north of the border, you take the warm weather when it comes and you go out and build something. When it’s cold you stay inside and watch a lot of hockey. I figure there’s gonna be a lot of hockey.

  19. AusieDan said

    Jeff, my first answer is that it depends on what you mean by warming and where it is to be measured.

    If you are referring to global warming as measured by the various surface indexes, then the clear answer is that – it all depends. It all depends on when the present interesting type of calculations are replaced by more boring ones and if the current figures can be properly corrected or not.

    If you are refering to temperature measurements at specific locations that are proplerly taken and recorded, then the answer depends on whether the climatic conditions that have prevailed for the last 150 years continue, or not. If they continue then the temperature is likely to fluctiate down and up, following the 60 odd year cycle that we have seen in the past (down in the immediate future for 30 years or so, then back up to where they are today).

    I presume here, that such measures will properly account for the varying amount of UHI at the points of measurement.

    I also presume that we are NOT about to enter a new little or major ice age. Otherwise all bets are off as we have nothing to go on as to the extent and the length of the chill.

    If I had to make a bet, I would say – more of the same and that we should forget about the climate completely and start to attend to the real problems facing the world.
    Or is that too boring as well?

  20. amabo said


  21. George said

    I expect cooling for the next 30 or 40 years and then warming. 100 years from now we will probably be on the back side of that warming into a cooling phase again. So I predict that 100 years from now it will be cooler than today.

  22. Steven Mosher said

    1.7C +-.5C

  23. MangoChutney said

    whatever the record keepers deem the warming to be 😉


  24. Eric Anderson said

    Uh, lessee . . .

    Assuming UHI is properly accounted for, assuming instrumentation changes and updates are properly accounted for, assuming we are talking about the non-real concept of “global average temperature” rather than temperatures in actual locations, assuming we are talking about surface temperatures, assuming we are talking about averaging the low-temps and high-temps, rather than just focusing on the increase in low-temps . . .

    Less than 1 degree C. If uncertainty bars are properly included, perhaps something just barely above the noise. I think it will be measurable, but only just barely . . .

  25. Oxbridge Prat said

    What TimG said at #5.

  26. John Silver said

    I have no idea, but whatever it will be, it will be normal.
    Global Normal.

  27. ArndB said

    I do not know!
    I prefere global warming,
    and fear global cooling,
    which is more likely as
    a continuation of the
    excellent conditions we
    have currently, or
    significantly higher average
    temperatures over a
    longer period of time.

  28. hempster said

    As RickA already pointed out, in XXI century we’ll have two full cooling cycles and only one of warming, this is opposite to last century, and I just hope we’ll have less than -1C cooling. CO2 will peak in this time at ~700 ppm with still no measurable influence on GATA.

  29. mondo said

    zero degrees, plus or minus 2 deg C.

  30. PaulM said

    0.5 +- 0.5

    BTW a There’s nothing wrong with slightly lazy posts like this if you are busy.

    BTW b Your paper is now up at JOC! But sadly we can’t read more than the abstract. Please could you send me a copy?

  31. Cementafriend said

    I am with Mark T at 7. Raw data such as Central England, Prague, New Zealand, rural US, rural Australia indicate that there has been no significant warming (trend)in the last 150 years. On the other hand there is evidence that it was in the past warmer (medieval time 900-1300) and colder in the little ice age (1500-1800). There is an indication that the sunspot pattern has changed to towards that in the little ice age. It is possible that the recent period has been a minor aberration in an extended cold period.
    Certainly, CO2 whether enhanced by human emission or mainly natural plays no part in atmospheric temperature changes.

  32. Kevin said

    It seems to me that there will always be localized warming/cooling because that’s what happens in a cyclical system. In a few years the masses may be complaining again about global cooling again as was the case in the 70’s.

  33. kim said

    Cooling from the Eddy Minimum. Inadequate warming to counteract it from the radiative effect of anthropogenic carbon dioxide. Widespread social upheaval from the consequences of the cooling.

    In other words, war, famine, plague and the rest of the string.

    Man-caused global warming? We should be so lucky.

  34. kim said

    But, as I’ve said before, Koutsoyiannis is about to make monkeys of us all.

  35. Carrick said

    About 1.0–2.0°C from CO2 increase (assumed a doubling from 1850-2100), perhaps another 0.5°C from decreased human pollution..

  36. Mark T said

    Cementafriend: my reasons for thinking a global temperature is meaningless has nothing to do with measurements themselves. Temperature is a function of several variables so it only makes sense to average the energy.

  37. Mike said

    I expect it to be no more than 1 to 2°C above what would result from natural variation — and, since we’ve already seen most of what CO2 can do, any change will almost certainly be primarily due to natural climate variation.

    I suspect our guesses here are at least as good as most models that are predicting warming — and my prediction would be that temperature would be where we are now or a little cooler.

  38. HLx said

    0 degrees. +/- 0,5.. Celsius

  39. patrioticduo said

    Temp100YearsFromNow = ! UNIPCC_prediction(GISSTEMP(),CRUTEMP(),HADCRUT(),now()+100);

  40. harrywr2 said

    No more then +0.4C every 60 year cycle until the next ice age kicks in.

  41. Retired Engineer said

    Well, if we have a nuclear war, it will be warmer for a short time, then colder for a longer time. After al-Gore moves on to the afterlife, it will be warmer, at least in the places where he doesn’t give speaches (give? … get paid for?) Unless someone continues Hansen’s adjustments, it could be a lot colder.

    As for the Earth itself? Whatever …

    FDR had the right answer when told Social Security would eventually go broke (they knew that 75 years ago) when he said “Yes, but we’ll all be dead by then.”

  42. David S said

    +0.75C from CO2 at 650-700ppm, combined with -1.0 from solar effects totalling -0.25 +/- 0.5. Keep burning that oil or we will all feel chilly!

  43. hunter said

    Nothing unusual or dangerous.

  44. I guess this will brand me a lukewarmer, but my answer is – I do not know, and neither does anyone else.

    Let’s see what the sun, ocean currents and even CO2 do in that period.Yellowstone may erupt and make the whole point moot.

  45. DeWitt Payne said

    Re: PhilJourdan (Dec 16 15:51),

    What he said.

    I think the probability of a big rock from the sky is higher than for a Yellowstone eruption, but both are pretty small.

  46. Greg. Cavanagh said

    Looking back at the Farmers Almanac for the last hundred years, and expecting a similar continuation…

    1895 cooling
    1930 warming
    1960 cooling
    1980 warming
    2000 cooling
    2040 warming
    2070 cooling
    2090 warming
    2120 cooling

    We may be on the cusp of a new ice age, or it might be another one or two hundred years off. It will happen one day, so I guess its reasonable to accept it might be starting now.

    It’s a shame more historians havn’t waded into this global warming debate.

  47. BPW said


  48. ScorpionDas said

    +1.0137624 degrees, +/- 3.0

  49. Steve Fitzpatrick said

    Based on:

    1) a 5-6 year ocean lag (best fit to the measured ocean heat accumulation)
    2) the historical radiative forcing (currently ~3 watts/M^2)
    3) increase in CO2 at 2.25 PPM for the next 20 years followed by a gradual decline in increase, peaking at ~550-560 PPM near 2090, followed by a slow decline
    4) modest net aerosol off-set proportional to rate of emissions (currently ~0.5 watt/M^2)

    It looks to me like ~0.11-0.12 per decade through 2060, followed by a very slow decline in rate of increase, until peaking near the turn of the century at ~0.8C warmer than today. There will then be a very slow decline as CO2 concentrations gradually fall, with current temperatures reached by about 2300. Sea levels will likely peak near the year 2300, at about 1 – 1.2 meters higher than today. But in the long run, we are all dead.

  50. Bruce of Newcastle said

    +0.3 due to GG’s based on empirical 2XCO2 of about 0.5 K
    -0.3 because PDO now at maximum will be at minimum in 2100
    +0.2 due to more UHI
    -0.2 due to soot control in China & India when they eventually get their act together on pollution
    -?.? due to solar influences (some are predicting Maunder style zero sunspots in SC25 & following)

    and last but not least:

    -0.0 due to the IPCC, carbon trading and unicorn farming

    Net = not much, except for whatever the sun decides it wants to do.

  51. Paul Callander said


    Shouldn’t that be +1.0137624 degrees, +/- 3.1519265 etc?

    Seriously, there are so many known unknowns let alone unknown unknowns in the climate, we can’t do better than expect the temperatures everywhere to be about the same.

  52. TGSG said

    glaciers or forests… hmmm i vote for forests.. + 1.5 please

  53. Steve Reynolds said

    Assuming CO2 of 560ppm in 2100 and both cooling and warming aerosols decrease together, then:
    1.8 +-0.6 C

  54. kim said

    With all these monkeys typing, someone’s bound to get it right. Hmmm. I like this model.

  55. Luis Dias said

    Peak oil around 2020-2030, peak coal around 2050-60, 600ppm in 2100.

    Between 1 and 2º Celcius of warming, with a wide 1.5ºC of uncertainty both ways, from other kinds of natural or even artificial mechanisms. This does not account for uncertainties of current science, which is almost uncountable.

  56. Kan said

    The actual temperature after 100 years – we have absolutely no way of predicting.

    However, we can hope, for our childrens’ children sake of course. Using the short recent warming period (150 years) as a guide, and the unprecedented advancement of human civilization during this time, I hope it will be .8 C warmer.

  57. Layman Lurker said

    1.5C +/- 2C per century.

    The uncertainty comes from: 1. accuracy of surface temperature record; 2. poorly understood solar forcing and feedback. 3. Poorly understood internal climate variability.

  58. Geoff Sherrington said

    Watch near earth object Victor Kilo 184. Last update in

  59. DeWitt Payne said

    Re: Geoff Sherrington (Dec 17 06:18),

    Only 150 MT energy. Peanuts, relatively speaking. Not that I’d want to be within 1,000 miles of the site, but the probability of my survival to 2048 is about the same as the probability of impact, 3.3E-04.

  60. truthsword said

    I agree with the -1 to +1 C on global average. Safe money in normal variation.

  61. AJ said

    Based on linear regressions that I have done, I get an “apparent” sensitivity to a doubling of co2 of about 2C using the surface record and about 1C using the satellite record. Since your question doesn’t concern itself with the “real” sensitivity, the heat in the pipeline doesn’t matter in this analysis. I do, however, have to make the tenuous assumption that the rate of deposit into and withdrawal from the pipeline have the same shape (i.e. linearly increasing rate, quadratic accumulation).

    My preferred model (again tenuous) for co2 growth is to increase emissions linearly and to absorb excess co2 concentrations at a constant percentage. This gives a co2 concentration of about 600ppm in 100 years.

    So based on the above, I get 0.62C [LN(600/390)/LN(2)] warning given an apparent 1C sensitivity and 1.24C for an apparent 2C sensitivity. So I’ll wager 1C +/- .5C.

  62. J said

    I agree on +-1degC. We dont know what the nature is hitting us and when and to which direction. CO2 might contribute a 1+-0.5degC warming effect (compared to preindustrial levels) though.

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