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Recent global temperature patterns

Discussion in 'Environmental Discussion' started by tochatihu, Apr 22, 2018.

  1. tochatihu

    tochatihu Senior Member

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    (Followed by lecture)
    Here I compare prominent compilations, starting from 1979 when look-down satellites joined much broader and earlier surface measurements. Some suggest surface measurements have been ‘adjusted’ in compilations, while others suggest that satellite T proxies don’t see earth’s surface well. Let’s just compare them to see what might be learned.

    Satellite TLT (temperature lower troposphere) are from UAH and RSS. Surface compilations are from Berkeley (BEST), HADCRUT4 and GISS. All are reported as temperature anomalies which are differences from T at particular baseline periods. I adjusted each to zero in 1979. I made them initially match. I consider this defensible because earth T in 1979 was same regardless of record chosen. All sources provide monthly values and I averaged them for each calendar year, 1979 through 2017; 39 years in total.

    This graph with each data-source’s annual dots is very busy. Those few who look closely at it may notice things I did not.

    T since 1979.png

    First, surface records show T increase through time ranging from 0.17 to 0.19 degrees C per decade, and their R^2 range from 0.81 to 0.83 (1.0 would be perfect fits). Satellite-T compilations range from 0.13 to 0.14 degrees C per decade, and their R^2 range from 0.51 to 0.57. Lower +T slopes from satellite compilations might not be statistically lower; a fella could work that out.

    Surface records track each other very closely through time. This is to be expected, even though (I understand) they don’t all use same thermometers and deal with spatial gaps in different ways

    Satellite-Ts are also close to each other within years. They use some different satellites and different processing. They show much more variability among years than surface records, especially in some ENSO-extreme years.

    It surprised me that all records have a particular consistency. In years where one record goes down, they all do. Likewise for ‘up’ years. So while there are quantitative differences, all appear to be measuring similar things, but with more or less noisy techniques. At least this provides a ‘degree’ of concordance. It argues against any record being artificially altered, which some folks used to suspect. Perhaps they still do.

    Why are satellite-Ts more noisy? No simple explanation seems to have been presented. They ‘see’ microwave emissions from oxygen and separate atmospheric layers in ways I can’t explain. But temperature of lower troposphere (TLT here) are centered 2 kilometers up and respond also (but less) to signals from higher or lower. Also note all values are anomalies, or departure from some reference value (here I based them all on 1979 T). Earth surface T is about 14 oC. Two km higher, atmospheric lapse rate means 1 oC. The next higher satellite level, T of middle troposphere is centered at 5 km; -18.5 oC.

    No matter what, satellites don’t measure surface T. They would if they could, I suppose. A year with greater ‘contamination’ from higher atmosphere would appear cooler. Conversely, with less, would appear warmer. I suspect but do not know that’s what’s going on. Don’t know why there would be less upper-air contamination during ENSO-positive year 1998 but not during ENSO-positive year 2016. But the much larger year-to-year variation calls for some mechanistic explanation. I do not think satellite T fall of 0.6 oC from 1998 to 1999 is representative of surface conditions. Seems like people with feet on ground would have noticed. Surface-T decrease then was reported as 0.23 oC.

    I show and discuss this because I have not seen it elsewhere.

    == And the lecture.
    Recent +T across these compilations might imply a century +T of 1.3 to 1.9 degrees C. IPCC suggests more than that, but why?

    Because IR-absorbing CO2 will increase faster? It may, depending on how emissions go and on how biota tamp that down. In this, we must also look to the logarithmic response of IR energy absorption.

    Because a (strong) secondary IR absorber, atmospheric water vapor could increase from +T and Clausius–Clapeyron. It could, but water vapor has only slightly increased and more rainout could tamp that down as well in future. Atmospheric water vapor has been increasing at 1.5% per decade which seems small to me.

    Because most of new net heat trapped has gone into oceans, and that might re-emit to where people live on a short dynamic? For me, no ocean model ‘does’ ENSO (among other problems), so they are hard to defend in terms of decadal patterns.

    ==
    What can we expect for +T in this century? Less than recent decadal rates seems unlikely. ‘Externalists’ appealing to low sunspot cycles for slow +T must be troubled by our current low one, during which +T continues apace.

    More +T than recent decades is espoused by IPCC, even to +4 to +6 degrees C in 21st century. I do not expect those for any reasonably expected level of +CO2 growth. Warmer during 21st century seems not our biggest challenge. We need more water, more energy, and more food because there will be more people and with higher aspirations. Achieving all those seems a much different and more complex goal than pure focus on +CO2 and +T.

    Separately, a super-linear increase in rate of sea-level rise is easier to imagine than for temperature. Parts of Greenland and Antarctica have a few meters (SL equiv) of ice ‘just hanging over the edge’. We don’t know how much (little) additional forcing would be required to release them. This situation differs from future accelerations of +T because that energy has not arrived yet. The ice is already at hand.
     
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  2. tochatihu

    tochatihu Senior Member

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    I know it's too long. But as Benjamin Franklin (may have) said "I apologize for the long letter. I did not have time enough to write a short one".

    Notice there are at least a few years when all dots are very close. That gave me a good feeling.
     
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  3. Jasmine James

    Jasmine James New Member

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    Engineer? Astrophysicist? I have no clue what you said, but I think it's safe to assume you're not a denier of climate change? ;)
     
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  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    It would be interesting to map the Arctic and Antarctic minimum and maximum sea ice to overlay the temperature records.

    As for the satellite record, they are measuring a volume with relatively little thermal inertia and significant mobility. So I can envision climate driven air currents that can induce significant variations. In recent years, we are seeing polar vortex changes that have been transporting a lot of heat to the poles.

    Bob Wilson
     
    #4 bwilson4web, Apr 23, 2018
    Last edited: Apr 23, 2018
  5. tochatihu

    tochatihu Senior Member

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    PriusChat has recently lacked a dedicated spokesman for climate denial. But elsewhere the beat goes on:

    Global Warming: Media Ignore Sharp Drop In Global Temperatures Over Past Two Years

    Following 2016 El Nino, T went down, especially in satellite retrievals. Just as was seen after 1998 El Nino.

    Just as they will, briefly, after the next El Nino, all within larger context of increase.

    But local readers ought not suppose that global rationality has suddenly bloomed.
     
  6. bisco

    bisco cookie crumbler

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    one day we have the heat on, the next, a/c. something odd is going on.
     
  7. tochatihu

    tochatihu Senior Member

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    Somebody needs to upgrade their home insulation :whistle:
     
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  8. fuzzy1

    fuzzy1 Senior Member

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    And also reduce air infiltration by sealing a lot more leaks. That made a significant difference in my house even before getting to the ceiling/attic portion of an insulation upgrade.

    When an energy audit was finally performed, it found that I had actually gone slightly past the recommended minimum for air changes, at least from natural airflow without mechanical ventilation. But since I had just put in programmable timers on the bathroom exhaust fans to help purge excess moisture, I still passed.

    A very well insulated house, with reasonable control of solar heat gain, should take several days to swing from needing heat to needing AC.
     
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  9. bisco

    bisco cookie crumbler

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    or just wait until the climate gets back to normal.
     
  10. tochatihu

    tochatihu Senior Member

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    I think large temperature swings in Boston (etc.) during May/June cusp are entirely normal.

    Since whenever heating degree day and cooling degree day stats began accumulating. Quite a few decades back, that was.

    Maybe those swings will be smaller in 2019?
     
  11. tochatihu

    tochatihu Senior Member

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    To be fair, old wood-framed houses with old windows present several challenges to thermal retrofits.

    Northeastern US has very many in the fleet. Fire Depts. are so 'pro' that few houses take that quick shortcut to returning to atmospheric CO2. Termites don't like the climate, and carpenter ants take a long time to chew them up. Keep roofs from leaking (as most do) keeps fungi away. Net effect is that those old energy-sucking buildings tend to last for a very long time.
     
  12. tochatihu

    tochatihu Senior Member

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    fuzzy1's airflow: Check for indoor radon next. Sigh...
     
  13. tochatihu

    tochatihu Senior Member

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  14. fuzzy1

    fuzzy1 Senior Member

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    While I ought to do this, my home is not in an area of known significant risk. The Wikipedia / EPA risk map puts me in a blue zone (<1% rate of afflicted dwellings), the house is over a well ventilated crawl space (no basement or slab foundation), over glacial till (not bedrock), and has utility-served water, not an on-site well.

    So this task never bubbled up to the top of my priority list. But if I lived near Spokane, I'd have tested this long ago.

    My air infiltration project included sealing off a number of leak paths from the crawl space. The floor hole around the bathtub drain was quite large.
     
  15. tochatihu

    tochatihu Senior Member

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    I get no financial benefit from Rn check kits. Evidence presented suggest you can slide by.

    It's just that meritorious house improvements can expose (or lead to) secondary issues.

    I think that radon map is fascinating. Read the radon wiki article and see that glacial till is exactly the problem in Iowa etc. Exports from Canada :)

    Maybe nobody runs old-school cathode-ray tubes (TVs) any more. Complete migration to flat screens. But if so, borrow a Geiger counter from some local lab. Wipe that old display screen with a paper tissue and put it on the gadget.

    Fun fun fun
     
  16. fuzzy1

    fuzzy1 Senior Member

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    In hindsight, this map seemed more optimistic, i.e. fewer areas at significant risk, than resources I'd seen years ago. A bit of searching found other maps showing greater risk to more geographies:

    Find Information about Local Radon Zones and State Contact Information | Radon | US EPA
    https://www.epa.gov/sites/production/files/2015-07/documents/zonemapcolor.pdf
    State Maps of Radon Zones | Radon | US EPA
     
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  17. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I nominate "Mo Brooks."

    Bob Wilson
     
  18. bisco

    bisco cookie crumbler

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    And less rivers.