Two thermometer fits, not one century-long smear. 1910–1938 already ran at +1.98. Then the record ducks: 1940–1970 is -0.72. That hole is extra planetary albedo from sulfate lofted into the stratosphere. After the pulse fades, 1976–2026 resumes at +2.95— steep because it starts at the bottom of the hole. The faint line is the 1910–1938 slope continued. Without the volcanic dimming, the century is one moderate, continuous climb, not a pause plus a blade. The stick hides all of this by flattening the shaft and splicing the instrument on at the recovery.
Sulfur dioxide oxidizes to sulfate aerosols in the stratosphere. The droplets scatter incoming sunlight — higher albedo, cooler surface — for a year or two per pulse. A cluster of them stacks. Mount Agung (Bali, March 1963, VEI 5) is the climate-scale eruption of the trough: several megatonnes of SO2 and a documented drop through 1964–66. Bezymianny, Taal, Awu, Fernandina and Fuego add further pulses. Together they dent an otherwise continuous 20th-century rise. Take the dent out, and 1976–2026 is not a new physics — it is the 1910–1938 slope recovering from extra reflected sunlight.
- 1956Bezymianny, KamchatkaVEI 5
- 1963 · majorAgung, BaliVEI 5
- 1965Taal, LuzonVEI 4
- 1966Awu, SulawesiVEI 4
- 1968Fernandina, GalápagosVEI 4
- 1974Fuego, GuatemalaVEI 4
Sheep Mountain (CA534) · ITRDB CA534
Apples and oranges
Each tree card is independently z-scored, so a tall wiggle is that site’s own variance — not degrees Celsius. Bristlecones with a 20th-century growth surge (Sheep Mountain, Hill 10842, Timber Gap) are the series the stick was built from. Most of the others are not hockey sticks.
Satellites, stations, ocean — pick any mix
Rebased to 1981–2010 so the shapes can sit on one axis. They are not the same thermometer. Toggle whatever you want; nothing here is a tree.
| Series | Layer | 1979–2024 °C/century | 2001–2023 | What it is |
|---|---|---|---|---|
| HadCRUT5 NH | 2 m air + SST mix | +2.91 | +2.92 | NH · land+ocean mix |
| CRUTEM5 land NH | 2 m air, weather stations | +3.54 | +3.23 | NH land · station UHI possible |
| HadSST4 NH | sea-surface temperature | +2.06 | +2.39 | NH ocean · no urban heat island |
| UAH TLT NH | MSU/AMSU lower troposphere | +1.81 | +1.95 | NH · no urban heat island |
| RSS TLT globe | MSU/AMSU lower troposphere | +2.28 | +2.23 | 70S–82.5N · no urban heat island |
Ground records are adjusted for time-of-observation, station moves, and instrument changes (CRS to MMTS). Pairwise homogenization can also spread an urban breakpoint into a neighboring rural site. The land series you overlay on satellites have already been through that mill. Ocean and MSU/AMSU have not.
A weather station is a 2-metre box, clustered in the US, Europe, and coasts. RSS TLT is a microwave brightness temperature of the bulk lower troposphere, 70°S–82.5°N, ~100 km footprints. UAH covers the globe but still not the surface. HadSST is buckets, buoys, and ships. Overlaying them is useful. Pretending they are one number is the original splice, again.
Cities run warmer than the countryside, especially at night, and the gap grows with asphalt and population — the urban heat island. Historical rural series were farms, villages, treelines. They are cooler and usually less trended than airport/city records. Ocean has no UHI. Satellites do not sit on a tarmac. CRUTEM (land stations) climbing faster than HadSST (ocean) and UAH (troposphere) is that contrast on one chart. The land–ocean residual is not “rural,” but it is the part of the surface record UHI can leak into.
Albedo dropped. Absorbed sunlight rose.
NASA CERES at the top of the atmosphere, 2000–2023, from the Nikolov & Zeller 2024 supplement. Their GSAT model (Eq. 16) is a toggle on the overlay desk above — albedo plus a sliver of TSI, not a greenhouse coefficient.
| CERES / N&Z | 2001–2023 / century | Read it as |
|---|---|---|
| CERES ASW | +7.81 W/m² | CERES absorbed shortwave anomaly |
| CERES EEI | +5.10 W/m² | CERES Earth energy imbalance anomaly |
| CERES OLR | +3.03 W/m² | CERES outgoing longwave anomaly |
| CERES albedo | -2.30 % | CERES Bond albedo anomaly |
| N&Z GSAT | +2.41 °C | CERES albedo + TSI → GSAT (Eq. 16) |
| N&Z albedo | +2.35 °C | CERES Bond albedo → GSAT (Eq. 15a) |
| N&Z TSI | +0.06 °C | TSI → GSAT (Eq. 8) |
Not 2-metre air temperature. Reflected sunlight, outgoing longwave, and the residual Earth energy imbalance at the top of the atmosphere. Albedo here is Bond albedo: reflected SW / incoming SW. It fell about 0.44 percentage points by 2023 versus the CERES climatology — more sunlight staying in the system, mostly from fewer low clouds over ocean.
Their Eq. 16 maps absorbed solar flux and TSI onto GSAT with a planetary sensitivity of 0.297 K per W/m² absorbed — pressure and sunlight, not a CO2 coefficient. In their supplement, albedo carries almost the whole 2000–2023 rise; TSI is a rounding error. Turn on N&Z GSAT in the overlay above to sit that curve on HadCRUT and UAH. It is their model of CERES, not another thermometer.
Controls
Short-centering subtracts the 1902–1980 mean, so any series that rises in the thermometer era is thrown far below zero in the earlier centuries. Principal components then hunt those series.
MBH98 never published that each North American tree-ring series was centered on the 1902–1980 mean, not the full record, before principal components were taken. A chronology that explodes in the calibration era then looks like a huge negative anomaly for five hundred years. PCA rewards that variance. The first North American PC becomes a portrait of the Graybill strip-bark bristlecones.
Sheep Mountain (ITRDB CA534), a Graybill Pinus longaeva site at 3,475 m in California’s White Mountains, was the most heavily loaded series — over 390 times Mayberry Slough, whose hockey-stick index is near zero. Fifteen bristlecone and foxtail sites accounted for 93% of that PC1. Many of those trees are strip-bark; Graybill & Idso (1993) already argued their twentieth-century surge is CO2 fertilization, not temperature.
Glue a thermometer onto that flattened shaft and the 20th century becomes a corner. Fit the instrument in two pieces — 1910–1938 and 1976–present — and the early climb is already the same class of slope as “today.” Between them sits a volcanic-albedo trough (Agung 1963 and a cluster of VEI 4–5 eruptions). Without that dimming the record is one moderate, continuous rise, not a pause plus a blade. And the splice itself is apples to oranges: ring-width growth indexes are not air temperature.
Take the files with you
Everything plotted here is public. Buttons save the lab’s copies. Links go to NOAA, the Met Office, and the papers.
- ITRDB — International Tree-Ring Data BankNOAA / World Data Service for Paleoclimatology. Chronologies used in this lab.
- ITRDB chronology filesRaw Tucson / NOAA txt, including Graybill bristlecones (CA534 Sheep Mountain).
- NOAA Paleo Search (tree rings)Study-level metadata, maps, and original investigator records.
- Mann et al. 1998 NOAA archivemannnhem.dat (MBH98 NH) and mann_pc1.txt as published to NCEI.
- Mann et al. 1999 NOAA archivenhem-recon.dat, NOAMER PC1, ice (Quelccaya, Greenland) and extra tree proxies.
- HadCRUT5 Northern HemisphereUK Met Office / CRU instrumental analysis. NH annual mean, 1850–present.
- HadCRUT5 NH annual CSVThe exact series plotted as the thermometer in this lab (HadCRUT.5.0.2.0).
- Moberg et al. 2005 NOAA fileMixed-proxy NH reconstruction with larger millennial variance.
- Ammann & Wahl 2007 NOAA fileIndependent emulation of the MBH reconstruction.
- Jones et al. 1998 NOAA fileEarly composite-plus-scale NH reconstruction.
- Ljungqvist 2010 NOAA fileExtra-tropical NH decadal reconstruction.
- Smithsonian Global Volcanism ProgramAgung 1963 and the 1940–1970 eruption cluster (VEI, dates, locations).
- UAH MSU/AMSU v6.1 lower troposphereSpencer & Christy satellite TLT — globe, NH, land, ocean, USA48.
- UAH v6.1 TLT monthly fileuahncdc_lt_6.1.txt — the satellite series in the overlay desk.
- RSS TLT v4.0Remote Sensing Systems MSU/AMSU lower troposphere, land and ocean.
- RSS TLT v4.0 monthly file70°S–82.5°N land+ocean anomalies.
- CRUTEM5 land stationsHomogenized 2 m air temperature over land. UHI-exposed network.
- HadSST4 sea-surface temperatureOcean only — no urban heat island. Ships, buoys, buckets.
- Berkeley Earth land and land+oceanKriged station average. Land series is UHI-exposed.
- NASA CERES EBAFTop-of-atmosphere SW, LW, albedo, energy imbalance. 2000–present.
- Nikolov & Zeller 2024 supplementCERES monthly series and Eq. 16 GSAT model (Excel).
- Mann, Bradley & Hughes 1998, NatureGlobal-scale temperature patterns and climate forcing over the past six centuries. doi:10.1038/33859
- Mann, Bradley & Hughes 1999, GRLNorthern Hemisphere temperatures during the past millennium. doi:10.1029/1999GL900070
- McIntyre & McKitrick 2005, GRLHockey sticks, principal components, and spurious significance. Sheep Mountain ~390×. doi:10.1029/2004GL021750
- Graybill & Idso 1993, Global and Planetary ChangeAerial fertilization of strip-bark bristlecones. doi:10.1016/0921-8181(93)90043-M
- Moberg et al. 2005, NatureHighly variable Northern Hemisphere temperatures. doi:10.1038/nature03265
- Wahl & Ammann 2007, Climatic ChangeRobustness of the MBH reconstruction — NOAA emulation file. doi:10.1007/s10584-006-9105-7
- Jones, Briffa, Barnett & Tett 1998, J. ClimateHigh-resolution palaeoclimatic records of the last millennium. doi:10.1175/1520-0442(1998)011<2622:HVATNL>2.0.CO;2
- Ljungqvist 2010, Climate of the PastA new reconstruction of temperature variability in the extra-tropical Northern Hemisphere. doi:10.5194/cp-6-379-2010
- Morice et al. 2021, JGR AtmospheresHadCRUT5 — an independent ensemble of global temperature. doi:10.1029/2019JD032361
- NRC 2006, National Academies PressSurface Temperature Reconstructions for the Last 2,000 Years. doi:10.17226/11676
- Spencer, Christy & Braswell — UAH v6 TLTUniversity of Alabama in Huntsville MSU/AMSU lower-troposphere. https://www.nsstc.uah.edu/climate/
- Mears & Wentz 2017, J. ClimateRSS TLT v4.0 satellite lower troposphere. doi:10.1175/JCLI-D-16-0399.1
- Kennedy et al. 2019, JGR AtmospheresHadSST.4 sea-surface temperature. doi:10.1029/2018JD029867
- Osborn et al. 2021, JGR AtmospheresCRUTEM.5 land air temperature. doi:10.1029/2019JD032113
- Wickham et al. 2013, Geosci. Instrum.Urban heating and the Berkeley Earth land average. doi:10.5194/gi-2-97-2013
- Nikolov & Zeller 2024, GeomaticsCERES albedo + TSI account for 21st-century GSAT in their Eq. 16 model. doi:10.3390/geomatics4030017
- Loeb et al. 2018, J. ClimateCERES Energy Balanced and Filled (EBAF) TOA Ed4. doi:10.1175/JCLI-D-17-0208.1
- This lab’s model: composite-plus-scale (CPS). Z-score each proxy (short-center 1902–1980 or full period), weighted mean, OLS calibrate to HadCRUT5. Not Mann’s 1998 climate-field reconstruction.
- OLS thermometer trajectories. Ordinary least squares on HadCRUT5 NH for 1910–1938 and 1976–present. No GCM.
- No climate model. HadCRUT5 is an instrumental analysis. MBH98’s climate-field reconstruction is not re-run; the dial shows the weighting effect with CPS.
Sheep Mountain original file: ca534-crn-noaa.txt · HadCRUT5 CSV: Met Office · MBH98 NH: mannnhem.dat