Earth's Radiative Energy Imbalance and Climate Sensitivity calculations
(change values in the yellow cells, then press the Tab key ↹ to recalculate)
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| Data-entry cells are yellow |
my best estimates |
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alternative scenarios |
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| Calculated cells are blue |
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alarmist |
skeptic |
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value |
units |
value |
value |
references & notes |
| Starting CO2 level |
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ppmv |
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Preindustrial / LIA (1751) level is usually estimated to have been 277 - 280 ppmv |
| Current CO2 level |
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ppmv |
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https://sealevel.info/co2.html |
| Current CO2 forcing, as fraction of a doubling, Fcd |
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log2( current_CO2_level / starting_CO2_level ) |
| For all the rest of the input fields, higher values are "more alarmist," and lower values are "more skeptical." |
| ECS / TCR, ETratio |
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Lewis & Curry, 2018 |
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IPCC AR5 WG1 Table 9.5, p.818 |
| Unealized portion of (ECS-TCR), Ufract |
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| Fraction of (Fcd% of) ECS realized, Fr |
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(1/ETratio) + ((1-Ufract)×((ETratio-1)/ETratio)) |
| Fraction of (Fcd% of) ECS unrealized ("in the pipe") |
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1 - Fr |
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| Actual realized warming to date since LIA (1780). Wtd |
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°C |
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Law dome ice cores show CO2 level was 280 ppmv in 1780 |
| Anthropogenic fraction of warming to date, Fa |
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| Assumed natural warming since LIA, Wn |
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°C |
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Wn = (1 - Fa) × Wtd |
| Fraction of anthropogenic warming that's from CO2, Fc |
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https://gml.noaa.gov/aggi/ |
| Realized warming since LIA due to CO2 alone, Wc |
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°C |
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Wc = Wtd × Fa × Fc |
| Expected equilibrium warming from CO2 alone, Ec |
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°C |
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Ec = Wc / Fr |
| Realized warming since LIA due to CO2 + other anthro, Wa |
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°C |
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Wa = Wtd - Wn ≡ Wc / Fc |
| Expected equilibrium warming due to CO2 + other anthro, Ea |
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°C |
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Ea = Wa / Fr (assuming same % unrealized for CO2 and other GHGs) |
| Expected equilibrium warming (natural+CO2+other GHGs), Ew |
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°C |
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Ew = Ea + Wn (assuming natural warming component will be unchanged) |
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| Practical climate sensitivity (between ECS & TCR), S |
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°C |
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Wc / Fcd (corrected 9/9/2023) |
| ECS |
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°C |
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https://sealevel.info/glossary.html#ecs |
| TCR |
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°C |
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ECS / ETratio |
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| Radiative forcing from a doubling of CO2, RFd |
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W/m² |
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https://sealevel.info/Radiative_Forcing_synopsis.html |
| Equilibrium warming per W/m² forcing, Ef |
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°C/(W/m²) |
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ECS / RFd |
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| Remaining unrealized warming "in the pipe", Wu |
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°C |
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Ew - Wtd |
| Radiative Imbalance calculated from unrealized warming |
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W/m² |
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Wu / Ef |
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| Radiative imbalance (assumed), Ri |
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W/m² |
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NCA4 Global Mean Energy Budget of Earth |
| Cross-check radiative imbalance & unrealized warming estimates: |
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| Unrealized warming calculated from assumed radiative imbalance, Ri |
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°C |
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Ri × Ef (compare this with Wu) |
| Note: "other anthro" means other anthropogenic forcings, including other GHGs, and aerosol / particulate pollution abatement |
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| Contact: |
Dave Burton |
https://sealevel.info/contact.html |
| This web page was created from a MS Excel spreadsheet using WebWorksheet: |
https://webworksheet.com |
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| The shreadsheet (source .xlsx file) can be downloaded here: |
https://sealevel.info/radiative_imbalance.xlsx |
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