About this episode
Joseph Fournier presents “part two” on how Pacific Walker circulation controls Earth’s largest greenhouse effect: cloud longwave radiative forcing. He explains cloud radiative forcing terminology, cites literature claiming cloud greenhouse warming dwarfs CO2 forcing, and shows satellite-era links between trade winds, cloud shifts during ENSO, outgoing longwave radiation, and global/tropical temperature anomalies. He contrasts absorbed solar radiation, OLR, and Earth energy imbalance, arguing global averages can be dominated by regional Pacific dynamics. He reviews multidecadal “dimming/brightening” sunshine trends in Europe, Japan and the U.S., discusses aerosols vs natural drivers, and briefly addresses future uncertainty, AMO/IPO impacts, and solar/cosmic-ray hypotheses. 00:00 Welcome Back: Joseph Fournier & Why This Is “Part Two”02:15 Cloud Basics 101: Shortwave vs Longwave, Net Cloud Radiative Forcing05:51 Albedo Matters: How Small Cloud Changes Rival CO? Forcing08:40 Evidence in the Literature: Trendberth and Early Satellite Cloud Forcing Maps14:28 Clouds vs CO? Since 2000: Step-Change in Cloudiness and OLR16:56 Geography Over Global Averages: The Western Pacific Warm Pool Hotspot20:12 Warm Pool Size, SST, and Real-World Impacts (Winters, ENSO Timescales)22:48 Walker Circulation Explained: Where Deep Convection Sits in La Niña vs El Niño25:34 Warm Pool “Thermal Capacitor”: Thermocline Slosh, Water Volume, and Cloud Shift30:32 Sea Level Pile-Up and the Gravity-Driven Discharge During El Niño32:36 Radiation Signatures of ENSO: DLW/OLR Links to Niño Indices36:13 Cloud Forcing Ratios & Decadal Patterns: What El Niño Does to Warm Pool Clouds40:34 Global Signals: OLR vs Global Air Temperature and the ENSO Lead–Lag45:14 Trade Winds as the Control Knob: Linking Pacific Easterlies to Global OLR47:44 Tropical temps, OLR & trade winds: Walker circulation link48:42 Clouds as the “other knob”: absorbed shortwave (ASR) vs temperature50:29 2023 El Niño cloud changes: low-cloud cover & shifting albedo53:49 ASR vs OLR since 2000: the hiatus ends and the energy budget shifts55:44 Earth Energy Imbalance (EEI) vs GAT: why the correlation breaks57:58 Seasonal cycle first: EEI swings, hemispheres, clouds & land–ocean contrast01:00:10 Wrap-up: two greenhouse effects & a call for academics to test it01:02:54 Sunshine hours & AMO: UK/Europe brightening over the 20th century01:07:26 Aerosols vs clouds: modern satellite trends and the “brightening” debate01:11:53 Global dimming/brightening goes global: Japan/China records & Pacific teleconnections01:12:56 Natural vs human drivers: when aerosols don’t explain surface radiation01:18:13 Forecasting the next decade: sun, AMO/IPO, cooling claims & big uncertainties01:26:17 Closing remarks: slides, Substack, and the climate–
