Caption: Schematic showing a possible mechanism toward an El Niño-like state, reviewed in Lee et al. (2022). The left column shows the relevant processes in the pre-industrial climate and the right column shows how these same processes initially respond to GHG warming (this schematic does not show the final state). Technical Details (left panel): Convection is strongest in the western Pacific where the SST is the highest. Latent heating warms aloft, and evaporation cools the ocean surface. Right panel: SSTs in the tropical Pacific increase leading to more condensational heating aloft and a higher tropopause, which increases dry static stability and gross moist stability, thus weakening the Walker circulation. At the same time, evaporative cooling and cloud shading are more sensitive to warming in the western Pacific, which weakens the zonal SST gradient. Schematic by climate.gov.