This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a set of 21st-century climate model experiments from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The results show that the strength of the atmospheric overturning circulation decreases as the climate warms, consistent with thermodynamic scaling arguments. This weakening primarily affects the zonally asymmetric (Walker) component rather than the zonal-mean (Hadley) component of the tropical circulation. The changes in the atmospheric and oceanic circulation over the tropical Pacific Ocean resemble "El Niño-like" conditions but are distinct from El Niño mechanisms. The Indian Ocean response to global warming is similar to that of Indian Ocean dipole mode events. The models' projections are consistent with observed changes in sea level pressure since the mid-19th century. The study also explores the spatial structure of circulation changes, showing a weakening of the Walker circulation and a more "El Niño-like" state in the Pacific. The oceanic response includes changes in thermal structure and circulation, such as a shoaling of the thermocline in the western Pacific and a reduction in surface currents. These findings highlight the significant impact of global warming on the tropical atmospheric and oceanic circulation.This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a set of 21st-century climate model experiments from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The results show that the strength of the atmospheric overturning circulation decreases as the climate warms, consistent with thermodynamic scaling arguments. This weakening primarily affects the zonally asymmetric (Walker) component rather than the zonal-mean (Hadley) component of the tropical circulation. The changes in the atmospheric and oceanic circulation over the tropical Pacific Ocean resemble "El Niño-like" conditions but are distinct from El Niño mechanisms. The Indian Ocean response to global warming is similar to that of Indian Ocean dipole mode events. The models' projections are consistent with observed changes in sea level pressure since the mid-19th century. The study also explores the spatial structure of circulation changes, showing a weakening of the Walker circulation and a more "El Niño-like" state in the Pacific. The oceanic response includes changes in thermal structure and circulation, such as a shoaling of the thermocline in the western Pacific and a reduction in surface currents. These findings highlight the significant impact of global warming on the tropical atmospheric and oceanic circulation.