The northern parts of the Larsen ice shelf, eastern Antarctic Peninsula (AP) have experienced dramatic break-up since the early 1990s as a result of strong summertime surface melt, which has been linked to stronger circumpolar westerly winds. Here we show extreme summertime surface melt and high temperatures over the eastern AP and Larsen C ice shelf occur because of enhanced deep convection in the central tropical Pacific, which produces cyclonic conditions across the middle and high-latitude South Pacific, and a strong high pressure anomaly over Drake Passage. Together these transport extreme heat and moisture from low latitudes to the AP, at times in the form of "atmospheric rivers", producing strong surface warming and melt on the Larsen ice shelf by the Foehn effect. Therefore, variability in central tropical Pacific convection is crucial for interpreting past and projecting future AP surface mass balance and extreme temperature events.