This study investigates how the extratropical transition (ET) of tropical cyclones influences downstream weather in the Southern Hemisphere. Two main ET downstream developments are identified: a propagating Rossby wave train along a strong, straight jet, and a more localised downstream ridge associated with a weaker, poleward-oriented jet. The strong ET events in the southwest Indian Ocean can increase the occurrence of high-impact weather over Australia.

Since 1977, Earth has become increasingly less effective in re-radiating the large energy imbalance at the top of the atmosphere. Global surface temperatures and effective radiative forcing estimates through 2025 show that the relationship between these two key parameters is not constant; increased forcing now causes a power-law increase in surface temperature. If forcing keeps rising at the current rate, Earth’s temperature anomaly compared to 1850–1900 will reach 2.8 ± 0.3 °C by 2050.