Context: Large volcanic eruptions can help to forecast the monsoon over India – the seasonal rainfall that is key for the country’s agriculture and thus for feeding one billion people.
- The tiny particles and gases that large volcano blasts into the air enter into the stratosphere and remain there for a few years.
- While the volcanic matter in the stratosphere to some extent blocks sunshine from reaching the Earth’s surface, the reduced solar forcing increases the probability of an El Niño event in the next year.
- This is because less sunshine means less warmth and hence a change of temperature differences between the Northern and Southern hemisphere, which in turn affects the atmospheric large-scale circulation and precipitation dynamics.
- Advanced data analysis now reveals that large volcanic eruptions are more likely to promote the coincidence of warm El Niño events over the Pacific and Indian monsoon droughts – or, in contrast, cool La Niña events over the Pacific and Indian monsoon excess.”
- Paleoclimate archives: tree-rings, corals, cave deposits and ice-cores from past millennia of Earth history