Climate change is causing the Indian Ocean to warm, and this is leading to more frequent and intense positive IOD events. Positive IOD events are associated with droughts in Australia, Indonesia, and East Africa, and floods in India, Sri Lanka, and South Africa.
How does climate change cause more frequent and intense positive IOD events?
Climate change is causing the sea surface temperatures in the western Indian Ocean to rise faster than the sea surface temperatures in the eastern Indian Ocean. This is because the western Indian Ocean is closer to the equator, and the air temperature over the equator is rising faster than the air temperature over the poles.
The rising air temperature over the equator is causing the atmosphere to hold more water vapor. This water vapor is then transported by the winds to the western Indian Ocean, where it falls as rain. The increased rainfall in the western Indian Ocean leads to a build-up of warm water in the region.
The warm water in the western Indian Ocean then causes the air pressure to rise. This high pressure system pushes the winds away from the western Indian Ocean and towards the eastern Indian Ocean. The winds then pick up the warm water from the western Indian Ocean and transport it to the eastern Indian Ocean.
The build-up of warm water in the eastern Indian Ocean leads to a positive IOD event. Positive IOD events are associated with droughts in Australia, Indonesia, and East Africa, and floods in India, Sri Lanka, and South Africa.
The impacts of positive IOD events
Positive IOD events can have a devastating impact on the countries that they affect. Droughts can lead to crop failures, food shortages, and water shortages. Floods can cause widespread damage to infrastructure and property, and can also lead to loss of life.
The following are some of the specific impacts of positive IOD events:
* Australia: Positive IOD events are associated with droughts in eastern Australia. The 2002-03 drought was one of the worst droughts on record in Australia, and it caused widespread crop failures, water shortages, and bushfires.
* Indonesia: Positive IOD events are associated with droughts in Indonesia. The 2015 drought was one of the worst droughts on record in Indonesia, and it caused widespread crop failures, water shortages, and forest fires.
* East Africa: Positive IOD events are associated with droughts in East Africa. The 2010-11 drought was one of the worst droughts on record in East Africa, and it caused widespread crop failures, food shortages, and malnutrition.
* India: Positive IOD events are associated with floods in India. The 2013 floods were some of the worst floods on record in India, and they caused widespread damage to infrastructure and property, and also led to loss of life.
* Sri Lanka: Positive IOD events are associated with floods in Sri Lanka. The 2017 floods were some of the worst floods on record in Sri Lanka, and they caused widespread damage to infrastructure and property, and also led to loss of life.
* South Africa: Positive IOD events are associated with droughts in South Africa. The 2015-16 drought was one of the worst droughts on record in South Africa, and it caused widespread crop failures, water shortages, and wildfires.
Conclusion
Positive IOD events are a natural climate phenomenon, but climate change is making them more frequent and intense. This is having a devastating impact on the countries that they affect, and it is likely to become even worse in the future.
