Drought, El Nino & Adaptation
What Is Drought?
A drought is a long period of lower-than-average rainfall that causes water shortages. Droughts can last months or many years, and they range from mild dry spells to disasters that destroy harvests and force communities to move. Drought is one of the world’s most damaging natural hazards because it affects food, drinking water, ecosystems and energy — everything that life depends on.
El Nino warms the central and eastern Pacific Ocean and is linked to drought in Australia, Indonesia and parts of southern Africa. La Nina cools that same Pacific region and is linked to drought in the southern USA and parts of South America.
El Nino and La Nina Explained
In a normal year, strong trade winds push warm surface waters across the Pacific from South America towards Indonesia and Australia. Warm, moist air rises in the western Pacific and brings heavy rainfall to Australia and South-East Asia. The cool eastern Pacific, off Peru, has rich fisheries.
During El Nino, the trade winds weaken or even reverse. The warm pool of water sloshes back eastwards. Rain that would normally fall on Australia and Indonesia instead falls over the eastern Pacific or Peru. Droughts follow in the western Pacific. La Nina is the mirror image — trade winds blow harder, the eastern Pacific off South America cools, and Australia and Indonesia receive heavier rainfall while the south-west USA, Argentina and parts of east Africa can dry out. The full pattern is called the El Nino–Southern Oscillation, or ENSO.
Strong El Nino and La Nina events occur on average every 3 to 7 years, although the cycle is not regular. Major El Nino events in 1997–98, 2015–16 and 2023–24 caused severe droughts and wildfires across the western Pacific, while the major La Nina from 2020 to 2022 brought repeated flooding to eastern Australia.
Case Study: The Millennium Drought, Australia (2001–2009)
Australia is highly exposed to ENSO. Between 2001 and 2009 south-eastern Australia experienced its worst drought since records began — the Millennium Drought. The Murray-Darling Basin, which produces around 40% of Australia’s farm output, lost more than half its inflows. The drought coincided with the strong El Nino of 2002 and a series of weaker El Nino events through the decade, plus higher background temperatures from climate change.
Effects on People
Wheat harvests fell by 36% in 2002 alone, and livestock numbers were cut sharply as farmers sold animals they could not water. Many family-run farms went out of business. City reservoirs around Melbourne, Adelaide and Sydney dropped below 30% capacity. Water restrictions banned hosepipes and limited shower times. Mental-health services reported a sharp rise in stress and depression in farming communities, and the Bureau of Statistics linked the drought to increased rural-to-urban migration.
Effects on the Environment
River flows in the Murray-Darling fell so low that the lower reaches stopped reaching the sea. Wetlands shrank, killing river red gum trees and threatening waterbirds. Bushfires intensified, including the ‘Black Saturday’ fires of February 2009 in Victoria, which killed 173 people. Dust storms swept thousands of kilometres — in September 2009 a single storm dumped red dust across Sydney, lowering visibility to less than 100m.
The Murray-Darling Basin produces around 40% of Australia’s farm output. During the Millennium Drought (2001–2009) it lost more than half of its normal river inflows, and Black Saturday bushfires (February 2009) killed 173 people.
How People Adapted
Australia’s response shows a wide range of adaptation strategies:
- Water-saving in cities — nationwide rules limited garden watering. Households fitted dual-flush toilets and rainwater tanks; greywater (used water from showers and basins) was reused for gardens.
- New water sources — large desalination plants opened in Sydney, Perth, Melbourne and Adelaide between 2006 and 2012, removing salt from sea water to give a drought-proof supply.
- Smarter farming — many farmers shifted to drip irrigation, drought-tolerant wheat varieties, and crops needing less water like canola.
- Murray-Darling Basin Plan (2012) — this huge agreement caps how much water farmers can take from the rivers, leaving more for the environment and downstream communities.
- Better forecasting — the Bureau of Meteorology now publishes ENSO outlooks so farmers and water managers can plan ahead.
By the time El Nino returned in 2015–16 and again in 2018–19, Australian cities were able to keep water flowing using their desalination plants and stricter rules. Farming losses, while still significant, were less severe than in 2002. Critics argue desalination is energy-hungry and expensive, and that the Murray-Darling Basin Plan has been weakened by political pressure from large agricultural users. The drought has not gone away — long-term climate projections suggest south-eastern Australia will keep trending drier.