Science

Extreme El Nino weather to double in frequency, study says

The extreme El Nino weather events that fuel deadly natural disasters around the world are on track to occur twice as often — every 10 years — over the next century, climate change scientists warn.

Calamitous weather patterns on track to occur every 10 instead of every 20 years

Cracked ground caused by drought at the Las Canoas Lake is shown in Nicaragua in 2010. (Oswaldo Rivas/Reuters)

The extreme El Nino events that fuel deadly weather around the world will occur twice as often over the next century, climate change scientists warn.

The intense meteorological events typically occur every 20 years, but an international team of researchers has published a report in the journal Nature Climate Change that suggests extreme El Ninos are now on track to happen once a decade.

Extreme El Nino events are known to trigger droughts, torrential rain and flooding around the world. (Reuters)

If these most powerful El Ninos do materialize that frequently, they will likely spawn more natural disasters.

The last extreme El Nino in 1997-1998 killed about 23,000 people and caused an estimated $35 billion in damage.

Unlike conventional El Nino events, which first develop in the western Pacific, the more unusual extreme El Ninos build as the water warms up over the cold and dry eastern equatorial Pacific Ocean. This temperature change throws off worldwide rainfall patterns.

20 climate models

The rainfall shift is known as "reorganization," and is to blame for causing global weather catastrophes such as droughts, floods and bush fires.

"During an extreme El Nino event, countries in the western Pacific such as Australia and Indonesia experienced devastating droughts and wild fire," said lead author Wenju Cai with the Commonwealth Scientific and Industrial Research Organization, Australia's national science agency.

'Extreme El Nino events are likely to double in frequency as the world warms, leading to direct impacts on extreme weather events worldwide'- Wenju Cai, Commonwealth Scientific and Industrial Research Organisation

Meanwhile, devastating floods occurred in the eastern equatorial region of Ecuador and northern Peru, he said.

The new paper involved an analysis of 20 climate models that simulated extreme rainfall.

The scientists found that the warming over the next century of waters in the eastern Pacific Ocean due to climate change would cause a spike in the number of extreme El Nino events.

Between 1890 and 1990, according to the models, extreme El Ninos occurred about every 20 years; from 1990 to 2090, this ramps up to every 10 years.

"This latest research based on rainfall patterns suggests that extreme El Nino events are likely to double in frequency as the world warms, leading to direct impacts on extreme weather events worldwide," Cai concluded.

Climate models show this trend should continue as long as greenhouse gas emissions remain unchecked and the planet continues to warm up.

Scientists have been trying to establish a connection between climate change and El Nino events for more than 20 years, the study's authors said.

"This research is the first comprehensive examination of the issue to produce robust and convincing results," said Mike McPhaden, one of the paper's authors and a researcher with the U.S. National Oceanic and Atmospheric Administration.