Scientists have discovered a climate phenomenon similar to El Nino, which started off the coast of New Zealand, could cause temperature changes across the Southern Hemisphere.
El Nino and La Nina, temperature swings in the eastern Pacific, impact the world, causing droughts and floods in different regions. Scientists have now discovered a similar phenomenon with impacts spreading across the Southern Hemisphere, starting in a small area of the Pacific Ocean, off the coast of New Zealand, IFL Science July 24 news.
Specifically, they simulated climate conditions over 300 years of pre-industrial times and found a pattern of sea surface temperatures that consistently repeated. The new study, published in the journal Geophysical Research: Oceansconducted by a team of experts at the Indian Institute of Technology Kharagpur and the Japan Agency for Marine-Earth Science and Technology.
The team has named the new phenomenon the Southern Hemisphere Circumpolar Wave Number 4, or W4. “This discovery is like finding a new ‘switch’ for the Earth’s climate. It shows that a relatively small ocean region can have a profound impact on the world’s climate and weather patterns,” said Balaji Senapati, a member of the team and an expert at the Indian Institute of Technology Kharagpur.
W4 begins off the coast of New Zealand, when an unusually warm or cool area of water forms during the Southern Hemisphere summer. This causes an atmospheric ripple, creating alternating regions of opposite temperatures around seas at similar latitudes. When complete, the wave pattern consists of four warm regions and four cool regions.
W4 tends to dissipate in late fall (Southern Hemisphere), meaning it typically lasts shorter than El Nino and La Nina. Many weather events are associated with either El Nino or La Nina. However, W4 can occur with both or occur in neutral years.
Most people don’t pay much attention to sea surface temperatures unless they influence conditions on land, which happens with El Nino and La Nina. In the new study, the team of scientists notes that W4’s influence on rainfall on land needs further study.
El Nino and La Nina can have devastating consequences in vulnerable areas. In bad years, droughts and floods can kill hundreds of thousands of people. Food supplies are also frequently disrupted, but improved knowledge and ability to predict El Nino and La Nina have significantly reduced the damage as farmers adjust their operations.
Senapati said the same is true for W4. “Understanding this new weather system could significantly improve weather forecasting and climate prediction, especially in the Southern Hemisphere. It also has the potential to help decipher previously unexplained climate changes and improve our ability to predict extreme weather and climate events,” he said.