evidence: Because of the vastness of the Pacific basin—covering one-third of the planet—these wind and humidity changes get transmitted around the world, disrupting circulation patterns such as jet streams (strong upper-level winds). We know these large-scale shifts in Pacific winds and waters initiate El Niño. What we don't know is what triggers the shift. This remains a scientific mystery. [...] Fires raging in Indonesia. Fisheries collapsing off Peru. Delayed monsoon rains over India. Floods and mosquito-borne disease outbreaks in South America. Epic drought and mass migrations in southern Africa. Once an El Niño is declared, it seems every extreme weather-related event in the world is blamed on this phenomenon. El Niño is the largest natural disruption to the Earth system, with direct impacts across most of the Pacific Ocean. Indirect impacts reverberate around the globe in patterns that scientists refer to as "teleconnections." Scientists are actively trying to understand how these changes in weather patterns in one area can alter the movement of air masses and winds in areas adjacent to and even far away from the source. According to the International Research Institute for Climate and Society at Columbia University, El Niño-Southern Oscillation is responsible for as much as 50 percent of year-to-year climate variability in some regions of the world.