
The International Research Institute for Climate and Society at Columbia University. Every month it collects the ENSO forecasts of two dozen modelling centres into one figure - the plume.The IRI also goes beyond just presenting forecasts. It works with partners in Africa, Asia, and Latin America to translate climate predictions into actionable information for agriculture, water management, and health. For example, a forecast of a dry season can help farmers choose drought-resistant crops or adjust planting dates. The institute's mission is to bridge the gap between climate science and real-world decision-making, making the vast amount of climate data generated by research institutions useful to those who need it most.
The IRI was established in 1996 as a cooperative agreement between Columbia University, the U.S. National Oceanic and Atmospheric Administration, and other partners, building on earlier efforts to apply climate forecasts to societal needs. The plume has been published monthly since the early 2000s and has become a standard reference in the climate community.
The plume is then plotted as a graph showing the observed temperature history up to the present and the forecasted range for the next several months. Each model's forecast is a single line, and the spread of lines gives a visual measure of uncertainty. The IRI also provides a probabilistic interpretation, indicating the likelihood of El Niño, La Niña, or neutral conditions based on how many models agree and their historical skill.
The IRI's forecasts are used by humanitarian organizations like the Red Cross to preposition aid before predicted disasters, by agricultural ministries to issue planting advisories, and by water managers to plan reservoir operations.
The plume is so widely watched that when it shows a strong El Niño developing, it can influence commodity markets—coffee, cocoa, and sugar prices often move in response to IRI's monthly updates.




















