Recent budget cuts have left a key ocean-monitoring warning system - built to track devastating El Nino and La Nina events in the eastern equatorial Pacific - near collapse.
This is set to deprive scientists of data on a region that influences global weather and climate trends.
Nearly half of the moored buoys in the Tropical Atmosphere Ocean (TAO) array - a network of deep-ocean buoys at 67 sites in the equatorial Pacific that collect ocean and atmospheric data - have failed in the last two years, says a report published in the journal Nature.
Scientists are now collecting data from just 40 percent of the array.
"It's the most important climate phenomenon on the planet, and we have blinded ourselves to it by not maintaining this array," said Michael McPhaden, a senior scientist at the US National Oceanic and Atmospheric Administration (NOAA) in Seattle, Washington, DC.
The network was developed over the course of a decade following the massive El Nino of 1982-83.
The array's troubles began in 2012 when budget cuts pushed NOAA to retire a ship dedicated to performing the annual servicing that keeps the TAO buoys in working order, added the report.
According to McPhaden, NOAA's annual budget for the project stood at about $10-12 million before 2012, including nearly $6 million to cover the dedicated ship.
In the fiscal year 2013, the agency spent $2-$3 million to charter boats for maintenance runs, but these operations have not been enough to keep the system going, warned McPhaden.
NOAA maintains some 55 buoys that monitor weather conditions as well as water temperatures down to 500 metres.
Apart from NOAA, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) maintains another dozen buoys in the western tropical Pacific.
Together, the early-warning system has become crucial for seasonal weather forecasting, added the report.
According to the report, to discuss possible solutions, researchers from around the world are scheduled to meet next week at Scripps Institution of Oceanography in La Jolla, California.
"The array revolutionised our science, and to let it deteriorate is such a waste of the investment the Americans have made over the last 30 years," said Wenju Cai, a climate modeller at the Commonwealth Scientific and Industrial Research Organisation in Aspendale, Australia.
In addition to supporting climate research, the TAO array also provides basic data for seasonal weather forecasts issued by various government agencies around the world.
Extreme El Ninos occur when sea surface temperatures exceeding 28 degrees Celsius develop in the normally cold and dry eastern equatorial Pacific Ocean.
