The "sleeping dragon" of climate change, an area in the western tropical Pacific Ocean, will have a bigger impact on global warming than previously believed, researchers have warned.
Using a new research technique, scientists at UCLA have reconstructed the 1,000 year temperature history of the region to establish what role it has on climate around the globe.
Published in Nature Geoscience, the team found that temperatures in the region near Indonesia have changed by between four and five degrees Celsius over the millennium, more than most models estimate.
The team also looked at how much ocean temperature affect tropical glaciers in the nearby archipelagos of Borneo and Papua New Guinea.
Findings showed the whole region is extremely sensitive to climate change and has warmed considerably since the last ice age 20,000 years ago.
Lead author Aradhna Tripati said: "The tropical Pacific ocean-atmosphere system has been called a sleeping dragon because of how it can influence climate elsewhere. Most global climate models underestimate the average temperature variations that the region has experienced."
The researchers looked specifically at this area because it is Earth's warmest open ocean region, so temperature changes there can influence climate globally.
Examining the calcium carbonate shells of marine plankton for differences in the amounts of carbon-13 and oxygen-18, which show changes in atmospheric carbon dioxide, the team found temperature increase of up to 5C, more than most models previously estimated.
Looking at glaciers in the region, the team found a process called entrainment, which involves atmospheric mixing, had not been factored into models before.
"We found that the large amount of ocean warming goes a long way to explaining why glaciers have retreated so much," Tripati said.
"Throughout the region, they have retreated by close to a kilometre since the last ice age, and are predicted to disappear in the next one to three decades. Previously, understanding this large-scale glacial retreat has been a puzzle. Our results help resolve this problem."
Concluding, the researchers say that sensitivity of the western tropical Pacific Ocean to ocean temperatures must be factored into scientific models to predict future climate change.