Pacific sea-level linked to global temperature changes

The rise and drop of sea level in the Pacific Ocean can be used to estimate future global surface temperatures, geoscientists have discovered.

Based on the Pacific Ocean's sea level in 2015, the researchers estimated by the end of 2016 the world's average surface temperature will increase up to 0.28 degree Celsius more than in 2014.

In 2015 alone, the average global surface temperature increased by 0.18 Celsius.

"Our prediction is through the end of 2016," said first author Cheryl Peyser, doctoral candidate in geosciences at University of Arizona in the US.

"The prediction is looking on target so far," Peyser noted.

Peyser and her colleagues used measurements of sea level changes taken by NASA/ US National Oceanic and Atmospheric Administration (NOAA)/European satellites starting in 1993.

Using sea surface height rather than sea surface temperatures provides a more accurate reflection of the heat stored in the entire water column, co-author Jianjun Yin, Associate Professor of Geosciences at University of Arizona, said.

"We are the first to use sea level observations to quantify the global surface temperature variability," Yin said.

When sea level in the western Pacific rises more than average -- as it did from 1998 to 2012 -- the rise in global surface temperatures slows, showed the study published online in the journal Geophysical Research Letters.

In contrast, when sea level drops in the western Pacific but increases in the eastern Pacific as it did in 2015, global surface temperatures bump up because the heat stored in the ocean is released, Yin said.

Yin was surprised to find the Pacific Ocean plays such an important role in the global surface temperature.

"Our research shows that the internal variability of the global climate system can conceal anthropogenic global warming, and at other times the internal variability of the system can enhance anthropogenic warming," he said.

The next step, he said, is figuring out the mechanisms that allow the Pacific to change the global surface temperature so quickly.

--IANS

gb/vm