Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


CU, Old Dominion team finds sea level rise in western tropical Pacific anthropogenic


Sea rise off coasts of Philippines, northeastern Australia rising at about 1 centimeter per year

A new study led by Old Dominion University and the University of Colorado Boulder indicates sea levels likely will continue to rise in the tropical Pacific Ocean off the coasts of the Philippines and northeastern Australia as humans continue to alter the climate.

The study authors combined past sea level data gathered from both satellite altimeters and traditional tide gauges as part of the study. The goal was to find out how much a naturally occurring climate phenomenon called the Pacific Decadal Oscillation, or PDO, influences sea rise patterns in the Pacific, said Assistant Professor Benjamin Hamlington of Old Dominion University in Norfolk, Va., a former CU-Boulder postdoctoral researcher and lead study author.

The PDO is a temperature pattern in the Pacific Ocean akin to El Niño but which lasts roughly 20 to 30 years and contributes significantly to the decadal trends in regional and global sea level, said CU-Boulder Research Professor Robert Leben, a study co-author. The research team performed sea level reconstructions going back to 1950 by fitting patterns of satellite altimeter data to tide gauge data, then stripped away the effects of the PDO to better understand its influence on current sea level increases in the Pacific.

"The conventional wisdom has been that if the Pacific Decadal Oscillation was removed from the equation this sea level rise in parts of the Pacific would disappear," said Hamlington, who received his doctorate from CU-Boulder. "But we found that sea level rise off the coasts of the Philippines and northeastern Australia appear to be anthropogenic and would continue even without this oscillation."

A paper on the subject was published online in the July 20 issue of Nature Climate Change. Other co-authors on the study included CU-Boulder doctoral student Matthew Strassburg, CU-Boulder Associate Professor Weiqing Han, CU-Boulder Professor R. Steven Nerem and Seoul National University faculty member K.Y. Kim. The study was funded primarily by NASA and the National Science Foundation.

The team also used NASA climate models to assess sea level rise in the tropical Pacific that included data on the warming tropical Indian Ocean, which has been shown in previous studies to be caused by increases in greenhouse gases. The climate modeling portion of the new study also showed sea level rise near the Philippines and Australia is caused at least in part by anthropogenic, or human-caused, warming said Hamlington, who got his doctorate under Leben.

The research team estimated that areas of the ocean near the Philippines and northeast Australia are being raised by about 1 centimeter per year due to anthropogenic warming, which can increase the intensity of severe weather. "When water starts piling up there and typhoon-like storms are traveling over higher sea levels, it can be a bad situation," said Hamlington.

Although global sea level patterns are not geographically uniform -- sea level rise in some areas correlate with sea level fall in other areas -- the average current global sea level rise is roughly 3 millimeters per year. Some scientists are estimating global seas may rise by a meter or more by the end of the century as a result of greenhouse warming.

"When the current PDO switches from its warm phase to its cool phase sea levels on the western coast of North America likely will rise," said Leben of CU-Boulder's aerospace engineering sciences department. "I think the PDO has been suppressing sea level there for the past 20 or 30 years."

In a broader sense, the new study shows that scientists may be able to look at other regions of the world's oceans and extract the natural climate variability in order to measure human-caused effects, said Hamlington, a researcher at CU-Boulder's Cooperative Institute for Research in Environmental Sciences. "This kind of research may start revealing patterns that we might not expect."

Most of the satellite altimeter data for the study came from NASA's Topex-Poseidon and Jason satellite series missions. Satellite altimetry measures sea level rise by bouncing radar pulses off the surface of the ocean at particular points and calculating the round-trip time it takes the pulse to return to the spacecraft said Leben, also a faculty member of CU-Boulder's Colorado Center for Astrodynamics Research, or CCAR.

A 2010 study led by CU-Boulder's Han published in Nature Geoscience concluded that greenhouse gases were responsible for rising seas in parts of the Indian Ocean. The changes are believed to be at least partially a result of the roughly 1 degree Fahrenheit increase in the Indo-Pacific warm pool -- an enormous, bathtub-shaped area stretching from the east coast of Africa to the International Date Line in the Pacific -- during the past 50 years.


For more information on CU-Boulder's aerospace engineering sciences department visit For more information on CCAR visit For more information on CIRES visit



Benjamin Hamlington, 303-735-0483

Robert Leben, 303-492-4113

Jim Scott, CU-Boulder media relations, 303-492-3114

Robert Leben | Eurek Alert!

Further reports about: El Niño Pacific greenhouse rise satellite sea level tropical

More articles from Earth Sciences:

nachricht Stretchy Slabs Found in the Deep Earth
30.11.2015 | University of Southampton

nachricht Rapid plankton growth in ocean seen as sign of carbon dioxide loading
27.11.2015 | Johns Hopkins University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How Cells in the Developing Ear ‘Practice’ Hearing

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular chain of events that enables the cells to make “sounds” on their own, essentially “practicing” their ability to process sounds in the world around them.

The researchers, who describe their experiments in the Dec. 3 edition of the journal Cell, show how hair cells in the inner ear can be activated in the absence...

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

All Focus news of the innovation-report >>>



Event News

Urbanisation and migration from rural areas challenging agriculture in Eastern Europe

30.11.2015 | Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Latest News

Teamplay IT solution enables more efficient use of protocols

30.11.2015 | Trade Fair News

Greater efficiency and potentially reduced costs with new MRI applications

30.11.2015 | Trade Fair News

Modular syngo.plaza as a comprehensive solution – even for enterprise radiology

30.11.2015 | Trade Fair News

More VideoLinks >>>