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Oceans slowed down global warming: Study

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Washington: In the recent years, extra heat from greenhouse gases has been trapped in the subsurface waters of the Pacific and Indian oceans accounting for the slowdown in the global surface temperature increase observed during the past decade, shows a study.

The climate researchers from University of California, Los Angeles and NASA’s Jet Propulsion Laboratory found the movement of warm water has affected surface temperatures.

“The western Pacific got so warm that some of the warm water is leaking into the Indian Ocean through the Indonesian archipelago,” said lead author Veronica Nieves and a researcher at the University of California, Los Angeles.

During the 20th century, as greenhouse gas concentration increased and trapped more heat on the Earth, global surface temperatures also increased, said the study that appeared in the journal Science.

However, starting in the early 2000s, though greenhouse gases continued to trap extra heat, the global average surface temperature stopped rising for about a decade and in fact cooled a bit.

Researchers analysed direct ocean temperature measurements, including observations from a global network of about 3,500 ocean temperature probes known as the Argo array.

These measurements show temperatures below the surface have been increasing.

The movement of the warm Pacific water westward pulled heat away from the surface waters of the central and eastern Pacific, which resulted in unusually cool surface temperatures during the last decade.

“Because the air temperature over the ocean is closely related to the ocean temperature, this provides a plausible explanation for the global cooling trend in surface temperature,” Nieves said.

Pauses of a decade or more in Earth’s average surface temperature warming have happened before in modern times, with one occurring between the mid 1940s and late 1970s.

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NASA’s Probe Discovers Signs Of Water on Asteroid Bennu

OSIRIS-REx will pass later this month just 1.2 miles (1.9 km) from Bennu, entering the asteroid's gravitational pull and analyzing its terrain.

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Asteroid
This Nov. 16, 2018, image provide by NASA shows the asteroid Bennu. NASA

NASA’s OSIRIS-REx spacecraft has discovered ingredients for water on a relatively nearby skyscraper-sized asteroid, a rocky acorn-shaped object that may hold clues to the origins of life on Earth, scientists said on Monday.

OSIRIS-REx, which flew last week within a scant 12 miles (19 km) of the asteroid Bennu some 1.4 million miles (2.25 million km) from Earth, found traces of hydrogen and oxygen molecules — part of the recipe for water and thus the potential for life — embedded in the asteroid’s rocky surface.

The probe, on a mission to return samples from the asteroid to Earth for study, was launched in 2016. Bennu, roughly a third of a mile wide (500 meters), orbits the sun at roughly the same distance as Earth. There is concern among scientists about the possibility of Bennu impacting Earth late in the 22nd century.

 

NASA, asteroid
NASA’s OSIRIS-REx. Flickr

 

“We have found the water-rich minerals from the early solar system, which is exactly the kind of sample we were going out there to find and ultimately bring back to Earth,” University of Arizona planetary scientist Dante Lauretta, the OSIRIS-REx mission’s principal investigator, said in a telephone interview.

Asteroids are among the leftover debris from the solar system’s formation some 4.5 billion years ago. Scientists believe asteroids and comets crashing into early Earth may have delivered organic compounds and water that seeded the planet for life, and atomic-level analysis of samples from Bennu could provide key evidence to support that hypothesis.

“When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system,” Amy Simon, a scientist at NASA’s Goddard Space Flight Center in Maryland, said in a statement.

OSIRIS-REx, NASA, Asteroid
This illustration provided by NASA depicts the OSIRIS-REx spacecraft at the asteroid Bennu. The rocky remnant from the dawn of the solar system may hold clues to the origins of life. VOA

“We’re really trying to understand the role that these carbon-rich asteroids played in delivering water to the early Earth and making it habitable,” Lauretta added.

OSIRIS-REx will pass later this month just 1.2 miles (1.9 km) from Bennu, entering the asteroid’s gravitational pull and analyzing its terrain. From there, the spacecraft will begin to gradually tighten its orbit around the asteroid, spiraling to within just 6 feet (2 meters) of its surface so its robot arm can snatch a sample of Bennu by July 2020.

Also Read: Wintertime Ice Growth in Arctic Sea Slows Long-Term Decline: NASA

The spacecraft will later fly back to Earth, jettisoning a capsule bearing the asteroid specimen for a parachute descent in the Utah desert in September 2023. (VOA)