Far Northern Permafrost May Unleash Carbon Within Decades

Permafrost in the coldest northern Arctic — formerly thought to be at least temporarily shielded from global warming by its extreme environment — will thaw enough to become a permanent source of carbon to the atmosphere in this century, with the peak transition occurring in 40 to 60 years, according to a new NASA-led study.

The study calculated that as thawing continues, total carbon emissions from this region over the next 300 years or so will be 10 times as much as all human-produced fossil fuel emissions in the single year 2016.

The study, led by scientist Nicholas Parazoo of NASA’s Jet Propulsion Laboratory in Pasadena, California, found that warmer, more southerly permafrost regions will not become a carbon source until the end of the 22nd century, even though they are thawing now. That is because other changing Arctic processes will counter the effect of thawing soil in these regions.

The finding that the colder region would transition sooner than the warmer one came as a surprise, according to Parazoo. “Permafrost in southern Alaska and southern Siberia is already thawing, so it’s obviously more vulnerable,” he said. “Some of the very cold, stable permafrost in the highest latitudes in Alaska and Siberia appeared to be sheltered from extreme climate change, and we didn’t expect much impact over the next couple hundred years.”

Permafrost is soil that has remained frozen for years or centuries under topsoil. It contains carbon-rich organic material, such as leaves, that froze without decaying. As rising Arctic air temperatures cause permafrost to thaw, the organic material decomposes and releases its carbon to the atmosphere in the form of the greenhouse gases carbon dioxide and methane.

Parazoo and his colleagues used data on soil temperatures in Alaska and Siberia from the University of Alaska, Fairbanks, with a numerical model from the National Center for Atmospheric Research in Boulder, Colorado, that calculates changes in carbon emissions as plants grow and permafrost thaws in response to climate change. They assessed when the Arctic will transition to a carbon source instead of the carbon-neutral area it is today — with some processes removing about as much carbon from the atmosphere as other processes emit. They divided the Arctic into two regions of equal size, a colder northern region and a warmer, more southerly belt encircling the northern region.

There is far more permafrost in the northern region than in the southern one. Over the course of the model simulations, northern permafrost lost about five times more carbon per century than southern permafrost.

The southern region transitioned more slowly in the model simulations, Parazoo said, because plant growth increased much faster than expected in the south. Plants remove carbon dioxide from the air during photosynthesis, so increased plant growth means less carbon in the atmosphere. According to the model, as the southern Arctic grows warmer, increased photosynthesis will balance increased permafrost emissions until the late 2100s.

Results of the study are published in the journal The Cryosphere. To read the paper, visit:

https://www.the-cryosphere.net/12/123/2018/

Updated on 3/6/18 at 4:10 p.m. to clarify the total amount of Arctic carbon emitted by thawing permafrost, in paragraph 2, and adding a link to the study

Mars Orbiter Recovering from Precautionary Pause in Activity

Mars Odyssey Mission Status Report

NASA’s Mars Odyssey orbiter, which has been in service at Mars since October 2001, put itself into safe mode — a protective standby status — on Dec. 26, while remaining in communication with Earth.

The Odyssey project team has diagnosed the cause — an uncertainty aboard the spacecraft about its orientation with regard to Earth and the sun — and is restoring the orbiter to full operations. Odyssey’s communication-relay service for assisting Mars rover missions is expected to resume this week, and Odyssey’s own science investigations of the Red Planet are expected to resume next week.

The orbiter’s knowledge of its orientation was restored Dec. 26 by resetting the inertial measurement unit and the circuit card that serves as interface between that sensor, the flight software and the star tracker, for determining spacecraft attitude. The mission last experienced a similar fault and solution in December 2013.

Mars Odyssey left Earth on April 7, 2001, entered orbit around Mars on Oct. 24, and began systematically examining Mars in February 2002. In December 2010, it surpassed the previous record for longevity of a robotic mission at Mars. The Mars Odyssey Project has been extending that record daily for more than six years.

In addition to its direct contributions to planetary science, Odyssey provides important support for other missions in NASA’s Journey to Mars through communication-relay service and observations of candidate landing sites.

NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Odyssey Project for NASA’s Science Mission Directorate in Washington. Lockheed Martin Space Systems, Denver, built the spacecraft and collaborates with JPL in mission operations. For more information about Odyssey, visit:

http://mars.jpl.nasa.gov/odyssey

NASA’s NEOWISE Mission Spies One Comet, Maybe Two

NASA’s NEOWISE mission has recently discovered some celestial objects traveling through our neighborhood, including one on the blurry line between asteroid and comet. Another–definitely a comet–might be seen with binoculars through next week.

An object called 2016 WF9 was detected by the NEOWISE project on Nov. 27, 2016. It’s in an orbit that takes it on a scenic tour of our solar system. At its farthest distance from the sun, it approaches Jupiter’s orbit. Over the course of 4.9 Earth-years, it travels inward, passing under the main asteroid belt and the orbit of Mars until it swings just inside Earth’s own orbit. After that, it heads back toward the outer solar system. Objects in these types of orbits have multiple possible origins; it might once have been a comet, or it could have strayed from a population of dark objects in the main asteroid belt.

2016 WF9 will approach Earth’s orbit on Feb. 25, 2017. At a distance of nearly 32 million miles (51 million kilometers) from Earth, this pass will not bring it particularly close. The trajectory of 2016 WF9 is well understood, and the object is not a threat to Earth for the foreseeable future.

A different object, discovered by NEOWISE a month earlier, is more clearly a comet, releasing dust as it nears the sun. This comet, C/2016 U1 NEOWISE, “has a good chance of becoming visible through a good pair of binoculars, although we can’t be sure because a comet’s brightness is notoriously unpredictable,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California.

As seen from the northern hemisphere during the first week of 2017, comet C/2016 U1 NEOWISE will be in the southeastern sky shortly before dawn. It is moving farther south each day and it will reach its closest point to the sun, inside the orbit of Mercury, on Jan. 14, before heading back out to the outer reaches of the solar system for an orbit lasting thousands of years. While it will be visible to skywatchers at Earth, it is not considered a threat to our planet either.

NEOWISE is the asteroid-and-comet-hunting portion of the Wide-Field Infrared Survey Explorer (WISE) mission. After discovering more than 34,000 asteroids during its original mission, NEOWISE was brought out of hibernation in December of 2013 to find and learn more about asteroids and comets that could pose an impact hazard to Earth. If 2016 WF9 turns out to be a comet, it would be the 10th discovered since reactivation. If it turns out to be an asteroid, it would be the 100th discovered since reactivation.

What NEOWISE scientists do know is that 2016 WF9 is relatively large: roughly 0.3 to 0.6 mile (0.5 to 1 kilometer) across.

It is also rather dark, reflecting only a few percent of the light that falls on its surface. This body resembles a comet in its reflectivity and orbit, but appears to lack the characteristic dust and gas cloud that defines a comet.

“2016 WF9 could have cometary origins,” said Deputy Principal Investigator James “Gerbs” Bauer at JPL. “This object illustrates that the boundary between asteroids and comets is a blurry one; perhaps over time this object has lost the majority of the volatiles that linger on or just under its surface.”

Near-Earth objects (NEOs) absorb most of the light that falls on them and re-emit that energy at infrared wavelengths. This enables NEOWISE’s infrared detectors to study both dark and light-colored NEOs with nearly equal clarity and sensitivity.

“These are quite dark objects,” said NEOWISE team member Joseph Masiero, “Think of new asphalt on streets; these objects would look like charcoal, or in some cases are even darker than that.”

NEOWISE data have been used to measure the size of each near-Earth object it observes. Thirty-one asteroids that NEOWISE has discovered pass within about 20 lunar distances from Earth’s orbit, and 19 are more than 460 feet (140 meters) in size but reflect less than 10 percent of the sunlight that falls on them.

The Wide-field Infrared Survey Explorer (WISE) has completed its seventh year in space after being launched on Dec. 14, 2009.

Data from the NEOWISE mission are available on a website for the public and scientific community to use. A guide to the NEOWISE data release, data access instructions and supporting documentation are available at:

http://wise2.ipac.caltech.edu/docs/release/neowise/

Access to the NEOWISE data products is available via the on-line and API services of the NASA/IPAC Infrared Science Archive.

A list of peer-reviewed papers using the NEOWISE data is available at:

http://neowise.ipac.caltech.edu/publications.html