Saturn’s second-largest moon, Rhea, is shown in this image obtained by the Cassini spacecraft. Rhea is about 1,527 kilometers in diameter. Cassini took the photograph in full light on Sept. 10, 2013 from a distance of about 1.6 million kilometers. Courtesy NASA, Jet Propulsion Laboratory – California Institute of Technology, Space Science Institute.
The U.S. National Academy of Sciences and Britain’s Royal Society have published a very readable guide to understanding climate change. Interestingly, it starts by posing common questions and answering them in a clear and concise manner.
The primer would likely be helpful to educators, journalists, and those who are seeking increased knowledge about the human-caused phenomenon that is already affecting life on Earth.
Titled Climate Change: Evidence & Causes, the paper is available here.
This image, obtained by NASA’s Solar Dynamics Observatory, shows coronal loops on the Sun between about Feb. 8-10, 2014. These structures are associated with magnetic fields on the surface of our star. The image was taken in ultraviolet light. Image courtesy NASA.
This photograph shows the locations of two embryos and one neonate, along with the female ichthyosaur, documented in a new study that indicates marine reptile viviparity may have evolved on land. Image courtesy Ryosuke Motani.
Scientists have discovered a fossil that preserves an infant prehistoric marine reptile in the process of being born, a find that indicates live birth may have first evolved among land-dwelling organisms.
The specimen dates to about 248 million years ago, during the early Triassic period, and is of a female ichthyosaur, along with two embryos and one neonatal individual.
One of the embryos was still inside its mother when death came, another was partially outside the adult individual’s pelvis, and a third was entirely outside its mother.
The position of the embryo that is half-way out of its mother’s body indicates that head-first birth occurred among ichthyosaurs. If so, then the birth may have occurred on land and not in the water, as has generally been presumed by scientists to be likely in the case of early Mesozoic animals.
Viviparity, as live birth of infants is known, has independently evolved across a wide variety of organisms. It is known in fishes, amphibians, reptiles, and mammals and, even among ichthyosaurs, the phenomenon has been observed in fossils dating from the middle Triassic period to the Cretaceous period.
Mosasaurs and plesiosaurs are other Mesozoic era marine organisms that were viviparous. Those reptiles lived during the Cretaceous period.
The fossil preserved individuals of the genus Chaohusaurus would have plied seas near present-day Chaohu and Yuanan, China. The adult specimen was about 100 centimeters long, while the embryos and neonate were about 18 centimeters long.
A paper documenting the fossil discovery appears in the Feb. 14, 2014 edition of PLOS One.
The fossils documented in it are at the Anhui Geological Museum in Hefei City, China.
Study: EPA underestimating methane emissions, natural gas-fueled vehicles will intensify climate change
This photograph of a natural gas flare was taken in North Dakota. Image courtesy Wikimedia.
A study published Feb. 14 indicates that the nation’s principal air quality regulator is not accurately measuring methane emissions and that conversion of motor vehicles to natural gas and away from diesel fuel is likely to worsen human-caused climate change.
Methane is a greenhouse gas that is far more effective at heat-trapping than is carbon dioxide. According to a website maintained by the U.S. Environmental Protection Agency, “pound for pound, the comparative impact of CH4 on climate change is over 20 times greater than CO2 over a 100-year period.”
That may be an under-estimate. A 2009 paper found that methane has at least 30 times the heat-trapping capability of CO2.
Its prevalence in the atmosphere is now approximately two-and-one-half times what it was during the pre-industrial stage of human history, according to the National Oceanic & Atmospheric Administration, although much less than it was during the first billion or so years of the planet’s existence.
“There does appear to be more methane at the national level than we expect to find,” Adam Brandt, an assistant professor of energy resources engineering at Stanford University and the lead author of this month’s paper, said.
Brandt found that atmospheric emissions of the powerful greenhouse gas are 25-75 percent higher than the U.S. Environmental Protection Agency estimates.
He explained that scientists are not sure of exactly how much of the country’s methane emissions are attributable to the natural gas industry, but that some of it is likely to come from drilling wells, pipelines, and other facilities used to extract and deliver to market a rapidly growing source of energy in the United States.
The cause of the industry’s methane leak problem can be traced to about 50 flawed components of the natural gas production system. This month’s study concluded that about 60 percent of methane leaks can be traced to those flaws.
“The real challenge is, this is a big infrastructure,” Brandt said. “The wells are dispersed across the countryside. There are a lot of pipes, a lot of joints. You’ve got a lot of territory to cover.”
Leaks happen for a variety of reasons. Equipment can be defective, for example, and even when it is operating correctly natural gas that is under pressure can easily escape through hard-to-detect gaps and punctures.
“Anytime you have high pressure gas in a system, it’s going to want to escape,” Brandt said. “It will escape in any hole or crack.”
Some methane is intentionally discharged to the atmosphere.
“There’s a lot of safety equipment, pressure release valves and such, that emit gas when something goes awry,” Brandt explained. “You prevent massive damage and loss of human life by venting gas.”
The problem of unintentional leaks poses financial and logistical challenges to operators. Because the industry’s infrastructure is spread out over a large area, and because leaks can come from very small and hard-to-detect flaws in it, the process of tracking them down and repairing them is expensive.
“These old fashioned ways of finding the leaks, they are labor intensive,” Brandt said. “They want to find them, but it takes lots of time, equipment.”
Human sources of methane account for about 60 percent of total worldwide emissions and the natural gas industry is not the only source of methane pollution of the atmosphere. Livestock, for example, is a major emitter, as are landfills.
Brandt said that his study did not focus on either of these possible avenues of methane pollution.
The paper’s conclusion that EPA may have underestimated the discharge of methane occurring in the United States is consistent with several other recent studies.
One, published last fall in the Proceedings of the National Academy of Sciences, found that total methane emissions in the U.S. were about 50 percent higher than EPA determined during 2007-2008.
Two others that examined local methane emissions in Texas and Utah also concluded that EPA may be inaccurately measuring them.
One commonly advocated mechanism for lowering greenhouse gas pollution is the introduction of natural-gas fueled vehicles. But even as the conversion of petroleum fuels in the vehicles to natural gas can reduce their greenhouse gas emissions by about 30 percent, the production of that natural gas leads to more methane emissions.
“Fueling trucks and buses with natural gas may help local air quality and reduce oil imports, but it is not likely to reduce greenhouse gas emissions,” Brandt said. “Even running passenger cars on natural gas instead of gasoline is probably on the borderline in terms of climate.”
The new study is a synthesis of more than 200 earlier investigations of methane pollution.
Titled “Methane Leakage from North American Natural Gas Systems,” it appears in the Feb. 14 issue of Science.
Graphic courtesy National Oceanic & Atmospheric Administration.
Image courtesy Wheaton College, Johns Hopkins University Applied Physics Laboratory, Brown University, Jet Propulsion Laboratory, Unites States Geological Survey.
Ganymede, one of the four satellites of Jupiter discovered by Galileo in 1610, has been mapped.
The geologic map of Ganymede’s entire surface is the first completed of any moon of the solar system’s outer planets.
Researchers led by Wes Patterson of the Johns Hopkins University Applied Physics Laboratory and Geoffrey Collins of Wheaton College used images obtained by the NASA probes Voyager and Galileo to produce the map.
“This is our best compilation of what we know so far,” Collins said.
He explained that the map was drawn on the basis of data obtained by the Voyager and Galileo probes, which visited the Jovian system in the 1970s and 1990s.
“We were working off a base mosaic, a mosaic put together from the Galileo camera and the Voyager camera that was done by the U.S. Geological Survey,” he said. “They have a lot of cartographic experts there to make sure that the data is located in the right place. The cartographic image data is all based on the cameras from Voyager and Galileo.”
Jupiter’s largest satellite and the largest moon in the solar system, Ganymede is larger than both Mercury and the dwarf planet Pluto. It has an icy outer shell, about 500 miles thick, that was probably primarily the result of tectonic activity.
Scientists suspect this because orbiting spacecraft have observed two different landforms on the moon’s surface. As explained by NASA’s Solar System Exploration site:
Forty percent of the surface of Ganymede is covered by highly cratered dark regions, and the remaining sixty percent is covered by a light grooved terrain, which forms intricate patterns across Ganymede. . . . This grooved terrain is probably formed by tensional faulting or the release of water from beneath the surface. Groove ridges as high as 700 m (2,000 feet) have been observed and the grooves run for thousands of kilometers across Ganymede’s surface. The grooves have relatively few craters and probably developed at the expense of the darker crust. The dark regions on Ganymede are old and rough, and the dark cratered terrain is believed to be the original crust of the satellite. Lighter regions are young and smooth (unlike Earth’s Moon).
Collins said that the map may help scientists figure out the source of Ganymede’s tectonic forces.
“This map is helping us concentrate on separating which part happens at the end and which part at the beginning,” he explained. “By doing that, we can pull back and look at this pattern of motion that was happening on Ganymede’s surface while it was being tectonically ripped apart and compare it to ideas of how those tectonics may be driven by internal processes.”
Ganymede’s tectonic activity is likely the result of either tidal forces or a heat source inside the moon. One clue as to its genesis lies in the fact that changes in Ganymede’s surface do not appear to be constantly occurring.
“The fact that it turned on and turned off again may have something to do with some short-lived internal activity, maybe some heat pulse that was happening inside Ganymede,” Collins said. “One of the theories is that Ganymede may have undergone a tidal heating episode that was short-lived and due to interactions between Ganymede and Europa. Right now they are in orbital resonance. Perhaps when they fell into that resonance Ganymede became very hot on the interior. That would have implications for what’s happening on the surface.”
While the map may help researchers gain a more complete understanding of the moon’s history, it is not likely to answer all the questions about Ganymede.
For example, while scientists are now reasonably sure that volcanism has not been the dominant shaper of Ganymede’s surface, there is a possibility that some craters are actually locations of volcanoes.
“There are these very odd, strange pits that we found in a few different locations on Ganymede,” Collins explained. “On the map they are labeled as depressions. There are about four clusters of them.
“If there were cryo-volcanoes on Ganymede, that’s our best guess about where they might be. They almost look like volcanic calderas.”
The map also provides no information about elevation on Ganymede. Scientists lack the detailed topographic data that could provide an answer to the question whether the more recent, light-colored areas on Ganymede’s surface have a different elevation than the older, dark-colored areas.
“Unlike Mars we’ve never orbited Ganymede,” Collins said. “So we’ve never collected the topographic data that Mars scientists enjoy. We don’t know the answer to that question.”
Despite the uncertainties about Ganymede that remain, Collins thinks the new map is a big step forward for the scientific community.
“It’s gone from being a point of light to being a world in its own right, with its own geology, its own history, its own geography,” he said.
While the map is the first of an outer solar system moon, it is the fourth made of any moon. Earth’s moon, Luna, and two other Jovian moons, Io and Callisto, have been mapped.
A map of Europa should be finished soon.
“There have been preliminary copies floating around,” Collins said.
The European Space Agency is scheduled to send the next probe to the Jovian moons. Known as the Jupiter Icy Moons Explorer, it will launch in 2022 and, upon arriving, spend three years studying Ganymede, Callisto, and Europa.
The map was published by the U.S. Geological Survey. You can download it here.
This image of Ganymede was obtained by NASA’s Galileo probe. Image courtesy Wikimedia.
NOTE: This story was updated on March 3, 2014.
Top: California as seen by NASA’s Terra satellite, Jan. 18, 2013
Bottom: California as seen by NASA’s Terra satellite, Jan. 18, 2014
Images courtesy NASA
The White House said Friday that President Barack Obama will ask Congress to invest $1 billion in a fund aimed at helping researchers improve understanding of climate change impacts, affected communities cope with impacts of the changing climate, and fund infrastructure needed to mitigate climate risk.
The proposal will be included in the administration’s fiscal year 2015 budget request to Congress.
“In addition to responding to the immediate drought in California, the President believes that we must do more to help communities across the country become more resilient to the effects of climate change,” according to a fact sheet released by the White House. “Recent events have reinforced our knowledge that our communities and economy remain vulnerable to extreme weather and natural hazards.”
Obama planned to pitch the Climate Resilience Fund idea during a speech in California Friday.
The fund is not the only financial response to ongoing climate change impacts pursued by the White House.
Obama is also planning to provide tens of millions of dollars of assistance to communities affected by drought, as well as watershed and soil conservation and protection of livestock.