The valley networks of Mars bear a strong resemblance to those found in arid landscapes on Earth. Researchers have been able to demonstrate this using the branching angles of river valley confluences. Based on these observations, they infer that Mars once had a primeval climate in which sporadic heavy precipitation eroded valleys.
In view of the glacial pace of geologic events and the time it takes for things to turn into rock or become encased in it, you might think there would be no hurry to name a new geologic epoch, especially because the current one, the Holocene, started only about 11,500 years ago. You would be wrong. In 2002, Crutzen published an article in Nature magazine, “Geology of Mankind,” which called on geologists “to assign the term ‘Anthropocene’ to the present, in many ways human-dominated, geological epoch, supplementing the Holocene — the warm period of the past 10–12 millennia” and the beginning of which roughly coincided with the advent of human agriculture.The idea of the Anthropocene, which Earth system scientists initiated and advocated, landed like a meteor, setting off a stampede among academics. Nature followed with an editorial that urged that the Anthropocene be added to the geologic timescale. “The first step is to recognize,” Nature editorialized, “that we are in the driver’s seat.”
On 27 and 28 September 2017, eight large rockfalls occurred from the southeast face of El Capitan. These rockfalls resulted in one fatality and two serious injuries, and spurred a complicated rescue and temporary closure of the main road exiting Yosemite Valley. In order to manage these challenging events, the National Park Service (NPS) had a critical, immediate need for quantitative information about the sequence of rockfalls and the potential for additional activity.
Using new “structure-from-motion” photogrammetry techniques in conjunction with baseline laser-scanning data, scientists from the NPS, the U.S. Geological Survey, and the University of Lausanne, Switzerland rapidly analyzed these rockfalls. By comparing 3-dimensional (3D) models of the cliff before, during, and after the rockfalls, the researchers were able to pinpoint the exact locations, dimensions, and volumes of the rockfalls, along with the spatial and temporal pattern of their progression up the cliff.
by M. Bastach, June 28, 2018 in ClimateChangeDispatch
A group of scientists at the University of Rhode Island stumbled on something unexpected when analyzing data brought back from a 2014 expedition to western Antarctica.
Scientists found an abundance of the noble gas Helium-3, indicating there is a volcanic heat source beneath the Pine Island glacier — the fastest melting glacier in the South Pole. The findings were published in a study in the journal Nature Communications.
“When you find helium-3, it’s like a fingerprint for volcanism. We found that it is relatively abundant in the seawater at the Pine Island shelf,” chemical oceanographer Brice Loose, the study’s lead author, said in a statement.
See also here (National Science Foundation) and here
In just the first 6 months of 2018, 254 scientific papers have been published that cast doubt on the position that anthropogenic CO2 emissions function as the climate’s fundamental control knob…or that otherwise serve to question the efficacy of climate models or the related “consensus” positions commonly endorsed by policymakers and mainstream media sources.
James Hansen issued dire warnings in the summer of 1988. Today earth is only modestly warmer.
What about Mr. Hansen’s other claims? Outside the warming models, his only explicit claim in the testimony was that the late ’80s and ’90s would see “greater than average warming in the southeast U.S. and the Midwest.” No such spike has been measured in these regions.
As observed temperatures diverged over the years from his predictions, Mr. Hansen doubled down. In a 2007 case on auto emissions, he stated in his deposition that most of Greenland’s ice would soon melt, raising sea levels 23 feet over the course of 100 years. Subsequent research published in Nature magazine on the history of Greenland’s ice cap demonstrated this to be impossible.
Scientists have argued for decades over what may have caused this mass extinction, during what is called the “Ediacaran-Cambrian transition.” Some think that a steep decline in dissolved oxygen in the ocean was responsible. Others hypothesize that these early animals were progressively replaced by newly evolved animals.
The precise cause has remained elusive, in part because so little is known about the chemistry of Earth’s oceans that long ago.
A research team, led by scientists from Arizona State University and funded by NASA and the National Science Foundation, is helping to unravel this mystery and understand why this extinction event happened, what it can tell us about our origins, and how the world as we know it came to be. The study, published in Science Advances, was led by ASU School of Earth and Space Exploration graduate student Feifei Zhang, under the direction of faculty member Ariel Anbar and staff scientist Stephen Romaniello. (…)
* Most of the plastic waste comes from just a few countries, mostly in Asia and Africa.
* 25% is “leakage” from Asian waste management processes — the rest is waste that has never been collected, but is simply thrown into rivers.
* But European countries ship inject huge quantities of waste into Asian waste management streams, ostensibly for recycling. As much as 20% — millions of tons every year — ends up in the oceans and will continue to do so.
* Since the Chinese banned waste imports at the start of the year, shipments have been diverted to other Asian countries with even weaker environmental controls (Figure 1).
* EU recycling is therefore a major contributor to marine waste and increasing recycling will therefore simply increase marine litter.
While U.S. drillers deploy more rigs than any time since 2015 amid a fracking surge in the Permian Basin, companies including ConocoPhillips, Royal Dutch Shell Plc and Equinor ASA have sold operations or pulled out of Canada’s oil sands, the world’s third largest source of crude reserves.
SPOTLIGHT: The event in which Jim Hansen put climate change on the media map has triggered hallucinations in high places.
BIG PICTURE: I’ve previously discussed how Timothy Wirth, who chaired an historic US senate committee hearing in 1988, has given two accounts of what happened prior to its commencement.
During a 2007 television interview, he jovially described taking measures to circumvent the air conditioning in the meeting room. Global warming was being discussed, and those in attendance were sweltering. After being challenged by a Washington Post fact checker in 2015, however, Wirth caved. In a written statement, he said the pre-hearing measures didn’t happen. Those were just rumours he’d heard. (…)
The discovery of the Durmid Ladder reveals the southern tip of the San Andreas Fault changes fairly gradually into the ladder-like Brawley Seismic zone. The structure trends northwest, extending from the well-known main trace of the San Andreas Fault along the Salton Sea’s northeastern shore, to the newly identified East Shoreline Fault Zone on the San Andreas’ opposite edge.
“We now have critical evidence about the possible nucleation site of the next major earthquake on the San Andreas Fault,” says Jänecke, professor in USU’s Department of Geology. “That possible nucleation site was thought to be a small area near Bombay Beach, California, but our work suggests there may be an additional, longer ‘fuse’ south of the Durmid Ladder within the 37-mile-long Brawley Seismic zone.” …
As readers of my posts know, I’ve held for many years that there are a variety of emergent phenomena that regulate the earth’s temperature. See my posts The Thermostat Hypothesisand Emergent Climate Phenomena for an overview of my hypothesis.
One of the predictions derivable from my hypothesis is that the earth should be relatively insensitive to small changes in forcing. According to my hypothesis, if the total energy entering the system changes in such a manner that the global temperatures start to drop, inter alia the system responds through changes in the time and strength of the daily emergence of the tropical cumulus field and the associated thunderstorms. This allows more sunlight to enter the system and decreases the thunderstorm-caused surface heat losses, balancing out the energy lost elsewhere and maintaining the temperature.
Some of the earliest complex organisms on Earth — possibly some of the earliest animals to exist — got big not to compete for food, but to spread their offspring as far as possible.
The research, led by the University of Cambridge, found that the most successful organisms living in the oceans more than half a billion years ago were the ones that were able to ‘throw’ their offspring the farthest, thereby colonising their surroundings. The results are reported in the journal Nature Ecology and Evolution.
Prior to the Ediacaran period, between 635 and 541 million years ago, life forms were microscopic in size, but during the Ediacaran, large, complex organisms first appeared, some of which — such as a type of organism known as rangeomorphs — grew as tall as two metres.
From the AGU and the “but, but, the continent is melting!” department.
COLDEST PLACE ON EARTH IS COLDER THAN SCIENTISTS THOUGHT
WASHINGTON — Tiny valleys near the top of Antarctica’s ice sheet reach temperatures of nearly minus 100 degrees Celsius (minus 148 degrees Fahrenheit) in the winter, a new study finds. The results could change scientists’ understanding of just how low temperatures can get at Earth’s surface, according to the researchers.
Scientists announced in 2013 they had found the lowest temperatures on Earth’s surface: Sensors on several Earth-observing satellites measured temperatures of minus 93 degrees Celsius (minus 135 degrees Fahrenheit) in several spots on the East Antarctic Plateau, a high snowy plateau in central Antarctica that encompasses the South Pole. But the researchers revised that initial study with new data and found the temperatures actually reach minus 98 degrees Celsius (minus 144 degrees Fahrenheit) during the southern polar night, mostly during July and August.
SPOTLIGHT: Competing accounts of an historic climate hearing.
BIG PICTURE: June 23rd, 1988 is considered the day the climate crusade hit the jackpot. Thirty years ago, a sea of television cameras recorded NASA’s James Hansen testifying before a US Senate committee.
The “greenhouse effect has been detected, and it is changing our climate now,” he said. There was “99 percent confidence” that human-caused global warming was underway.
The person chairing the committee was Democratic Senator Timothy Wirth. Nine years later, when interviewed by PBS’s Frontline, he cheerfully revealed that the date of the hearing had been specially chosen.
La géologie, une science plus que passionnante … et diverse