New York Times: Greenland’s glaciers at a “tipping point.”
John Schwartz
Greenland’s enormous ice sheet is melting at such an accelerated rate that it may have reached a “tipping point” and could become a major factor in sea-level rise around the world within two decades, scientists said in a study published on Monday.
The Arctic is warming at twice the average rate of the rest of the planet, and the new research adds to the evidence that the ice loss in Greenland, which lies mainly above the Arctic Circle, is speeding up as the warming increases. The authors found that ice loss in 2012, more than 400 billion tons per year, was nearly four times the rate in 2003. After a lull in 2013-14, losses have resumed.
With cold air rolling down over much of the eastern United States, it’s the season of the year in which climate change is most easily ignored. In fact, while PBS reports on a new study showing that more Americans than ever understand the unfolding crisis of climate change, another new survey puts climate change at 18th in a list of concerns for Republicans — on a list of 18 items. Denial of climate change has become a shibboleth for Republicans in the age of Trump, and that’s a purity test that may end up costing millions of lives.
The study is the latest in a series of papers published this month suggesting that scientific estimates of the effects of a warming planet have been, if anything, too conservative. Just a week ago, a separate study of ice loss in Antarctica found that the continent is contributing more to rising sea levels than previously thought.
Democrats are going to have to demonstrate unflinching resolve in dealing with climate change, because Republicans are not ready to admit the truth of events that are not predictions of things yet to come, but observations of events already underway. Facing down the wall has proven the mettle of Democrats in DC. But there are bigger tests ahead.
Medicine and Health
STAT News: Ebola vaccine proving to be effective against latest outbreak.
Helen Branswell
There’s some good news related to an Ebola crisis that has offered very little up until now. The World Health Organization now predicts there are adequate supplies of an experimental Ebola vaccine to control the outbreak in the Democratic Republic of the Congo.
As children in the United States are suffering from a renewed out break of measles, here’s a story about how deliberate use of a adequate supply of vaccine is stopping an outbreak of Ebola. This vaccine is still in a clinical trial that might not be completed for months. However, the vital need is pushing its use in the field immediately — and it appears to be working.
“I believe we will have enough vaccine to stop this outbreak unless something very dramatic changes,” Dr. Peter Salama, WHO’s deputy director-general of emergency preparedness and response, told STAT.
Nature: Gut microorganisms in the human gut can boost immune system.
Nathan Reticker-Flynn and Edgar Engleman
The bacteria that live in our bodies have a pivotal role in the maintenance of our health, and can influence a range of conditions, such as obesity and cancer. Perhaps the most important role for the community of microorganisms that live in our gut — termed the microbiota, which include bacteria, fungi and archaea — is to aid immune-system development. Writing in Nature, Tanoue et al. report the identification of 11 strains of bacteria that reside in the guts of some healthy humans and that can boost immune responses that fight infection and cancer.
This is mostly mouse-model data, but it does seem to back up a good deal of statistical research. However, it doesn’t make 99.9 percent of “probiotic” foods or pills any more than wishful thinking.
Geology
National Geographic: What could be the oldest piece of the Earth … was found on the Moon.
Michael Greshko
Scientists may have just found the oldest intact Earth rock—on the moon. A study published Thursday in Earth and Planetary Science Letters makes the case that one of the rocks collected by Apollo 14 astronauts in 1971 contains a fragment of Earth's ancient crust, dating back more than 4.011 billion years.
That rock contains minerals that only form in the presence of water — something that’s decidedly lacking not just in the lunar “seas,” but in other materials retrieved from the Moon’s surface.
It's possible that the fragment formed in a weirdly water-rich pocket of magma deep within the ancient moon. But the study authors think it's likelier that the rock formed within our planet's crust and got jettisoned to the moon by one of the many meteor impacts that bombarded early Earth.
The best evidence is that the Moon was formed from the results of a collision between the Earth and a Mars-sized planet that met in a glancing collision around 4.6 billion years ago. This rock would post-date that event by at least half a billion years, but during that time the Earth and Moon were still getting regularly pelted by big objects. Rocks from the Moon, along with some from Mars and other planetary bodies, have been identified on Earth. So it’s not unexpected that Earth rocks would have bombarded the Moon.
PNAS: Did glaciers cause the Great Unconformity?
C. Brenhin Keller et. al.
For those who didn’t spend their formative years swinging a rock hammer, the Great Unconformity may not ring a bell. It doesn’t represent something that was mismatched, so much as missing — an unconformity in a geologic sense is a place where an expected sequence of rocks is simply missing. The Great Unconformity is a place where, in a lot of places around the world, a lot of rocks are missing. Like much of the planet’s history over a period of a billion years or more.
It has long been observed that the sequence of sedimentary rocks deposited in the past half-billion years often sharply overlies older igneous or metamorphic basement at an erosional surface known as the Great Unconformity. We provide evidence that this unconformity may record rapid erosion during Neoproterozoic “snowball Earth” glaciations. We show that the extent of Phanerozoic sedimentation in shallow continental seas can be accurately reproduced by modeling the accommodation space produced by the proposed glacial erosion, underlining the importance of glaciation as a means for lowering erosional base level. These results provide constraints on the sedimentary and geochemical environment in which the first multicellular animals evolved and diversified in the “Cambrian explosion” following the unconformity.
If all that made little sense, here’s the “hey, you’re not thrilling anyone with your terminology” translation — in the period from about one billion years ago to 540 million years ago, the Earth seemed to have several periods of “global cooling.” These events likely occurred due to the opposite of what we’re seeing now, a real lack of greenhouse gases in the atmosphere. That caused the whole planet, pole to pole, to be covered in ice. Goodbye Earth, Hello Hoth. (Note: there is no paleontological evidence of tauntauns. They were far away.) The new research suggests that, while sedimentary rocks were certainly laid down around the planet over that span, the multiple periods of pole to pole glaciers scrubbed them clean, leaving a layer of older igneous rock to serve as the foundation for new material when Earth finally shrugged off multi-million year winters.
The presence of the Great Unconformity could also be a big part of why the Cambrian Explosion, that point where animals appear in great diversity, looks so explody. There simply isn’t much pre-Cambrian sedimentary material to examine.
Paleontology