'A World Without Clouds': New Study Details Possibility of Devastating Climate Feedback Loop
By Jessica Corbett
As people across the globe mobilize to demand bold action to combat the climate crisis and scientific findings about looming "environmental breakdown" pile up, a startling new study published Monday in the journal Nature Geoscience warns that human-caused global warming could cause stratocumulus clouds to totally disappear in as little as a century, triggering up to 8°C (14°F) of additional warming.
Stratocumulus clouds cover about two-thirds of the Earth and help keep it cool by reflecting solar radiation back to space. Recent research has suggested that planetary warming correlates with greater cloud loss, stoking fears about a feedback loop that could spell disaster.
For this study, researchers at the California Institute of Technology used a supercomputer simulation to explore what could lead these low-lying, lumpy clouds to vanish completely. As science journalist Natalie Wolchover laid out in a lengthy piece for Quanta Magazine titled A World Without Clouds:
The simulation revealed a tipping point: a level of warming at which stratocumulus clouds break up altogether. The disappearance occurs when the concentration of CO2 in the simulated atmosphere reaches 1,200 parts per million [ppm]—a level that fossil fuel burning could push us past in about a century, under "business-as-usual" emissions scenarios. In the simulation, when the tipping point is breached, Earth's temperature soars 8 degrees Celsius, in addition to the 4 degrees of warming or more caused by the CO2 directly...
To imagine 12 degrees of warming, think of crocodiles swimming in the Arctic and of the scorched, mostly lifeless equatorial regions during the [Paleocene-Eocene Thermal Maximum or PETM]. If carbon emissions aren't curbed quickly enough and the tipping point is breached, "that would be truly devastating climate change," said Caltech's Tapio Schneider, who performed the new simulation with Colleen Kaul and Kyle Pressel.
Quanta Magazine also broke down the study's key findings in a short video shared on social media:
The study elicited alarm from climate campaigners along with calls for the "radical, disruptive changes" to society's energy and economic systems that scientists and experts have repeatedly said are necessary to prevent climate catastrophe:
New study finds that business-as-usual global warming could produce...a world without clouds. Think about that a mi… https://t.co/lBFiTLCXJP— Bill McKibben (@Bill McKibben)1551119491.0
The future is radical. We face a stark choice btw radical, disruptive changes to our physical world or radical, dis… https://t.co/A0CFefyTvG— Naomi Klein (@Naomi Klein)1551114769.0
Since the beginning of the Industrial Revolution, the amount of carbon dioxide in Earth's atmosphere has surged from about 280 ppm to more than 410 ppm today. Although concentrations will continue to rise as long as the international community maintains unsustainable activities that generate greenhouse gas emissions, some observers pointed out that atmospheric carbon hitting 1,200 ppm is far from a foregone conclusion.
And, as Penn State University Climatologist Michael E. Mann noted, "if we let CO2 levels get anywhere near that high we're already in big trouble."
That’s just one model — and it’s at co2 levels of 1200ppm (more than 4 x pre-industrial). If we let co2 levels get… https://t.co/8h7ZmSK3Kb— Michael E. Mann (@Michael E. Mann)1551111118.0
However, as Washington Post climate reporter Chris Mooney concluded in a series of tweets, "the point is not that this scary scenario is going to happen. Given the current trajectory of climate policy and renewables, it seems unlikely. Rather, the key point—and it's a big deal—is that there are many things we don't understand about the climate system and there could be key triggers out there, which set off processes that you can't easily stop."
In other words, as MIT Prof. Thomas Levenson put it: "The really terrifying aspect of this research is the reminder that we do not yet know all the ways catastrophic outcomes can emerge from this uncontrolled experiment on our only habitat."
Smart thread re the no-cloud climate change piece I just tweeted. TL/DR: The really terrifying aspect of this resea… https://t.co/dATFOUBKwD— Thomas Levenson, Zṓiarchos (@Thomas Levenson, Zṓiarchos)1551116574.0
Reposted with permission from our media associate Common Dreams.
Sweden's reindeer have a problem. In winter, they feed on lichens buried beneath the snow. But the climate crisis is making this difficult. Warmer temperatures mean moisture sometimes falls as rain instead of snow. When the air refreezes, a layer of ice forms between the reindeer and their meal, forcing them to wander further in search of ideal conditions. And sometimes, this means crossing busy roads.
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By Aaron W Hunter
A chance discovery of a beautifully preserved fossil in the desert landscape of Morocco has solved one of the great mysteries of biology and paleontology: how starfish evolved their arms.
The Pompeii of palaeontology. Aaron Hunter, Author provided<h2></h2><p>Although starfish might appear very robust animals, they are typically made up of lots of hard parts attached by ligaments and soft tissue which, upon death, quickly degrade. This means we rely on places like the Fezouata formations to provide snapshots of their evolution.</p><p>The starfish fossil record is patchy, especially at the critical time when many of these animal groups first appeared. Sorting out how each of the various types of ancient starfish relate to each other is like putting a puzzle together when many of the parts are missing.</p><h2>The Oldest Starfish</h2><p><em><a href="https://www.biorxiv.org/content/10.1101/216101v1.full.pdf" target="_blank" rel="noopener noreferrer">Cantabrigiaster</a></em> is the most primitive starfish-like animal to be discovered in the fossil record. It was discovered in 2003, but it has taken over 17 years to work out its true significance.</p><p>What makes <em>Cantabrigiaster</em> unique is that it lacks almost all the characteristics we find in brittle stars and starfish.</p><p>Starfish and brittle stars belong to the family Asterozoa. Their ancestors, the Somasteroids were especially fragile - before <em>Cantabrigiaster</em> we only had a handful of specimens. The celebrated Moroccan paleontologist Mohamed <a href="https://doi.org/10.1016/j.palaeo.2016.06.041" target="_blank" rel="noopener noreferrer">Ben Moula</a> and his local team was instrumental in discovering <a href="https://www.sciencedirect.com/science/article/abs/pii/S0031018216302334?via%3Dihub" target="_blank" rel="noopener noreferrer">these amazing fossils</a> near the town of Zagora, in Morocco.</p><h2>The Breakthrough</h2><p>Our breakthrough moment came when I compared the arms of <em>Cantabrigiaster</em> with those of modern sea lilles, filter feeders with long feathery arms that tend to be attached to the sea floor by a stem or stalk.</p><p>The striking similarity between these modern filter feeders and the ancient starfish led our team from the University of Cambridge and Harvard University to create a new analysis. We applied a biological model to the features of all the current early Asterozoa fossils in existence, along with a sample of their closest relatives.</p>
Cantabrigiaster is the most primitive starfish-like animal to be discovered in the fossil record. Aaron Hunter, Author provided<p>Our results demonstrate <em>Cantabrigiaster</em> is the most primitive of all the Asterozoa, and most likely evolved from ancient animals called crinoids that lived 250 million years before dinosaurs. The five arms of starfish are a relic left over from these ancestors. In the case of <em>Cantabrigiaster</em>, and its starfish descendants, it evolved by flipping upside-down so its arms are face down on the sediment to feed.</p><p>Although we sampled a relatively small numbers of those ancestors, one of the unexpected outcomes was it provided an idea of how they could be related to each other. Paleontologists studying echinoderms are often lost in detail as all the different groups are so radically different from each other, so it is hard to tell which evolved first.</p>
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