Scientists Confirm Burning Fossil Fuels Significantly Worsens Australian Drought
American scientists have just confirmed that parts of Australia are being slowly parched because of greenhouse gas emissions, which means that the long-term decline in rainfall over south and south-west Australia is a consequence of fossil fuel burning and depletion of the ozone layer by human activity.
Such a finding is significant for two reasons. One remains contentious: it is one thing to make generalized predictions about the consequences overall of greenhouse gas levels, but it is quite another to pin a measured regional climatic shift directly on human causes, rather than some possible as-yet-unidentified natural cycle of climatic change.
The other is contentiously political. Australia’s prime minister, Tony Abbott, has in the past dismissed climate science as “crap,” and more recently has cut back on Australian research spending.
Australia has already experienced a pattern of heat waves and drought—punctuated by catastrophic flooding—and even now, in the Australian winter, New South Wales is being hit by bush fires.
Tom Delworth, a research scientists at the U.S. National Oceanic and Atmospheric Administration, reports in Nature Geoscience that he and a colleague conducted a series of long-term climate simulations to study changes in rainfall across the globe.
Photo credit: Bidgee via Wikimedia Commons
Pattern of change
One striking pattern of change emerged in Australia, where winter and autumn rainfall patterns are increasingly a cause of distress for farmers and growers in two states.
The simulation showed that the decline in rainfall was primarily a response to man-made increases in greenhouse gases, as well as to a thinning of the stratospheric ozone layer in response to emissions of destructive gases by human sources.
The computer simulations tested a series of possible causes for this decline, such as volcanic eruptions and changes in solar radiation. But the only cause that made sense of the observed data was the greenhouse explanation.
South Australia has never been conspicuously lush and wet, but decline in precipitation set in around 1970, and this decline has increased in the last four decades. The simulations predict that the decline will go on, and that average rainfall will drop by 40 percent over south-west Australia later this century.
Dr Delworth described his model as “a major step forward in our effort to improve the prediction of regional climate change.”
In May, scientists proposed that greenhouse gas emissions were responsible for a change in Southern Ocean wind patterns, which in turn resets the thermostat for the world’s largest island.
Australian scientists report in Geophysical Research Letters that they, too, have been using climate models to examine Antarctic wind patterns and their possible consequence for the rest on the planet.
“When we included projected Antarctic wind shifts in a detailed global ocean model, we found water up to 4°C warmer than current temperatures rose up to meet the base of the Antarctic ice shelves,” said Paul Spence, a researcher at Australian Research Council's Centre of Excellence for Climate System Science. This temperature rise is twice previous estimates.
“This relatively warm water provides a huge reservoir of melt potential right near the grounding lines of ice shelves around Antarctica,” Dr Spence said. “It could lead to a massive increase in the rate of ice sheet melt, with direct consequences for global sea level rise.”
Since the West Antarctic ice sheet holds enough water to raise sea levels by 3.3 meters, the consequences would indeed be considerable.
“When we first saw the results it was quite a shock,” Dr Spence said. “It was one of the few cases where I hoped the science was wrong."
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.
- San Antonio, Texas Unveils Largest Highway Crossing for Wildlife in ... ›
- Wildlife Crossings a Huge Success - EcoWatch ›
EcoWatch Daily Newsletter
- Climate Change Will Be Sudden and Cataclysmic Unless We Act Now ›
- There's a Heatwave at the Arctic 'Doomsday Vault' - EcoWatch ›
- Marine Heatwaves Destroy Ocean Ecosystems Like Wildfires ... ›
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>
- Biden Reaffirms Commitment to Rejoining Paris Agreement ... ›
- Biden Likely Plans to Cancel Keystone XL Pipeline on Day One ... ›
- Joe Biden Appoints Climate Crisis Team - EcoWatch ›