How the Ancient Antarctic Explains Today’s Warming World
By Tim Radford
Glaciers in Patagonia and in New Zealand began to retreat. Lakes in the Bolivian Andes began to swell with meltwater. Rain fell in the desert of Australia, and the gusts of dust that normally leave a trace in polar snows began to diminish.
The ocean waters warmed, the sea ice retreated, and the westerly winds that normally circled the southern continent began to veer further south, towards the pole.
And 29 scientists from six nations have worked out why. A series of volcanic eruptions on the Antarctic continent that lasted for almost two centuries began to pump vast quantities of sulphates, and chloride and other halogen gases, high into the air, to create—long before humans were to do the same thing—a huge hole in the stratospheric ozone layer, bringing more intense radiation and rapid warming to a vast area of the frozen south.
The researchers reported in the Proceedings of the National Academy of Sciences that they have identified the geophysical equivalent of a smoking gun: tiny traces of once-massive discharges in ice cores that tell a story of dramatic climate change long before humans had begun to smelt metal, or plough fields.
So while retreat of the Northern Hemisphere ice sheets at that time could be linked to an increase in the sun's intensity as a consequence of shifts in orbit and planetary axis, other forces were at work far to the south.
The discovery in the mid-1980s of a hole in the protective ozone layer—it blocks ultraviolet radiation but is vulnerable to a class of gases known as chlorofluorocarbons, once used in refrigeration systems—shook the world, and triggered a global ban on such gases. But the evidence from the latest study is that such things have happened before, thanks to volcanic violence.
"We postulate that these halogen-rich eruptions created a stratospheric ozone hole over Antarctica that, analogous to the modern ozone hole, led to large-scale changes in atmospheric circulation and hydroclimate throughout the Southern Hemisphere," said Joseph McConnell, of the Desert Research Institute in Reno, Nevada, who led the study.
"Although the climate system already was primed for the switch, we argue that these changes initiated the shift from a largely glacial to a largely interglacial climate state. The probability that this was just a coincidence is negligible."
Humans' role confirmed
In effect, the scientists have confirmed something everybody knew anyway: that climate change occurs naturally, and has done so throughout planetary history.
But the study illustrates why basic research is so vital: to be sure that humans are indeed precipitating potentially catastrophic climate change—driven by fossil fuel combustion that spills billions of tons of carbon dioxide and other greenhouse gases into the atmosphere—geophysicists, oceanographers, glaciologists and atmospheric scientists need to identify those other mechanisms that must have been at work to change climate without human help in the past, or might be making contemporary climate change even more certain.
So in addition to understanding the ways in which human impact on the planet translates into shifts in temperature, wind and snow or rainfall, researchers have become increasingly interested in explaining some of the crises of the distant past.
And to do that, they have had to unravel the intricate shifts of wind and water, sunshine and cloud, dust and atmosphere, deserts and ice sheets over many millions of years, to understand what is a natural mechanism for climate change, and why human influence on the climate is of a different scale and kind.
Quest for detail
In recent years, they have confirmed the basic orbital machinery that drives Ice Ages and interglacial warm spells. They have established limits to how low planetary temperatures could fall: fortunately, the earth will never become a snowball.
Unfortunately, they have yet to set a limit to how hot the climate could become: in theory, at least, the notorious greenhouse effect linked to fossil fuel combustion could boil the oceans dry and make the planet uninhabitable.
They have used dramatic natural climate shifts in the past to confirm that oxygen levels in the ocean could fall, with dramatic consequences for marine life. They have evidence that ever-greater levels of carbon dioxide can make the seas more acidic, and once again threaten marine life.
They have confirmed that, because of human actions now, temperatures could rise and mammalian body sizes dwindle, because such things have happened in other warm spells.
The pressure is on, not just to measure the impact of humankind on modern climate, but to understand in fine detail all the mechanisms at work that could turn forest into grassland, or grassland into desert, or send the glaciers back uphill, or swell the sea levels and drown low-lying coasts.
So the latest evidence that Mt Takahe in Antarctica erupted repeatedly over a period of 192 years, dramatically changed the climate and sent the ice into retreat, and dumped trace evidence of heavy metals and hydrofluoric acid across 2,800 kilomters (approximately 1740 miles) of sea and ice, as far as South America, is just another piece in the mosaic of fundamental research.
The science behind such studies is testament to the care taken in exhuming the past. Scientists drilled 3,405 meters (approximately 2.11 miles) into the West Antarctic ice sheet to begin making a record of the evidence preserved in ice layers that preserved the annual falls of snow, in the form of 30 different elements and chemical compounds. Some of these existed in concentrations as low as one part in a million billion.
The result is a clearer picture of natural violence in a landscape far from any Stone Age human settlement. It is also a reminder that the Earth remains a dangerous place.
"Imagine the environmental, societal and economic impacts if a series of modern explosive eruptions persisted for four or five generations in the lower latitudes of the Northern Hemisphere where most of us live," said Michael Sigl, a Swiss scientist who worked at the Desert Research Institute.
Reposted with permission from our media associate Climate News Network.
EcoWatch Daily Newsletter
By Eoin Higgins
Over 300 groups on Monday urged Senate leadership to reject a bill currently under consideration that would incentivize communities to sell off their public water supplies to private companies for pennies on the dollar.
<div id="fea63" class="rm-shortcode" data-rm-shortcode-id="9a6f211c2bc5aedd34837944cb8eeedf"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1281000111481294849" data-partner="rebelmouse"><div style="margin:1em 0">Water in Illinois is overwhelmingly public. Why is Tammy Duckworth sponsoring a bill that aims to change that? https://t.co/1V36Kkd99s</div> — The American Prospect (@The American Prospect)<a href="https://twitter.com/TheProspect/statuses/1281000111481294849">1594249201.0</a></blockquote></div>
- DNC Ignores Progressive Climate Activists - EcoWatch ›
- Who's a Climate Champion and Who's a Climate Disaster? - EcoWatch ›
- California Makes Face Masks Mandatory to Fight Pandemic ... ›
- Here's Why COVID-19 Can Spread So Easily at Gyms and Fitness ... ›
- Hot Weather and COVID-19: Added Threats of Reopening States in ... ›
- Trump Plans to End Federal Funding for COVID-19 Testing Sites ... ›
The Washington Redskins will retire their controversial name and logo, the National Football League (NFL) team announced Monday.
By Alyssa Murdoch, Chrystal Mantyka-Pringle and Sapna Sharma
Summer has finally arrived in the northern reaches of Canada and Alaska, liberating hundreds of thousands of northern stream fish from their wintering habitats.
A Good News Story?<p>On the surface, the <a href="https://doi.org/10.1111/fwb.13569" target="_blank">results from our study</a> appear to provide a "good news" story. Warming temperatures were linked to higher numbers of fish, more species overall and, therefore, potentially more fishing opportunities for northerners.</p><p>Initially, we were surprised to learn that warming was increasing the distribution of cold-adapted fish. We reasoned that modest amounts of warming could lead to benefits such as increased food and winter habitat availability without reaching stressful levels for many species.</p>
Photo of Arctic grayling (left) and Dolly Varden trout (right). Alyssa Murdoch / Lilian Tran / Nunavik Research Centre and Tracey Loewen / Fisheries and Oceans Canada<p>Yet, not all fish species fared equally well. Ecologically unique northern species — those that have evolved in colder, more nutrient-poor environments, such as Arctic grayling and Dolly Varden trout — were showing declines with warming.</p>
Fish Strandings and Buried Eggs<p>Recent news headlines run the gamut for Pacific salmon — from their increased escapades <a href="https://nunatsiaq.com/stories/article/more-pacific-salmon-showing-up-in-western-arctic-waters/" target="_blank">into the Arctic</a> to <a href="https://www.juneauempire.com/news/warm-waters-across-alaska-cause-salmon-die-offs/" target="_blank">massive pre-spawning die-offs</a> in central Alaska. Similarly, results from our study revealed different outcomes for fish depending on local climatic conditions, including Pacific salmon.</p><p>We found that warmer spring and fall temperatures may be helping juvenile salmon by providing a longer and more plentiful growing season, and by supporting early egg development in northern regions that were previously too cold for survival.</p><p>In contrast, salmon declined in regions that were experiencing wetter fall conditions, pointing to an increased risk of flooding and sedimentation that could bury or dislodge incubating eggs.</p>
Headwaters of the Wind River within the largely intact Peel River watershed in northern Canada. Don Reid / Wildlife Conservation Society Canada / Author provided<p>Interestingly, we found that certain climatic combinations, such as warmer summer water temperatures with decreased summer rainfall, were important in determining where Pacific salmon could survive. Summer warming in drier watersheds led to declines, suggesting that lowered streamflows may have increased the risk of fish becoming stranded in subpar habitats that were too warm and crowded.</p>
The Fate of Northern Fisheries<p>The promise of a warmer and more accessible Arctic has attracted mounting interest in new economic opportunities, <a href="https://doi.org/10.1016/j.marpol.2019.103637" target="_blank">including fisheries</a>. As warming rates at higher latitudes are already <a href="https://www.ipcc.ch/sr15/" target="_blank">two to three times global levels</a>, it seems probable that northern biodiversity will experience dramatic shifts in the coming decades.</p><p>Despite the many unknowns surrounding the future of Pacific salmon, many fisheries are currently <a href="https://doi.org/10.1080/03632415.2017.1374251" target="_blank">thriving following warmer and more productive northern oceans</a>, and some <a href="https://doi.org/10.14430/arctic68876" target="_blank">Arctic Indigenous communities are developing new salmon fisheries</a>.</p><p>As warming continues, the commercial salmon fishing industry is poised to expand northwards, but its success will largely depend on extenuating factors such as <a href="https://www.eenews.net/stories/1060023067" target="_blank">changes to marine habitat and food sources</a> and <a href="https://www.yukon-news.com/news/promising-chinook-salmon-run-failed-to-materialize-in-the-yukon-river-panel-hears/" target="_blank">how many fish are caught during the freshwater stages of their journey</a>.</p><p>Even with the potential for increased northern biodiversity, it is important to recognize that some northern communities may be unable to adapt or may <a href="https://thenarwhal.ca/searching-for-the-yukon-rivers-missing-chinook/" target="_blank">lose individual species that are associated with important cultural values</a>.</p>
- New England Fishing Communities Being Destroyed by 'Climate ... ›
- Shrimp Fishing Banned in Gulf of Maine Due to Ocean Warming ... ›
- Atlantic Salmon Is All But Extinct as a Genetically Eroded Version of ... ›
A heat wave that set in over the South and Southwest left much of the U.S. blanketed in record-breaking triple digit temperatures over the weekend. The widespread and intense heat wave will last for weeks, making the magnitude and duration of its heat impressive, according to The Washington Post.
- Hot Weather and COVID-19: Added Threats of Reopening States in ... ›
- 50 Million Americans Are Currently Living Under Some Type of Heat ... ›
- Second Major Heat Wave This Summer Smashes Records Across ... ›
By Joni Sweet
If you get a call from a number you don't recognize, don't hit decline — it might be a contact tracer calling to let you know that someone you've been near has tested positive for the coronavirus.
Interviews With Contact Tracers<p>Contact tracing is a public health strategy that involves identifying everyone who may have been in contact with a person who has the coronavirus. Contact tracers collect information and provide guidance to help contain the transmission of disease.</p><p>It's been used during outbreaks of sexually transmitted infections (STIs), Ebola, measles, and now the coronavirus that causes COVID-19.</p><p>It starts when the local department of health gets a report of a confirmed case of the coronavirus in its community and gives that person a call. The contact tracer usually provides information on how to isolate and when to get treatment, then tries to figure out who else the person may have exposed.</p><p>"We ask who they've been in contact with in the 48 hours prior to symptom onset, or 2 days before the date of their positive test if they don't have symptoms," said <a href="https://case.edu/medicine/healthintegration/people/heidi-gullett" target="_blank">Dr. Heidi Gullett</a>, associate director of the Center for Community Health Integration at the Case Western Reserve University School of Medicine and medical director of the Cuyahoga County Board of Health in Ohio.</p>
“You’ve Been Exposed”<p>After the case interview, contact tracers will get to work calling the folks who may have been exposed to the coronavirus by the person who tested positive.</p><p>"We give them recommendations about quarantining or isolating, getting tested, and what to do if they become sick. If they're not already sick, we still want them to self-quarantine so that they don't spread the disease to anyone else if they were to become sick," said Labus.</p><p>Generally, the contact tracer won't ask for additional contacts unless they happen to call someone who is sick or has a confirmed case of the virus. They will help ensure the contact has the resources they need to isolate themselves, if necessary. The contact tracer may continue to stay in touch with that person over the next 14 days.</p><p>"We follow the percentage of people that were contacts, then converted into being actual cases of the virus. It's an important marker to help us understand what kind of transmission happens in our community and how to control the virus," said Gullett.</p>
Why You Should Participate (and What Happens If You Don’t)<p>A <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30457-6/fulltext" target="_blank">Lancet study</a> from June 16, which looked at data from more than 40,000 people, found that COVID-19 transmission could be reduced by 64 percent through isolating those who have the coronavirus, quarantining their household, and contacting the people they may have exposed.</p><p>The combination strategy was significantly more effective than mass random testing or just isolating the sick person and members of their household.</p><p>However, contact tracing is only as effective as people's willingness to participate, and a small number of people who've contracted the coronavirus or were potentially exposed are reluctant to talk.</p><p>"Contact tracers have all been hung up on, cussed at, yelled at," said Gullet.</p><p>The hesitation to talk to contact tracers often stems from concerns over privacy — a serious issue in healthcare.</p>
- Anti-Racism Protests Are Not Driving Coronavirus Spikes, Data ... ›
- Cell Phone Tracking Analysis Shows Where Florida Springbreakers ... ›
NASA scientists say that warmer than average surface sea temperatures in the North Atlantic raise the concern for a more active hurricane season, as well as for wildfires in the Amazon thousands of miles away, according to Newsweek.