First direct evidence of ocean mixing across the Gulf Stream

https://phys.org/news/2020-07-evidence-ocean-gulf-stream.html

First direct evidence of ocean mixing across the gulf stream
The “Triaxus” towing platform breaks through the choppy surface of the ocean during a storm. By towing such a platform with monitoring instruments through the water, changing its depth in a ‘yo-yo’ pattern as it traveled, scientists created high-resolution snapshots of how a dye released upstream evolved across the Gulf Stream front. Credit: Craig M. Lee, UW APL

New research provides the first direct evidence for the Gulf Stream blender effect, identifying a new mechanism of mixing water across the swift-moving current. The results have important implications for weather, climate and fisheries because ocean mixing plays a critical role in these processes. The Gulf Stream is one of the largest drivers of climate and biological productivity from Florida to Newfoundland and along the western coast of Europe.

“This long-standing debate about whether the Gulf Stream acts as a blender or a barrier to ocean mixing has mainly considered big ocean eddies, tens of kilometers to a hundred kilometers across,” said Jacob Wenegrat, an assistant professor in UMD’s Department of Atmospheric and Oceanic Science and the lead author of the study. “What we’re adding to this debate is this new evidence that variability at the kilometer scale seems to be doing a lot of mixing. And those scales are really hard to monitor and model.”

As the Gulf Stream courses its way up the east coast of the U.S. and Canada, it brings warm salty  from the tropics into the north Atlantic. But the current also creates an invisible wall of water that divides two distinct ocean regions: the colder, fresher waters along the northern edge of the Gulf Stream that swirl in a counterclockwise direction, and the warmer, saltier waters on the southern edge of the current that circulate in a clockwise direction.

First direct evidence of ocean mixing across the gulf stream
A research crew deployed a float from the R/V Knorr before releasing a fluorescent dye into the water. Scientists then tracked the drift of both dye and float through the Gulf Stream revealing significant mixing of waters across the swift current. Credit: Craig M. Lee, UW APL

How much ocean mixing occurs across the Gulf Stream has been a matter of scientific debate. As a result, ocean models that predict climate, weather and biological productivity have not fully accounted for the contribution of mixing between the two very different types of water on either side of the current.

To conduct the study, the researchers had to take their instruments to the source: the edge of the Gulf Stream. Two teams of scientists aboard two global-class research vessels braved winter storms on the Atlantic Ocean to release a  along the northern front of the Gulf Stream and trace its path over the following days.

The first team released the dye along with a float containing an acoustic beacon. Downstream, the second team tracked the float and monitored the concentration of dye along with , salinity, chemistry and other features.

Back on shore, Wenegrat and his coauthors developed high-resolution simulations of the physical processes that could cause the dye to disperse through the water in the manner the field teams recorded. Their results showed that turbulence across areas as small as a kilometer exerted an important influence on the dye’s path and resulted in significant mixing of water properties such as salinity and temperature.

First direct evidence of ocean mixing across the gulf stream
Fluorescent dye provides a unique way to track the evolution and mixing of water across the Gulf Stream. In a recent study fluorescein dye (as pictured here) was released along the north wall of the Gulf Stream, and tracked by ship as it mixed horizontally across the current. Credit: Lance Wills, WHOI

“These results emphasize the role of variability at very small scales that are currently hard to observe using standard methods, such as satellite observations,” Wenegrat said. “Variability at this scale is not currently resolved in global climate models and won’t be for decades to come, so it leads us to wonder, what have we been missing?”

By showing that small-scale mixing across the Gulf Stream may have a significant impact, the new study reveals an important, under-recognized contributor to ocean circulation, biology and potentially climate.

For example, the Gulf Stream plays an important role in what’s known as the ocean biological pump—a system that traps excess carbon dioxide, buffering the planet from global warming. In the surface waters of the Gulf Stream region, ocean mixing influences the growth of phytoplankton—the base of the ocean food web. These phytoplankton absorb carbon dioxide near the surface and later sink to the bottom, taking carbon with them and trapping it in the deep ocean. Current models of the ocean biological pump don’t account for the large effect small-scale mixing across the Gulf Stream could have on phytoplankton growth.

“To make progress on this we need to find ways to quantify these processes on a finer scale using theory, state-of-the-art numerical models and new observational techniques,” Wenegrat said. “We need to be able to understand their impact on large-scale circulation and biogeochemistry of the ocean.”

The research paper, “Enhanced mixing across the gyre boundary at the Gulf Stream front,” Jacob O. Wenegrat, Leif N. Thomas, Miles A. Sundermeyer, John R. Taylor, Eric A. D’Asaro, Jody M. Klymak, R. Kipp Shearman, and Craig M. Lee, was published in the July 6, 2020 issue of the Proceedings of the National Academy of Sciences.

There’s A Place On Earth Getting Cooler, Not Hotter. A New Study Sheds Light On Why

main article image
Sea surface average temperatures, 2015 (NOAA)

MIKE MCRAE
3 JULY 2020

Earth’s oceans are simmering with the heat trapped by increasing amounts of greenhouse gases. But one patch of water in the North Atlantic is stubbornly resisting the trend, and actually dropping in temperature.

This ‘cold blob‘ has been a subject of interest for climatologists ever since it was first spotted back in 2015. Unfortunately, the complexities of ocean circulation make it a tricky thing to easily explain.

A new study adds detail to the phenomenon, revealing there’s more than one cause at work.

A team of researchers from the Max Planck Institute for Meteorology in Germany applied long-term climate modelling to simulate various configurations to find which match the observed plunge in temperature.

One of the factors they identified comes as no real surprise, backing up previous studies that show a current of water called the Atlantic meridional overturning circulation (AMOC) has weakened significantly since the mid-20th century.

When running at full steam, the circulation takes warm, salty surface waters from the tropics near the Gulf of Mexico north towards the European coast, exchanging it for cold, fresh water supplied by melting ice.

Exactly what might be causing this highway of tropical water to slow down isn’t all that clear, though some models suggest more meltwater from Greenland coupled with rising global temperatures would fit what we’re seeing.

With warmer temperatures making the ocean water more buoyant, it’s less likely to drop as quickly, slowing the spiral. Meanwhile, a good dose of fresh water trickling in from melting Arctic ice and higher rainfall would also impede the circulating currents by forming a layer of less salty water on the surface.

Still, data on the AMOC aren’t the highest quality prior to 2004, leaving open the small possibility that the slow-down could be a return to business as usual rather than something triggered by a warming planet.

To tease out connections between Earth’s climate and the cold blob, the researchers behind this latest study used a detailed planetary climate model to couple variations in energy, carbon dioxide, and water across the ocean, land, and atmosphere.

Simulations run through this model allowed them to see what might happen if they forced the AMOC to churn away at full speed, leaving the atmosphere to act as a major influencing factor all on its own.

Sure enough, there was a small but noticeable effect. As the incoming warm waters cooled down, they produced low-lying clouds that would reflect incoming radiation, in turn cooling the surface even further.

Next, the team ran another scenario that looked only at the AMOC’s transport of heat, finding it wasn’t just carrying less energy, but was dumping more of it into the Arctic’s circulating water currents.

For complicated reasons, these subpolar circulations are picking up speed, drawing heat from the AMOC and leaving the cold blob even colder.

There’s still plenty of work to be done on building up these explanations and determining how much of an impact our insatiable desire to burn fossil fuels has had on what would otherwise be a natural cycle.

But the study goes a long way in showing how important it is that we take into account diverse factors in assessing local and global changes to the climate.

No doubt researchers will be paying even closer attention to the AMOC’s strength in coming years. But knowing exactly how this cold blob operates in a changing climate will help us better understand what to expect in a future that’s likely to be several degrees warmer.

Researchers reveal changes in water of Canadian arctic

https://phys.org/news/2020-06-reveal-canadian-arctic.html?fbclid=IwAR2Ik8ceg9Bruut17dLemcAREflZvwAsp3V-E6PVhU-9VPSaxZKa3WODmXk

UM researcher helps reveal changes in water of Canadian arctic
Crew members deploy equipment onto the ice from a Canadian icebreaker, CCGS Louis S. St. Laurent, in the Arctic Ocean. Credit: Gary Morgan, Canadian Coast Guard

Melting of Arctic ice due to climate change has exposed more sea surface to an atmosphere with higher concentrations of carbon dioxide. Scientists have long suspected this trend would raise CO2 in Arctic Ocean water.

Now University of Montana researcher Michael DeGrandpre and his patented  have helped an international team determine that, indeed, CO2 levels are rising in water across wide swaths of the Arctic Ocean’s Canada Basin. However, some areas have exhibited slower increases, suggesting other processes—such as biological uptake of CO2—have counteracted expected increases.

The work was published this month in the journal Nature Climate Change.

DeGrandpre is a UM chemistry professor, and in 2015 he and the company he founded, Sunburst Sensors, won two coveted XPRIZE awards for developing inexpensive, durable sensors to better understand ocean acidification. Sunburst Sensor technology also was used in this recent study for a CO2 measurement system placed on board a Canadian icebreaker, the CCGS Louis S. St. Laurent.

DeGrandpre said ocean measurements are taken while the icebreaker is underway, sometimes crashing through ice one to two meters thick. DeGrandpre and UM research associate Cory Beatty have participated in these research cruises since 2012 with support from the National Science Foundation Office of Polar Programs.

UM researcher helps reveal changes in water of Canadian arctic
University of Montana chemistry Professor Michael DeGrandpre poses with a research buoy deployed through the ice in the Canada Basin of the Arctic Ocean. Credit: Jeff O’Brien, Woods Hole Oceanographic Institution

“Because of the inaccessibility of the Arctic and the typically harsh work conditions, we really need a world-class icebreaker to access these areas,” DeGrandpre said. “It also has given us a high-quality, consistent dataset, which really helped with this latest study. Most Arctic CO2 datasets are from infrequent cruises that do not visit the same locations year to year.”

He said the new study combines sporadic data dating back to 1994 with the more-frequent data they have collected since 2012. DeGrandpre said their consistent dataset will only improve, as NSF recently awarded them an $890,000 grant to continue the icebreaker project through 2023.


Explore further

Arctic Ocean acidification worse than expected

NEW STUDY PREDICTS THE OCEAN ECOSYSTEM WILL COLLAPSE THIS DECADE

Dire Warning

The global ecosystem is in far greater danger than scientists previously thought, according to a new study — and that’s really saying something.

The research predicts that without dire action to reverse global climate change, entire ocean ecosystems could suddenly collapse this decade, The Guardian reports. It’s a dire warning: as various organisms face temperatures higher than anything they have before, the study predicts sudden, massive die-offs.

Free Fall

The study, published Tuesday in the prestigious journal Nature, examines the temperatures that 30,000 land and sea organisms can withstand, and plots those ranges against the expected temperature increases through the year 2100.

“It’s not a slippery slope, but a series of cliff edges, hitting different places at different times,” research leader Alex Pigot of University College London told The Guardian.

Flattening Curves

Unless world leaders act to stop the direst effects of climate change, the study predicts a similar terrestrial die-off during the 2040s.

READ MORE: Wildlife destruction ‘not a slippery slope but a series of cliff edges’ [The Guardian]

More on the environment: Doomsday Report Author: Earth’s Leaders Have Failed

Kate Marvel, climate scientist: “Some day I must tell my son what I have done”

Excerpt : Someday I must tell my son what I have done. My comfortable, safe life is in large part a product of the internal combustion engine. Fossil fuels power the trains that take us to the beach, the factories that make his plastic bucket and spade, the lights I switch off when I kiss him good night. We can make small adjustments: recycling, buying reusable bottles for our water and ice coffee, foregoing the occasional plastic bag. But these small things, even multiplied by a large population, are still small in the end.
I cannot deny my son or myself the ease of modern life, and I have no wish to isolate him from friends and family by insisting on radical changes. A carbon-free life seems a solitary one: no travel to see grandparents, awkward refusals of invitations, precious time with friends replaced by gardening, canning, mending, building, working. 
I search for political solutions, an advocacy muted by the cowardice of my personal choices. In the end, I am responsible for the gases that are changing the climate and, in raising my son in comfort and convenience, am passing on that responsibility and guilt to him.
Greenhouse gases are indisputably warming the whole planet. We are moving toward a future where the natural variations of El Niño are swamped by rising ocean temperatures. There will be no weather that we have not somehow touched. And our legacy travels deeper than we think: We have left to our children a time bomb of warming. Even if we somehow managed to halt the increase in greenhouse gases, freezing them at today’s levels, the planet’s temperature would continue to rise as the heat trickles into the deep, slowly creating a new equilibrium. The ocean will eventually know what we have done to the atmosphere. The process is slow, but inexorable. We have committed ourselves to this warming, a legacy to future generations.
To be a climate scientist is to be an active participant in a slow-motion horror story.
 

Increasing Escape of Oxygen From Oceans Under Climate Change

Geophysical Research Letters June 16, 2020

 

Abstract

The global oxygen cycle is one of the most important cycles on Earth for all aerobic organisms, and it is a basic constraint sustaining aerobic life. As a major component of the cycle, oceans are now experiencing widespread declines in oxygen concentrations. Here, based on model simulations we found that ocean deoxygenation occurs as a result of oceanic oxygen outgassing, which is tightly related with the marine warming. Although the O2 flux from the ocean to atmosphere is quite small compared with that of oceanic oxygen production, this outgassing accounts for almost all of the decline in marine oxygen and even exceeds the amount of the loss. The model projections indicate accelerated oxygen escape from the ocean under climate change. The oceanic outgassing will increase from 1.6 to 4.3 Gt/yr over the 21st century due to solubility and circulation changes related with warming, which may eventually lead to a more hypoxic ocean in the future.

Plain Language Summary

It is well‐known that O2 is fundamental for all aerobic life. However, the oxygen content of the ocean has been declining during the past few decades. This phenomenon, known as the “ocean deoxygenation,” will have widespread consequences, which could eventually threaten the marine ecosystems. In this study, we systematically diagnosed the global oceanic oxygen budget on the basis of earth system models and found enhanced O2 escape from the ocean to atmosphere. The O2 outgassing is directly responsible for ongoing deoxygenation, and it will continue to increase in the future. A shift in the oceanic oxygen cycle characterized by increasing oxygen escape has been occurring as a consequence of human‐induced climate change, followed by intensified ocean deoxygenation and resulting in severe damage to marine biota.

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PNAS first published November 7, 2019.
Tony E. Wong

The emission of greenhouse gases into Earth’s atmosphere is a by-product of modern marvels such as the production of vast amounts of energy, heating and cooling inhospitable environments to be amenable to human existence, and traveling great distances faster than our saddle-sore ancestors ever dreamed possible. However, these luxuries come at a price: climate changes in the form of severe droughts, extreme precipitation and temperatures, increased frequency of flooding in coastal cities, global warming, and sea-level rise (1, 2).

This is the price we pay for the luxury of about 200 y of relatively unchecked greenhouse gas emissions.

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“But the scale of climate change engulfs even the most fortunate. There is now no weather we haven’t touched, no wilderness immune from our encroaching pressure. The world we once knew is never coming back.
“I have no hope that these changes can be reversed. We are inevitably sending our children to live on an unfamiliar planet.
“We need courage, not hope.”
Kate Marvel, physicist, climate scientist, NASA’s Goddard Institute for Space Studies and Columbia University’s Department of Applied Physics and Applied Mathematics
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“An ecologist must either harden his shell and make believe that the consequences of science are none of his business, or he must be the doctor who sees the marks of death in a community that believes itself well and does not want to be told otherwise.”
Aldo Leopold – A Sand County Almanac
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“The fact is that we, humans, have changed the composition of the atmosphere with respect to heat-trapping gases enough to start the progression of global climate, not into a new steady state, but into an open-ended warming that is pulling the environment out from under this civilization.”
George Woodwell

An Ancient Type of El Niño Could Awaken Because of Climate Change

The drought-ridden Puzhal reservoir on the outskirts of Chennai, India in June 2019
The drought-ridden Puzhal reservoir on the outskirts of Chennai, India in June 2019
Photo: Getty Images

El Niño is one of the most familiar climate patterns on Earth. Pools of water in the eastern tropical Pacific Ocean become abnormal warm, triggering changes in global weather patterns.

Thanks to the climate crisis, El Niño may have some competition. A new study published in Science Advances on Wednesday shows that as early as mid-century, global warming could cause an ancient climate pattern similar to El Niño in the Indian Ocean to reawaken. It would throw weather further into disarray, particularly in places in the global south that depend on rainfed agriculture.

The study builds on a previous one published by some of the same authors last year, which found that this climate pattern in the Indian Ocean may have existed during the last Ice Age, 20,000 years ago. Back then, thanks to abrupt global warming driven by natural causes, fluctuating ocean temperatures wreaked havoc on global weather patterns.

Now, human activities are driving the climate into a similarly unsteady state. To examine how our rising carbon emissions could influence the Indian Ocean, the researchers used climate models of what the rest of the century will look like if world leaders do nothing to curb greenhouse gas emissions (a scenario known as RCP8.5). They found that if current global warming trends continue, we could see huge fluctuations in the Indian Ocean’s surface temperatures by 2050 similar to what happened 20,000 years ago.

“The Indian Ocean today experiences very slight year-to-year climate swings because the prevailing winds blow gently from west to east, keeping ocean conditions stable,” Pedro Di Nezio, the study’s lead author and a geophysicist at the University of Texas, told Earther in an email. “According to the simulations, global warming could reverse the direction of these winds, destabilizing the ocean and tipping the climate into swings of warming and cooling.”

Though it’s a separate phenomenon, the possible new pattern would be linked in many ways to El Niño and its opposite counterpart, La Niña. Every three to seven years, temperatures would increase or decrease by up to 2 degrees Celsius (3.6 degrees Fahrenheit), depending on whether it’s an El Niño year or a La Nina year. The changes would last between three and six months.

Changes of a mere degree or two may not seem like a huge deal. But if this pattern re-emerges, floods, storms, and droughts will become worse and more frequent, especially in Africa, Australia, Indonesia, and Indiaareas already severely impacted by climate change. Warm events could drive droughts over the Horn of Africa and southern India (both of which have already seen grave climate effects) and increased rainfall in Indonesia and northern Australia. Cold events could create opposite effects—for instance, the Indian peninsula could see increased rainfall.

The effects would be disastrous. A number of these locations rely on rainfed agriculture, and any shifts in precipitation could be disastrous for farmers. Drought conditions in Australia also raise the risk of dangerous bushfires, which the world got a glimpse of earlier this year. The swing between drought and flood in the Horn of Africa created the conditions for massive locust swarms, which are currently threatening food security for tens of thousands of people.

Malte Stuecker, an Oceanography Professor at the University of Hawaii at Manoa, who didn’t work on the study, said these findings were “robust.” He also noted even the comparatively small temperature variations that already occur in the Indian Ocean have a huge influence on weather patterns in the global south.

“As Earth continues to warm, these new type of future temperature variations in the Indian Ocean will have much amplified impacts on rainfall across all Indian Ocean rim countries and beyond,” he said.

It’s not clear exactly what threshold global warming would have to cross to trigger these shifts. But that’s actually disconcerting because the unknowns and tipping point-driven shifts make it harder to plan for the future.

“The exact magnitude of global warming… at which the first of these El Niño (or La Niña) events will be triggered is hard to know with precision,” said Di Nezio. He said scientists will soon begin research to determine whether or not these changes will occur once we pass 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming above pre-industrial levels.

To learn more, Stuecker suggested researchers compare their findings with the latest climate models being used for an upcoming United Nations climate report.

“These simulations were not available during the time that this paper was written,” he said.

Though there is much more to learn about the potential of an Indian Ocean El Niño, one thing is clear: The biggest factor in whether or not it will emerge is our actions.

“The re-emergence will depend strongly on the rate of global warming, so ultimately on whether greenhouse gas emissions are abated or not,” said Di Nezio. “We are certain that the risks of these extreme events is becoming larger and larger as we pump more CO2 into the atmosphere, and certainly going to have an unequal impact on countries in the tropics.”

Warmest Oceans on Record Could Set Off a Year of Extreme Weather

  • Pacific, Atlantic and Indian Oceans have reached record highs
  • Hurricanes, wildfires and severe thunderstorms all affected

The world’s seas are simmering, with record high temperatures spurring worry among forecasters that the global warming effect may generate a chaotic year of extreme weather ahead.

Parts of the Atlantic, Pacific and Indian Oceans all hit the record books for warmth last month, according to the U.S. National Centers for Environmental Information. The high temperatures could offer clues on the ferocity of the Atlantic hurricane season, the eruption of wildfires from the Amazon region to Australia, and whether the record heat and severe thunderstorms raking the southern U.S. will continue.

In the Gulf of Mexico, where offshore drilling accounts for about 17% of U.S. oil output, water temperatures were 76.3 degrees Fahrenheit (24.6 Celsius), 1.7 degrees above the long-term average, said Phil Klotzbach at Colorado State University. If Gulf waters stay warm, it could be the fuel that intensifies any storm that comes that way, Klotzbach said.

“The entire tropical ocean is above average,” said Michelle L’Heureux, a forecaster at the U.S. Climate Prediction Center. “And there is a global warming component to that. It is really amazing when you look at all the tropical oceans and see how warm they are.”

Simmering Seas

The deeper the red, the warmer the water in this illustration from NOAA’s National Environmental Satellite, Data and Information Service.

NOAA

The record warm water in the Gulf of Mexico spilled over into every coastal community along the shoreline with all-time high temperatures on land, said Deke Arndt, chief of the monitoring section at the National Centers for Environmental Information in Asheville, North Carolina. Florida recorded its warmest March on record, and Miami reached 93 degrees Wednesday, a record for the date and 10 degrees above normal, according to the National Weather Service.

While coronavirus has the nation’s attenton right now, global warming continues to be a threat. Sea water “remembers and holds onto heat” better than the atmosphere, Arndt said.

Overall, the five warmest years in the world’s seas, as measured by modern instruments, have occurred over just the last half-dozen or so years. It’s “definitely climate-change related,” said Jennifer Francis, a senior scientist at the Woods Hole Research Center in Massachusetts. “Oceans are absorbing about 90% of the heat trapped by extra greenhouse gases,”

Worldwide, sea temperatures were 1.49 degrees Fahrenheit above average in March. That’s the second highest level recorded since 1880 for the month of March, according to U.S. data. In 2016, temperatures were 1.55 degrees above average.

The first of Colorado State’s 2020 storm reports, led by Klotzbach, forecast this year that eight hurricanes could spin out of the Atlantic with an above-average chance at least one will make landfall in the U.S. during the six-month season starting June 1. The U.S. is set to issue its hurricane forecast next month.

Arctic Systems

The searing global temperatures this year can also be traced back to intense climate systems around the Arctic that bottled up much of that region’s cold, preventing it from spilling south into temperate regions. Combined with global warming, this was a one-two punch for sea temperatures that’s brought them to historic highs.

One of the best-known examples of how oceans drive global weather patterns is the development of the climate system known as El Nino. It occurs when unusually warm waters in the equatorial Pacific interact with the atmosphere to alter weather patterns worldwide. In the Atlantic, for instance, El Ninos can cause severe wind shear that can break up developing storms with the potential to become dangerous hurricanes.

This year, the chance of an El Nino developing are small, and scientists are theorizing one reason could be that climate change is warming all the world’s oceans. El Nino “depends on contrasts, as well as absolute values of sea-surface temperatures,” according to Kevin Trenberth, a scientist at the National Center for Atmospheric Research.

Strengthening Their Fury

Meanwhile, if the Atlantic stays warm through the six-month storm season that starts June 1, the tropical systems can use it as fuel to strengthen their fury.

The oceans also play a role in setting the stage for wildfires. In the case of Australia and the Amazon, really warm areas of the ocean can pull rain away from the land, causing drier conditions and, in extreme cases, drought. Last year, for instance, the Indian Ocean was really warm off Africa, so that is where all the storms went. Australia was left high and dry.

Back in the Atlantic, research by Katia Fernandes, a geosciences professor at the University of Arkansas, has also shown a correlation between sea surface temperatures in the northern tropical Atlantic and drought and wildfires in the Amazon. The warmer the water, the further north rainfall is pulled across South America.

According to Fernandes model, even Atlantic temperatures in March can serve to predict if the Amazon will be dry and susceptible to fires.

For California, the outlook isn’t as clear. Wildfires there depend as much on how well vegetation grows, providing fuel for the flames, as it does on the weather conditions coming off the Pacific.

“Tricky question,” said Mike Anderson, California state climatologist. “Our weather outcomes are influenced by sea-surface temperatures in the Pacific, but it depends on where and when the warm waters appear and how long they persist. In the end we have a highly variable climate that doesn’t map in a statistically convenient way to patterns of sea-surface temperatures.”

Unchecked Global Warming Could Collapse Whole Ecosystems, Maybe Within 10 Years

A new study shows that as rising heat drives some key species extinct, it will affect other species, as well, in a domino effect.

BY BOB BERWYN, INSIDECLIMATE NEWS

APR 8, 2020

https://insideclimatenews.org/news/07042020/global-warming-ecosystem-biodiversity-rising-heat-species

Global warming is about to tear big holes into Earth’s delicate web of life, pushing temperatures beyond the tolerance of thousands of animals at the same time. As some key species go extinct, entire ecosystems like coral reefs and forests will crumble, and some will collapse abruptly, starting as soon as this decade, a new study in the journal Nature warns.

Many scientists see recent climate-related mass die-offs, including the coral bleaching of the Great Barrier Reef and widespread seabird and marine mammal mortality in the Northeastern Pacific linked to a marine heat wave, as warning signs of impending biodiversity collapse, said lead author Alex Pigot, a biodiversity researcher at University College, London. The new study shows that nowhere on Earth will escape the impacts.

“In the U.S., the southern states from Texas to Florida, the Appalachians and the West Coast are projected to be at particularly high risk, with between 20 and 40 percent of species facing conditions beyond anything they have previously experienced,” Pigot said.

In those regions many species live in small geographic areas under a narrow range of climatic conditions. As global warming heats their habitat to the point that it is intolerable, many species have no place to go. Some will go extinct, with a domino effect that affects scores of other species. If it gets too hot for bumblebees, for example, it affects the reproduction of plants. If it gets too warm for insects and reptiles, it affects food supplies for birds and mammals.

“I hope our predictions are wrong. But increasingly, what we’re observing around us are the signs of this happening,” Pigot said, referring to research showing how global warming affects individual species. “I think these studies are showing that many species are already living very near their thermal limits. Our results suggest that these losses are likely to involve multiple species near simultaneously rather than happening gradually, one species at a time,” he said.

At the current rate of warming, abrupt exposure events in tropical oceans will begin before 2030 and spread to tropical forests and higher latitudes by 2050. The risks decrease and arrive more slowly if global warming is capped at less than 3.6 degrees Fahrenheit, as per the goals of the 2015 Paris climate agreement, the study concluded.

“If we can avert the worst of the warming we can buy extra time,” Pigot said. “Even if we can get a few extra decades, it gives us time to work on expanding protected areas, or deciding on whether to try things like assisted migration and assisted evolution.”

Even an immediate curb on greenhouse gas emissions doesn’t preclude warming of up to 7 degrees Fahrenheit by the end of the century because the current amount of warming could be magnified by big increases of heat-trapping methane in the Arctic or by changes to cloud processes, he said.

Jennifer Sunday, a research biologist at McGill University, said the new study for the first time shows when species will be faced with warmer temperatures than they’ve ever experienced for five years in a row. And it turns out that a surprising number of animals within various ecosystems will hit those climate thresholds at the same time, which can lead to widespread ecosystem disruptions or collapse, said Sunday, who was not involved in the research.

“We did not know about the time-course of events. We have lots of models that compare species ranges today to those at a future date, but we did not know when most of the changes were going to happen,” she said. The research also makes it clear that global warming’s impacts on ecosystems could arrive very suddenly.

“I think we often and maybe subconsciously expect climate change to be a gradual process, but this helps to illustrate that the impacts may be in fits and spurts,” she said. “As we know today, our human adaptive systems are not great at dealing with synchronous events,” she said, referring to the global response to the coronavirus pandemic. The findings show that some climate impacts could be as sudden and widespread as the pandemic, challenging our adaptive management systems.

Species in Tropics, Polar Regions, Will be Hardest Hit

In the study, Pigot’s team assessed temperatures ranges for more than 30,000 land and sea species—birds, mammals, reptiles, amphibians, fish and other marine animals and plants—to estimate when they will start experiencing unprecedented temperature conditions. Capping global warming at 2.7 degrees Fahrenheit would decrease the risk of ecosystem failures significantly, but allowing global warming to continue unchecked would lead to widespread biodiversity decline quickly, they found.

Ecological communities in tropical regions near the equators will be hard hit because many species there are already living near the upper end of their heat tolerance spectrum. In high latitudes, toward the poles, communities of species will struggle because those areas are warming about twice as fast as the global average, giving them even less time to adapt, he said.

Pigot said the study shows how the risks from climate change will change from year to year. “The key finding of our study, that exposure to potentially dangerous climate conditions is likely to occur abruptly, hasn’t been previously detected.” he said.

Pigot said he sees parallels between the new study and current discussions about the response to the coronavirus pandemic, which seems to be raising general awareness of how nonlinear systems work, changing slowly at first, then dramatically spiking all at once. The study shows how risks to biodiversity are highly magnified in a non-linear way with warming of 3.6 degrees Fahrenheit or more, he said.

“By the time things get really bad it’s going to be too late,” he said. “But our results show very clearly that it is not too late to act to delay the risk or even avert it entirely for many thousands of species. By holding warming below 2 degrees Celsius (3.6 degrees Fahrenheit), we can effectively flatten the curve of how climate risks to biodiversity accumulate over time.”

Coronavirus at beaches? Surfers, swimmers should stay away, scientist says

Kim Prather, a leading atmospheric chemist at the Scripps Institution of Oceanography, wants to yell out her window at every surfer, runner, and biker she spots along the San Diego coast.

“I wouldn’t go in the water if you paid me $1 million right now,” she said.

The beach, in her estimation, is one of the most dangerous places to be these days, as the novel coronavirus marches silently across California.

Many beachgoers know they can suffer skin rashes, stomach illness and serious ear and respiratory infections if they go into the water within three days of a heavy rain, because of bacteria and pathogens washing off roads and into the ocean. Raw or poorly treated sewage entering the ocean also poses major health risks.

Prather fears that SARS-CoV-2, the virus that causes COVID-19, could enter coastal waters in similar ways and transfer back into the air along the coast.

In her research, Prather has found that the ocean churns up all kinds of particulate and microscopic pathogens, and every time the ocean sneezes with a big wave or two, it sprays these particles into the air. She believes that this new coronavirus is light enough to float through the air much farther than we think. The six-feet physical distancing rule, she said, doesn’t apply at the beach, where coastal winds can get quite strong and send viral particles soaring.

“It’s not going to kill you if you miss a few surfing sessions, but it could if you go out there and get in the wrong air,” she said.

“You can’t see the virus, you can’t smell it … It’s a real silent killer right now.”

Scientists across the globe are scrambling to learn the basic characteristics of the virus, and so far, neither the World Health Organization, the U.S. Centers for Disease Control and Prevention nor local health agencies have warned that the virus can be spread by ocean spray or coastal breezes. However, they have warned that it can be spread by droplets from sneezes and coughs, and by coming into contact with it on surfaces.

And though the virus has been detected in sewage, scientists are still investigating whether it remains infectious in fecal matter — and whether it survives treatment in a wastewater facility.

Coronado

People walk along the beach in Coronado, which is among the few remaining beaches open in San Diego County on March 29, 2020.
(K.C. Alfred/The San Diego Union-Tribune)

In the eyes of California health officials, beaches pose a health threat by drawing large crowds of people who will congregate too closely and trigger a chain of infections.

It hasn’t been easy keeping Californians off the beach even with those concerns, despite stay-at-home orders and officials urging the public to avoid crowding popular areas. By now most beaches, trails and parks in California have been roped off in an effort to slow the spread of COVID-19, which has overwhelmed hospitals and escalated medical emergencies across the nation and world.

Even the Coastal Commission, usually the gatekeeper of California’s landmark law that declares access to the beach is a fundamental right, is allowing local officials to put up temporary signs and barricades — citing the emergency need to protect public health and safety.

Patrol cars and loudspeakers can be heard blasting social distancing rules along Ocean Avenue in Santa Monica. In Manhattan Beach, a surfer was slapped with a $1,000 fine after he ignored numerous warnings by police and lifeguards cautioning him not to go in the water.

coronavirus beach closure

The Hermosa Beach Police Department closed off the strand.
(Jay L. Clendenin/ Los Angeles Times)

Prather, who directs the Center for Aerosol Impacts on Chemistry of the Environment, a large research hub at Scripps backed by $40 million from the National Science Foundation, sent her researchers and students home long before California officials issued stay-at-home orders. She suspected this virus was contagious by air, and knew from past studies that coronaviruses can be excreted in fecal matter. She worries SARS-CoV-2 could enter the ocean from sewage spills and outfalls, and then reenter the atmosphere.

Wastewater treatment plants don’t necessarily deactivate viruses before sending the sewage into the ocean — they tend to target bacteria like E. Coli, she said. And in areas like Imperial Beach, sewage from the Tijuana River often spills into the ocean completely untreated.

Coronaviruses are encased by what she calls a “hydrophobic” lipid, or fatty, membrane. Fat tends to float to the surface of water, similar to oil in a vinaigrette dressing. When waves break in the surf zone and all the foam and bubbles pop, Prather said, “all that stuff — the viruses, the bacteria, pollutants, all the gooey, oily stuff — just launches into the air.”

The ocean, in fact, is the largest natural source of aerosol particles after dust. These marine aerosols affect the formation of clouds over the ocean and can spread over large distances.

Once in the air, studies have shown that aerosols can travel around the globe in as little as two weeks. Prather has found dust in microbes from Africa that changed the snowfall in California. She’s been tracing the bacteria and sewage pollution dumped into the ocean from the Tijuana River, showing how much ends up transferring to the atmosphere.

“Once things are in the air, they can go pretty darn far. People are shocked whenever I talk about stuff becoming airborne,” she said. “I see pictures of the beach shut down, and the signs tell you don’t walk on the beach, don’t swim, don’t surf, but nobody tells you: Don’t breathe.”

Scientists are still debating the characteristics of this latest coronavirus. Recent research in the New England Journal of Medicine found that when the virus was suspended in a mist under laboratory conditions, it remained “viable and infectious” for three hours — though researchers have said that time period would probably be no more than half an hour in real-world conditions.

Charles Gerba, a professor of microbiology at the University of Arizona who has studied coronaviruses in wastewater since the SARS outbreak, said these kinds of viruses have typically been found to survive two or three days in raw sewage.

With this new coronavirus, he’s done a few molecular tests: Though he’s confirmed that the virus does wind up in sewage, he found that more than 90% of this new coronavirus was removed by typical wastewater treatment —“it’s very sensitive to disinfectants.”

Still up for debate, however, is whether the virus in the sewage is still infectious.

“One report says yes, another report says no, so we don’t really know yet for certain,” said Gerba, whose research focuses on wastewater removal of viral pathogens. As for how long the virus could survive in saltwater, there’s not much data, he said, but pathogens like hepatitis A or norovirus tend to survive much longer in wild environments.

For Prather, she hopes to fill in more data gaps and is preparing to test the air particles along the coast for signs of the virus — especially in areas known for inconsistent water quality.

“People kept saying respiratory droplets and surfaces, surfaces, surfaces, but I just felt like no way, this is something special,” she said. “This thing is so contagious …. Look at that choir in Washington — those people weren’t coughing. They were just singing! But it got so many of them.”

In the meantime, California beaches are likely to remain close to empty. Even beach advocacy groups have joined the Coastal Commission in urging people to avoid crowding the beaches and ocean. Fresh air and connecting with the outdoors are important, they said, but these are extraordinary times.

Some people worry the temporary closures could lead to permanent beaches behind lock and key — public beach access, after all, has been a contentious battle along the coast for decades. Coastal officials say they’ve been keeping track of which beaches have closed, and city and county leaders have been told that access restrictions expire immediately whenever shelter-in-place orders are lifted.

“We recognize there is an inequity in coastal access and we strongly encourage local governments to consider approaches that balance public health order requirements and equitable public access — the coast belongs to all,” Jack Ainsworth, the coastal commission’s executive director, wrote in a letter to local officials.

Surfrider Foundation, one of the most passionate public access groups in California, assured beachgoers that they will be out in full force once the restrictions are lifted to ensure that no oceanfront property owners took advantage of this unprecedented situation.

“We in California have fought for open beaches for decades,” said Jennifer Savage, Surfrider’s policy manager in California. “But we also believe in being responsible citizens and protecting the health and safety of our community.

“Right now, you can be the  difference between life and death for somebody you don’t know.”

https://www.latimes.com/california/story/2020-04-02/coronavirus-ocean-swimming-surfing-safe-beaches-los-angeles