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Friday, February 19, 2021

Cold Snaps Expose Climate Science Fragility

Cold snaps can be deadly. A 2014 National Health Statistics report found, “During 2006–2010, about 2,000 U.S. residents died each year from weather-related deaths; 63% were attributed to exposure to natural cold. The recent cold snap in Texas and Germany highlighted our energy system’s vulnerabilities. During times of our greatest need, inadequate natural gas supplies, frozen wind turbines and snow-covered solar panels, left too many shivering in the dark. Why were we unprepared for such cold when the northern hemisphere had been experiencing a winter cooling trend since 1990? Were government officials too gullible, lulled by narratives that global warming would make snow disappear and cold snaps less likely?

 

After every deadly cold snap, defenders of CO2-driven-climate-change repeat the same unbelievable narrative “increased warming causes more cold”. Their argument is based on a sliver of truth regards the polar vortex’s influence on cold air. In the winter without sunlight, polar air cools much faster than the lower latitude air. The stark temperature contrast between cold and warm air intensifies the polar jet stream which defines the vortex’s boundary. The sliver of truth is intruding warmth can indeed weaken the vortex

 

 

The vortex was heavily studied in the 1990s due to concerns about ozone holes. Although typically ignored by the media, increasing CO2 both warms the lower atmosphere (troposphere) and cools the stratosphere. Climate models all predicted the vortex would strengthen because greenhouse gases would enhance stratospheric cooling by 5–7°C during December and January by 2019. Because ozone depletion requires extreme cold, it was feared increasing CO2 would enhance the ozone holes. Furthermore, climate scientists argued a warming troposphere and a cooling stratosphere was the undeniable “human fingerprint” of CO2 caused climate change. But their science was woefully incomplete. Stratospheric warming increased, the 2019 ozone hole was smallest on record and the vortex weakened despite CO2-caused cooling.

 

High in the stratosphere, the boundary of the vortex is symmetrical simply based on the contrast between colder and warmer latitudes. However, near the surface, mountains and land-sea temperature contrasts naturally cause the jet stream to be wavy. The Pacific high-pressure system and USA’s western mountain ranges cause the jet stream to veer northward, pulling warm subtropical air north over North America’s west coast. Moving eastward the jet stream then plunges southward driving extreme cold into the USA east of the Rocky Mountains. This natural undulation likely explains the “warming hole” in southeastern USA where temperatures have not warmed for over a century. Over 36% of the long-term USA weather stations, concentrated mostly in the eastern USA, experienced 70-year cooling trends despite urban heat island affects.

 

Some climate scientists argue CO2 induced “Arctic Amplification” causing warmer polar temperatures which increases the jet stream’s waviness. However, there is no consensus for their hypothesis, and some argue there is little evidence at all for that effect. Nonetheless there is an excellent, albeit ignored, explanation for the warming Arctic/cooling mid-latitudes paradox. The natural quasi-permanent Aleutian Low nearly explains it all, with similar dynamics in the north Atlantic.

 

The Arctic Ocean radiates away more heat (~100 watts/m2) than it absorbs from sun and greenhouse effects combined. (human-added CO2 offsets less than 2 watts/m2) It’s the inflow of warm ocean water that determines if the Arctic ocean cools or warms. Like the stratospheric vortex, the Aleutian Low forms every year as the northern hemisphere cools, but its position and strength vary due to natural El Nino cycles, the Pacific Decadal Oscillation and the Arctic Oscillation. When the Aleutian Low is positioned over the Bering Sea it drives warm southern air and warm storms further northward. That dynamic also raises sea level south of the Bering Strait, increasing warm water flows through the strait. Increased warm water flows melt more sea ice and triggers Arctic Amplification and higher temperatures.

 

Simultaneously, when the Aleutian Low is positioned over the Bering Sea its strength increases, intensifying upward motions of relatively warm air into the stratosphere. It’s that warmth that weakens the polar vortex and unleashes the cold Arctic air. When natural weather re-positions the Aleutian Low over the Gulf of Alaska, wind direction changes, blowing water away from the Bering Strait. That reduces warm water flows into the Arctic. The Aleutian Low also weakens reducing upward atmospheric motion, allowing the vortex to strengthen.

 

The Aleutian Low’s position changes throughout the winter and from year to year. However, before the Pacific Decadal Oscillation (PDO) switched phases, between 1950–1976 the Aleutian Low spent, on average, 16 months over the Bering Sea and 20 months over the Gulf of Alaska. After the PDO shifted, the Aleutian Low only spent 7 months during the next 25 years over the Gulf Alaska and more time over the Bering Sea.  That shift changed the balance to a warmer Arctic, a more common weaker vortex and more cold snaps.

 

Clearly energy policy must be better prepared to deal with natural climate change and its periodic extreme cold.

Tuesday, February 9, 2021

Kivalina Disappearance Not Caused by Climate Change

In 2017 Huffington Post wrote, “It is disappearing. Fast. Kivalina could be uninhabitable by 2025, all thanks to climate change.” Like so many media outlets and politicians, they were ignoring Kivalina’s real problem. Kivalina was never a place the Inupiaq freely chose to settle. With survival on the line, they were intimately aware of Alaska’s everchanging environments, long before the theory of CO2?induced?climate?change could be blamed. Kivalina was a good seasonal hunting camp, but never valued as a permanent settlement. Indigenous Alaskans had wisely chosen to be semi-nomadic. Nonetheless the Inupiaq were victimized by  mis-guided government attempts to enforce “permanence” in an everchanging climate when the US Department of the Interior’s Bureau of Indian Affairs (BIA) made it a permanent settlement in 1905.

 

As REVEAL reported, “The Inupiaq used to spend summers in tents along Kivalina's beach. When winter set in, they'd move inland to hunt caribou for food. They were semi-nomadic but in 1905 the federal government built a school on the island. Parents were threatened with jail time or losing their kids all together if they didn't send them to school.” In 1911 just 6 years after forced settlement, and long before any “dangerous sea level rise” or “dangerous sea ice reduction”, Kivalina’s schoolteacher Clinton Replogle warned that Kivalina should be relocated due to threats of flooding from ocean storms.

 

As with most  barrier islands, Kivalina island was formed from a loosely consolidated sand bar. Ocean waves drove sand and gravel back towards the coast where in the shallows it accumulated into a sand bar. Erosion by river flow on its landward side maintained a lagoon and the bar’s narrow width. Barrier islands form when rivers seeking an outlet to the ocean cut the sand bars into pieces. Kivalina’s river outlet is unstable. Some years it’s blocked by sand piled up during winter storm waves. Later it’s re-opened by river erosion. As Tribal Administrator Millie Hawley recently stated, “Kivalina was always eroding.”

 

Barrier islands form where shallow?sloping ocean floors minimize any loss of sand that might irretrievably wash away into the deeper ocean. However, such shallow ocean floors also amplify wave heights of approaching storms. Kivalina’s ultimate height, a mere 13 feet, was determined by the sediments dropped from overtopping waves. Kivalina was established within 1 to 2 feet of the high tide mark even though storms in late summer and the ice?free fall deliver waves 10 feet or higher. No wonder the threat of devastating storm surge and floods was so clear to Clinton Replogle. Indeed, geological surveys have revealed flooding from waves that had overtopped Kivalina happened at least twice between1905 and 1990.

 

In 1994, before climate change reduced Chukchi Sea ice, Inupiaq residents initiated a study to relocate. However,  in an economy based on subsistence harvesting of seals, walrus, whale, salmon, and caribou, funding for relocation was scarce. State and federal governments offered little support. So, after government reports touted “destructive global warming”, in 2011 the residents opted to file a lawsuit against the major oil companies arguing “Kivalina must be relocated due to global warming” and sought funds to cover an estimated cost of $95 million to $400 million. Although their lawsuit failed, previously little?cared?about Kivalina was thrust into the limelight as an icon of the “climate crisis”. Alarmist media outlets repeatedly claimed Kivalina was disappearing because increasing CO2 concentrations were raising sea levels and reducing sea ice. But the science suggests otherwise.

 

Sea levels across the Arctic vary as winds remove water from one region and pile it up in another. Along the Chukchi coast bordering Kivalina sea level had not risen since the 1990s.  Furthermore, summer winds cause warmer waters to flow northward through the Bering Strait, which initiates sea ice melt every year. Over the past few decades those winds doubled the volume of warm water flowing through the strait, melting more ice. In contrast to fears about less ice, more open water enhanced photosynthesis and increased the  marine food web that the Inupiaq depend on by 30% .

 

Air temperatures had risen twice as fast as elsewhere, because more Intruding warm water released more heat to the atmosphere and more open water absorbed more sunlight. That temperature dynamic was dubbed “Arctic Amplification”. However, most climate models now agree, it’s not the rising CO2 concentration but intruding warm Pacific water that drives Arctic Amplification.

 

Any connection between a greenhouse effect, increased warm water flow through the Bering Strait and Kivalina’s erosion remains to be seen. Kivalina is still an iconic example, not of a climate change crisis, but of media and government inattention to injustices perpetrated on indigenous Alaskans until it’s a useful political tool to fabricate a crisis. I suggest defunding the BIA for forcing settlements on vulnerable habitat and use BIA’s 1.9?billion?dollar budget to relocate the Inupiat to a place of their choosing.

 

Jim Steele is Director emeritus of San Francisco State University’s Sierra Nevada Field Campus, authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism, and a member of the CO2 Coalition

 

 

Contact: naturalclimatechange@earthlink.net


Wednesday, January 27, 2021

Endangered Cloud Forests, Clouds and Climate Change

 

Demagogues trumpet ecosystems are collapsing and allude to scientific assessments. For example, the International Union for the Conservation of Nature (IUCN) listed the Gnarled Mossy Cloud Forest as “critically endangered”. So, what constitutes “critically endangered”? The Gnarled Mossy Cloud Forest story is telling.

 

The Gnarled Mossy Cloud Forest is located on the 5.6 square mile Lord Howe Island situated between Australia and New Zealand. For perspective, 54 islands could fit within the limits of New York City. Still, Lord Howe Island is an evolutionary marvel. Forty-four percent (105) of the island’s plant species, and 37% of all its invertebrate species are found nowhere else in the world. Additionally, the island supports the most poleward of all coral reefs. So, in 1982 Lord Howe Island was designated a World Heritage Area.

The “critically endangered” cloud forest is restricted to just 0.1 square miles atop the island’s extinct volcanic mountain. Researchers worried the cloud forest’s unique collection of species would have nowhere to go if global warming disrupted its environment.  Accordingly, the IUCN designates ecosystems with such limited distributions as critically endangered. Although confined to a small micro-climate, its species are very resilient to changing climates. Hundreds of thousands of years were required for the island’s unique species to evolve from their ancestors (after arriving from Australia, New Zealand and New Caledonia). During that time, they survived alternating ice ages and warm inter-glacials.

 

Unchanging geography permits the existence of cloud forests. Most are found in the tropics where they experience 78-102 inches of annual rainfall. (For perspective, “rainy” Seattle averages just 38 inches of rain.) The photo below also illustrates why cloud forests are typically confined to zones within 220 miles of the coast, and above elevations of 1600 feet. Sea breezes are laden with water vapor. As they rise and cool, vapor condenses to form clouds. Rising air saturated with water vapor can cool enough to create clouds by rising over 20-story buildings. The Gnarled Mossy Cloud Forest exists around 2800 feet.

 

As human populations increased, land cultivation threatened cloud forests across the globe. However, due to low human populations and steep slopes the Gnarled Mossy Cloud Forest was spared excessive losses. However, as with Hawaii and all of earth’s unique island species, introduced species are the greatest extinction threat. Introduced cats, pigs and goats were damaging Lord Howe Island since the mid 1800s. Having recognized this threat, humans began programs to preserve the island’s species. Pigs and goats were eradicated by the 1980s, but the island’s plague of introduced rats remain problematic. To date, an introduced owl and poison bait projects struggle to limit rat populations.

 

In addition to rats, scientists suggested the cloud forest was threatened by a “loss of moisture from declining rainfall and cloud cover due to climate change.” However, scientists admitted their estimates were “based on limited information” and the real level of threat to the cloud forest could range from “Least Concern” to “Collapsed.” “Least Concern” may prove to be the correct designation as long-term global precipitation data show a slight increasing trend in the region.

 

Nonetheless, to support their catastrophic claims their study ill-advisedly alluded to a debunked 1999 study that claimed CO2-caused warming was drying the Costa Rican cloud forests by raising cloud elevations, and allegedly drove the Golden Toad to extinction. That climate attribution was absolutely wrong. The cloud forest amphibians were killed by an introduced chytrid fungus, spread by pet trade collectors, researchers and animals like introduced bullfrogs. Remarkably, the proposed worrisome warming and drying actually benefitted amphibians by killing the fungus. Similarly, Lord Howe’s cloud forest vegetation is potentially threatened by introduced fungi (Phytophthora), spread by tourists. So, steps are being taken to encourage “social distancing” near vulnerable native plants.

 

As with Costa Rica, Lord Howe Island endures periodic dryness associated with El Nino cycles. The island’s lowest recorded rainfall happened during the 1997 El Nino. Unfortunately, to blame climate change for a short-term drying trend, researchers ignored the fact that the second lowest rainfall happened in cool 1888 and differed from the “record low” 1997 rainfall by a scant 0.3 inches. Furthermore, research has determined cloud cover shifts across the Pacific due to El Nino cycles and the Pacific Decadal Oscillation, and regional tree rings reveal 55-year dry cycles amplified by El Nino.

 

Ecologists know surviving cloud forest species had to adapt to natural cycles of periodic dryness they endured over millennia, and indeed they did. One example is the Kentia Palm. Native only to Lord Howe Island, it’s a globally popular indoor house plant, in part, because it withstands long periods of neglect and irregular watering. So, take heart. The Gnarled Mossy Cloud Forest will not collapse with a changing climate. And although introduced species certainly are a threat, it is something people are rectifying.

Wednesday, January 13, 2021

Betting Against Collapsing Ocean Ecosystems

Betting Against Collapsing Ocean Ecosystems

In summer 2020, the media hyped various versions of “Tropical Oceans Headed For Collapse Within The Next 10 Years”. One outlet warned, “Global warming is about to tear big holes into Earth’s delicate web of life.” A single peer-reviewed paper instigated those apocalyptic headlines predicting CO2­­-caused warming would ramp-up species extinctions starting in tropical oceans. In contrast, I’ll confidently bet any climate scientist $1000 that no such thing will happen.

 

Sadly, some researchers hope to enhance their fame and fortune by offering dooms day scenarios. Profit hungry media and scientific journals with “if it bleeds, it leads” business models, abet that fear mongering.  Scientists also get consumed by their own fearful visions. Gaia scientist James Lovelock predicted by 2100 global warming would make the tropics uninhabitable and "billions of us will die” with a few breeding pairs surviving in the Arctic. (To his credit, Lovelock recanted his alarmism) Stanford’s Dr. Paul Ehrlich falsely predicted “hundreds of millions of people will starve to death” in the 1970s. So, we must ask, are collapsing oceans a real concern, or just another scientist from the “chicken little school of science” crying wolf?  We’ll know by 2030.

 

Fortunately, good scientists are urging “ocean optimism”, promoting lessons learned from our mistakes and successes. Overfishing and overhunting is definitely a significant threat to ocean ecosystems. Once hunted to near extinction for their oils, whales and sea lions are now rapidly recovering. Thanks to wise hunting regulations, Hawaii’s endangered humpback whales grew from just 800 individuals in 1979 to 10,000 by 2005. Turtle nests in Florida increased from “62 in 1979 to 37,341 in 2015” as North and South Atlantic green turtle populations increased by 2,000% and 3,000% respectively.

 

Likewise, fish populations are recovering with better fisheries management. Off the USA’s west coast,  uncontrolled bottom trawling extirpated several species. So, fishery managers implemented a complete fishing ban, as scientists expected recovery to take 100+ years. However within just 10 years a dramatic improvement prompted both environmentalists and regulators to agree to reopen much of the coast to trawling. Critical photosynthesizing algae, diatoms, rapidly flourish when upwelling brings nutrient rich, high CO2 deep waters back to sunlit surfaces. Diatom blooms stimulate zooplankton abundance which feeds fast-growing bait fish, like anchovies and sardines, thus sustaining a food web from tuna to whales. And more good news, since the 1850s warming has spurred dramatic increases in upwelling and marine life.

 

Michael Mann and Kevin Trenberth rule the roost within the chicken little school of science. They recently co-authored a “scary” paper titled Record-Setting Ocean Warmth Continued in 2019. Using the energy metric Zetta (1021) Joules, an incomprehensible foreign language for the public, they estimated 2019 warmed by 25 Zetta Joules. That converts to a not so scary  0.016 °F (0.009 °C) increase. Five thousand years ago, marine organisms thrived in waters that were about 2.7°F to 3.6°F warmer than today. At their alleged “record setting” warming pace, it would take four to six hundred years to reach those earlier temperatures.

 

To be fair, it’s extremely difficult to measure the oceans’ heat content. To improve our knowledge, a world-wide array of floating buoys, ARGO, was established by 2003 to measure temperature down to 2000 meters and periodically transmits data via satellite. We now realize ocean currents are far more complex than once thought, and due to constant changes in ocean heat transport, such as caused by El Niño, the ocean heat content requires distinguishing warmer temperatures due to heat redistribution versus warming from the sun or CO2. Unpredicted by climate models, ocean heat transport caused 90% of recently increased ocean heat to accumulate in a narrow band of the Southern Ocean outside the tropics, while the rate of northern hemisphere warming is decreasing.  However, ARGO data also reported cooler temperatures than previous less reliable ship measurements. Oddly, 0.216°F is added to the ARGO data. Such a large adjustment makes the estimated increase of 0.016°F/year highly uncertain.

 

There’s a further complication. Outside the tropics, the earth loses more heat than the sun or a greenhouse effect  can provide. It’s the transport of heat towards the poles that keeps temperatures outside the tropics much warmer than they would be otherwise.  In ancient climates of the Cretaceous and early Eocene, polar regions were far warmer than today with crocodiles in Greenland and lush coastal vegetation in Antarctica. Such “equable climates” are explained by changing continental configurations and stronger ocean currents carrying more heat from the tropics towards the poles. Yet, the tropics did not cool. Exported tropical heat was compensated by reduced cloud cover, which increased solar heating. Ocean oscillations that increase ocean heat transport today most likely explain the Arctic warming of the 1930s.  

Similarly, recent poleward, ice-melting heat transport, with reduced cloud cover that increases solar heating may explain much of our recent climate change. By 2030, we should know.

Thursday, December 31, 2020

Preventing Ecosystem Collapse: Seagrass

Seagrass ecosystems enable a wondrous diversity of marine life. Seagrass feeds ancient (but currently threatened) animals like green turtles, manatees and dugongs, sea urchins, parrot fish and geese. Seagrass supports major fisheries of pollock and cod and they’re home to seahorses. The ecosystem serves as a nursery ground for hundreds of species of juvenile fish. Seagrass supports clams, scallops, shrimp and spiny lobsters. Recently, seagrass meadows have also been shown to reduce disease that can infect people, coral or fish. So, recent losses of seagrass have generated great concern and motivated restoration efforts world-wide. Still, they are not doomed to collapse. The good news is most of the human factors that have reduced seagrass meadows can be and are being remedied. Furthermore, rising levels of carbon dioxide will benefit their growth and recovery.
Unlike seaweeds that are anchored to hard surfaces, seagrass thrives on muddy or sandy bottoms where their roots absorb the rich supply of nutrients stored in the sediments. However, storms and heavy waves easily disturb such habitat. So, seagrass prefers sheltered estuaries, coves and bays. Unfortunately, sheltered waters are also prime real estate for humans to harbor their boats. Much seagrass habitat has been lost to dredging of boat harbors. The chains that anchor boats to their moorings can scour the sea floor as the boats shift with the tides and currents. Nets seeking tasty bottom fish are dragged across the seafloor but also plow up seagrass meadows. Fortunately, people are working to prevent such damage by restricting fishing zones or inventing seagrass friendly moorings. The ancestors of today’s seagrasses were flowering land plants that returned to the ocean a 100 million years ago. To photosynthesize, seagrass colonization was limited to shallow coastlines with clear water and adequate sunlight. Most species prefer water that’s only 3 to 9 feet deep. But to remain at the proper depths, seagrass had to be resilient. Ice ages caused sea levels to rise and fall 400 feet eliminating old habitat and creating new ones. None of today’s seagrass meadows existed 6000 years ago. The Everglades’ Florida Bay formed 4000 years ago. Since then, seagrass meadows have flourished and disappeared periodically, but are now at their greatest extent.
It would have been extremely difficult for seagrass ancestors to successfully invade the oceans under today’s atmospheric CO2 concentration and still photosynthesize. Carbon dioxide is quickly converted to less usable ions after entering the water. Under current concentrations, only 1% remains as vital CO2. However, a 100 million years ago, plants flourished under increased atmospheric CO2 that was up to 7 times greater (3000 ppm) than today (410 ppm). The biggest evolutionary hurdle for seagrasses was surviving toxic sediments. Seagrass meadows accumulate organic matter as leaves and shoots are grown and shed. Unfortunately, as bacteria decompose organic matter, they consume all the oxygen. Without oxygen, different bacteria convert sulfur molecules into toxic sulfides that could kill the grass. So, seagrasses evolved channels that transported oxygen from their leaves to their roots, creating an “oxygen shield.” Many species evolved symbiotic relationships with specific bacteria and clams. The clams benefit from the grass’ added oxygen and help aerate the sediment further. Bacteria sheltering in clams then convert toxic sulfides into harmless chemicals. Seagrass success largely depends on generating more oxygen than bacterial decay can consume, and that battle explains many seagrass die-offs, such as recent die-offs in the Everglades’ Florida Bay.
As human populations grew and settled along the coast, they altered seagrass ecosystems by clearing the land for lumber and agriculture, and by overgrazing. Increased soil erosion was carried to the sea creating murky ocean waters that reduced sunlight. Sewage runoff and agricultural fertilizers added nutrients that promoted plankton blooms, which also reduced sunlight. With less light, there is less photosynthesis to generate oxygen. Without enough oxygen, toxic sulfides can invade and kill the seagrass. The good news is such lost seagrass ecosystems are not happening everywhere, and many unaffected regions support prosperous seagrass ecosystems. It is not a global crisis. The losses due to past ignorance of the ecosystem’s natural dynamics are now being repaired. Seagrass meadows with improved water quality are thriving and people are now managing sediment runoff better and developing waste-water treatment to reduce nutrient pollution. A 2010 die-off of seagrass in Australia’s Shark Bay, now a World Heritage site, generated scary headlines in scientific journals and the mass media drumming up fears of an existential crisis. The seagrass died during a “marine heat wave” supporting beliefs that only global warming could kill seagrass in a relatively pristine and protected ocean bay. However, the “marine heat wave” alleged to have killed the seagrass, was caused by a strong La Niña that caused warmer tropical waters to be transported (via the Leeuwin current) down the west coast of Australia. These periodic and natural warm water intrusions have been dubbed the “Ningaloo Niño”. The northerly winds that drove that warm water southward also suppresses the normally cold air arriving from the Southern Ocean region. The normal upwelling of colder deep waters is also suppressed. Once the strong La Nina conditions waned, the regional climate reversed causing several years of cold spells.
The greatest diversity of seagrass species thrives in the warmest waters. So normally, scientists would expect that organisms exposed to a constantly changing climate, induced by periodic warm Ningaloo Niño, would have adapted to those natural temperature fluctuations. Indeed, the immediate seagrass killer now appears not to have been warmer temperatures. Years of heavy grazing by non-native cattle and sheep made the watershed that drained into Shark Bay increasingly vulnerable to erosion. La Niña’s coincidentally increase rainfall during Australia’s monsoon season. Those heavy rains and eroding soil combined to produce a murky river discharge that flowed 10 miles out into the bay. The closer Shark Bay’s seagrass meadows were to the river delta, the greater the die-off. Seagrass meadows escaping those light?reducing waters were typically still thriving. Hopefully the wrong analysis that blamed global warming, will not lead to bad remedies and misguide any efforts to protect Shark Bay from further lethal river discharge. Lastly, the legacy of seagrass reproduction created one other problem. In the 1930s along the coast of Virginia, hurricanes and disease had completely denuded several seagrass meadows. Seventy years later the seagrass had yet to return. Without flowering grasses there are no local seeds to initiate recovery. Seagrass seeds are heavy and quickly fall to the seafloor, so many seagrasses spread slowly. Without a very nearby seed supply, a denuded meadow may take centuries to recover. The good news is people are now harvesting seeds from distant healthy patches and sowing them where seagrass once thrived. By maintaining good water quality and minimizing boat-related damage, seagrass meadows are on the mend. Dependent fish and scallops are slowly recovering. Florida’s manatees have increased 6-fold and are no longer rated as endangered. But manatees need warm winter refuges. So, counter-intuitively, the biggest threat to manatees living in Florida’s seagrass ecosystem is the loss of power plants and the warm water discharge that has served as a manatee winter sanctuary.
12/31/2020 modified online version to be printed in BattleBorn Media newspapers Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism Contact: naturalclimatechange@earthlink.net

Friday, December 18, 2020

Preventing Ecosystem Collapse: Pt 2 Caribbean Coral


Media headlines have been promoting unrealistic fears of ecosystem collapse due to climate change. Such fears get supported when the International Union for the Conservation of Nature (IUCN) designates some ecosystems as endangered, such as Caribbean Coral Reefs. But reefs are resilient and the human factors threatening individual reefs can be remedied.

 

The Caribbean reef ecosystem consists of thousands of individual reefs spanning from the east coast of Mexico and Central America to Florida and the Bahamas and south to the coast of Venezuela. Fifteen thousand years ago these reefs did not exist because sea level had fallen by 400 feet during the ice age. Modern reefs became established 8,000 years ago by colonizing newly flooded coastlines.

 

Caribbean Coral Reef Boundary

Based on one IUCN criterion the Caribbean reef ecosystem was designated “Least Concern” due to the widespread occurrence of individual reefs. In contrast, the loss of 59% of total coral cover between 1971 and 2006 prompted the IUCN to designate the reef system as “Endangered”.

 

Coral cover naturally fluctuates with seaweeds (macro-algae). Coral are killed by hurricanes, disease or bleaching,  which allows seaweeds too colonize the vacated space. The seaweed is gradually reduced by algae-eating animals which allows coral to return to their former dominance. Coral usually recover within 15 to 20 years, but recently their recovery has been extremely limited thus reducing coral cover. Unlike the demonized sea urchins that threaten Alaska’s kelp forest, algae-eating urchins are vitally important in maintaining the balance between seaweeds and Caribbean coral. The recent lack of coral recovery is largely attributed to a new disease that devastated urchin populations in the 1980s and minimized the urchins’ consumption of seaweeds.

 

Caribbean corals had been decimated in the 1980s by the novel White Band disease. However, that disease only affected two coral species from the genus Acropora - staghorn and elkhorn coral. Those species are now considered endangered. Acropora’s evolutionary strategy was to quickly colonize vacated shores produced by natural disturbances like hurricanes. These coral species thus dedicated their energy to rapid growth to out compete the seaweeds. That adaptation allowed staghorn and elkhorn coral to rapidly colonize flooded coasts as sea level recovered from the last Ice Age and dominate modern Caribbean reefs. But that strategy required diverting energy from building stronger reefs or resisting disease.  

 

Because Acropora require shallow habitat they’re vulnerable to storm damage. So, they evolved a reproductive strategy that produced new colonies by cloning new coral from storm damaged fragments. However, cloning reduces genetic diversity which also made them more vulnerable to new diseases.

 

Mortality from bleaching also reduced coral cover. Bleaching from unusually warm temperatures during summer 2005 and the 1998 El Nino is often highlighted. Surprisingly, fatal cold weather bleaching is rarely mentioned. Yet in January 2010 along the Florida Keys, cold weather killed 11.5 percent of the coral, which was 20 times worse than the 2005 warm weather mortality. Understanding why both warm and cold weather causes bleaching provides insight into how coral have successfully adapted to ever changing climates over the past 220 million years.

 

Shallow water corals depend on photosynthesizing symbiotic algae (aka symbionts) that provide over 90% of the coral’s energy. However, those corals will remove one symbiont species and acquire a new symbiont that is better adapted to the changing weather conditions. During the winter, colder temperatures and less light reduce photosynthesis. So, coral increase their density of symbiotic algae to counteract reduced productivity. But if it is too cold, the symbionts keep their energy supply for themselves. As a result, coral remove the “freeloaders” causing bleaching. A more productive cold?tolerant symbiont must then be acquired, or the coral die.

Coral polyp with inner symbiotic algae 

 


In contrast during the summer, more light and higher temperatures produce so much energy, coral reduce their number of symbionts. Because photosynthesis also produces potentially harmful chemical by-products, coral remove symbionts to reduce the production of harmful chemicals. That too causes coral to bleach, and unless a better adapted symbiont is  acquired, the coral will die. Despite that mortality risk, research now shows by switching their symbionts, coral can quickly adapt to warmer or cooler climates and enhance the species survival.

 

Studying fossil reefs, scientists determined that Caribbean corals had been declining decades before widespread bleaching and disease outbreaks occurred. Growing human populations cleared the land for farms, sugarcane and banana plantations. Resulting soil runoff reduced water clarity required for efficient photosynthesis. Increased sewage also reduced clarity and introduced pathogens. Those stressors made coral more susceptible to subsequent bleaching and disease. Soil runoff also added nutrients that tipped the ecological balance to favor seaweed growth, while overfishing removed seaweed?eating fish that once restricted seaweed dominance.

 

We can, and are controlling soil runoff and treating sewage. Fishing regulations are restoring the ecosystem that had balanced seaweeds and coral. And with those protections, naturally resilient coral will steadily recover.

Thursday, December 3, 2020

Preventing Ecosystem Collapse: Alaska’s Kelp Forests



Over the past few years the media, such as the NY Times, have hyped a coming apocalypse and an existential crisis as ecosystems collapse. Inside Climate News, one of the more egregious fear mongers suggests “Global Warming Could Collapse Whole Ecosystems, Maybe Within 10 Years”. In contrast, most scientists agree ecosystems are very complex and still not well understood. By understanding each ecosystem’s unique pressures from humans, other organisms and natural climate change, perhaps we can make ecosystems more resilient and prevent the alleged "crises".


The International Union for the Conservation of Nature (IUCN), the foremost scientific organization evaluating threats to species and ecosystems, has created the “Red List of Ecosystems” that provides assessments that characterize threats to individual ecosystems.  To date, only one ecosystem has collapsed, central Asia’s Aral Sea. It’s the world’s fourth largest inland water body. Landlocked, its fate is determined by the balance between inflowing water and evaporation. But 2000 years of irrigation has disrupted that balance. Between 1950 and 2007, irrigation nearly quadrupled causing the Aral Sea to largely dry up, eliminating most of its species. The Aral Sea has been sacrificed in order to feed a growing population. However most other ecosystems have a more optimistic future.

 

The first IUCN Endangered ecosystem I’ll examine in a series of articles is Alaska’s giant kelp forests. The fate of kelp forests is largely determined by the interactions between urchins, otters, humans and killer whales.  Hungry kelp-eating urchins can quickly convert a kelp forest into an urchin barren stripped of kelp. However, urchins are regulated by their primary predator, sea otters. Before Alaska’s fur trade began in the mid 1700s, otter populations and kelp forests flourished. One hundred and fifty years later overhunting exterminated or reduced all otter populations, urchins proliferated and kelp forests declined. Alarmed, a 1911 international treaty forbade hunting otters. To further their recovery, otters were re-introduced to islands where they had been eliminated. With improved human stewardship, otters rebounded to their pre-hunting abundance by 1980. With fewer urchins, kelp forests flourished again. But then killer whales began overhunting otters.

FIg 1.  Extent of Alaska's kelp forests: From the Aleutian Islands in the west to southeastern Alaska.


Each killer whale population has a specialized feeding strategy. Some strictly eat fish while others feed on marine mammals. Some congregate around Alaska’s eastern Aleutian Islands near Unimak pass to prey upon migrating gray whale calves. In the 1980s some killer whales began reducing Steller sea lion and harbor seal populations along Alaska’s Aleutian Islands. An autopsy of one killer whale revealed 14 research tags originally attached to endangered Steller sea lions. As seal and sea lion populations declined, killer whales increased their intake of otters, which allowed urchins to again multiply.  

 

Mostly due to killer whale predation, otter populations declined by 50% to 80% and kelp forests declined by 50% between 1980 and 2000  Those declines prompted the designation of kelp forests as Endangered and possibly Critically Endangered. However more recent surveys evoke hope. Along the coast of Alaska from the peninsula south, otter populations have been steadily increasing at a rate of 12-14% a year and there kelp forests dominate. However depleted otter populations throughout Alaska’s Aleutian Islands still remain at 50% of their 1980 abundance. There, with fewer otters sea urchin barrens became more common.

 



 

 

Although these biological interactions control ecosystem shifts between kelp forests and urchin barrens, climate factors play a role, and in a most positive way. Otters are limited by ice. In places like Glacier Bay where ice has retreated, otter habitat is expanding. Likewise, kelp benefit from less sun-blocking ice while greater concentrations of carbon dioxide enhance photosynthesis and promote more growth. Life is good.

 

published in Battle Born Media What's Natural column

Jim Steele is Director emeritus of San Francisco State’s Sierra Nevada Field Campus, authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism, and member of the CO2 Coalition

Contact: naturalclimatechange@earthlink.net