Preface. Two forms of soil erosion may bring back the Great Depression Dustbowls. The first is that Great Plains grasslands have been replaced with corn crops to grow ethanol, which have increased the amount of dust 100% over the past 20 years. The second is the destruction of biocrusts (also known as cryptobiotic soils). These are a thin glue containing a thriving community of fungi, lichen, moss, cyanobacteria, and other microbes that cover 12% of Earth’s surface and provide essential nutrients for plants and retain moisture.
It’s destruction by livestock, farming and climate change releases 700 million tons of dust a year, though wherever the dust lands may get a brief boost of fertilization. As climate change, livestock, and farm machinery break the delicate biocrust, dust storms are increasing and will only grow greater as 3 billion more people arrive by 2050, with up to 40% of these valuable crusts disappearing by 2085. Enormous amounts of land will be required to feed them all, much of it marginal land vulnerable to dust storms.
Dust also melts glaciers and snow faster than before, depriving millions of people water to drink and grow crops with.
A warming planet will make dust storms more intense in the Mediterranean and the Atlantic and increase the frequency of North Atlantic hurricanes.
More dust in the air will worsen air quality and public health from disease like Valley Fever, meningitis, Kawasaki, and increase lung and heart disease.
It isn’t known for sure how dust affects climate change, so it isn’t modeled. It could go either way. Dust is the largest aerosol by mass, and both absorbs and scatters sunlight to alternately warm or cool the planet, though a recent study found that large dust causes warming and is more plentiful than fine dust, which cools, perhaps tipping dust towards warming the climate even more.
Alice Friedemann www.energyskeptic.com Author of Life After Fossil Fuels: A Reality Check on Alternative Energy; When Trucks Stop Running: Energy and the Future of Transportation”, Barriers to Making Algal Biofuels, & “Crunch! Whole Grain Artisan Chips and Crackers”. Women in ecology Podcasts: WGBH, Jore, Planet: Critical, Crazy Town, Collapse Chronicles, Derrick Jensen, Practical Prepping, Kunstler 253 &278, Peak Prosperity, Index of best energyskeptic posts
***
Lambert A et al (2020) Dust Impacts of Rapid Agricultural Expansion on the Great Plains. Geophysical Research Letters. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL090347
Dustbowl 2.0
Just as replacing grasslands with crops caused the 1930s dustbowl, so too will the replacement of grasslands with corn crops bring on Dustbowl 2.0 and potentially desertification. From 2006 to 2011 there was a 10% increase in land growing corn for ethanol over 2046 square miles. Before that, grasslands protected the soil by holding it tightly in place. Dust storms remove nutrients from the soil, making it harder for crops to grow and for even more wind erosion to occur. This destructive cycle, now aggravated by drought, can eventually lead to desertification, and is also a health hazard. The ultrafine dust particles can penetrate cells in the lungs and cause lung and heart disease. Dust storms increased by 5% a year for a whopping 100% increase over the 20 years of the study from 1998-2018. Even the Midwest is seeing dust storms grow after the planting and harvesting of soybeans in June & October, an area also threatened by drought from climate change.
The lead author of the findings in Geophysical Research Letters, Andrew Lambert, points out that “It’s particularly ironic that the biofuel commitments were meant to help the environment.”
Pennisi E (2022) Hard ‘skin’ on the surface of soils helps keep dust storms at bay. Science.
https://www.science.org/content/article/hard-skin-surface-soils-helps-keep-dust-storms-bay
Two years ago, 24 million tons of dust lifted high above Africa to create a plume that swirled across the Atlantic Ocean and covered Puerto Rico in a pink patina. An unusually meandering jet stream helped launch the monster dust cloud. But this week, ecologists fingered another factor in such storms: the disappearance of biocrust, a microbial mat that coats dryland soil and helps keep dust in place. “It glues the sand together,” says Bettina Weber, an ecologist at the University of Graz and co-author on the new study.
Trampled by livestock and scorched by climate change, that glue is likely to become weaker in the future, researchers say, leaving the soil prey to wind. The dust study “demonstrates that the loss of biocrust in one area of the world can have wide-ranging and far-flung impacts,” says Rebecca Finger-Higgens, an ecologist at the U.S. Geological Survey.
A biocrust is a hard surface coating or “skin,” typically a few millimeters thick, containing a thriving community of fungi, lichen, moss, cyanobacteria, and other microbes. Historically ecologists have paid little mind to biocrusts, which cover soils in arid, semiarid, and extremely cold places all over the world. But researchers have realized these coatings produce and process nutrients that nearby organisms need to thrive, especially in arid environments. They also help a dryland soil retain its little moisture.
In 2018, Weber, postdoc Emilio Rodriguez-Caballero, and their colleagues mapped all of Earth’s biocrusts, concluding they cover 12% of the land surface. They then teamed up with climate modelers and dust experts to figure out how much dust formation the biocrust glue currently averts. First, the researchers compiled data about how much wind it takes to destroy the biocrust and blow the soil away. They calculated dust emissions at 31 different sites, then fed the results into a model that predicted worldwide dust emission—and how much it would rise without the biocrusts.
Biocrusts reduce dust in the air by 700 million tons per year, Weber and her team report this week in Nature Geoscience. That amount would bury all of New York City under 13.8 inches (35 centimeters) of dust. The study “places biocrusts as key players in preventing dust emissions globally,” Maestre says.
Over the next 65 years, between 25% and 40% of these crusts will vanish, says Rodriguez-Caballero, now at the University of Almeria. Climate change that threatens soil organisms will account for about half the destruction; other damage will come from trampling by humans, livestock, and farm machinery.
Finger-Higgens and colleagues have documented the impact of climate. In a long-term biannual survey of plots in Utah’s Canyonlands National Park, they found that biocrust lichens in particular suffer when temperatures increase. As Canyonlands temperatures rose by 0.27°C per decade, lichens, especially those that help convert nitrogen in the air to a form that other organisms can use, have almost disappeared, the team reported on 11 April in the Proceedings of the National Academy of Sciences. With less nitrogen, fewer plants can survive, leaving ever more bare ground and more dust emission, Finger-Higgens says. Biological soil crust composed of lichens, cyanobacteria, next to a succulent plant.
Some implications of a dustier climate are unclear, researchers say. The impact of airborne dust on temperatures depends in part on the size of the particles. Dust particles provide nuclei for cloud formation and can cause snow to melt faster. Although dust helps transport important nutrients for plant life, it can make respiratory problems and other health issues worse for people.
Up to now, dusty places like the Sahel were expected to get greener and less dusty as higher carbon dioxide levels have a fertilizing effect, but biocrust loss will likely counteract this process to some degree, Weber and her colleagues note. “Biocrust, dust, [and] climate all exert feedback on each other,” says Diana Francis, an atmospheric scientist at Khalifa University who is not part of the work.
Climate modelers have often overlooked how biocrusts affect temperature and rainfall, says Michael Mann, an atmospheric scientist at Pennsylvania State University, University Park. The effects of diminishing biocrusts shouldn’t be dramatic enough to make much difference in global climate models, he says. But Joseph Prospero, an atmospheric chemist at the University of Miami, cautions that “there are large areas of the Earth for which we have essentially no information” about biocrusts. That may change. Weber, Maestre, Finger-Higgens, and other biocrust experts are seeking funding for standardized measurements of biocrusts around the world.
But researchers say the need to protect these fragile communities is already clear. Reducing emissions and changing farming and other land use practices can help reverse their decline, Maestre says. “The findings provide strong arguments for preserving biocrust communities worldwide.”
Other issues:
Snow melt & drinking water: in the Four Corners region—which includes portions of Arizona, Colorado, Utah and New Mexico—millions of people rely on water that comes from snow in the San Juan Mountains that melts and eventually flows downstream into the Colorado River. Dust from the atmosphere falls on the snow, darkening it and accelerating snowmelt. As the snow melts more quickly, it evaporates faster, impacting water supplies in an area already affected by extreme drought.
A new groundbreaking study shows that warming planet will make dust storms more intense in the Mediterranean and the Atlantic. More dust in the air will worsen air quality and public health, while also affecting the frequency of North Atlantic hurricanes. The study is another milestone in the collaboration between the Initiative for the Science of the Human Past at Harvard and the Climate Change Institute at the University of Maine.
Dust storms can carry sand, silt, bacteria, fungi, aerosols and particle pollution over long distances. Dust particles frequently transport PM10 and PM2.5 particles – with a diameter less than 10 µm or 2.5 µm – which cause many types of respiratory and cardiovascular diseases. The UN Convention to Combat Desertification has linked outbreaks of Valley Fever in the United States and meningitis in Africa to dust storms. In 2000, there were 2,757 reported cases of Valley Fever. By 2019, that number had risen to 18,407. In China and Japan, a childhood vascular condition called Kawasaki disease that can cause irreparable cardiac damage is believed to be spread by spores of the Candida fungus, which blows in with dust from the farmlands of China. A link between wind-blown dust and poor respiratory health among Indigenous children in Western Australia has been established by research at the University of Tasmania.
Around the world, 151 countries experience dust storms, but only 45 of these countries actually generate dust themselves. In Asia, dust from the Gobi and Taklimakan Deserts affects air quality in Central and Eastern Asian countries such as Korea and Japan. In the United States, 41 per cent of the worst dust days are produced from sources in Asia. In early March this year, an intense storm originating in the Mongolian desert lifted dust plumes high into the air and deposited them as far away as China and South Korea. The storm killed nine people, grounded flights and closed schools. It led to an explosion in particulate matter pollution in China’s major cities, including a sharp spike in PM10 and PM2.5 levels, which were up to 8 times World Health Organization acceptable levels.