EC3C. Stay Current—Studying Desert Ecosystems
Staying current for Chapter 3
2021-02-11. The Great Green Wall could save Africa. But can the massive forestry effort learn from past mistakes? By Rachel Cernansky, Science Magazine. Excerpt: After returning home from college to northwest Cameroon in 2004, Tabi Joda felt a sense of profound loss. Trees that once bore fruit, provided medicine, and created shade had been cut down. Rich soils had turned to dust. “The land I used to know as a forest was no longer a forest,” he recalls. Joda, a business consultant, got to work, calling on what he’d learned in school and from local knowledge passed down over generations. He collected seeds, started a tree nursery, and launched an agroforestry initiative that enlisted local people in planting trees. They chose species that provided food and timber, supported livelihoods, and helped wildlife thrive. The effort soon spread to nearby communities. And Joda ultimately became a vocal advocate for an even bigger dream: the Great Green Wall, which aims to transform the lives of some 100 million people by planting a mosaic of trees, shrubs, and grasses along a corridor stretching some 8000 kilometers across Africa by 2030 (see map ,…). …the African Union first launched the Great Green Wall in 2007…. Made up of local efforts across 11 countries, it has reached just 16% of its overall goal to vegetate 150 million hectares. But last month, the project—which analysts estimate will cost at least $30 billion—got a major boost: a pledge of $14 billion in funding over the next 5 years from a coalition of international development banks and governments. The money is meant to accelerate the effort to sustain livelihoods, conserve biodiversity, and combat desertification and climate change, French President Emmanuel Macron said in announcing the pledges on 11 January…. [https://www.sciencemag.org/news/2021/02/great-green-wall-could-save-africa-can-massive-forestry-effort-learn-past-mistakes]
2020-02-12. In Somalia, an unprecedented effort to kill massive locust swarms with biocontrol. By Erik Stokstad, Science Magazine. Excerpt: Somalia, one of several African nations being hit hard by enormous swarms of locusts, is planning to control them with a fungus in what would be the largest use of biopesticides against these insects. …The moment is crucial, because the next generation of locusts is now maturing and could devastate crops planted at the end of March. “We have a short window of opportunity to act,” Dominique Burgeon, director of emergencies at the Food and Agriculture Organization of the United Nations (FAO), said at a briefing Monday in New York City. In recent months, the Horn of Africa has been invaded by desert locusts that have consumed food crops and pasture. For Kenya, it is the worst infestation in 70 years. One swarm there was estimated at 100 billion to 200 billion locusts, marauding through 2400 square kilometers. FAO warned again this week that the insects pose a severe humanitarian risk, as nearly 10 million people in the affected area already face food shortages because of recent floods and droughts. …Several factors caused the massive outbreak. In May 2018, a cyclone hit the desert “empty quarter” of Oman, Yemen, and Saudi Arabia. After the unusual rainfall, vegetation flourished, and the well-fed locusts increased their population 400-fold over 6 months. Normally, the populations would shrink when plants die after the desert dries out again…. In this case, however, a second cyclone hit in October 2018 and the population continued to increase—an estimated 8000-fold by March 2019. The locusts headed to southern Iran, crossing territory that hadn’t seen the insects in 50 years, and moved east into India and Pakistan. Last summer, many flew south with prevailing winds into Yemen, where civil war prevented any spraying of pesticides. The swarms moved to Ethiopia and Somalia in October 2019…. [https://www.sciencemag.org/news/2020/02/somalia-unprecedented-effort-kill-massive-locust-swarms-biocontrol]
2019-10-14. Dusting Off the Arid Antiquity of the Sahara. By Sarah Derouin, Eos/AGU. Excerpt: The Sahara desert looms large in Africa, stretching across the northern third of the continent. The intensely arid nature of the Sahara means that wind is able to loft sediment—especially dust— into the air and carry it to all corners of the globe. …new research published in Palaeogeography, Palaeoclimatology [https://doi.org/10.1016/j.palaeo.2019.109245], Palaeoecology has narrowed in on the age of the Sahara. …Prior estimates of the age of the Sahara “range all the way from [the] Holocene, sometime in the last 10,000 years, back to the Miocene, around 7 million years. … understanding when the Sahara first became arid allows researchers to investigate other important questions. “For example, we do not know if the onset of arid conditions was abrupt or progressive, how ecosystems have been impacted by the aridification, and how prehuman and human societies have adapted.” Understanding past climates is crucial for understanding the future climate, said Muhs, and that’s why every Intergovernmental Panel on Climate Change report has a chapter on paleoclimate….
2016-10-24. Living in China’s Expanding Deserts. By Josh Haner, Edward Wong, Derek Watkins, and Jeremy White, The New York Times. Excerpt: People on the edges of the country’s vast seas of sand are being displaced by climate change. In the Tengger Desert, China — This desert, called the Tengger, lies on the southern edge of the massive Gobi Desert, not far from major cities like Beijing. The Tengger is growing. For years, China’s deserts spread at an annual rate of more than 1,300 square miles. Many villages have been lost. Climate change and human activities have accelerated desertification. China says government efforts to relocate residents, plant trees and limit herding have slowed or reversed desert growth in some areas. But the usefulness of those policies is debated by scientists, and deserts are expanding in critical regions. Nearly 20 percent of China is desert, and drought across the northern region is getting worse…. http://www.nytimes.com/interactive/2016/10/24/world/asia/living-in-chinas-expanding-deserts.html
2013 February 12. NASA Satellite Data Find Freshwater Losses in Middle East. NASA RELEASE 13-049. Excerpt: A new study using data from a pair of gravity-measuring NASA satellites finds that large parts of the arid Middle East region lost freshwater reserves rapidly during the past decade. …during a seven-year period beginning in 2003, parts of Turkey, Syria, Iraq and Iran along the Tigris and Euphrates river basins lost 117 million acre feet (144 cubic kilometers) of its total stored freshwater. That is almost the amount of water in the Dead Sea. The researchers attribute about 60 percent of the loss to pumping of groundwater from underground reservoirs. …NASA’s twin Gravity Recovery and Climate Experiment (GRACE) satellites, are essential. GRACE is providing a global picture of water storage trends and is invaluable when hydrologic observations are not routinely collected or shared beyond political boundaries. “GRACE data show an alarming rate of decrease in total water storage in the Tigris and Euphrates river basins, which currently have the second fastest rate of groundwater storage loss on Earth, after India,” said Jay Famiglietti, principle investigator of the study and a hydrologist and professor at UC Irvine. “The rate was especially striking after the 2007 drought. Meanwhile, demand for freshwater continues to rise, and the region does not coordinate its water management because of different interpretations of international laws.” …The team calculated about one-fifth of the observed water losses resulted from soil drying up and snowpack shrinking, partly in response to the 2007 drought. Loss of surface water from lakes and reservoirs accounted for about another fifth of the losses. The majority of the water lost …was due to reductions in groundwater. …”The Middle East just does not have that much water to begin with, and it’s a part of the world that will be experiencing less rainfall with climate change,” said Famiglietti. “Those dry areas are getting dryer. …Study co-author Matt Rodell of Goddard added it is important to remember groundwater is being extracted unsustainably in parts of the United States, as well. “Groundwater is like your savings account,” Rodell said. “It’s okay to draw it down when you need it, but if it’s not replenished, eventually it will be gone.”….
2010 October 19. VIDEO: Protected areas in Kuwait and their potential long-term role in adaptation to climate change. Rio Conventions’ Pavilion. Video Description: Dr. Samira Omar Asem, whose work studying the desert ecosystem of Kuwait following the 1990-1991 Iraq war is featured in Ecosystem Change chapter 3, presents more recent research on the Sabah Al Ahmad Nature Reserve.
2010 July 17. After Oil Spills, Hidden Damage Can Last For Years. By Justin Gillis and Leslie Kaufman, The New York Times.Excerpt: Only 20 years ago, the conventional wisdom was that oil spills did almost all their damage in the first weeks, as fresh oil loaded with toxic substances hit wildlife and marsh grasses, washed onto beaches and killed fish and turtles in the deep sea.
…But disasters like the Valdez in 1989, the Ixtoc 1 in Mexico in 1979, the Amoco Cadiz in France in 1978 and two Cape Cod spills, including the Bouchard 65 barge in 1974 — all studied over decades with the improved techniques of modern chemistry and biology — have allowed scientists to paint a more complex portrait of what happens after a spill.
…[E]ven before the spill, the land was under enormous environmental stress, largely due to human activity. Dams on the Mississippi River and its tributaries have slowed the flow of sediment to the marshes, and global warming has caused sea level to rise.
…Oil spills produce a powerful impulse to clean up the oil and restore as much of the environment as possible. But that impulse can itself be a source of destruction.
…The lesson, scientists say, is not that people should never try to clean up an oil spill. It is possible to do too little as well as too much. But the calculation of how much to do is tricky, demanding deep scientific understanding of an area’s ecology. Applying supposed common sense has repeatedly led to mistakes.
…Already in Louisiana, battles have erupted between the Army Corps of Engineers and local residents, led by Gov. Bobby Jindal, over proposals to build sand and rock barriers to block the oil from coming into the marshes. The corps has been cautious on approval permits and recently rejected a plan to build a rock barrier outside Barataria Bay, arguing that such structures would change water-flow patterns to the possible detriment of the marsh ecology.
2009 November 5. Climate Change, Nitrogen Loss Threaten Plant Life in Arid Desert Soils. NSF Release 09-218. Excerpt: …As Earth’s climate warms, arid soils lose more nitrogen, which could lead to deserts with even less plant life than they sustain today.
Available nitrogen is second only to water as the biggest constraint to biological activity in arid ecosystems, but ecologists have struggled to understand the balance of the input and output of nitrogen in deserts. For the first time, however, researchers have discovered a mechanism that balances the nitrogen budget in deserts: Higher temperatures cause nitrogen to escape as gas from desert soils.
…In the past, researchers focused on biological mechanisms in which soil microbes near the surface produce nitrogen gas that dissipates into the air, but ecologists Jed Sparks and Carmody (“Carrie”) McCalley, both at Cornell University and co-authors of the paper, found that non-biological processes are playing a bigger role in nitrogen losses from soil to air.
“This is a way that nitrogen is lost from an ecosystem that people have never accounted for before,” said Sparks. “It allows us to finally understand the dynamics of nitrogen in arid systems.”
…Further temperature increases and shifting precipitation patterns due to climate change may lead to more nitrogen losses in arid ecosystems, making their soils even more infertile and unable to support most plant life, according to McCalley. Although some climate models predict more summer rainfall for desert areas, the water, when combined with heat, would greatly increase nitrogen losses, she said.
“We’re on a trajectory where plant life in arid ecosystems could cease to do well,” said McCalley….
2007 June 28. Likely Spread of Deserts to Fertile Land Requires Quick Response, U.N. Report Says. The New York Times. By Elisabeth Rosenthal. Excerpt: Enough fertile land could turn into desert within the next generation to create an ”environmental crisis of global proportions,” large-scale migrations and political instability in parts of Africa and Central Asia unless current trends are quickly stemmed, a new United Nations report concludes. ”The costs of desertification are large,” …
2007 January 3. Defining Desertification. By Holli Riebeek. NASA Earth Observatory. [This article gives some insight into the origins and significance of the development of NDVI (Normalized Difference Vegetation Index) which the GSS Interpreting Digital Images software helps students to understand. —Alan Gould]
Botswana, 1984. Cattle roam over grasslands at the edge of the Kalahari Desert. …A full 77 percent of the country’s 576,000 square kilometers is already used for grazing, but even this isn’t enough to support the cattle. The grasslands are prone to drought, and the government is forced to import food for them. British biogeographer Stephen Prince is among the scientists that the United Nations Food and Agriculture Organization has asked to assess the health of the rangelands. How is drought impacting the land? Is overgrazing occurring? …Conditions could vary widely; healthy vegetation could be growing meters away from barren land. “You couldn’t measure vegetation change over the entire country with 50 data points.” …Prince stopped by the house of a colleague, John Townshend. … from NASA Goddard Space Flight Center…remote-sensing ecologist Compton Tucker had developed a new scale, or index, of global vegetation based on satellite data. …the index could show how much photosynthesis was happening in every 8-by-8-kilometer patch of ground. Displayed as a map, the index revealed the productivity of the grazing land over a broad area over successive 15-day periods. …”It blew me away that we could see a complete continent at frequent time intervals,” Prince says. “It was a career-changing moment.” …the vegetation index would be able to answer even larger questions about Africa’s vegetation. …Prince had seen the effect of devastating drought in Africa’s Sahel, a…semi-arid, sparse savanna immediately south of the Sahara Desert. A list of Sahelian countries is a yearbook of famine: Sudan, Chad, Niger, Mali, Mauritania, Ethiopia, Burkina Fasso, and Senegal. A string of dry years leading up to the early 1980s shriveled vegetation throughout the Sahel, causing some people to fear that the Sahara Desert was steadily marching southward, …. Ground studies had produced dramatic pictures of formerly productive lands reduced to apparent desert. Many people extrapolated from these local examples of desertification to propose that the whole Sahel was becoming a desert, but no one had surveyed the entire Sahel. It was far too large a task. …”When I saw the vegetation index data, I realized that it was exactly the scale we wanted for studying desertification,” says Prince. “There is no other way of seeing big enough areas at high enough frequency.” ….
8 March 2005. For Iraq’s Great Marshes, a Hesitant Comeback. By JAMES GLANZ for The New York Times. Excerpt: ABU SUBAT, Iraq, March 1 – ….A dike that Saddam Hussein’s government finished nine years ago had drained this marsh, once part of an incomparable ecosystem spread across 7,000 square miles of southern Iraq that Mr. Hussein systematically destroyed. After sealing this dike, the government gave families 24 hours to leave and never come back, Mr. Hashim said. The ruined houses were left sitting on dusty little hills in a barren and bone-dry desert…. But when Mr. Hussein’s government fell in April 2003, villagers went to the dike and gouged holes in it using shovels, their bare hands and at least one piece of heavy equipment, a floating backhoe. Since then, something miraculous has occurred: reeds and cattails have sprouted up again; fish, snails and shrimp have returned to the waters; egrets and storks perch on the jagged remains of the walls, coolly surveying the territory as if they had never left…. Mr. Hussein’s obsessive and vindictive drainage program, in fact, was intended to obliterate this prime refuge for deserters from his army and the southern Shiite guerrillas, many of them marsh Arabs who fought his government long before the Americans arrived…. The scientists reported that less than 10 percent of the original marshes still function as true wetlands, but that about 20 percent of the original area had been reflooded by March 2004, according to satellite imagery. High salt content in soil and water, threatens the recovery of the marshes in certain areas, the paper said. As Dr. Hussain’s team pulled up muck and spinachlike aquatic plants from the bottom of this marsh for testing, he confirmed the problems and said the thickets of reeds in this marsh were still only about half as dense as they had been before the marsh dried up. Some plants, like water lilies, had not come back at all, he said.
18 September 2003. Just Add Water: A Modern Agricultural Revolution in the Fertile Crescent. NASA’s Earth Observatory. A kind of agricultural revolution is underway in the northern part of the Fertile Crescent, this one due to a major infrastructure development in Turkey’s Southeast Anatolia region.
13 December 2002. From Wetland to Wasteland. Due to drought and over irrigation, the once fertile Hamoun wetlands on the Iran-Afghan border have all but disappeared. Using remote sensing satellites developed by NASA, researchers with the United Nations Environmental Program are cataloguing the extent of the wetlands degradation and exploring ways to restore them.