About The Dust Bowl About The Dust Bowl For eight years dust blew on the southern plains. It came in a yellowish-brown haze from the South and in rolling walls of black from the North. The simplest acts of life  breathing, eating a meal, taking a walk  were no longer simple. Children wore dust masks to and from school, women hung wet sheets over windows in a futile attempt to stop the dirt, farmers watched helplessly as their crops blew away. [ source ] [ Map source ] The Dust Bowl of the 1930s lasted about a decade. Its primary area of impact was on the southern Plains. The northern Plains were not so badly effected, but nonetheless, the drought, windblown dust and agricultural decline were no strangers to the north. In fact the agricultural devastation helped to lengthen the Depression whose effects were felt worldwide. The movement of people on the Plains was also profound. As John Steinbeck wrote in his 1939 novel The Grapes of Wrath: "And then the dispossessed were drawn west- from Kansas, Oklahoma, Texas, New Mexico; from Nevada and Arkansas, families, tribes, dusted out, tractored out.

Car-loads, caravans, homeless and hungry; twenty thousand and fifty thousand and a hundred thousand and two hundred thousand. They streamed over the mountains, hungry and restless - restless as ants, scurrying to find work to do - to lift, to push, to pull, to pick, to cut - anything, any burden to bear, for food. The kids are hungry. We got no place to live. Like ants scurrying for work, for food, and most of all for land." Poor agricultural practices and years of sustained drought caused the Dust Bowl. Plains grasslands had been deeply plowed and planted to wheat. During the years when there was adequate rainfall, the land produced bountiful crops. But as the droughts of the early 1930s deepened, the farmers kept plowing and planting and nothing would grow. The ground cover that held the soil in place was gone. The Plains winds whipped across the fields raising billowing clouds of dust to the skys. The skys could darken for days, and even the most well sealed homes could have a thick layer of dust on furniture. In some places the dust would drift like snow, covering farmsteads.

Timeline of The Dust Bowl 1931 Severe drought hits the midwestern and southern plains. As the crops die, the 'black blizzards" begin. Dust from the over-plowed and over-grazed land begins to blow. 1932 The number of dust storms is increasing. Fourteen are reported this year; next year there will be 38. 1933 March: When Franklin Roosevelt takes office, the country is in desperate straits. He took quick steps to declare a four-day bank holiday, during which time Congress came up with the Emergency Banking Act of 1933, which stabilized the banking industry and restored people's faith in the banking system by putting the federal government behind it. May: The Emergency Farm Mortgage Act allots $200 million for refinancing mortgages to help farmers facing foreclosure. The Farm Credit Act of 1933 established a local bank and set up local credit associations. September: Over 6 million young pigs are slaughtered to stabilize prices With most of the meat going to waste, public outcry led to the creation, in October, of the Federal Surplus Relief Corporation. The FSRC diverted agricultural commodities to relief organizations.

Apples, beans, canned beef, flour and pork products were distributed through local relief channels. Cotton goods were eventually included to clothe the needy as well. October: In California's San Joaquin Valley, where many farmers fleeing the plains have gone, seeking migrant farm work, the largest agricultural strike in America's history begins. More than 18,000 cotton workers with the Cannery and Agricultural Workers Industrial Union (CAWIU) went on strike for 24 days. During the strike, two men and one woman were killed and hundreds injured. In the settlement, the union was recognized by growers, and workers were given a 25 percent raise. 1934 May: Great dust storms spread from the Dust Bowl area. The drought is the worst ever in U.S. history, covering more than 75 percent of the country and affecting 27 states severely. June: The Frazier-Lemke Farm Bankruptcy Act is approved. This act restricted the ability of banks to dispossess farmers in times of distress. Originally effective until 1938, the act was renewed four times until 1947, when it expired.

Roosevelt signs the Taylor Grazing Act, which allows him to take up to 140 million acres of federally-owned land out of the public domain and establish grazing districts that will be carefully monitored. One of many New Deal efforts to reverse the damage done to the land by overuse, the program was able to arrest the deterioration, but couldn't undo the historical damage. December: The "Yearbook of Agriculture" for 1934 announces, "Approximately 35 million acres of formerly cultivated land have essentially been destroyed for crop production. . . . 100 million acres now in crops have lost all or most of the topsoil; 125 million acres of land now in crops are rapidly losing topsoil. . . " 1935 January 15: The federal government forms a Drought Relief Service to coordinate relief activities. The DRS bought cattle in counties that were designated emergency areas, for $14 to $20 a head. Those unfit for human consumption - more than 50 percent at the beginning of the program - were destroyed. The remaining cattle were given to the Federal Surplus Relief Corporation to be used in food distribution to families nationwide.

Although it was difficult for farmers to give up their herds, the cattle slaughter program helped many of them avoid bankruptcy. "The government cattle buying program was a God-send to many farmers, as they could not afford to keep their cattle, and the government paid a better price than they could obtain in local markets." April 8: FDR approves the Emergency Relief Appropriation Act, which provides $525 million for drought relief, and authorizes creation of the Works Progress Administration, which would employ 8.5 million people. April 14: Droughts: Questions and answers (U.S. Geological Survey) Answers What is a drought? While it is relatively easy to define what a hurricane or earthquake is, defining a drought is more subjective. Droughts do not have the immediate effects of floods, but sustained droughts can cause economic stress throughout an area. The word "drought" has various meanings, depending on a person's perspective. To a farmer, a drought is a period of moisture deficiency that affects the crops under cultivation—even two weeks without rainfall can stress many crops during certain periods of the growing cycle. To a meteorologist, a drought is a prolonged period when precipitation is less than normal.

To a water manager, a drought is a deficiency in water supply that affects water availability and water quality. To a hydrologist , a drought is an extended period of decreased precipitation and streamflow. What causes droughts? A drought is a period of drier-than-normal conditions that results in water-related problems. Precipitation (rain or snow) falls in uneven patterns across the country. The amount of precipitation at a particular location varies from year to year, but over a period of years, the average amount is fairly constant. In the deserts of the Southwest, the average precipitation is less than 3 inches per year. In contrast, the average yearly precipitation in Atlanta is about 50 inches. The amount of rain and snow also varies with the seasons. In Georgia, most of the yearly precipitation falls during winter, early spring, and in July. Even if the total amount of rainfall for a year is about average, rainfall shortages can occur during a period when moisture is critically needed for plant growth, such as in the early summer. When little or no rain falls, soils can dry out and plants can die.

When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought. Reference: Moreland, 1993. When does a drought begin? The beginning of a drought is difficult to determine. Several weeks, months, or even years may pass before people know that a drought is occurring. The end of a drought can occur as gradually as it began. Dry periods can last for 10 years or more. During the 1930's, most of the United States was much drier than normal. In California, the drought extended from 1928 to 1937. In Missouri, the drought lasted from 1930 to 1941. That extended dry period produced the "Dust Bowl" of the 1930's when dust storms destroyed crops and farms. The first evidence of drought usually is seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease.

The effects of a drought on flow in streams and reservoirs may not be noticed for several weeks or months. Water levels in wells may not reflect a shortage of rainfall for a year or more after a drought begins. Reference: Moreland, 1993. Does a shortage of rain mean that a drought will occur? A period of below-normal rainfall does not necessarily result in drought conditions. Some rain returns to the air as water vapor when water evaporates from water surfaces and from moist soil. Plant roots draw some of the moisture from the soil and return it to the air through a process called transpiration. The total amount of water returned to the air by these processes is called evapotranspiration. Sunlight, humidity, temperature, and wind affect the rate of evapotranspiration. When evapotranspiration rates are large, soils can lose moisture and dry conditions can develop. During cool, cloudy weather, evapotranspiration rates may be small enough to offset periods of below-normal precipitation and a drought may be less severe or may not develop at all. Reference: Moreland, 1993. Why doesn't a drought go away when it rains? Rainfall in any form will provide some drought relief.

A good analogy might be how medicine and illness relate to each other. A single dose of medicine can alleviate symptoms of illness, but it usually takes a sustained program of medication to cure an illness. Likewise, a single rainstorm will not break the drought, but it may provide temporary relief. A light to moderate shower will probably only provide cosmetic relief. It might make folks feel better for awhile, provide cooling, and make the vegetation perk up. During the growing season, most of the rain that falls will be quickly evaporated or used by plants. Its impact is short term. A thunderstorm will provide some of the same benefits as the shower, but it also may cause loss of life and property if it is severe. Thunderstorms often produce large amounts of precipitation in a very short time, and most of the rain will run off into drainage channels and streams rather than soak into the ground. If the rain happens to fall upstream of a reservoir, much of the runoff will be captured by the reservoir and add to the available water supply. No matter where the rain falls, stream levels will rise quickly and flooding may result. Also, because the rainfall and runoff can be intense, the resulting runoff can carry significant loads of sediment and pollutants that are washed from the land surface.

Soaking rains are the best medicine to alleviate drought. Water that enters the soil recharges ground water, which in turn sustains vegetation and feeds streams during periods when it is not raining. A single soaking rain will provide lasting relief from drought conditions, but multiple such rains over several months may be required to break a drought and return conditions to within the normal range. Tropical storm rains are usually of the soaking variety, although they may also be intense such as during a thunderstorm and lead to some of the same problems. Tropical storms often produce more total rainfall than a "regular" soaking rain and can provide longer relief than a single soaking rain. However, tropical rains may also be of such intensity that they exceed the capacity of soil to absorb water and often result in significant runoff and flooding. Tropical rains can help to fill water-supply reservoirs and provide long-term drought insurance. If significant rainfall does not occur upstream of reservoirs, the drought relief aspects of tropical storms may be of only little consequence. All things considered, a single tropical storm at the right place, at the right time, and with the right amount of rainfall can break a drought. Considering all of the above, even when a drought has been broken it may not be truly over.

The benefits of substantial rainfall such as from a tropical storm may last for months, but a return to normal rainfall patterns and amounts is necessary for conditions in streams, reservoirs, and ground water to also return to normal. Reference: Moreland, 1993. Can drought affect the water level in wells? Groundwater, which is found in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is used to provide a large portion of the Nation's population with drinking water, it provides business and industries water for their purposes, and is used extensively for irrigation. The water level in the aquifer that supplies a well does not always stay the same. Droughts, seasonal variations in rainfall, and pumping affect the height of the underground water levels. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation or other underground flow, then water levels in the well can be lowered. This can happen during drought, due to the extreme deficit of rain. The water level in a well can also be lowered if other wells near it are withdrawing too much water. References drought - National Geographic Society drought A cracked, parched landscape is often an effect of drought.

Photograph by James L. Stanfield, National Geographic Comparing Natural Disasters 2004 tsunami in Indonesia: affected 2 million people 2010 earthquake in Haiti: affected 3 million people Current drought/famine/war in the Horn of Africa: affecting 13 million people Dust Bowl John Steinbeck’s 1939 novel The Grapes of Wrath describes the Dust Bowl drought of the 1930s: “Every moving thing lifted the dust into the air: a walking man lifted a thin layer as high as his waist, and a wagon lifted the dust as high as the fence tops, and an automobile boiled a cloud behind it. The dust was long in setting back again.” Drought in the USA In August 2012, drought conditions extended over 70 percent of the United States. Counties in 33 states were designated “disaster counties” by the government. In the beginning of 2013, drought still affected more than 60 percent of the country. Yunnan Drought The ongoing drought in Yunnan Province, China, has forced some families to transport water from more than 10 kilometers (6 miles) away.

Drought is an extended period of unusually dry weather when there is not enough rain. The lack of precipitation can cause a variety of problems for local communities, including damage to crop s and a shortage of drinking water. These effects can lead to devastating economic and social disasters, such as famine , forced migration away from drought-stricken areas, and conflict over remaining resource s. Because the full effects of a drought can develop slowly over time, impacts can be underestimated. However, drought can have drastic and long-term effects on vegetation , animals, and people. Since 1900, more than 11 million people have died and more than 2 billion people have been affected by drought. Drought is also one of the costliest weather-related disasters. In the past 30 years, the U.S. has experienced 16 billion-dollar droughts, totaling $195 billion in losses. Defining Drought Drought is a complicated phenomenon , and can be hard to define. One difficulty is that drought means different things in different regions. "Drought" is not a set number or equation. It is defined depending on the average amount of precipitation an area is accustomed to receiving.

For example, in Atlanta, Georgia, the average rainfall is about 127 centimeters (50 inches) a year. If significant ly less rain falls, there may be water shortages and a drought may be declared. However, arid regions, such as the desert s of the American Southwest, receive less than 8 centimeters (3 inches) of rainfall each year. A drought in Atlanta would be a very wet period in Phoenix, Arizona! Determining the start of a drought can be tricky. Unlike many natural hazard s that bring about sudden and dramatic results—such as earthquake s, tornado es, and hurricane s—the onset of a drought can be gradual and subtle. It can take weeks, months, or even years for the full effects of long-term inadequate rainfall to become apparent. The end of a drought can also be difficult to determine. While a single rainstorm will provide short-term relief from a drought, it might take weeks or months before levels of precipitation return to normal. The start and end of a drought are often only clear in hindsight. Causes of Drought Most droughts occur when regular weather patterns are interrupted, causing disrupt ion to the water cycle .

Changes in atmospheric circulation patterns can cause storm tracks to be stall ed for months or years, dramatically impacting the amount of precipitation a region normally receives and resulting in droughts or floods. Changes in wind patterns can also affect how much moisture a region can absorb. Scientists have found a link between certain climate patterns and drought. El Niño is a weather event where the surface water in the Pacific Ocean along the central South American coast rises in temperature. These warmer waters alter storm patterns and are associated with droughts in Indonesia, Australia, and northeastern South America. El Nino events are not predictable and can occur every two to seven years. La Niña is the counterpart to El Niño, when the surface water in the Pacific Ocean along the coast of South America decreases in temperature. The cooler waters affect storm patterns by contributing to drier-than-normal conditions in parts of North and South America. While El Niño usually lasts less than a year, La Niña can extend for one to three years. The effects of La Niña on weather patterns are often more complex than El Niño.

Two of the most devastating droughts in the history of the United States—the 1930s Dust Bowl and the 1988 drought in the Midwest—are associated with the effects of La Niña. There is still a lot of debate about the connection between drought and global warming , the current period of climate change . A 2013 NASA study predicts warmer worldwide temperatures will mean increased rainfall in some parts of the world and decreased rainfall in others, leading to both more flooding and more droughts worldwide. Other scientists question the prediction that there will be more droughts and believe global warming will create a wetter climate around the world. Impacts of Drought Trees and other plants have adapted to withstand the effects of drought through various survival methods. Some plants (such as grasses) will slow their growth or turn brown to conserve water. Trees can drop their leaves earlier in the season to prevent losing water through the leaf surface. However, if drought conditions persist, much vegetation will die. Certain plants have adapted so they can withstand long periods without water. Yuccas, for instance, have deep root system s that can seek out water with incredible efficiency.

Cacti have spiny, hairy leaves that limit how much water they lose to evaporation . Mosses can withstand complete dehydration . Juniper trees can self- prune by steering water only toward the branches they need to survive. Other plants only grow when there is enough water to support them. In periods of drought, their seeds can survive under the soil for years until conditions are favorable again. However, many organisms cannot adapt to drought conditions, and the environmental effects of extended, unusual periods of low precipitation can be severe . Negative impacts include damage to habitat s, loss of biodiversity , soil erosion , and an increased risk from wildfire s. During the U.S. drought of 1988, rainfall in many states was 50 to 85 percent below normal. Summer thunderstorms produced lightning without rain and ignite d fires in dry trees. More than 4 million acres of forest in the Northwest burned in a single summer. In Yellowstone National Park alone, 36 percent of the park was destroyed by fire. Drought can also create significant economic and social problems. The lack of rain can result in crop loss, a decrease in land prices, and unemployment due to declines in production.

As water levels in rivers and lakes fall, water-supply problems can develop. These can bring about other social problems. Many of these problems are health-related, such as lack of water, poor nutrition , and famine. Other problems include conflicts over water usage and food, and forced migration away from drought-stricken areas. While drought is a naturally occurring part of the weather cycle and cannot be prevented, human activity can influence the effects that drought has on a region. Many modern agricultural practices may make land more vulnerable to drought. While new irrigation techniques have increased the amount of land that can be used for farming, they have also increased farmer s’ dependence on water. Traditional farming techniques allow land to “rest” by rotating crops each season and alternating areas where livestock graze . Now, with many areas in the world struggling with overpopulation and a shortage of farmland, there is often not enough arable land to support these sustainable farming practices. Over-farming and overgrazing can lead to soil being compact ed and unable to hold water. As the soil becomes drier, it is vulnerable to erosion. This process can lead to fertile land becoming desert-like, a process known as desertification .

The desertification of the Sahel in North Africa is partly blamed on a prolonged drought whose effects were intensified by farming practices that result in overgrazing. Increased drought conditions in Kenya have been attributed to deforestation and other human activities. Trees help bring precipitation into the ground and prevent soil erosion. But in 2009, it was reported that one-quarter of a protected forest reserve had been cleared for farming and logging , leading to drought conditions affecting 10 million people around the country. Historical Droughts Scientists often study historical droughts to put modern-day droughts in perspective. Since our data from thermometer s and rain gauge s only goes back about 100 to 150 years, scientists must research paleoclimatology , the study of the atmosphere of prehistoric Earth. Scientists gather paleoclimatic data from tree ring s, sediment s found in lakes and oceans, ice core s, and archaeological feature s and artifact s. This allows scientists to extend their understanding of weather patterns for millions of years in the past. Analyzing paleoclimatic data shows that severe and extended droughts are an inevitable part of natural climate cycles. North America has experienced a number of long-lasting droughts with significant effects.

It is thought that droughts brought about the decline of the Ancestral Puebloans in the Southwest during the 13th century, and the central and Lower Mississippian societies in the 14th to 16th centuries. In South America, massive migration out of the once-fertile Atacama Desert 9,500 years ago can be explained by the onset of extreme drought. In Africa, the Sahel region experienced a series of droughts from 1400 to 1750 that radically altered the landscape . The water level in Lake Bosumtwi, Ghana, for instance, fell so low that an entire forest grew on the lake’s edges. Today, visitors can still see the tops of trees growing out of the lake—where the water is now more than 15 meters (50 feet) deep. What scientists have learned by looking at Earth’s drought history is that periods of severe drought are a regular part of nature’s cycle. As devastating as droughts in the last century have been, they are considered relatively minor compared to the severity of earlier droughts that have lasted more than a century.

Major Droughts in the Past Century The Dust Bowl of the 1930s is probably the most well-known drought experienced by the U.S. By 1934, 80 percent of the U.S. was struggling with moderate-to-severe drought conditions. The drought lasted nearly a decade and had devastating effects on crop production in the Great Plains . The combination of lack of rain, high temperatures, and strong winds affected more than 50 million acres of land. Massive clouds of dust and sand formed as unusually strong winds lifted the dry soil into the air. These clouds could block out the sun for days, giving the period the name “dust bowl.” In 1934, one dust cloud infamously traveled 2,414 kilometers (1,500 miles), from the Great Plains to the eastern U.S. Mass migration was an indirect effect of the Dust Bowl. Farmers and their families were forced to migrate to other areas in search of work, and by 1940, 2.5 million people had fled the Great Plains. Of those, 200,000 moved to California.

The influx of migrants into existing economies already strained by the Great Depression led to a rise in conflict, unemployment, and poverty . In the 1950s, severe drought returned to the Great Plains and southwestern United States, affecting half of the continental U.S. Low rainfall and high temperatures caused the production of crops in some areas to drop nearly 50 percent. Hay became too expensive for ranchers, and they had to feed their cattle prickly pear cactus and molasses to keep them alive. By the end of the five-year drought in 1957, 244 of Texas’ 254 counties had been declared federal drought disaster areas. In the late 1980s, the U.S. experienced the costliest drought in its history. The three-year spell of high temperatures and low rainfall ruined roughly $15 billion of crops in the Corn Belt . The total of all the losses in energy, water, ecosystem s, and agriculture is estimated at $39 billion. Federal assistance programs were able to help many farmers, but a longer-lasting drought would make it more difficult for the government to provide nationwide aid. Droughts continue to affect the U.S.

Texas has been suffering from drought since 2010, with 2011 ranking as the driest year in the state’s history. A September 2012 National Geographic magazine article called Texas “The New Dust Bowl.” By 2013, 95 percent of the state was dealing with drought. Australia is also a frequent victim of drought. The last decade has been especially severe, earning it the name The Big Dry or The Millennium Drought. Much of the country was placed under water restrictions, wildfires spread in the dry weather, and the water level in some dam s fell to 25 percent. In 2007, 65 percent of viable land in Australia was declared to be in a drought. The drought was officially declared over in April 2012. Droughts that occur in the developing world can cause even greater devastation. The Sahel region in Africa, which includes eight countries, endured a series of droughts in the 1970s and 1980s where annual rainfall dropped by 40 percent.

In the early 1970s, more than 100,000 people died and millions of people were forced to migrate. Conditions continue to be critical in the area due to drought, overpopulation, failing crops, and high food prices. Drought emergencies for the region have been declared four times since 2000. The Horn of Africa , which includes the countries of Ethiopia, Somalia, Eritrea, and Djibouti, is particularly vulnerable to droughts. Because almost 80 percent of the population is rural and depends on agriculture for food and income, famine often accompanies drought. Struggles for the region’s limited, remaining resources can lead to conflict and war. In 1984 and 1985, the Horn of Africa suffered one of the worst droughts of the 20th century. The U.N. estimates that in Ethiopia alone, 1 million people died, 1.5 million livestock died, and 8.7 million people were affected by the drought—including being hospitalized, forced to migrate, or forced to change professions. In Sudan, 1 million people died, 7 million livestock died, and 7 million people were affected.

The cycle of drought-famine-conflict has persisted in the region, with drought conditions returning every few years since 2000. In 2006, drought affected 11 million people across the Horn of Africa, and in 2008-09, more than 20 million were affected. In 2011, drought and the resulting crisis killed between 50,000 and 100,000 people and affected more than 13 million. Forecasting and Measuring Drought Even though scientists are unable to predict how long a drought will last or how severe it will be, early warning systems and monitor ing tools can minimize some of drought’s damaging impacts. There are a number of tools used to monitor drought across the U.S. Due to the limitations of each system, data from different sources are often compiled to create a more comprehensive forecast . The Palmer Drought Severity Index (PDSI), developed in 1965 by the National Weather Service , is the most commonly used drought monitor. It is a complex measurement system and an effective way to forecast long-term drought.

Its limitations are that it does not provide early warnings for drought and is not as accurate for use in mountainous areas because it does not account for snow (only rain) as precipitation. The PDSI is often used by the U.S. Department of Agriculture to determine when to begin providing drought relief. Information from the Standardized Precipitation Index (SPI) is often used to supplement the PDSI data. The SPI, developed in 1993, is less complex than the PDSI and only measures precipitation—not evaporation or water runoff . Many scientists prefer using the SPI because the time period being analyzed can easily be customize d. The SPI can also identify droughts many months earlier than the PDSI. The National Drought Mitigation Center uses the SPI to monitor drought conditions around the U.S. The U.S. Drought Monitor, started in 1999, is a joint effort between three U.S. government agencies—the Department of Agriculture, the Department of Commerce, and the National Oceanic and Atmospheric Administration (NOAA). The Monitor synthesize s data from academic and federal scientists into a weekly map indicating levels of dryness around the country.

It is designed to be a blend of science and art that can be used as a general summary of drought conditions around the country. It is not meant to be used as a drought predictor or for detailed information about specific areas. The Famine Early Warning System Network (FEWS NET) monitors satellite data of crops and rainfall across Africa and some parts of Central America, the Middle East, and Central Asia. Analysis of the data allows for early intervention to try to prevent drought-induced famine. Preparing for Drought People and governments need to adopt new practices and policies to prepare as much as possible for inevitable future droughts. Emergency spending once a crisis has begun is less effective than money spent in preparation. The Federal Emergency Management Agency (FEMA) estimates that every $1 spent in planning for a natural hazard will save $4 in the long term. Many areas are extremely vulnerable to drought as people continue to be dependent on a steady supply of water. The U.S. Department of Agriculture recommends a series of conservation practices to help farmers prepare for drought.

Some preventative measures include installing an efficient irrigation system that reduces the amount of water lost to evaporation, storing water in ditches along fields, regularly monitoring soil moisture, planting crops that are more drought-resistant, and rotating crops to allow water in the soil to increase. In urban area s, many cities are promoting water conservation by addressing water usage habits. Some enforce water restrictions, such as banning car-washing at home, limiting days when lawns and plants can be watered, and offering rebates and assistance programs to fix household leaks. Some drought-ravaged cities are taking even more extreme measures to prepare for future droughts. In Australia, the city of Perth is planning to start a massive wastewater-recycling program in 2016 that will eventually provide one-quarter of the city’s water demands. Perth has been dealing with a decline in rainfall since the mid 1970s. The city, which is on the edge of a huge desert, is also struggling with its history of over-consumption of water. Water-hungry traditions such as planting large, lush lawns and parks will need to be addressed through conservation measures. Term person or thing having to do with school, particularly college or university education.

agriculture Noun Ancestral Puebloans Plural Noun (1200 BCE-1300 CE) people and culture native to what is now the southwestern United States. Also called Anasazi. arable land able to produce crops. artifact material remains of a culture, such as tools, clothing, or food. atmospheric circulation Noun large-scale movement of air that helps distribute thermal energy (heat) on the surface of the Earth. biodiversity a disagreement or fight, usually over ideas or procedures. conservation Corn Belt Noun region whose economy is dominated by the agricultural production of corn. In North America, the Corn Belt sits between the Ohio and Missouri Rivers. crop to change or modify an object to a unique set of preferences. dam structure built across a river or other waterway to control the flow of water. data (singular: datum) information collected during a scientific study. deforestation destruction or removal of forests and their undergrowth. dehydration illness in which the body loses too much water. desert Noun the spread of desert conditions in arid regions, usually caused by human activity. developing world nations with low per-capita income, little infrastructure, and a small middle class.

disaster area region that has been physically and economically damaged by a natural, technological, or social hazard. disrupt Dust Bowl Noun (1930-1940) term for the Great Plains of the U.S. and Canada when severe dust storms forced thousands of people off their farms. earthquake Noun the sudden shaking of Earth's crust caused by the release of energy along fault lines or from volcanic activity. economic having to do with money. ecosystem performing a task with skill and minimal waste. El Nino Noun an extreme shortage of food in one area during a long period of time. farmer person who cultivates land and raises crops. feature non-portable archaeological remains, such as pyramids or post-holes. federal having to do with a nation's government (as opposed to local or regional government). Federal Emergency Management Agency (FEMA) Noun U.S. Homeland Security agency responsible for coordinating response and aid distribution after natural and manmade disasters. fertile able to produce crops or sustain agriculture. flood forced migration Noun the movement of people away from their homes due to political conflict, natural disaster or environmental hazard. forecast to predict, especially the weather. forest ecosystem filled with trees and underbrush.

frequent to feed on grass, usually over a wide pasture. Great Depression (1929-1941) period of very low economic activity in the U.S. and throughout the world. Great Plains grassland region of North America, between the Rocky Mountains and the Mississippi River. habitat recognition of the importance, significant features, or realities of a situation after it has occurred. Horn of Africa Noun large peninsula in northeast Africa, including the countries of Somalia, Djibouti, Eritrea, and Ethiopia. Also called the Somali Peninsula. hurricane Noun tropical storm with wind speeds of at least 119 kilometers (74 miles) per hour. Hurricanes are the same thing as typhoons, but usually located in the Atlantic Ocean region. ice core sample of ice taken to demonstrate changes in climate over many years. ignite not enough or not of high-enough quality. inevitable animals raised for sale and profit. logging industry engaged in cutting down trees and moving the wood to sawmills. Middle East region of southwest Asia and northeast Africa.

minimize MIssissippian Adjective (800-1500) having to do with a network of Native American cultures indigenous to the Mississippi Valley. monitor to observe and record behavior or data. National Weather Service Noun branch of the National Oceanic and Atmospheric Association (NOAA) whose mission is to provide "weather, hydrologic, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy." natural hazard event in the physical environment that is destructive to human activity. nutrition process by which living organisms obtain food or nutrients, and use it for growth. onset beginning or start of something. overgrazing process of too many animals feeding on one area of pasture or grassland. paleoclimatology study of the atmosphere of prehistoric Earth. phenomenon an unusual act or occurrence. poverty status of having very little money or material goods. precipitation to cut or trim branches from a tree, bush, or shrub. rain gauge Noun device for measuring rain or other forms of liquid precipitation, usually in millimeters.

Also called a precipitation gauge, udometer, pluviometer, or ombrometer. resource available supply of materials, goods, or services. Resources can be natural or human. root system all of a plant's roots. runoff Sahel Noun transition zone in northern Africa between the Sahara Desert in the north and the savanna ecosystems in the south. sand small, loose grains of disintegrated rocks. sediment top layer of the Earth's surface where plants can grow. stall to cause to slow or come to a stop. storm severe weather indicating a disturbed state of the atmosphere resulting from uplifted air. supplement to increase or add to. sustainable able to be continued at the same rate for a long period of time. synthesize cloud that produces thunder and lightning, often accompanied by heavy rains. tornado Noun a violently rotating column of air that forms at the bottom of a cloud and touches the ground. tree ring Noun layered formation in the trunk of a tree that marks its growth at least once a year. unemployment state of not having a job. urban area all the plant life of a specific place. vulnerable water that has been used for washing, flushing, or industry.

water cycle water shortage Noun reduction in the amount of fresh water available for drinking, hygiene, and industrial and agricultural use. weather Drought and Carbon Cycling of Grassland Ecosystems under Global Change: A Review "In fact, ecosystems suffer from the effects of a single event by switching into alternative ecological regimes and cannot withstand the combination of multiple extreme events [61]. Grassland ecosystems are able to withstand moderate drought and maintain ecosystem functions [38,62], but severe, extended droughts may induce catastrophic consequences, such as the 1930s Dust Bowl in North America [12,63]. Droughts can significantly and divergently alter the resilience to new disturbances, such as insects, disease, or the next drought [59]. " [Show abstract] [Hide abstract] ABSTRACT: In recent years, the increased intensity and duration of droughts have dramatically altered the structure and function of grassland ecosystems, which have been forced to adapt to this change in climate. Combinations of global change drivers such as elevated atmospheric CO2 concentration, warming, nitrogen (N) deposition, grazing, and land-use change have influenced the impact that droughts have on grassland C cycling.

This influence, to some extent, can modify the relationship between droughts and grassland carbon (C) cycling in the multi-factor world. Unfortunately, prior reviews have been primarily anecdotal from the 1930s to the 2010s. We investigated the current state of the study on the interactive impacts of multiple factors under drought scenarios in grassland C cycling and provided scientific advice for dealing with droughts and managing grassland C cycling in a multi-factor world. Currently, adequate information is not available on the interaction between droughts and global change drivers, which would advance our understanding of grassland C cycling responses. It was determined that future experiments and models should specifically test how droughts regulate grassland C cycling under global changes. Previous multi-factor experiments of current and future global change conditions have studied various drought scenarios poorly, including changes in precipitation frequency and amplitude, timing, and interactions with other global change drivers. Multi-factor experiments have contributed to quantifying these potential changes and have provided important information on how water affects ecosystem processes under global change.

There is an urgent need to establish a systematic framework that can assess ecosystem dynamic responses to droughts under current and future global change and human activity, with a focus on the combined effects of droughts, global change drivers, and the corresponding hierarchical responses of an ecosystem. Full-text · Article · Oct 2016 Multi-species coral Sr/Ca based sea-surface temperature reconstruction using Orbicella faveolata and Siderastrea siderea from the Florida Straits "The warm, tropical SSTs observed during this interval are thought to result in a cyclonic circulation anomaly in the lower troposphere that inhibits transport of moisture northward from the GOM into the central United States (Schubert et al., 2004). Observational and modeling data show that the precipitation deficit during the peak of the Dust Bowl drought (1932–1938) occurred primarily in the spring and summer (Schubert et al., 2004). As noted above, SSTs in the southwestern GOM (del Luna et al., 2015) and the Dry Tortugas area were cool during the Dust Bowl interval.

" [Show abstract] [Hide abstract] ABSTRACT: We present new, monthly-resolved Sr/Ca-based sea-surface temperature (SST) records from two species of massive coral, Orbicella faveolata and Siderastrea siderea, from the Dry Tortugas National Park, FL (DTNP). We combine these new records with published data from three additional S. siderea coral colonies to generate a 278-year long multi-species stacked Sr/Ca-SST record from DTNP. The composite record of mean annual Sr/Ca-SST at DTNP shows pronounced decadal-scale variability with a range of 1 to 2 °C. Notable cool intervals in the Sr/Ca-derived SST lasting about a decade centered at ~ 1845, ~ 1935, and ~ 1965 are associated with reduced summer Sr/Ca-SST (monthly maxima < 29 °C), and imply a reduction in the spatial extent of the Atlantic Warm Pool (AWP).

There is significant coherence between the composite DTNP Sr/Ca-SST record and the Atlantic Multidecadal Oscillation (AMO) index, with the AMO lagging Sr/Ca-SST at DTNP by 9 years. Low frequency variability in the Gulf Stream surface transport, which originates near DTNP, may provide a link for the lagged relationship between multidecadal variability at DTNP and the AMO. Full-text · Article · Oct 2016

Question: With what decade was the Dust Bowl, the period of prolonged dust storms and severe drought, in the USA and Canada mainly associated?
Answer: 1930s