September 19, 2011
Although not often talked about in an urgent manner, desertification is one of the most relevant and concerning environmental problems the world currently faces. It will be one of the most difficult problems to combat because of the many intricacies and challenges involved with it. The United Nations Convention to Combat Desertification defines desertification as, “land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities.” A recent study evaluating desertification indicators has shown that 38% of the world’s land area is at risk of desertification. In fact it is estimated that 1 billion people are under threat if the trend of desertification continues.
With that many people at risk we have to look at what is causing the desertification and why its effects are so bad. Desertification is caused by two main factors: human interference and climate change. The human interference comes from our farming and animal grazing practices. When we overuse farming fields in dry areas the crops take nutrients from the soil faster than they can be replaced. Along with this, poor irrigation techniques remove water from the land faster than it can be replenished. Also adding to the removal of water from the land is climate change that causes higher temperatures and more/longer droughts. With less water holding the soil together erosion increases greatly, therefore removing the topsoil that is so vital to plant growth. Exacerbating this problem is overgrazing which removes plants that would usually anchor the soil and lessen the wind’s effects. All of these issues together change the soil structure leaving it sandy, saline, without nutrients, lacking biodiversity, and generally unable to support crops and animals.
Once the land has reached this level of degradation the effects are fairly obvious: without adequate food from the land some or all of the humans in the area are forced to leave or starve. In developed nations this may not seem likely because most people are not growing their own food, sustainable farming practices are available/affordable, and if worst comes to worst support systems are in place to take care of displaced people. In contrast in developing nations (especially in Africa) the opposite is true: most people grow their own food, there is no knowledge of sustainable farming practices, even if there was most practices do not make sense economically, and when people are displaced they have nowhere to go. Considering this it is shocking to know that 90% of the inhabitants of drylands live in developing countries. This means that the people most at risk from desertification have almost no resources to combat it due to poverty. As ex-UN Secretary-General Kofi Annan says, “[Desertification] is partly caused by poverty, and exacerbates it. Together with other problems, it leads to forced migration from impoverished rural areas to cities that are themselves often ill-equipped to adequately shelter and employ new arrivals.” The link between poverty and desertification is the crux of the challenge of stopping desertification. If things stay the way they are by 2020 an estimated 60 million people will be uprooted from sub-Saharan Africa and burden of the resulting refugees will be placed on the rest of the world.
The way to overcome this challenge will be through a coordinated humanitarian and environmental effort aimed at helping developing countries where desertification hits hardest. The combined effort needs to work to educate these people on desertification while also aiming to reduce poverty, therefore providing them with alternatives to unsustainable farming. This shows why desertification is such a daunting challenge because it requires revitalizing entire nations before progress can be made. The UN Convention to Combat Desertification is currently trying to do this but large scale, international initiatives need to be taken before we can even begin to combat desertification.
About the authors: Stephen Lowe is working towards his bachelors degree in Environmental Studies in the USC Dana and David Dornsife College of Letters, Arts and Sciences.
September 12, 2011
Water supply in California’s Sierra Nevada range is primarily determined by seasonal precipitation, which occurs for the most part in the fall and winter seasons. The runoff from this precipitation provides substantial flow during spring snowmelt for animals, plants and humans. Through various measurements taken by various stations posted throughout the Sierra mountain range, it is evident that annual snowfall and precipitation has decreased and will continue to do so as climate change and anthropogenic influences heat the earth (Hall and Kapnick 2010). The decreases in snowmelt coupled with anthropogenic influences in the Sierras are posing many abiotic and biotic pressures on plants and animals living in the region and many are on the verge of extinction. Home to 135 threatened plant species and providing “as much as 65 percent of California’s water supply”, the Sierra mountain range remains a crucial habitat for humans, animal and plant species.
Decreased snow melt and anthropogenic influences, such as the introduction of non native species to the Sierra Nevada’s water sources, have posed a serious threat to species such as the Sierra Nevada yellow-legged frog or Rana sierrae, which are native to the area. The Rana sierrae relies on perennial sources of water in order to survive into adulthood, but with the introduction of trout, which prey on Rana sierrae in all three stages of their life, into deeper bodies of water, the Rana sierrae has had to rely on inferior and shallower fishless water sources, which often times run dry in the summer due to decreased snow melt and climate change (Mathews and Preisler 2010). As climate change and anthropogenic influences encroach on the Rana sierra’s habitat, they will eventually become extinct in the region and thereby decrease the rich biodiversity.
Unfortunately, other species inhabiting the Sierra Mountains are reacting more severely to increased temperatures than scientists had anticipated. “What surprised us are how sensitive these trees are to short-term changes in climate,” says U.S. Geological Survey’s Phillip van Mantgem, who conducted a study measuring the mortality rate of Sierra’s coniferous species. Beginning in 1983, Mantgem found that by 2007 the death rate had nearly doubled. The conifer’s lower survival rates can greatly be attributed to increased temperatures. The Sierra Forest Legacy notes that during a recent 22-year period, “the Sierra Nevada warmed by 1.8 degrees Fahrenheit”. Despite no apparent fluctuation in the average precipitation during this 22-year period, increased temperatures have led to higher evaporation rates creating dryer soil conditions. The University of California Santa Cruz also conducted a study on the impact of climate change on Sierra’s Pinus contorta and P. jeffreyi seedlings. The study noted a significant decrease in the survival rate of the seedlings – attributed to the seedling’s shallow root system and lower capacity to store water (Alpert 48-49). In addition to decreased irrigation, the conifers also currently suffer from an increased infestation of fungi and insects, which gravitate towards warmer climates. Additionally, the combination of warmer temperature and more dried dead plant species, makes the environment more susceptible to fires, threatening the release of CO2 previously stored in the trunks of the trees. This release of CO2 will create a positive feedback to the global climate dilemma, sadly leading scientists and conservationist back to where they started.
About the authors: Stephen Holle and Birka Burnison are working towards their bachelor’s degrees in Environmental Studies in the USC Dana and David Dornsife College of Letters, Arts and Sciences.
The Sierra mountain range in Nevada is extremely important for the water supply of California. The runoff from melting snow flows into several bodies of water, such as the Colorado River and Owens Lake that are crucial for meeting the increasing water needs of California. Due to the importance of the mountain range, many people are now concerned about that potential impacts that global warming could have on the snow pack of the Sierra Nevada. The theory goes, global warming would mean that spring comes sooner making winter shorter. Therefore, decreasing the snowpack would greatly affect the amount of melting snow during the spring and summer.
A fresh water supply is important for California especially during the spring and summer because of its extremely dry weather and very limited amounts of rain. However, people’s concerns over the harmful effects that global warming could have on the snowpack level and freshwater supply are overstated. There is plenty of freshwater available from the Sierra snowpack and there will continue to significant amounts of freshwater supplied from the melting snowpack for many years to come. While this may not be enough to support California’s growing population and all of it’s future needs, the Sierra snowpack will continue to provide everything that it has provided Southern California for the past 100 years. Instead, California should be more concerned with, is finding ways to deal with the increased extremeness in weather that may be associated with global warming and the effect that this could have on the annual supply of water.
The west coast of the United States, including the Sierra Nevada region, is coming off a record snowpack in 2011 due to increased levels of precipitation in the winter and a relatively cool spring. In fact, there was even concern over the flooding potential that could be caused by the melting of the snowpack. While certain scientists, who have observed that the Sierra Nevada has had a decreased snowpack in recent years say, will say that one year does not make a trend, how do they know that whatever period they have used to observe the decreasing levels of the snowpack was simply a cycle and that this year may possibly be the start of a new cycle? The water supply in Lake Mead, one the lakes that was most affected by the recent drought, is now expected to keep rising for the year and a half. Excess runoff that was not expected this year has even allowed California to put water in reserve, which is a complete turnaround than previous years.
The Sierra snowpack is dependant on precipitation, which changes on a year-to-year basis. Because of this, in some years, like this past one, there will be abundant water supply, while other years there may a drought and water supply could become critical. So the statement that the Sierra snowpack is running out is not accurate, nor is the statement that the Sierra snowpack can meet all of California’s future water needs accurate. It’s possible that global warming can make the weather more extreme on a year-to-year basis, which makes relying entirely on the Sierra snowpack a daunting prospect. Instead, people need to conserve water as much as possible, no matter how deep the snowpack is in the Sierra’s. If people do this, then surviving drought years will be much easier.
About the authors: Sherwood Egbert and Matt Goldberg are working towards their bachelor’s degrees in the USC Dana and David Dornsife College of Letters, Arts and Sciences.
The Sierra Nevada Snowpack is one of California’s most important natural water reservoirs. The snowpack is formed during the fall and winter and as it melts in the spring and summer (the two seasons when California’s water demand is greatest), slowly releases about 15 million acre-feet of water. Because of its role in the water supply within California, changes in its formation and melting cycles can play a major role in the economy, infrastructure, and land development of the state overall.
The 2011 snowpack made headlines for its large size; over the winter it developed to 165% its average size, momentarily putting Californians at ease about their water demands being met. This good news comes after years of smaller snowpacks and subsequent droughts. Yet even in a year when the snowpack is projected to meet California’s water needs, there is still cause for concern.
Though it is well known that the size of the snow pack varies, recently there have also been changes in the pack’s melting cycle. Research published in 2008 suggests that the rate at which the snowpack melts has been increasing annually. So much so, scientists predict that by 2100 the snowpack will melt completely a full two months earlier than it does now. Current infrastructure, dams and other water storage and transportation facilities, have been built to best deal with the previous predictable cycle of snow melt. As the climate changes and temperatures in the area increase, the sudden burst of water earlier than expected and larger than these structures were built for threatens to overwhelm the storage facilities and threatens to increase the risk of both floods and waters shortages. Uncontrolled floods and the inability to properly store water from a mass runoff endangers development and the economy in that it threatens to damage development, which render the dams and other storage facilities useless, and after the runoff has ended suddenly there is little water left over for the seasons in which it is most desperately needed.
Land in the Sierras has long been considered prime for development. Since 1973, some 800,000 acres of woodland have been converted to new land uses. It has been projected that by 2040 almost 20% of private forests in the area will be affected or altered by even more development. More development would add more greenhouse gas emissions and increase erosion and runoff, all changing the behavior of the snowpack further. Development and industry could also introduce pollutants to the snowpack, as they have in the past.
The ecosystem accounts for approximately $2.2 billion of commodities and services annually. In 2005, agriculture production in California counties using Sierra Nevada water was valued at more than $18 billion. Any change or damage to the Sierra Nevada ecosystem has dramatic repercussions for tourism /recreation, agriculture and resource extraction opportunities. The water resources themselves contribute more than 60% and yield 65% of the developed urban and rural water supplies for California. In addition, the Sierra is also home to one of the greatest areas of biodiversity, and many rare organisms.
The main strategies for preserving the Sierra snowpack recently have been greenhouse gas emission reduction and water conservation and recycling. The fact remains, however, that the population of California continues to grow while their main water supply source does not. The steps proposed by the California Department of Water Resources can only counteract the observed changes in the snowpack’s melting cycle, but even a healthy snowpack will reach a point where it cannot meet California’s growing needs.
About the authors: Makena Crowe and Minda Monteagudo are working towards their bachelor’s degrees in Environmental Studies and Political Science, respectively, in the USC Dana and David Dornsife College of Letters, Arts and Sciences.
September 5, 2011
Though Governor Jerry Brown officially declared the three-year California drought to be over on March 30, 2011, water scarcity is still a huge issue for Californians. The drought was declared over because after three very dry winters, this winter resulted in 159% of normal Sierra Nevada snowpack for that time of year. The Sierra Nevada snowpack is a critical source of California water, as “almost two-thirds of the water used to irrigate millions of acres of farmland” and “water supply for 38.8 million people is contained in the Sierra snowpack.” Governor Brown states though, “while this season’s surplus of rain and strong snowpack has clearly ended the dry spell for now, it is critical that Californians continue to conserve water.” If the state of California does not begin to conserve water in this time of dryness, water sources will dry up and agriculture, industry, and residents will all be seriously affected.
In 2008, “Governor Schwarzenegger declared the first statewide drought in seventeen years,” a drought being defined as a prolonged period of abnormally low precipitation resulting in a shortage of water. In this state of emergency, solutions were proposed to alleviate the matter such as rationing of water and huge cutbacks. The drought lasted for three years until the Sierras had above-average snowpack in 2011. In this image, which shows the severity of drought in 2007 across the nation, it is clear that California is one of the most affected regions by drought, ranking in the “extreme category” in much of southern California. The entire state was experiencing dryness to some degree, though the southern half was hardest hit.
California residents on average use 80 to 100 gallons of water each day, and as a state, California was ranked number one, responsible for 11% of all the freshwater use in the United States. These numbers are just simply too high to be sustainable with the limited water resources that California has. “California produces more than half of the nations fruits, vegetables, and nuts” and growing these requires a huge amount of water. This accounts for a major portion of the water use in California. A water shortage would affect all state of the state from the economy with unemployment and overall revenue. There are already many lawsuits in place over distribution of water and water rights by many local farmers.
In 2009, most of California’s major water reservoirs remained below 50% capacity. Lake Shasta, California’s largest reservoir remained at an extreme low of 30% (Dept. CA Water Resources). California’s reservoirs are rapidly draining and are not having enough time to be replenished. We are beginning to see the same situations as the Owen’s and Mono Lake misfortune at many of California’s major reservoirs, where the growing Los Angeles population diverted too much water for expansion and ended up draining the entire reservoir. Not only does this water shortage from drought have a damaging affect on the people, but also the land is becoming more susceptible to dangerous wildfires, which are becoming “some of the costliest and most damaging in U.S. history” (Dept. CA Water Resources).
Even though the drought is officially classified as over, we still need to work hard and find new strategies and technologies for conserving water due to the yearly fluctuations of snowpack and precipitation. Water is one of the most important aspects of life, especially in California where millions of crops are being grown to supply food for the rest of the country. If the water were to decline suddenly, there would be major conflicts within the state. Therefore, we should live using water sparingly in case of another major drought.
About the authors: Sara Bethel and Megan Won are working towards their bachelor’s degrees in Environmental Studies and Biological Sciences, respectively, at USC Dana and David Dornsife College of Letters, Arts and Sciences.