February 27, 2012
California Desertification: Too Dry or Not Too Dry
Desertification is defined as the deterioration of land in typically arid areas due to changes in climate and human activities. In the United States, desertification is typically caused by poor farming practices and the conversion of grazing areas to cropland. Climate change intensifies desertification in arid areas because not only are global temperatures rising and natural disasters becoming more extreme, but also the global water cycle and precipitation patterns are such that rainfall is decreasing in most areas and concentrating in a few others. Furthermore, because California is in a climactic region that can be defined as dry subtropical, the effects of climate change and agriculture has led to increased desertification. The short-term and long-term effects of this desertification are numerous and will have many repercussions for both humans and the environment.
The environmental costs of desertification are quite serious and can eventually destroy natural ecosystems. Topsoils lose their fertility and the growth and support of organic life in the pedosphere becomes much more difficult. As topsoil drys out it becomes susceptible to movement from winds, creating new natural disasters such as the Dust Bowl of the 1930’s. Furthermore, this dust can be blown out into the ocean and can affect weather patterns. In order to salvage lands affected by desertification, farmers begin to invest more in irrigation, which in turn diminishes groundwater resources and is the beginning of long-term impacts such as drought and famine. Additionally, as the topsoil becomes less nutrient rich from desertification plants become less productive and many of the ecosystem services they were providing are diminished.
Unfortunately, California becomes more susceptible to desertification there is a tendency to focus only on the immediate effects. Important long-term impacts on the environment also need to be addressed, such as the effects on the carbon cycle, biodiversity, and freshwater supply. Vegetation in arid areas stores a substantial amount of carbon (about 30 tons per hectare) and when desertification causes drought and the vegetation dies, that storage is lost. In addition, desertification dries out soil, the organic matter of which is the largest known carbon sink, resulting in increased greenhouse gas effects as that carbon is released into the atmosphere. As soils and vegetation are affected by desertification, ecosystems lose key resources that result in a loss of biodiversity. Desertification also poses a threat to freshwater resources. River flow rates decrease, leading to silt build up in estuaries, which incites saltwater intrusion into the water tables. As the demand for water increases there is a tendency to over-pump aquifers, which can result in water depletion and land compaction. For example, the San Joaquin Valley of California experienced subsidence at a maximum of 28 feet between 1925-1970 from overdrawn aquifers. Because California relies so much on agriculture, farmers exploit aquifer water for irrigation without considering these long-term issues. However, if the agricultural industry were to collapse from drought, we’d be facing the threat of famine and a huge economy crash.
Clearly there are many negative effects from the process of desertification that need to be addressed. Some of the most popular decisions to combat the effects of the land drying out include sustainable farming practices, such as drip irrigation, integrated crops, or no-till farming, and drought prevention. As stated in the 2010 California Drought Contingency Plan, “California’s water resources have been stressed by periodic drought cycles and unprecedented restrictions in water diversions from the Sacramento-San Joaquin Delta in recent years. Climate change is expected to increase extreme weather. It is not known if the current drought will abate soon or if it will persist for many years. However, it is certain that this is not the last drought that California will face.” The DCP has moved towards enhancing monitoring and early warning capabilities, assessing water shortage impacts, and creating preparedness, response, and recovery programs, which should help California to conserve water and slow down the desertification process.
Sources:
http://www.waterplan.water.ca.gov/docs/cwpu2009/0310final/v4c06a01_cwp2009.pdf
http://pubs.usgs.gov/circ/circ1182/pdf/06SanJoaquinValley.pdf
http://www.fao.org/sd/EPdirect/EPan0005.htm
http://onlinelibrary.wiley.com/doi/10.1111/j.1468-5973.2010.00633.x/full
Harriet Arnold and Divya Rao are undergraduates in the USC Dornsife College of Letters, Arts and Sciences.
October 30, 2011
Overuse and Abuse of Nitrogen Fertilizers in California Agricultural Lands
Without the use of nitrogen fertilizer, California agricultural lands could risk not reaching its optimum yield. As a consequence, food production companies would lose a certain amount of profit and consumer demands could possibly not be reached. Often times as nitrogen passes through plants and soil in a repetitive cycle the loss of nitrogen is greater than the benefit and as a result, the plant growth is no longer as significant. This ultimately puts a limit on crop production rate. However, scientists have come up with farming techniques that have revolutionized agriculture. Nitrogen fertilizer is one of those inventions and is a product of the Haber-Bosch process. This fertilizer has ‘allowed agricultural production to keep pace with world population growth,’ according to the International Fertilizer Industry Association.
Nitrogen fertilizers have many effects on the Nitrogen cycle that can lead to negative anthropogenic effects as well as environmental. There are several disruptions in the natural cycle of Nitrogen that can occur.
First of all, artificial nutrients dumped into soil can result in a loss of its capacity to hold nutrients (Lowe, pg.10). It is estimated that plants have no use for up to 50% of the chemical fertilizers placed on them.
Agricultural regions of the Southwest are composed of mainly shallow, coarse-textured and therefore highly permeable soils and aquifers. It is common for these areas to be vulnerable to nitrate contamination (Harter pg.3).
Nitrates are the most readily formed and available use of Nitrogen, and they are extremely soluble. It is easily carried through the soil with water to be taken up by plants. If the land is irrigated, there is a chance nitrate can move past the plant roots and into the groundwater or other agricultural tile drainage or surface waters (Mosier, pg.13). In major agricultural areas such as the Imperial, Central, Salinas, and other coastal valleys in California, there is groundwater nitrate contamination (Harter pg.3). When nitrate levels exceed those of the EPA’s Maximum Containment level set at 10mg/l, certain health risks occur. One of these being methemoglobinemia (infants especially are vulnerable).
In addition, when converting ammonium into nitrate, nitrite will naturally occur. Nitrite is similar to nitrate in its movement through the soil and possibility of contaminating groundwater (Reid para.7).
Ammonia volatilization also contributes to nitrogen losses. Ammonia volatilization occurs in areas where the soil is warm, dry, and too much of a nitrogen fertilizer is applied (Buchholz). There is a concern with concentrations becoming toxic. This can happen when too many of these tiny particulates enter a confined area. Ultimately, one of the biggest concerns is reducing air quality (Reid, pg. 11).
Moreover, the effects that Ammonia and nitrate can have on biodiversity can be disastrous. Eutrophication that can lead to algal blooms and a die-off of fish species are a concern from Nitrogen fertilizer use such as ammonia emissions that can deposit on bodies of water and nitrate leached from the soil (Mosier pg.17). Ultimately, the impacts this is having can decrease fish populations resulting in less available resources for people to consume.
Lastly, the process of denitrification can transform the nitrogen fertilizer into nitrous oxide. This is a greenhouse gas, which has approximately three hundred times more impact than carbon dioxide on climate change (Lowe, pg.10). The effects of using these nitrogen fertilizers may not be shown right away as can be seen from eutrophication, but the long-term impacts may be detrimental.
If California continues with overusing and abusing its Nitrogen fertilizer use, it makes itself susceptible to the outcomes seen in China’s croplands. The soil became more acidic so that it was unproductive, and in addition to water contamination, China experienced increases in greenhouse gas emissions. All of these disastrous consequences were negligent monitoring of nitrogen fertilizers.
China’s overuse of nitrogen fertilizers has forced the government to take action against the pollution. One of their solutions is a five-year plan, which calls for a reduction in carbon intensity by implementing new domestic laws that legally require companies to meet emission reduction targets.
Although California may not have a government plan to target the nitrogen pollution, there are other ways in which farmers, themselves can become proactive in reducing the pollution. Some example solutions include securing stored manure in order to prevent runoff or enforcing livestock feed rations that are not above the necessary.
Another solution is to completely phase out chemical fertilizers and instead use organic fertilizers. According to the Third World Network’s report, “Avoiding Nitrogen fertilizer over-use is a “multiple win”: farmers save money, there is less water pollution, smaller greenhouse gas emissions, and a smaller acidification burden on soil and water.”
Image Source:
Harter, Thomas. “Agricultural Impacts on Groundwater Nitrate.” Nitrates in Groundwater. University of California, Davis, July-Aug. 2009. Web. 10 Oct. 2011. <http://www.swhydro.arizona.edu/archive/V8_N4/feature2.pdf>.
Citations:
Mosier, Arvin, John K. Syers, and J. R. Freney. Agriculture and the Nitrogen Cycle: Assessing the Impacts of Fertilizer Use on Food Production and the Environment. Washington, D.C.: Island, 2004. Print.
Lowe, Marcy, and Gary Gereffi. “A Value Chain Analysis of Selected California Crops.” Center on Globalization. Duke University, 04 July 2008. Web. 10 Oct. 2011. <http://www.cggc.duke.edu/environment/valuechainanalysis/CGGC_CACropsReport_7-4-08.pdf>.
Reid, Keith, Kevin McMcKague, and Hugh Simpson. “Environmental Impacts of Nitrogen Use in Agriculture.” Ontario Ministry of Agriculture, Food and Rural Affairs / Ministère De L’Agriculture, De L’Alimentation Et Des Affaires Rurales. Web. 10 Oct. 2011. <http://www.omafra.gov.on.ca/english/engineer/facts/05-073.htm>.
Harter, Thomas. “Agricultural Impacts on Groundwater Nitrate.” Nitrates in Groundwater. University of California, Davis, July-Aug. 2009. Web. 10 Oct. 2011. <http://www.swhydro.arizona.edu/archive/V8_N4/feature2.pdf>.
Buchholz, Killpack. “WQ257 Nitrogen in the Environment: Ammonia Volatilization | University of Missouri Extension.” University of Missouri Extension Home. Department of Agronomy. Web. 10 Oct. 2011. <http://extension.missouri.edu/p/WQ257>.
About the authors: Ticia Lee and Wendy Whitcombe are working towards their bachelor degrees in the USC Environmental Studies Program.
October 10, 2011
California Desalination
As global population continues to rise, the amount of freshwater available for human consumption becomes an increasing issue. Though sources are rapidly depleting, the United States in general has yet to understand the importance of conserving water.
For coastal states such as California, an alternative means to obtaining freshwater is right at their disposal: the ocean.
The spotlight on desalination has been glowing brighter in recent years, as researchers debate on whether or not it is an adequate provider of water for the public. But while desalination provides a new source of freshwater, the environmental and monetary costs outweigh the potential benefits considering the lack of focus on conservation in California.
As far as the environment goes, negative effects of desalination are far too great at this point; the debris left over from distilling the water is put back into the ocean, increasing salinity and killing off biodiversity that is not adapted to such high levels of salt. According to David Rosenfeld, “desalination plants have the potential to entrap sea lions, millions of fish and other marine life,” their environmental impacts also including “the heavy concentrates of salt and the remains of other chemicals that could be dumped into the ocean,” as he writes in his article, Conservationists Push Back Against Desalination in California. When species all around the world are already rapidly declining due to anthropogenic reasons, consciously decreasing ocean biodiversity is not the answer to finding more sources of freshwater.
In addition, desalination is an extremely energy intensive process. Rosenfeld furthers his argument to say that desalination has a massive carbon footprint—around 40 percent of the operating cost is the cost of electricity used to power to plant.
Even while the issue of wasted energy can be mitigated with improved technology, the biodiversity lost cannot be replaced, and the costs put into the additional technology renders the whole business impractical.
While desalination seems like one of the only options for increasing our freshwater resources, in addition to the environmental degradation, it is currently not economical. A proposed plant in Carlsbad is estimated to cost $700 million dollars and will satisfy only 8% of San Diego’s water needs. For this 8% of the water supply it will use as much electricity as 45,000 homes, which is an additional recurrent operating cost on top of the $700 million. The amount of energy required for desalination is extremely high and will be very costly. The cost of water from the desalination plant will be tied to the cost of energy and as the price of energy rises, so will the price of water. “The Public Utilities Commission has approved a plan to allow publicly traded California American Water to potentially quadruple water bills on 40,000 ratepayers in order to pay for the proposed plant,” writes Rosenfeld. Consumers are unaware that the cost of desalination plants will be passed on to them, which is why they are cost-effective for the owners of the plant.
In terms of the allocation of state money, while our education system struggles on budget cuts, Proposition 50 (passed in 2002) provide $50 million to support desalination projects. This year, the Metropolitan Water District of Southern California reduced its conservation to $10 million while allocating $350 million for the Carlsbad desalination plant and promising $250 per acre-foot of fresh water produced to future desalination plants. Rather than spending tons of money on desalination plants that are harmful to the environment, we should first focus on maximizing conservation. While at some point, desalination might be necessary for human survival, we should increase our conservation first: “In parts of Southern California, up to 70 percent of all household water is used outdoors, mostly to water lawns, and an estimated 1.3 billion gallons of wastewater drains into the ocean each year” (Rosenfeld). Southern California is a desert and people living here need to accept that they cannot have a green lawn. If you want a green lawn, move to Northern California or Oregon. Otherwise plant some native plants that don’t need as much water and stop exploiting our water resources just to have a pretty front yard. In terms of in house conservation, low-flow toilets and showerheads, efficient washing machines and dishwashers could all be made extremely affordable if state subsidies were reallocated from desalination plants to conservation technologies.
Desalination plants cause too much environmental degradation and are too expensive to be implanted when there so much there is so much left to be done as far as conservation. We can reevaluate the need for desalination plants when excessive water use has been reduced significantly.
About the authors: Leslie Chang and Lauren Taymor are working towards their bachelor degrees in the USC Dornsife College of Letters, Arts and Sciences.
September 19, 2011
Global Desertification: An Extensive and Intricate Challenge
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.