Geog 9 Final Exam

Importance of nitrogen to plants

1. Nitrogen is critical for plant health and development, and it is often limiting. 2. It is a component of vitamins, amino acids, and energy systems within the plant that form its proteins. It is thus directly responsible for increasing protein content in plants. 3. Lack of nitrogen and chlorophyll means the plant will not utilize sunlight as an energy source to carry on essential functions such as nutrient uptake 4. Nitrogen is necessary for chlorophyll synthesis and, as a part of chlorophyll molecules, is involved in photosynthesis 5. Adequate nitrogen is important for water use efficiency in a plant

US Warming Hole

A warming hole is a place where warming is not happening. Wavier jet stream allows colder air to come down into the Midwest where most crops in the US are grown. Dec-Feb: Center is SE Mar-May: Center shifts NW June-Aug: Center is near Kansas Sep-Nov: Center is near Iowa

Water Resources

About 97.5% of water is in the ocean, which means only about 2.5% of water is freshwater. The majority of that is inaccessible. 68.7% is in glaciers; about 30% is groundwater; only about 0.36% is surface water. Very little water is in the atmosphere at any one time (about 0.04%).

African and South Asian Agricultural Context

Africa and South Asia have high prevalence of undernourishment. Africa and Asia lack financial resources. Africa's and Asia's populations are growing rapidly. Africa and Asia have large yield gaps.

********African and South Asian Agricultural Climate Change Impacts and Adaptation

Agricultural Model and Intercomparison and Improvement Project (AgMIP) is evaluating agricultural climate change impacts in Africa and South Asia.

Climate Variability

Climate variability is the year-to-year or month-to-month in a climate variable, such as temperature or precipitation. To determine climate variability in the first problem set, we used standard deviation.

Global Warming Potential

Global Warming potential (GWP) is used to compare greenhouse gases. It is a measure of the total energy that a gas absorbs over a particular period of time compared to C02-eq. C02-eq is determined by converting the emissions from various greenhouse gases to C02 based on GWP.

Runoff

Nitrogen is carried off the soil by the elements. It can run into streams and other water sources, which harms the water quality and the lifeforms. It can be to some extent by using different fertilization methods. Nitrogen runoff (often due to floods) reduces plant productivity and water quality.

Organic Agriculture

Organic food cause lots of greenhouse gas emissions. (E.g., Spring Mix costs 4,600 calories of fossil fuel for 80 calories of food.) But organic food sales have been rapidly increasing ($35B sector of the broader $575B food retail sales). Over 25,000 farmers, ranchers, and other food producers have certified their operations as USDA Organic. USDA Organic foods: 1. USDA Organic Crops verify that irradiation, sewage sludge, synthetic fertilizers, prohibited pesticides, and genetically modified organisms were not used. 2. USDA Organic livestock verifies that producers met animal health and welfare standards, did not use antibiotics or growth hormones, used 100% organic feed, and provided animals with "access" to the outdoors. USDA Organic Multi-ingredient verifies that the product has 95% or more certified organic content; if the label claims that it was made with specific organic ingredients, then you can be sure that those specific ingredients are certified organic.

Radiative Forcing

Radiative forcing is the difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space. Equation: Watts per meter squared of additional energy due to climate change (due to increased GHG in the atmosphere). A positive radiative forcing has a warming effect on the Earth's surface. A negative radiative forcing has a cooling effect on the Earth's surface.

Sustainable Agricultural Solutions

Sheaffer & Moncada: 1. Protect existing land used for crop and animal production 2. Practice water conservation 3. Expand alternative approaches to crop production 4. Continue plant-breeding research aimed at increasing production efficiency 5. Preserve genetic diversity of existing crops 6. Expand the use of crops for renewable energy Godfray, et al: 1. Close the yield gap 2. Increase production limits 3.Reduce food waste 4. Change diets 5. Expand aquaculture Tilman, et al: 1. Agricultural improvement and tech transfer is critical 2. Land sparing (with increased nitrogen) minimizes GHG emissions

Traditional Breeding

Traditional breeding is the process of selecting the seeds of plants that have favored traits. Over time, those traits become more abundant in a population.

Agricultural Greenhouse Gas Emissions

Agriculture is responsible for 1/3 of the total greenhouse gas emissions. Importantly, this number (33%) includes all of the various aspects of farming, not simply farming. It also includes, for example, transportation. Farming itself accounts for roughly 12.5% of total greenhouse gas emissions.

Agroforestry

Agroforestry could help reduce undernourishment in developing countries, since its front-end cost is so low. Its yield per acre could never compete with industrial farms, though. It could mitigate greenhouse gas emissions. For instance, trees will retain C02 emitted by crops and bioenergy buffers can reduce nitrogen runoff. It can enhance resiliency to climate change and variability by making farms more resilient through increased crop diversity. It can also help repair social structures. There are six types of agroforestry. Riparian energy buffer: A riparian buffer is a vegetated area near a stream, usually forested. This prevents nutrient loading of streams (enhances water quality). Windbreaks: Windbreaks increase yields through Silvopasture: A silvopasture is a combination of trees and pasture. They provide food and shelter for livestock. Trees benefit from livestock nutrients; livestock benefit from shade, which yields reductions in heat stress. Alley cropping: Alley Cropping is planting rows of trees at wide spacings with a companion crop grown in the alleyways between the rows. Alley cropping can diversify farm income, improve crop production and provide protection and conservation benefits to crops. It offers a blend of nitrogen-consuming and nitrogen-fixing crops. It protects crops and reduces crop canopy temperatures. Forest farming: Forest farming is a complex mix of biodiversity and staple crops. Short-rotation woody crops: Another form of microcropping/intercropping shrubs with field crops

Aquaculture

Aquaculture is the breeding, rearing, and harvesting of animals and plants in all types of water environments. Generally, fish are enclosed upstream and plants are grown downstream. The waste of the fish offers nutrients to the plants. This is used in developing countries as a dietary source of protein. It may not, however, increase calorie count. To the extent that it offsets consumption of different protein sources (mainly red meat), aquaculture can mitigate greenhouse gas emissions. It is not a great way to enhance resiliency to climate change and variability. However, it is good to diversify protein sources. It can hurt the environment in several ways. First, non-native can fish escape from their encasement and cause damage to the ecosystem. Second, predators can get caught in the net. Third, concentrated waste downstream can wreak havoc on environments. Fourth, drugs administered to the fish population can travel to other environments and harm the species living there.

Aquaponics

Aquaponics is a combination of fish and plant production using aquaculture and hydroponics systems. An example of urban aquaponics can be found in Chicago, where plants are grown using the waste of tilapia. It is a niche agricultural model that is energy intensive and rather expensive. Because of this, it is unlikely to reduce undernourishment, except to the extent that it increases the food available in the market and thereby drives down prices of less "niche" foods.

Killing Degree Days

Butler and Huybers define a killing degree day as a day on which the maximum temperature exceeds 29 ̊C. KDDs thus stand in contrast to GDDs: whereas GDDs indicate higher yields, KDDs indicate decreased crop yield. This decrease may be due to poor development, perhaps because the excessive heat damages the plant tissue or enzyme (Butler 2013, p. 68).

*********Climate Change Adaptation and Mitigation

Climate Change Adaptation: The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. Potential Adaptations to Climate Change in Agriculture: SLIDE!!!!! Climate Change Mitigation: Human intervention to reduce the sources or enhance the sinks of greenhouse gases. The most effective mitigation measures ate to restore cultivated organic soils and cropland management. Other methods: restored degraded lands, switch proportions of livestock, manure management, agroforestry (reduce slash and burn)

Climate Change

Climate change is the change in temperature over decades caused by atmospheric greenhouse gases that absorb and re-radiate energy back to the surface. Impacts: effects on natural and human systems Vulnerability: the propensity to be adversely affected Risk: the potential for consequences where something of value is at stake and where the outcome is uncertain. Resilience: The capacity of social, economic, and environmental system to cope with a hazardous event or trend or disturbance

Representative Concentration Pathway (RCP)

Descriptions of potential future emissions of radiatively active substances. They provide an input to climate models

CO2 Impacts on Crops

Direct: CO2 is necessary for photosynthesis. The direct response of plants can be difficult to measure. One technique is soil-plant atmospheric research chambers, but this method is not best for mimicking true field conditions. Indirect: Changes in temperature; precipitation; relative humidity; wind; solar radiation; etc. Enhanced CO2 increases C3 photosynthesis and C3/C4 Water Efficiency For elevated CO2 concentrations of ~550ppm: -Increased photosynthesis in C3 crops by 10-45% -Increased photosynthesis in C4 crops by 0-10% -Enhanced photosynthesis was reduced by soil nitrogen -Increases were higher at temps greater than 25˚C. Elevated C02 decreased stomatal conductance and evapotranspiration and increased cnaopy temperatures and water use efficiency of both C3 and C4 plants

Nitrogen Impacts on Environment and Health

Eutrophication: Nitrogen runoff produces algal blooms in lakes, rivers, and oceans. Algae die and their decomposition depletes oxygen in the water. (E.g., Gulf of Mexico dead zone) Blue baby syndrome: Nitrate levels above 10mg/L (10ppm) in drinking water lead to decreased oxygen carrying capacity of hemoglobin Heavy metal accumulation: Global warming: Nitrous oxide produced during denitrification, which is a process by which nitrate is converted to atmospheric nitrogen (N2) by soil bacteria relying on anaerobic conditions. Also, methane emissions from rice paddies increase with fertilization. Energy use: Inorganic fertilizer production is energy intensive (1-2% of global energy use) Soil acidification: Nitrification produces nitrous and nitric acid

Evapotranspiration

Evapotranspiration is the total water loss by an agricultural system. Water is lost through transpiration (plants) and evaporation from plant surfaces and soil. It depends on several factors, including type of photosynthesis, and water efficiency adaptations.

Carbon Cycle

Fast Carbon Cycle: 10-100 Gt C/year. Largely the movement of carbon through the biosphere (life forms on Earth). It is a balance between photosynthesis and respiration/decay. Net primary productivity is the net carbon consumed by plants both on land and in the oceans. Plants sequester 3 Gt C/year. Shallow ocean sequester 2 Gt C/year. Slow Carbon Cycle: 0.01-0.1 Gt C/year Carbon fluxes between rocks, soil, ocean, and atmosphere. Carbon is sequestered as calcium carbonate in ocean sediments or as organic matter embedded in mud. Carbon is returned to atmosphere by volcanoes. Humans are anomalous to the carbon cycle. Humans emit 9 Gt C/year.

Fertilizer Application

Fertilizing increases crop yields (but only to a certain extent - so no point putting on too much fertilizer). The method used depends on the agricultural production system, equipment, and the crop. There are five main types of fertilizer application methods: Disked-in fertilizer: Plow into the field. Easiest method. Injected fertilizer: A gas that reacts with soil water and becomes immediately available for use by crops Broadcast fertilizer: Done when crop is in the ground. Downside is that fertilizer is exposed to the elements. Banded fertilizer: either top-dress or side-dress. Fertilizer is put two inches below seed when planting, and then along roots after germination. Fertigation: Put nitrogen into irrigation water.

*******Genetically Engineered Crops

Genetically engineered crops (GE crops) are modified using tools from genetic engineering. They may or may not be transgenic (meaning they may or not not contain DNA from an unrelated organism). Plants are genetically modified using bacterias. Modified bacterias are introduced into plant cells

Global Climate Model

Global Climate Models (GCMs) are computational models to predict future climate. IPCC uses it to assess future effects of climate change. They use basic geophysical equations (conservation of momentum/mass/energy) to simulate fluid flow on a spherical surface (temperature, precipitation , wind, etc) An integrated assessment model gives levels of greenhouse emissions, which goes into GCM that projects temperature and/or precipitation. They contain significant inaccuracies and have coarse resolution.

Global Warming's Six Americas

Global Warming's Six Americas is a study by Yale Program on Climate Change Communication; found that majority of Americans believe in climate change and are concerned about it. The Six Americas: 1. Alarmed: Fully convinced of the reality of climate change and its seriousness and are already taking action (21%) 2. Concerned: Convinced that global warming is happening and a serious problem, but have not yet engaged the issue personally (30%) 3. Cautious: Not sure climate change is happening or human caused (21%) 4. Disengaged: Don't know anything about it (7%) 5. Doubtful: Don't think that climate change is happening, and if it is then it is either natural or not a threat (12%) 6. Dismissive: Very sure that climate change is not happening and oppose reducing greenhouse gas emissions (9%)

*******Irrigation

Irrigation is the supplementation of precipitation with water from another source. Crop irrigation is the largest use of freshwater globally. About 40% of global agricultural productivity is from irrigated croplands. Irrigation can be renewable or non-renewable. Surface water is renewable (and it might otherwise flow to the ocean). Soil and ground water can be renewable (for instance, wells are renewable sources of water) but they can also be non-renewable (India is pumping more unsustainable soil/ground water than anyone else). Ideally applied based on measurement of soil moisture status or estimation of crop water use. Kinds of irrigation: Surface irrigation: Applies water directly to the coil surface. It is used in areas where land is level or graded to achieve uniform flooding. -E.g., flood/furrow irrigation: easy to deploy, inefficient (lose a lot of water to ground and evaporation), specialty applications Sprinkler Irrigation: Applies pressurized water by using pipes or sprinklers. It is more efficient than surface irrigation. -Center pivot sprinklers dominate US irrigation (relatively easy to deploy, more efficient than flood/furrows) -Drip irrigation: Expensive to install, very (most) efficient, but only makes sense for specialty crops (e.g., would never install it in corn fields)

*******Climate Impacts on Crop Yields

Lobell studies this. He detrends yields to control for technology, which allows him to assume that all changes not due to technology are weather-related. Lobell's article (see Table 1) finds that maize and wheat were the big losers to climate change during the past 20some years. For wheat, climate reduced the effect of technology on yields by half. Climate impacts on global soybean and rice production had winners and losers, but they largely balanced out. Climate trends were large enough in some countries to offset a significant portion of the increases in the average yield that arose from technology, carbon dioxide fertilization, and other factors

Atmospheric Nitrogen Fluxes

Natural cycle: 40-50 terragrams of nitrogen annually Humans produce roughly 200 terragrams of nitrogen annually. The breakdown: -n-fixing crops: 40 terragrams -fossil fuels: 20 terragrams -industrial processes: 5 terragrams Haber Bosch: 135 terragrams

Clausius-Clapeyron Relationship

The Clausius-Clapeyron Relationship holds that as you cool air, it holds less water. Likewise, as you warm it, it holds more water.

Haber-Bosch Process

The Haber-Bosch Process takes nitrogen from the air and creates ammonia in a liquid form on an industrial scale. This is used as fertilizer in agriculture. It has enabled humans to double the natural rate of nitrogen fixation on Earth and thereby increase agricultural productivity. It accounts for 135 of the 200 terragrams of nitrogen produced by humans each year. It has negative implications. It is a massive energy use and the nitrogen produced is often released to the ecosystem. Most of the nitrogen produced is sent to developed countries. There is enough to serve the entire world, but some countries/regions get too much of the nitrogen share.

Intergovernmental Panel on Climate Change (IPCC)

The IPCC is a scientific intergovernmental body of over 3,000 scientists set up by the World Meteorological Organization (WMO) and by the United Nations Environment Program (UNEP). It provides decision-makers and others interested in climate change with an objective source of information about climate change. The IPCC does not conduct any research nor does it monitor climate related data or parameters. Its role is to assess on a comprehensive, objective, open and transparent basis the latest scientific, technical and socio-economic literature produced worldwide relevant to the understanding of the risk of human-induced climate change, its observed and projected impacts, and options for adaptation and mitigation. In its Fifth Assessment Report, Working Group 1 (2013), the IPCC presents a global assessment of climate change science. It finds that warming in the climate system is unequivocal, with many of the observed changes being unprecedented over decades to millennia. These findings show that the atmosphere and ocean are warming that snow and ice are diminishing; that sea levels are rising; that concentrations of greenhouse gases are increasing. Moreover, each of the last three decades has been successively warmer at the Earth's surface than any preceding decade since 1850. They determine with 95% certainty that human activity is the dominant cause of climate change since 1850.

Relative Humidity

The amount of actual water vapor in the atmosphere relative to the max amount of water vapor that the atmosphere can hold at a particular temperature. (Actual water vapor/Water Vapor Max)

Agricultural Greenhouse Gas Mitigation

The most effective mitigation measures are to restore cultivated organic soils and to engage in crop management. These measures can be incentivized by the government, which can give tax breaks in the amount of a set number of dollars per tonne of Co2-eq. The greater the incentive, the more effective the mitiagation.

*******Nitrogen Cycle

The nitrogen cycle is the transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere. Plants rely on nitrogen for photosynthesis. Which means they need nitrogen as an input. Their main way of getting nitrogen is through carbon fixation (conversion process of inorganic carbon to organic compounds by living organisms). They can also get nitrogen from the atmosphere, although this is rare. The primary way that crops get nitrogen for carbon fixation is through fertilization; humans can produce nitrogen (fertilizer) and put it on the field.

Anthropogenic Greenhouse Gas Emissions

The total amount of greenhouse gases emitted by humans per year. Humans are anomalous to the carbon cycle because they remove lots of carbon from the Earth's stores (which are part of the slow cycle) and emit that carbon into the atmosphere (thereby introducing it into the fast cycle); therefore they fit neither in the fast cycle nor the slow cycle. Humans emit 9 Gt C/year. Of all nations, the United States and China produce the most GHG emissions, then Brazil and Russia. In developing countries, emissions are produced almost entirely by agriculture (slash and burn is a big emitter of GHG).

Urban Farming/Greenhouses

Urban farming can increase food production, cause prices to drop, increase distribution, make distribution more equitable, and increase regional self-sufficiency. It can decrease GHG emissions from transportation. And on a large enough scale it can enhance resiliency to climate change and variability. There are three primary examples of urban farming: 1. Vertical farming in Singapore 2. Rooftop farming in NYC 3. Greenhouse farming in Netherlands (Netherlands has 36 square miles of greenhouses)

Hydrologic Cycle

Water exists in three states: solid (ice); liquid (water); gas (water vapor). Transformations: -To more energetic state: evaporation, melting, sublimation -To less energetic state: freezing, condensation, deposition