AICE ENVIRO EXAM
population density formula
# of individuals/land area
Outline how ozone depletion occurs
1 Emissions (from humans & naturally) 2 Accumulation (build up in atmosphere & distributed globally) 3 Transport (moved to stratosphere) 4 Conversion (gases react with sun) 5 Chemical reaction (reactive gases deplete stratospheric ozone) 6 Removal (gases back to troposphere - & removed by moisture in clouds & rain)
Biodiversity index
A simple biodiversity index is calculated as follows: number of species in the area ÷ total number of individuals in the area = biodiversity index.
What are the major sources of GHG emissions from human activities?
CO2 and water vapor released during combustion of fossil fuels, power stations, industry, and transport. CO2 = 3 times contribution of methane, but CH4 infrared absorbing ability greater. Hydraulic fracturing (fracking), used to extract oil, releases CH4. Landfills, rice paddies, ruminant animals have methanogens (anaerobic respiration) that reduce CO2 to produce methane gas as a byproduct.
Outline the impacts associated with the use of some alternatives to ozone depleting substances
Could we find a replacement for CFCs? HCFCs - are they the answer? Used in refrigeration, air conditioning, foam blowing, solvents, aerosols, and fire suppression. They contain chlorine and therefore, still deplete stratospheric ozone... but, to a lesser extent. HCFCs are still planned to be phased out
8.2.2 Describe the impacts of climate change on human populations
Decline in food production → an increase in hunger & water crises, especially in developing countries Threat to livelihoods from floods and forest fires Health risks due to increase in frequency and intensity of heat extremes Economic implications of dealing with secondary damage related to climate change Increasing spread of pests and pathogens Loss of biodiversity - less resources/medicines/etc. for humans Ocean acidification due to increased HCO3 concentrations in the water as a consequence of increased CO2 concentrations The need for adaptation in all areas (e.g. agriculture, forestry, energy, infrastructure, tourism, etc.)
Define energy security as the reliable availability of energy sources at an affordable price with a consideration of the environmental impacts
Definition: the reliable availability of energy sources at an affordable price with a consideration of the environmental impacts The Energy Sector consists of thousands of electricity, oil, and natural gas assets that are geographically dispersed and connected by systems and networks. The energy infrastructure provides fuel to the Nation, and in turn depends on the Nation's: transportation, communications, finance, and government infrastructures. The energy systems and networks cross the Nation's borders, making international collaboration a necessary component of the Energy Sector's efforts. As this diversification increases, energy security improves.
Describe the two types of acid deposition
Dry Acid Deposition- deposition of acidic material on dust, smoke, or other aerosols (small, microscopic particles in the air) Wet Acid Deposition- deposition of acid in precipitation (rain, snow, or fog)
Define greenhouse gases as gases in the atmosphere that absorb infrared radiation and identify some common greenhouse gases
Gases in the atmosphere that contribute to the greenhouse effect by absorbing and emitting radiant energy within the infrared range. Primary greenhouse gases are: CO2 carbon dioxide, CH4 methane, H2O water, NOx nitrous oxides, HCFC, CFC halogen gases, O3 ozone.
State that ozone concentration is measured using the Dobson Unit
How do we measure the thickness of the Ozone Layer? Using Dobson Units What is a Dobson Unit (DU)? 0.01 mm thickness at STP (0C and 1 atmosphere pressure) A slab 3mm thick corresponds to 300 DU
Describe the impacts of ozone depletion due to the increased amounts of ultraviolet radiation
Ozone layer depletion increases the amount of UVB that reaches the Earth's surface. UVB causes: Skin cancer Eye damage - development of cataracts, a clouding of the eye's lens. Reduction in phytoplankton
Describe the impacts of photochemical smog
Photochemical smog can have an effect on the environment, on people's health and even on various materials. The main visible effect is the brown haze that can be seen above many cities. The brown tinge is caused by very small liquid and solid particles scattering the light. Plants Chemicals such as nitrogen oxides, ozone and peroxyacetyl nitrate (PAN) can have harmful effects on plants. These substances can reduce or even stop growth in plants by reducing photosynthesis. Ozone, even in small quantities, can achieve this, but PAN is even more toxic to plants than ozone. Health The biggest concern about photochemical smog is the effect it has on people's health. The effects of the major primary and secondary pollutants in smog are given in Table 1
Describe and explain the causes of energy insecurity
Physical factors - fossil fuels were formed millions of years ago. New supplies of fossil fuels are sometimes found, but only in places that have the right geology. Cost of exploitation and production - wages count towards the overall cost of energy production. This has led to some resources being unprofitable, e.g. the UK has coal supplies, but it is too expensive to exploit them. When the global price of oil increases, drilling becomes profitable in many harder to reach locations. Technology - improvements in technology can open up new opportunities for energy use. Fracking is the process of extracting shale gas. The USA now carries out fracking, which has increased their energy supplies. Wind turbines and solar panels are becoming more efficient and so these are being used in more countries. Political factors - war can destroy energy resources or make them difficult to exploit. Corruption can mean that money is spent on things other than energy projects. Conflict between consumers - price & demand Between home produced goods and imported goods War (Gulf War and Iraq War were driven by the West's fear of global oil shortage and rising prices Those with and those without Oil and other fossil fuel depletion (peak oil, etc) Reliance on foreign sources of energy Geopolitics (such as supporting dictatorships, rising terrorism, stability of nations that supply energy) Energy needs of poorer countries, and demands from advancing developing countries such as China and India Economic efficiency versus population growth debate Environmental issues, in particular climate change Renewables and other alternative energy sources
benefits of biofuels
Potential to reduce some undesirable aspects of fossil fuel production and use: conventional and greenhouse gas (GHG) pollutant emissions, exhaustible resource depletion, and dependence on unstable foreign suppliers. Demand for biofuels could also increase farm income.
Describe strategies for managing air pollution
Prevention!!! Use less Find alternatives What else can be done to prevent air pollution? Laws & Regulations - local, state & governments pass laws/ regulations/ recommendations Example: requiring manufacturers to add catalytic converters to vehicles Example: on bad smog days, people with asthma are warned to stay indoors in L.A. Example: In Santiago - on high smog days, cars are banned from entering the city... based on their registration plates (rotated on different days of the week) -- this is only for vehicles without catalytic converters in their exhausts Can you think of any strategies which could be adopted by a city or government? T-P-S Economic Tools emissions trading, banking, and emissions caps - allows producers of air pollutants to buy & sell government air pollution allotments in the marketplace. For example: each coal plant is given a number of pollution credits, which allow it to emit a certain amount of SO2. If less is emitted, the facility will have a surplus of credits; which it can use to offset SO2 emissions at the companies other plants, keep them for future plant expansions or sell them to other utilities or private citizens or groups. 1990-2012 - this trading system helped reduce SO2 emissions from power plants in the U.S. by 76% Proponents - say it's cheaper & more efficient than government regulations of air pollution Critics - say it allows utilities with older, dirtier plants to BUY their way out of their environmental responsibilities & continue to pollute. What can you do to help? Here are some actions you can take to help minimise the pressures on our environment: REDUCE energy you use! Service vehicles regularly & keep tires inflated to spects → ensures car is running efficiently & NOT emitting EXCESS pollutants; when purchasing a vehicle → look for fuel-efficiency (check out the fuel consumption label); Instead of using a car, try riding a bike or walking, and use buses, trams or trains whenever you can. Use energy efficient appliances. Look for the Energy Star logo when buying a computer, printer or scanner, TV, VCR, audio or DVD product; or the Energy Rating on the next air conditioner, clothes dryer, washing machine, dishwasher, fridge or freezer you purchase. If renovating or building, use energy-efficient designs and materials. Turn off unnecessary electrical appliances at the power point wherever possible.
State the impacts of climate change on the environment
Sea Level Rise Warming Oceans & acidification Negative impacts on Large River Systems Ecosystem Collapse/Biome Loss Extreme Weather / Stronger hurricanes Changes in rainfall patterns/drought and heat waves Increased wildfires Decline in Arctic sea ice and snow cover Glacier recession Permafrost thawing Biodiversity loss
dependency ratio
The number of people under age 15 and over age 64 compared to the number of people active in the labor force
Define the term ozone hole as an area where the average concentration of ozone is below 100 Dobson Units
The ozone hole is an area where the average concentration of ozone is below 100 DU.
Biodiesel
a liquid fuel produced from renewable sources, such as new and used vegetable oils & animal fats Cleaner-burning replacement for petroleum-based diesel fuel. Nontoxic & biodegradable Produced by combining alcohol with vegetable oil, animal fat, or recycled cooking grease. Biodiesel can be blended with petroleum diesel in any percentage, including B100 (pure biodiesel) and, the most common blend, B20 (a blend containing 20% biodiesel and 80% petroleum diesel).
What is Acid Deposition?
a mix of air pollutants that deposit from the atmosphere as acidic wet deposition (with a pH <5.6) or acidic dry deposition
What is water scarcity?
an imbalance between "supply" and "demand" that varies according to local conditions. Water use - increasing globally - more than twice the rate of population increase in the last century An increasing number of regions are reaching the limit at which water services can be sustainably delivered. Problems are especially bad in arid regions.
why is water important
essential for agricultural production and food security. It is the lifeblood of ecosystems, including forests, lakes and wetlands, on which our present and future food and nutritional security depends. The 'water we eat' daily through the food we consume is much more than what we drink. Did you know, depending on the diet, we need 2 000 to 5 000 litres of water to produce the food consumed daily by one person?
6.1.1 Describe the distribution of the Earth's water
total water= 97%, 3% freshwater. Freshwater= 30.1% ground water, 68.7% icecaps and glaciers, surface water 0.3%, other 0.9% surface water= lakes 87%, swamps 11%, rivers 2%
Evaluate the international agreements used to reduce and phase out the use of ozone depleting substance
1985 - Vienna Convention for the Protection of the Ozone Layer - international cooperation on this issue formalized (framework for Montreal Protocol) This cooperation lead to the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer In 1992, Copenhagen Amendment - parties decided to alter the terms of the 1987 agreement to end production of halons by 1994 and CFCs by 1996 in developed countries
How many people in the world live in poverty?
780 million people, 11 percent of the world's population, live in extreme poverty At least 14 million children suffer from severe acute malnutrition around the world. Severe acute malnutrition is the direct cause of death for 2 million children every year. Every day, 1,000 children under 5 die from illnesses like diarrhea, dysentery, and cholera caused by contaminated water and inadequate sanitation.
price setting
Agricultural commodity prices are an indicator of changes in supply and demand, and as such, can detect abnormal conditions that need to be brought to attention. Price monitoring is important as a basis for evidence-based decision making & food security strategies. Timely market information & analysis is important so negative effects on low-income groups can be reduced.
increase in homogeneity in global food supply
All the same kind... What does this have to do with the food supply? What do you think is the problem with having less variety of food crops? more vulnerable to changes in: the climate, crop pests diets concentrated on a few crops may accelerate the worldwide rise in obesity, heart disease and diabetes Also, the impacts of mass crop production on soil, water quality, and biodiversity
Outline the impacts of acid deposition on: aquatic environments vegetation and crops stone and brick buildings
Aquatic Environments Freshwater macroinvertebrates, plants, and fish populations are damaged when acidic water disrupts their reproductive cycle. Aluminum leaches from the soil into the water, altering the chemistry and clogging the fish's gills. As water bodies become acidified, one species after another disappears. Vegetation & Crops Acid rain leaches aluminum from the soil -- which may be harmful to plants as well as animals. Removes needed minerals & nutrients from the soil (for growth) Leaves trees vulnerable to stresses (severe cold, diseases, insects, drought) Stone & Brick Buildings Damages statues & buildings Acidic particles corrode metal and cause paint and stone to deteriorate more quickly
Outline the impacts of energy insecurity
Exploitation of difficult and environmentally-sensitive areas countries like to find new sources of energy and this sometimes means that they use environmentally-sensitive areas. Fragile ecosystems can be put at risk as the desire for energy is greater than the desire for environmental protection. Deforestation Oil spills Damage to seabed Impacts of animal migrations Increased transport Climate change Economic and environmental costs - imported fuel is expensive. Exporting countries set the prices for fuel, leaving importing countries vulnerable. Some fuels cause a lot of pollution, eg coal causes smog and releases greenhouse gas when burnt. Mining for the raw materials for energy can also cause environmental problems with loss of habitats, noise and visual pollution. Food production - exploiting energy resources often uses valuable farmland. The growth of the biofuel market has also led to crops being grown as a fuel, rather than as food. This can cause food shortages and push food prices up as supply falls lower than demand. Machinery needed to produce fertilizers and chemicals to help with food production will suffer. Industrial output - manufacturing relies on energy. When energy is in short supply, it costs more to buy. This makes manufacturing more expensive. Countries that experience energy insecurity usually have a lower industrial output. Lower production Job losses Impact on how industry runs Product prices increase Conflict - energy insecurity can cause conflict. Dams are a good example of this. Rivers often flow through more than one country. If a country upstream builds a dam to generate hydroelectric power (HEP), then a country downstream will have less water. Energy insecurity impacts LICs in many ways Disrupted electricity supply Increasing prices for energy resources Increasing costs for industry Job losses/economic recession Increased levels of poverty/ low standards of living Reliance on imported sources of energy Civil disruption/conflict
drawbacks of biofuels
Feedstocks for biofuels require land, water, and other resources → biofuel production may give rise to several undesirable effects: Changes to land use patterns that may increase GHG emissions, Pressure on water resources, Air & water pollution, Increased food costs. Could (depending on the process used) emit even more GHGs than some fossil fuels on an energy-equivalent basis. Also tend to require subsidies and other market interventions to compete economically with fossil fuels, which creates deadweight losses in the economy.
Outline the formation of acid deposition
Formation of Acid Deposition Acid rain - caused by a chemical reaction that begins when compounds like sulfur dioxide & nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.
Explain the causes of water insecurity
Natural Causes Global Warming Lack of Rain Flooding Human Causes Global Warming Population - increased human demand poor consumption practices Pollution Industrial Agriculture Political Interests / Wars
Outline geo-engineering strategies to counteract climate change
Geoengineering is sometimes called solar radiation management (SRM). These methods all involve albedo enhancement. They could quickly reverse GW, and could be the only way to keep warming below 2 degrees C if cutting GHG proves insufficient. However, it: has side effects, could cause political tensions, and could distract politicians from GHG cuts. Carbon Capture Storage (CCS) Strategies can slow CC. Planting trees, restoring wetlands on a global scale. Geoengineering strategies manipulate natural conditions to counter the greenhouse effect. Examples include: releasing sulfate aerosols into the atmosphere. Large orbital mirrors, ships releasing salt water into the sky to make clouds more reflective. CCS reduces GHG emissions but is expensive & risk of CO2 leakage is a concern. Carbon mineralization involves injecting CO2 into rocks so it can be stored as solid MgCO3 or CaCO3. Direct air capture involves collecting carbon from air and storing it underground or in long-lasting products.
soil erosion
Increased demand for agriculture commodities generates incentives to convert forests and grasslands to farm fields and pastures. The transition to agriculture from natural vegetation often cannot hold onto the soil and many of these plants, such as coffee, cotton, palm oil, soybean and wheat, can actually increase soil erosion beyond the soil's ability to maintain itself. Half of the topsoil on the planet has been lost in the last 150 years. In addition to erosion, soil quality is affected by other aspects of agriculture. These impacts include: compaction, loss of soil structure, nutrient degradation, and soil salinity. Some other effects of soil erosion are: loss of carbon, gaseous emissions, non-point source pollution and sedimentation of waterways
Describe and evaluate strategies for managing energy security
Long Term Energy Security Supply of energy that is in line with economic development and environmental needs Short Term Energy Security Systems that react promptly to sudden changes in the supply demand balance New Energy Transition Improving energy efficiency and reducing energy waste Decreasing our dependence on nonrenewable fossil fuels Relying more on a mix of renewables from sun, HEP, wind, biomass, biofuels, geothermal energy, perhaps hydrogen. Increasing cheaper renewable energy such as solar and wind energy Develop modern smart electrical grids to distribute electricity produced from these resources New Energy economy could be further accelerated if citizens, the leaders of emerging energy companies, and energy investors demanding the following from their elected official/representatives: Use full cost pricing to include the harmful health of environmental costs of fossil fuels and all other energy resources in their market prices. Tax carbon emissions. This is supported by most economists and many business leaders, and is now done in 40 countries. Use the revenue to reduce taxes on income and wealth and to promote investments and research in new energy efficient and renewable energy technologies. Sharply decrease and eventually eliminate government subsidies for fossil fuel industries, which are well established and profitable. Establish national feed in tariff systems that guarantee owners of wind farms, solar power plants, and home solar systems a long term price for energy that they feed into their electrical grids (as is being done in more than 50 countries, many of them in Europe). Mandate that a certain percentage (typically 20-40%) of the electricity generated by utility companies must come from renewable resources (as is done in 24 countries and in 29 U.S. states). Increase government fuel efficiency (CAFE) standards for new vehicles to 43 km/l (100 miles/gallon) by 2040.
Describe and explain causes of food insecurity and threats to food security population growth
More people (especially in poor countries with limited amounts of land & water) = fewer resources to meet basic needs. Basic needs not met = development stalls → economies begin to unravel. In some poor countries, rapid population growth has undermined attempts to increase food production Other issues: migration from rural to urban areas; unequal land distribution; shrinking landholdings; deepening rural poverty; and widespread land degradation.
water shortages
Rainfall patterns changing = issues with flooding and times of drought - both extremes can destroy crops. Flooding washes away fertile topsoil that farmers depend on for productivity, Droughts dry it out, making it more easily blown or washed away. Higher temperatures = increase in water needs for crops → making them even more vulnerable during dry periods. Certain species of weeds, insects, and other pests benefit from higher temperatures and elevated CO2, increasing their potential to damage crops and creating financial hardship for farmers. Shifting climates also mean that agricultural pests can expand to new areas where farmers hadn't previously dealt with them. Elevated levels of atmospheric carbon dioxide (CO2) are also expected to lower levels of zinc, iron, and other important nutrients in crops.
Describe and evaluate strategies for managing food security
Reduce Food Waste; Reduce the Risk of Commercialising - growing food to feed the community or nation; Improve Existing Infrastructural Programs - roads, storage facilities, food processing equipment; Improve Trade Policies - Corporate giants have already stepped in and commercialized food, making it harder for small-scale farmers to have their products in the market. Promote Diversification - no single crops... diversified and healthy diets for better nutrition Close the Yield Gap - don't over farm... use methods of sustainable agricultural intensification such as soil management and land improvement. Work Towards Defeating Climate Change
Describe strategies for managing climate change through the reduction of greenhouse gas emissions
Reduction in global & individual carbon footprint; Switching to low-carbon fuels; Reducing the use of fossil fuels; Using alternative forms of energy; Transport policies; Use of carbon capture & storage; Reducing deforestation, increasing reforestation & afforestation; Energy efficient buildings and infrastructure; Adaptation to climate change; National & international agreements such as Kyoto Protocol 1992, Paris Agreement 2016
Outline the importance of experimental evidence to support a hypothesis, using the ozone destruction hypothesis suggested by Rowland-Molina as an example
Sherwood Rowland & Mario Molina, 1974 Chemists at the University of California_Irvine What did they find out? Chlorofluorocarbons (CFCs) were lowering the average concentration of ozone in the stratosphere. CFCs are put in troposphere & remain a long time Over 11-20 years → they rise into stratosphere Reach stratosphere - CFC molecules break down in sunlight → releases highly reactive chlorine, fluorine and bromine atoms which accelerate the breakdown of ozone (O3) into O2 and ) → destroys ozone Each CFC molecule can last for 65-385 years in the stratosphere → breaking down hundreds of chlorine molecules Received the Nobel Prize in chemistry DuPont officials finally acknowledged (1988) that CFCs were depleting the ozone layer.
Describe and evaluate strategies for managing water security
Some methods include: reduction in water usage sustainable water extraction and improved supply education on sustainable water use poverty reduction international agreement and water-related aid Rationing
Explain why ozone depletion has been greatest over Antarctica
Strong circular winds form that blow around the whole continent, this is known as the "polar vortex" - this isolates the air over Antarctica from the rest of the world. Special clouds form called Polar Stratospheric Clouds (PSCs). Clouds don't normally form in the stratosphere and these turn out to have the effect of concentrating the pollutants that break down the ozone (chlorine & bromine), so speeding the process up. By the time spring arrives and the sun comes back after the long polar night, the ozone levels are severely depleted around the Antarctic continent causing the "ozone hole". Unfortunately, there then follows a particularly long period of high sunshine and long days, just to make the effect of the ozone hole worse with all that UV light around.
land degradation
The result of complex interrelationships between biophysical and socio-economic issues & affects many, especially in the tropics and developing countries. Involves both soil & vegetation degradation. Land degradation is usually described in terms of the loss in natural resources (soil, water, fauna and flora) or in the biophysical process by which it functions. Two most important driving forces of land degradation in many countries: limited land resources and population increase the resultant effect is: small farms, low production per person and increasing landlessness. Land shortage & productivity decrease, taken together, lead to unsustainable land management practices, the direct causes of degradation. Poor farmers are led to clear forest, cultivate steep slopes without conservation, overgraze rangelands and make unbalanced fertilizer applications (Mythili, 1993). Land degradation then leads to reduced productivity. Thus increasing land shortage still further → leading to more food insecurity. Most of the countries are experiencing rapid population growth → have to cultivate increasing areas of available land, ranging from arable land to all other types of soil. Destroys natural vegetation → replacing it with cultivated fields. Fertile land → constant farming → loss of fertility → loss in productivity = food insecurity.
agricultural disease
Transboundary plant pests and diseases - organisms that spread across national or. geographical (physical) boundaries, indicating that disease or pest events in one country may have direct effects or potential effects in another country). Can easily become epidemics = huge losses in crops and pastures The most destructive transboundary plant pests and diseases: Locusts, armyworm, fruit flies, banana diseases, cassava diseases and wheat rusts how do they spread? trade or other human-migrated movement environmental forces - weather and windborne insect or other vector-borne - pathogens Case Study: Cassava, Africa
Evaluate strategies for maintaining climate change
Transport policies to reduce CC include: Transportation demand management Fuel economy standards and emissions tests for transportation machines Increased fees for inefficient vehicle sales Shifting from petroleum fuels to biofuels or electricity Catalytic converters Carpooling and carsharing
Explain the impacts of water insecurity
Waterborne disease. Drinking or using dirty water puts people at risk of waterborne diseases and illnesses, such as diarrhea, malaria and schistosomiasis. Schistosomiasis is a parasitic worm that enters the body through the skin coming into contact with water that contains untreated sewage. Food production. Water insecurity can lead to lower levels of food production. Irrigation can increase crop yields by as much as 400%. Places that do not have enough water to irrigate crops have less food to eat. Industrial output. Industry needs water for all stages of production. Water is used as a raw material, a coolant, a method of transport, and in some cases a source of energy. Areas that experience water insecurity are unable to operate factories and make products. This leaves them relying on imports, which may be expensive. Conflicts Water is a source of conflict in some parts of the world. Seizing dams is a powerful way of controlling water and electricity supplies
Define photochemical smog as a mixture of air pollutants and particulates, including ground level ozone, that is formed when oxides of nitrogen and volatile organic compounds (VOCs) react in the presence of sunlight
What is Photochemical Smog? a mixture of air pollutants and particulates, including ground level ozone, that is formed when oxides of nitrogen and volatile organic compounds (VOCs) react in the presence of sunlight How is Photochemical Smog Created? Below is a simplified explanation of the chemistry of smog formation. Nitrogen dioxide (NO2) can be broken down by sunlight to form nitric oxide (NO) and an oxygen radical (O)
Define acid deposition as a mix of air pollutants that deposit from the atmosphere as acidic wet deposition (with a pH <5.6) or acidic dry deposition
What is air pollution? the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types of air pollutants, such as gases, particulates, and biological molecules.
climate change
What is happening to the crop yields? Some crops (e.g., maize and wheat) in many lower-latitude regions have been affected negatively Some higher-latitude regions, yields of some crops (e.g., maize, wheat, and sugar beets) have been affected positively over recent decades. Warming compounded by drying - caused large negative effects on yields in parts of the Mediterranean. Climate change - affecting food security in drylands, particularly those in Africa, and high mountain regions of Asia and South America.
What is Stratospheric Ozone?
What? It is formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (O2). Where? The "ozone layer," approximately 6 through 30 miles above the Earth's surface Benefit? Reduces the amount of harmful UV radiation reaching the Earth's surface.
unsustainable production
Why is the food we eat today unsustainable? the food system causes unacceptable environmental impacts it is depleting non-renewable resources. Why do you think that our food can be regarded as 'fossil food'? What does this mean? Its production relies on fossil fuel, non-renewable mineral resources, depletion of groundwater reserves and excessive soil loss. Energy Use We are depleting resources: energy, nutrients, water, soil and land To date, the agri-food system has converted non-renewable fossil fuel energy into food by enabling mechanisation, amplified fertiliser production, improved food processing and safe global transportation. agri-food sector (crop cultivation and animal rearing) accounts for around 30% of the world's total energy consumption To date, renewable energy has had limited penetration of the agri-food sector with fossil fuels accounting for almost 79% of the energy consumed by the food sector. From an energy perspective, the food system can be regarded as unsustainable (cannot meet the 'continued satisfaction' requirement) due to its reliance on fossil energy sources. Fertilizers are created using fossil fuels Fertilizers Why use fertilizers? → Increase yield to feed more people/make more money Most fertilizers used in industrialized farming are manufactured (not organic). Potash reserves (the source of most potassium (K) fertilisers) are of great concern & that it is time to start evaluating other sources of K for agriculture If things stay the same (how we source and use P) = agricultural yields will be severely compromised in the future. Will we run out of P? → Estimates for when world peak P will be reached range from 2027to 2033. Another issue... The 'power imbalance' - only three countries control >85% of the known global phosphorus reserves, a concentration of power far greater than that of crude oil, Increasing demand, dwindling reserves and geopolitical constraints could result in reduced production & supply of chemical P fertilisers & increased global P price. Irrigation How much of the world's freshwater is used in modern food production? 70% of freshwater withdrawals worldwide Excessive removal of groundwater for irrigation is leading to rapid depletion of aquifers in key food-producing regions, such as: North-Western India, the North China Plain, Central USA and California Do aquifers replenish quickly? No - so slowly that they are effectively a non-renewable resource. The depletion of these large freshwater stocks threatens food production and security locally and globally via international food trade. a vast majority of the world's population lives in countries sourcing nearly all their staple crop imports from partners who deplete groundwater to produce these crops'.18 Water and energy use: Since a lot of water needs to be moved/managed, energy is needed. in California, 20% of electricity production is used for moving and pumping water for agriculture,21 What happens when water becomes more difficult to access? Energy demand increases :-( = unsustainable!
Outline the difficulties of monitoring and predicting climate change
limited historical data from ice cores, tree rings, and historical accounts. Computer models often use different variables to make predictions such as albedo, solar output, volcanoes, which provide different outcomes. Time delay between the cause of climate change and its effects confound efforts to reduce GHG. Maximum warming effects of GHG pulse is estimated to be around 10 years. Most of the warming occurs quickly, however, uncertainty over use of data in drawing conclusions has resulted in differences in scientific and political opinion. Feedback mechanisms are not fully understood. Ocean ability to remove CO2 from atmosphere decreases with increasing temperature. Ice has a higher albedo than ocean surface. Quantity of water vapor which the atmosphere can hold increases with temperature, could lead to more warming if cloudcover doesn't increase. Increased cloud thickness could limit warming. However, different cloud types reflect or absorb varying quantities of infrared. Cloud properties change with climate. Model predictions vary widely based on these variables.
