Unit 9: People, Development and Environment mind map

Greenhouse gases, global warming potential, feedbacks, ozone, and the Kyoto and Paris agreements.

Greenhouse effect and warming

Greenhouse effect and feedbacks

Greenhouse gases absorb infrared heat from the Earth's surface and send part of it back down.

• Sunlight heats the surface; the surface sends out infrared.
• Greenhouse gases absorb that infrared and re-radiate it.
• Negative feedback reduces warming: oceans absorb CO2, clouds reflect sunlight.
• Positive feedback adds to warming: more water vapour, less snow and ice.

A cloudier troposphere reflects more solar flux, which cools the Earth. That works against warming, so it is a negative feedback. Methane comes from landfills, wetlands and paddy fields, where organic matter rots without oxygen. Mountain rivers and construction debris are not sources.

Global warming potential

GWP compares how much heat a gas traps with CO2 over 100 years.

• CO2 = 1. Methane about 28. Nitrous oxide about 265.
• CFC-11 about 4,750. SF6 about 23,500.
• Order: CO2, CH4, N2O, CFC-11, SF6.
• CFCs are in the thousands.

Learn the ladder: CO2 then CH4 then N2O then CFCs then SF6. CFCs are potent greenhouse gases and also destroy ozone, but destroying ozone does not explain their heat trapping.

Social impacts

Climate change is linked to food security and social tension.

• More frequent and intense extreme weather events.
• Floods, droughts and storms cut food production.
• This can raise social tension in India.

Both the assertion (more social tension in India) and the reason (extreme weather hurts food security) were true, and the reason explained it.

Climate agreements

Kyoto Protocol

Kyoto set binding targets for developed (Annex I) countries.

• First commitment period 2008 to 2012.
• Average cut: 5.2 percent below the 1990 level.
• Flexibility mechanisms: Joint Implementation, Emissions Trading, Clean Development Mechanism.
• Doha Amendment (2012): second commitment period 2013 to 2020.

The CDM lets an industrialised country fund a project in a developing country and earn Certified Emission Reduction credits. INDCs belong to the Paris process, not Kyoto. The United States, Russia and Canada were asked to cut; India and China were not.

Paris Agreement and Indian missions

Paris aims to keep warming well below 2 degrees Celsius and strive for 1.5.

• Adopted in 2015.
• Countries make pledges, called INDCs.
• India's NAPCC (2008) has eight core national missions.
• Missions: Solar, Energy Efficiency, Sustainable Habitat, Water, Himalayan Ecosystem, Green India, Sustainable Agriculture, Strategic Knowledge.

The Green Hydrogen Mission is not among the original eight. COP-11 was Montreal, COP-13 Bali, COP-15 Copenhagen, COP-19 Warsaw. The Kigali Agreement phases down HFCs.

Ozone

Montreal Protocol

The Montreal Protocol (1987) phases out ozone-depleting substances.

• Substances: CFCs, halons, carbon tetrachloride.
• Developing countries (Article 5) get extra time.
• It regulates nearly 100 man-made chemicals.
• Co-benefit: lower CO2-equivalent emissions.

CFC concentrations in the atmosphere have fallen in recent years, but CFCs are stable and last for decades. Kofi Annan called it the most successful international environmental agreement. Halocarbons both warm the Earth and destroy ozone.

Smog, acid rain, carbon monoxide, the Air Quality Index, noise levels, persistent pollutants and toxic effects.

Air pollution

Smog and acid rain

Photochemical smog needs sunlight, nitrogen dioxide and volatile organic compounds.

• Carbon monoxide and carbon dioxide are not essential.
• VOCs come from vehicles, power plants, plants, termites and bogs.
• Pure rain is slightly acidic, pH about 5.6.
• Acid rain is below pH 5.6; SO2 and NO2 cause it.

Acid rain falls when SO2 and NO2 turn into sulphuric and nitric acid. The best control is to burn less fossil fuel. Lime in lakes only treats damage.

Carbon monoxide and the AQI

Carbon monoxide binds haemoglobin about 200 times more strongly than oxygen.

• It forms carboxyhaemoglobin and blocks oxygen transport.
• India's AQI covers eight pollutants.
• PM10, PM2.5, NO2, SO2, CO, ozone, ammonia, lead.
• CO2, CFCs and methane are not in the AQI.

Carbon monoxide poisoning causes headache and dizziness, and death at high doses.

Noise pollution

Noise indices, limits and effects

Noise indices describe how loud a place is over time.

• L90: level exceeded 90 percent of the time, the background level.
• L10 is the peak level; L50 is the median.
• Silence zone such as schools: 50 dB(A) by day, 40 dB(A) at night.
• Heavy city traffic: 70 to 95 dBA.

A 10 dB rise is a ten-fold rise in intensity. A 20 dB rise is 100-fold, not 20-fold. Noise causes high blood pressure, sleeplessness and speech interference. Bronchitis is not a noise effect. Typical levels in increasing order: office, speech, street corner, highway, aircraft take-off.

Persistent pollutants and toxicity

POPs and accumulation

Persistent organic pollutants stay in the environment and accumulate in food webs.

• Examples: dioxins, PCBs, organochlorine pesticides, furans.
• Formaldehyde and VOCs are not POPs.
• Bioconcentration is uptake from the surrounding water.
• Biomagnification is the rise up the food chain.

Eating fish moves a substance up the food chain, which is biomagnification and not bioconcentration. The Stockholm Convention deals with POPs. The most harmful pollutants are non-biodegradable chemicals.

Toxicology terms

Match the toxicant to the organ and the substance to the effect.

• Nephrotoxic: kidney. Haematotoxic: blood. Pulmonotoxic: lungs. Hepatotoxic: liver.
• Allergen: immune reaction. Mutagen: damages DNA.
• Carcinogen: cancer. Teratogen: embryo harm.
• NOAEL: highest dose with no observed adverse effect.

Acute effects follow short exposure; chronic effects follow long exposure. Pollutants enter by inhalation, ingestion or the dermal route. Nickel, cadmium and benzene are known carcinogens. EPA Group A is human carcinogen, B probable, C possible, D not classified.

Water quality parameters, trophic status, eutrophication, oxygen demand and treatment steps.

Water quality

Physical and chemical parameters

Physical parameters can be sensed or measured without a chemical reaction.

• Physical: temperature, turbidity, total suspended solids, conductivity.
• Chemical: pH, hardness.
• Warmer water holds less dissolved oxygen.
• Eutrophic water has high COD.

COD is chemical oxygen demand, the oxygen needed to chemically oxidise matter in water. Dead algae raise it. Too much fluoride causes fluorosis, while optimum fluoride helps prevent dental cavities.

Trophic status and eutrophication

Nutrient level names the water body.

• Oligotrophic: low nutrients, clear.
• Mesotrophic: medium.
• Eutrophic: high nutrients.
• Eutrophication: algae bloom, then rot, then oxygen loss.

Phototropic and chemotrophic describe how organisms get energy, not nutrient level. Over-fertile lakes produce poor-quality fish because oxygen runs out.

Oxygen-demanding waste

Oxygen-demanding wastes use up dissolved oxygen as microbes break them down.

• Sources: agricultural run-off, food processing, sewage effluent.
• Ore mining gives metal pollution instead.
• Landfill sites give leachate.
• Bacteria use up oxygen; they do not release it.

The most important river pollutants are bacteria, nutrients and metals. Hydrogen sulphide shows pollution by darkening a sample with a metal salt: darker means more pollution.

Water treatment

Treatment sequence

Drinking water goes through settling, flocculation, filtration, then disinfection.

• Gravity settling of large particles first.
• Flocculation joins fine particles.
• Filtration, then disinfection.
• Aeration removes excess and objectionable gases.

Chlorine disinfects, treats odour and oxidises iron and manganese. It does not remove hardness or control turbidity. In wastewater, primary removes large pieces, secondary follows flocculation, tertiary uses activated charcoal.

Renewable energy, India's targets, nuclear reactors, and how waste is treated.

Energy sources

Renewables and India's targets

Know the targets and the alliance.

• International Solar Alliance: launched by India and France at Paris, 2015.
• Rooftop solar target by 2022: 40 GW of 100 GW solar.
• Wind target by 2022: 60 GW.
• 175 GW total: 100 solar, 60 wind, 10 biomass, 5 small hydro.

Silicon is the main solar cell material. Biomass power is the cheapest renewable to develop, but needs large land for energy crops. Hydropower is inexhaustible because the water cycle refills rivers. Natural gas gives less CO2 per unit of energy than other fossil fuels.

Biomass, producer gas, energy crops

Biomass energy uses plant material and waste.

• Energy crops are fast growing and have high calorific value.
• They can become biogas and ethanol.
• Producer gas comes from gasification at high temperature.
• Producer gas: mostly nitrogen, then CO, then CO2, then a little methane.

Energy crops do not need a particular season or necessarily fertile land. Producer gas can fuel internal combustion engines.

Nuclear energy

Reactors and fuel

Fission needs fissile fuel and a moderator.

• Natural uranium is 99.3 percent U-238 and about 0.7 percent U-235.
• A moderator slows neutrons so the chain reaction continues.
• Breeders make more fissile material than they use.

Heavy water, graphite and ordinary water are moderators. Control rods limit the chain reaction. India's prototype fast breeder reactor is at Kalpakkam. Plant steps: neutron bombards nucleus, absorption, moderation, controlled chain reaction, heat.

Enrichment raises U-235: ore, natural, reactor grade (3 to 5 percent), weapon grade (90 percent or more).

Waste

Waste treatment methods

Match the waste to its treatment.

• Dry waste: recycle. Wet waste: compost. Toxic waste: engineered landfill.
• Composting is aerobic; pit composting takes 3 to 6 months.
• Pyrolysis: heating without oxygen, gives bio-oil, less pollution than incineration.
• Leachate: liquid that drains from a landfill.

Composting is a biological method. Compost has low nitrogen, phosphorus and potassium, so it cannot compete with commercial fertiliser. Pyrolysis is thermochemical, not biochemical.

Millennium and sustainable development goals, the dates of environmental agreements, and Indian environmental laws.

SDGs and MDGs

MDGs and SDGs

The MDGs came first; the SDGs succeeded them.

• MDGs: 8 goals, 21 targets, to be achieved by 2015.
• SDGs: 17 goals, 2015 to 2030.
• Universal primary education was an MDG, replaced by Quality Education.
• Rio +20 (2012) launched the process to develop the SDGs.

A wrong option says the MDGs had 40 targets, or that the MDGs succeeded the SDGs. 'Employment to everyone' and 'Green agriculture' are not SDG titles. SDG 8 is Decent Work and Economic Growth.

SDG numbers

Learn the goal numbers that are asked.

• 1 No Poverty. 2 Zero Hunger. 4 Quality Education. 5 Gender Equality.
• 6 Clean Water and Sanitation. 7 Affordable and Clean Energy.
• 10 Reduced Inequalities. 11 Sustainable Cities. 13 Climate Action.
• 15 Life on Land. 16 Peace and Justice. 17 Partnerships.

Targets also appear: SDG 7.3 doubles the rate of energy-efficiency improvement by 2030; SDG 8 aims at 7 percent growth in least developed countries.

Agreements and laws

Dates of agreements

Put the agreements in time order.

• Stockholm Conference 1972.
• Montreal Protocol 1987.
• Rio Earth Summit 1992.
• Kyoto Protocol 1997; Paris Agreement 2015.

Rio produced the UNFCCC and the CBD, and Agenda 21. The CBD was opened for signature in 1992, came into force in 1993, and India became a party in 1994. The United States has not ratified it. Stockholm Convention: POPs. Basel Convention: transboundary movement of hazardous waste.

Indian environmental laws

Learn the years of the main Acts.

• Wildlife Protection Act: 1972. Water Act: 1974.
• Forest (Conservation) Act: 1980. Air Act: 1981.
• Environment (Protection) Act: 1986, an umbrella law.
• National Green Tribunal Act: 2010.

Order: Wildlife, Water, Forest, Air, Environment Protection, NGT. The 1986 Act covers protection and improvement of environmental quality and prevention and control of pollution.

Disasters

Types and management

Disasters are grouped by cause, and managed in a cycle.

• Geological: earthquake. Hydrological: snow avalanche, drought.
• Anthropogenic: nuclear disaster, some floods and forest fires.
• Cycle: mitigation, preparedness, response, recovery.
• NDMA: under the Ministry of Home Affairs, set up by the 2005 Act.

The National Disaster Management Plan came in 2016. Richter measures magnitude on a log scale; each step is 10 times the amplitude and about 32 times the energy. Mercalli measures effects on people. Fukushima, Chernobyl and Three Mile Island were nuclear accidents.