Pollution, Climate and Conventions for CUET General Aptitude

AnswerB · Methyl isocyanate

1. Methyl isocyanate (MIC) leaked from the Union Carbide plant in Bhopal, killing thousands and injuring many more.

2. It is among the worst industrial disasters in history, and it led to the Environment (Protection) Act of 1986.

AnswerD · binds to haemoglobin and stops the blood carrying oxygen

1. Carbon monoxide combines with haemoglobin far more strongly than oxygen does, forming carboxyhaemoglobin.

2. The blood then carries less oxygen, causing headache, drowsiness and even death.

AnswerA · Vegetable peels

1. Biodegradable waste is broken down by bacteria and fungi into harmless substances.

2. Vegetable peels rot within weeks and can be composted; plastic, glass and aluminium last for years.

AnswerC · mercury

1. A factory released mercury compounds into Minamata Bay; they built up in fish and then in the people who ate them.

2. Mercury damages the nervous system.

AnswerA · changes carbon monoxide, unburnt hydrocarbons and nitrogen oxides into less harmful gases

1. Metals such as platinum and rhodium in the converter speed up reactions in the hot exhaust.

2. Carbon monoxide and hydrocarbons become carbon dioxide and water, and nitrogen oxides become nitrogen.

AnswerA · the burning of paddy stubble in the fields of Punjab and Haryana

1. After the rice harvest, farmers burn the leftover straw to clear fields quickly for wheat.

2. The smoke drifts over the region just as cool, still air traps pollutants near the ground.

AnswerB · Sulphur dioxide

1. Sulphur in coal burns to sulphur dioxide, which enters the atmosphere with the flue gases.

2. There it reacts with water vapour to form sulphuric acid, which falls as acid rain.

3. Carbon monoxide is a product of incomplete burning and is toxic but not a major cause of acid rain; nitrogen itself is unreactive in air.

AnswerB · nitrate

1. Nitrate from fertilisers can seep into wells.

2. In infants it reduces the blood's ability to carry oxygen, so the skin can look bluish.

AnswerC · fluoride

1. A little fluoride protects teeth, but too much causes fluorosis.

2. Dental fluorosis mottles the teeth, and skeletal fluorosis stiffens the bones and joints.

AnswerA · eutrophication

1. Nitrates and phosphates from fertilisers and sewage feed an algal bloom.

2. Bacteria decomposing the dead algae use up the dissolved oxygen, so the fish suffocate.

AnswerD · The water holds a lot of organic pollution

1. BOD is the oxygen that microbes need to break down the organic matter in a water sample.

2. More sewage or organic waste means more oxygen demanded, so a high BOD means badly polluted water.

AnswerC · fine particles 2.5 micrometres or less across, which can reach deep into the lungs

1. PM stands for particulate matter; the number is the largest particle size in micrometres.

2. PM2.5 particles are about thirty times thinner than a human hair and pass deep into the lungs and even the blood.

AnswerB · remove fine ash particles from the smoke

1. The smoke passes between charged plates or wires; the particles pick up a charge and stick to the oppositely charged plates.

2. This removes most of the fly ash, but not gases such as carbon dioxide or sulphur dioxide.

AnswerB · West Bengal and the Ganga–Brahmaputra delta

1. Arsenic occurs naturally in the delta's sediments and dissolves into the groundwater that tube wells tap.

2. Long-term drinking of it causes skin lesions and cancers.

AnswerC · Warm water holds less dissolved oxygen

1. Gases dissolve less well in warm water, so heated water carries less oxygen.

2. At the same time, warmth speeds up the fish's own need for oxygen. This is thermal pollution.

AnswerD · nitrogen oxides and hydrocarbons from vehicles react in sunlight, making ground-level ozone

1. Vehicle exhaust supplies nitrogen oxides and unburnt hydrocarbons.

2. Sunlight drives reactions between them that produce ozone and other irritants such as PAN, which sting the eyes and harm the lungs.

AnswerC · 1 April 2020

1. Bharat Stage VI norms, roughly equal to Euro VI, came into force nationwide on 1 April 2020.

2. They sharply cut the allowed particulate and nitrogen oxide emissions, especially from diesel vehicles.

AnswerD · The Environment (Protection) Act, 1986

1. The Environment (Protection) Act of 1986 is an umbrella law covering air, water and land.

2. The Water Act (1974) and the Air Act (1981) came before Bhopal and deal with one medium each.

AnswerC · Stratosphere

1. Most of the atmosphere's ozone lies in the stratosphere, roughly 15 to 35 km above the ground.

AnswerB · ultraviolet radiation

1. Ozone absorbs harmful ultraviolet (UV) rays, especially UV-B, before they reach the ground.

AnswerD · Methane

1. Greenhouse gases absorb the heat (infrared) given off by the Earth.

2. Methane does; nitrogen, oxygen and argon, which make up most of the air, do not.

AnswerA · Antarctica

1. British scientists at Halley station reported the Antarctic ozone hole in 1985.

2. Very cold polar clouds there help chlorine from CFCs destroy ozone when the sunlight returns in spring.

AnswerB · Methane

1. Bacteria that live without oxygen, in waterlogged soil, in cattle's stomachs and in buried rubbish, produce methane.

AnswerA · Carbon dioxide

1. Burning coal, oil and gas and cutting forests release huge amounts of carbon dioxide.

2. It stays in the air for centuries, so it causes the largest share of human-made warming.

AnswerC · Chlorofluorocarbons

1. Chlorofluorocarbons drift up to the stratosphere, where ultraviolet light breaks them apart and releases chlorine atoms.

2. Each chlorine atom then destroys many ozone molecules before it is removed, which is why small quantities did so much damage.

3. Carbon dioxide and methane are greenhouse gases and drive warming; sulphur dioxide causes acid rain. Neither problem is the same as ozone depletion.

AnswerD · Dobson units

1. One Dobson unit would be a layer of pure ozone 0.01 mm thick at normal pressure and temperature.

2. A healthy layer is about 300 Dobson units; the ozone hole is defined as less than 220.

AnswerA · It is a harmful pollutant that irritates the lungs and damages crops

1. Ground-level ozone forms in photochemical smog from vehicle exhaust and sunlight.

2. It is a strong oxidising gas that harms breathing and plant leaves; it does not rise to refill the stratosphere.

AnswerC · Some gases in the air trap heat given off by the Earth, keeping the surface warm

1. Sunlight warms the ground, which gives off heat as infrared radiation.

2. Greenhouse gases absorb much of it and send part back down, like the glass of a greenhouse.

AnswerD · It traps much more heat, but stays in the air for a much shorter time

1. Each methane molecule absorbs far more heat than a carbon dioxide molecule; over a century it has several tens of times the warming effect per kilogram.

2. But methane breaks down in about a decade, while carbon dioxide lingers for centuries.

AnswerD · skin cancer and cataracts

1. UV-B damages the DNA in skin cells, which can lead to skin cancer.

2. It also clouds the lens of the eye (cataract) and weakens the immune system.

AnswerC · Nitrous oxide

1. Soil bacteria turn part of the extra fertiliser nitrogen into nitrous oxide, N₂O.

2. It is a powerful, long-lived greenhouse gas and, in the stratosphere, destroys ozone.

AnswerA · −18 °C

1. Calculations of the heat the Earth receives and gives off show it would average about −18 °C with no greenhouse gases.

2. The natural greenhouse effect keeps it about 33 °C warmer, which allows liquid water and life.

AnswerB · Water vapour

1. Water vapour is present in far larger amounts than any other greenhouse gas and causes most of the natural greenhouse effect.

2. Its amount follows the temperature, so it amplifies warming caused by carbon dioxide rather than starting it.

AnswerC · Each chlorine atom released acts as a catalyst and can destroy thousands of ozone molecules

1. Ultraviolet light breaks CFC molecules apart and frees chlorine atoms.

2. A chlorine atom breaks an ozone molecule, is released again, and repeats the cycle many thousands of times before it is removed.

AnswerB · above 400 ppm

1. Measurements at Mauna Loa in Hawaii and elsewhere show carbon dioxide passed 400 ppm in the 2010s and is still rising.

2. That is roughly a 50% rise, mainly from burning fossil fuels.

AnswerA · the long-term rise in the Earth's average surface temperature

1. Global warming is the rise in average temperature over decades, driven mainly by the extra greenhouse gases added since the Industrial Revolution.

2. One hot season is weather; the long-term trend is climate.

AnswerB · Burning fossil fuels such as coal, oil and gas

1. Burning fossil fuels releases carbon dioxide that had been locked underground for millions of years.

2. Scientists' assessments (the IPCC) find human activity is the dominant cause of recent warming.

AnswerD · A growing forest

1. Growing trees take in carbon dioxide by photosynthesis and store the carbon in wood and soil.

2. Forests and the oceans are the main natural carbon sinks.

AnswerC · the total greenhouse gases released because of that person's activities

1. It adds up the emissions from travel, electricity, food and goods used, usually in tonnes of carbon dioxide equivalent.

AnswerA · A wind turbine

1. A wind turbine turns the energy of moving air into electricity without burning anything.

2. Coal, diesel and gas all release carbon dioxide when burnt.

AnswerA · land ice melts into the sea and sea water expands as it warms

1. Glaciers and the ice sheets of Greenland and Antarctica add water to the oceans as they melt.

2. Warmer water also takes up more space (thermal expansion).

AnswerC · warm water makes corals expel the colourful algae that live in them and feed them

1. Corals live in partnership with tiny algae that give them colour and most of their food.

2. Under heat stress the corals expel the algae, showing the white skeleton; if the heat lasts, the corals starve and die.

AnswerB · The water becomes more acidic, making it harder for corals and shellfish to build shells

1. Dissolved carbon dioxide forms carbonic acid, lowering the pH of sea water.

2. More acidic water dissolves calcium carbonate, the material of shells and coral skeletons. This is ocean acidification.

AnswerA · balanced the greenhouse gases it still releases with an equal amount removed from the air

1. Net zero does not mean zero emissions.

2. It means cutting emissions as far as possible and removing the rest, through forests or carbon capture, so the net addition is zero.

AnswerD · adaptation

1. Mitigation tackles the cause by cutting emissions, as with solar power.

2. Adaptation copes with the effects that are already happening, such as sea walls, drought-resistant crops and heat plans.

AnswerA · a weaker monsoon with below-normal rainfall

1. El Niño shifts the Pacific's warm water and rising air eastwards, changing wind patterns across the tropics.

2. Many El Niño years have brought weak monsoons and droughts to India, though not every one.

AnswerC · 2070

1. India set 2070 as its net-zero year, as part of a five-point pledge often called the Panchamrit.

AnswerD · one tonne of carbon dioxide (or its equivalent) cut or removed

1. A project that avoids or removes one tonne of CO₂-equivalent can earn one credit.

2. Credits can be sold to others who need to offset their emissions. The Kyoto Protocol's Clean Development Mechanism started this trade.

AnswerC · Dark open water absorbs much more sunlight than the white ice it replaces

1. White ice reflects most sunlight back to space; it has a high albedo.

2. Open ocean is dark and absorbs it, warming further and melting more ice: a positive feedback.

AnswerB · eight national missions, such as the National Solar Mission

1. The plan set up eight missions, including solar energy, enhanced energy efficiency, sustainable habitat, water, the Himalayan ecosystem, a Green India, sustainable agriculture and strategic knowledge.

AnswerD · the World Meteorological Organization and the UN Environment Programme

1. The WMO and UNEP created the IPCC in 1988 to review climate research for governments.

2. It shared the 2007 Nobel Peace Prize with Al Gore.

AnswerB · phase out substances that deplete the ozone layer

1. The Montreal Protocol set dates for phasing out CFCs, halons and other ozone-depleting substances.

2. It is signed by every UN member and is widely seen as the most successful environmental treaty.

AnswerC · hold global warming well below 2 °C above pre-industrial levels and try to limit it to 1.5 °C

1. Adopted at COP21 in Paris, the agreement asks every country to set its own emission targets, called nationally determined contributions (NDCs), and to raise them over time.

AnswerB · wetlands

1. The Ramsar Convention protects wetlands of international importance, such as lakes, marshes, mangroves and coral reefs.

2. India's Ramsar sites include Chilika Lake, Keoladeo and Loktak Lake. World Wetlands Day, 2 February, marks its signing.

AnswerD · international trade in endangered wild animals and plants

1. CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) lists species whose trade is banned or controlled.

2. It covers products such as ivory, tiger skins and rhino horn.

AnswerC · 5 June

1. World Environment Day, led by UNEP, is observed on 5 June.

2. 22 April is Earth Day, 16 September is World Ozone Day and 2 February is World Wetlands Day.

AnswerD · 16 September

1. The Montreal Protocol was signed on 16 September 1987, and the UN made the date the International Day for the Preservation of the Ozone Layer.

AnswerC · set binding greenhouse-gas cuts for developed countries

1. Under the Kyoto Protocol, industrialised countries accepted legally binding targets to cut their emissions; it came into force in 2005.

2. It also created carbon trading through the Clean Development Mechanism.

AnswerA · the movement of hazardous wastes across national borders

1. The Basel Convention stops rich countries from simply shipping toxic waste to poorer ones and requires consent before any such transfer.

AnswerA · the Earth Summit in Rio de Janeiro, 1992

1. The 1992 UN Conference on Environment and Development in Rio, the Earth Summit, produced the UNFCCC, the CBD and Agenda 21.

2. The Kyoto Protocol and the Paris Agreement were later agreements under the UNFCCC.

AnswerB · hydrofluorocarbons (HFCs), which do not harm ozone but are powerful greenhouse gases

1. HFCs replaced CFCs in refrigerators and air conditioners because they spare the ozone layer.

2. But they trap heat strongly, so the Kigali Amendment, agreed in Rwanda, set a timetable to cut them.

AnswerA · access to genetic resources and fair sharing of the benefits from their use

1. If a company develops a medicine from a plant used by a community, the Nagoya Protocol says the community should share the benefits.

2. India's Biological Diversity Act puts the same principle into Indian law.

AnswerD · sustainable development

1. It defined sustainable development as development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

AnswerC · France

1. India and France launched the International Solar Alliance at COP21 in Paris in 2015.

2. Its headquarters are in Gurugram, Haryana.

AnswerD · persistent organic pollutants such as DDT and dioxins

1. Persistent organic pollutants last for years, travel far and build up in food chains.

2. The 2001 Stockholm Convention aims to eliminate or restrict them.

AnswerB · the safe handling and movement of genetically modified organisms

1. The Cartagena Protocol on Biosafety (2000) sets rules for moving living modified organisms, such as GM seeds, between countries.

AnswerB · The Vienna Convention of 1985

1. The Vienna Convention for the Protection of the Ozone Layer (1985) set up the framework for cooperation.

2. The Montreal Protocol of 1987 then added the binding phase-out schedules.