Environmental glossary for students and teachers, A to Z

A

abiotic — The non-living part of a place: rock, soil, water, air, sunlight, temperature. The opposite of biotic.
absorption — One substance taking another right inside itself, the way a dry sponge takes up water.
absorption pit (soakaway) — A pit dug in ground that drains freely, packed with broken stone and covered over, so water soaks away instead of standing.
abundance — Having more than enough. The opposite of scarcity, and an argument that a system with slack in it is a steadier system.
acclimation — An organism adjusting to a lasting change around it — a sapling moved from a shaded nursery bed into open sun.
acid — A substance with a pH below 7, which reacts with a base. Lemon juice, curd and vinegar are mild ones; battery acid is not.
acid mine drainage — Acidic water running out of a coal or metal mine, usually carrying dissolved metals with it. It keeps running long after the mine has closed.
acid rain — Rain, snow or fog turned acidic by pollution — mainly the sulphur and nitrogen oxides given off by burning coal and oil.
acre — A unit of land area: 43,560 square feet, a little under half a hectare. India also measures land in bighas, which are not the same size in any two states.
adaptation — A feature of an organism that natural selection has favoured, because it helps the organism survive where it lives.
adaptive radiation — One ancestor, many descendants that look nothing like each other, because each has adapted to a different way of living.
adsorption — One substance sticking to the surface of another without going inside it. This is how activated carbon in a water filter holds on to what it removes — the opposite side of the coin from absorption.
aerobic — With oxygen. Aerobic decay is rotting that needs air: a compost heap turned often.
aerosols — Tiny solid or liquid particles floating in the air — dust, sea salt, smoke, soot.
afforestation — Planting trees on land that has carried no forest in recent memory. Replanting what was cleared is reforestation.
agroforestry — Farming with trees in the field rather than only along its edge, so one piece of land yields crop, fodder, fruit and timber together.
air pollution — Anything in the air that does not belong there in that quantity — particles, gases, living matter — from vehicles, industry, burnt waste, cooking fires or stubble.
algal bloom — Algae multiplying out of control, usually because the water is loaded with nutrients from sewage or fertiliser. The bloom strips the water of oxygen, and the fish die.
alloy — A material made by blending others under controlled conditions. Brass and bronze are metal alloys; plastics are blended the same way.
alternative fuels — Fuels used in place of petrol and diesel — ethanol, compressed natural gas — that burn cleaner.
anaerobic digestion — Organic matter broken down by microbes without air, giving methane that can be burnt for energy and a residue that goes back on the soil. A gobar gas plant is exactly this.
anaerobic respiration — Getting energy from food without oxygen. Microbes do it in waterlogged soil, in a sealed digester and in the gut of a cow.
ancient forest — A forest never cleared and replanted: old trees, standing deadwood, deep litter, and species a young plantation does not have. Also called old growth.
anoxic — With almost no oxygen left in it. The Yamuna through Delhi runs close to this.
anthropogenic — Made by people, not by nature.
application efficiency — How much irrigation water actually reaches the crop, after what runs off, sinks past the roots or evaporates on the way.
appropriate living — Choosing the thing that is the right size for the job — the technology, the house, the amount of stuff — rather than the newest or the largest.
appropriated carrying capacity — Another name for the Ecological Footprint, used when the point is that a country's imports draw on land and water somewhere else.
aquaculture — Farming fish, prawns or other water life in ponds, tanks or cages.
aquifer — A layer of rock, sand or gravel underground that holds water and gives it up to wells and springs. A confined aquifer is sealed under rock water cannot cross and refills very slowly; an unconfined one takes in water from above; in an artesian aquifer the pressure pushes water up the bore on its own.
arable land — Land you can plough and crop.
atmosphere — The layer of gases held around a planet. Earth's runs from the troposphere at ground level, where all the weather happens, up through the stratosphere, mesosphere, thermosphere and exosphere.
autotroph — A living thing that makes its own food from simple raw materials, using sunlight or chemical energy. Plants, algae and some bacteria.
available water capacity — The share of the water in a soil that roots can actually pull out. The rest is held too tightly to be of any use.
avoidance — Not making the waste in the first place. The top step of the waste hierarchy, and the only one that costs nothing to handle.

B

backflow — Water running the wrong way down a pipe, which can pull dirty water back into a clean supply.
baffle — A barrier set across a drain or channel to slow the water and catch the silt and rubbish it is carrying.
bagasse — The fibre left after sugarcane is crushed. Mills burn it for steam and power, and it is also pressed into plates and packaging.
base of the pyramid — The poorest and largest group in an economy, named this way by businesses that see it as a market. Shortened to BoP.
baseload power — The steady round-the-clock demand on the grid, and the supply that meets it. Coal is slow to change its output but holds steady; gas can be brought up fast for the evening peak; sun and wind arrive when they arrive.
batters — The slope cut into the side of an earthwork — a bund, a channel, the shoulder of a road.
best practice — The way of doing something that has been shown to work best so far. Not a law, and not permanent.
bioaccumulation — A substance building up inside a living body faster than the body can get rid of it — a pesticide or a heavy metal collecting in a fish, and then in whoever eats the fish.
biocapacity — How much a given area can grow and absorb in a year. It depends on the land itself and on how it is farmed or forested.
biodegradable — Able to be broken down by living things, mostly bacteria and fungi. A thing can be biodegradable and still take years.
biodiversity — The variety of life — between ecosystems, between species, and within a single species.
bioelement — A chemical element a living thing needs: carbon, nitrogen, phosphorus, iron and the rest.
bioenergy — Energy from living or recently living material. Narrowly it means biofuel; broadly it takes in the whole business of growing, collecting and burning biomass.
biofuel — Fuel made from plant or animal material. Solid, like charcoal; liquid, like ethanol from molasses; or gas, like methane from dung.
biogas — The methane-rich gas given off when organic matter rots without air — in a landfill, in a sewage works, or in a farm digester fed on dung.
biogeochemical cycle — The path a chemical element takes as it moves round and round between living things, air, water and rock.
biogeochemical cycles — These cycles taken together — carbon, nitrogen, phosphorus, sulphur and water, each moving between organisms, the air, the sea and the soil.
biological oxygen demand (BOD) — A test of how much oxygen the microbes in a water sample use up. A high BOD means heavy organic pollution — sewage, distillery waste — and little oxygen left for anything alive.
biological pest control — Controlling a pest with its own enemies — a predator, a parasite, a disease — instead of a spray.
biological productivity — How much living matter an area grows in a given time. A forest, a pasture and a desert sit at very different levels.
biologically productive land — Land fertile enough to carry forest, crops or animals. Add up a country's share of it and you have its biological capacity.
biomass — Living or recently living material, measured as weight: trees, crops, crop residue, dung, and the organic part of waste. Also that same material seen as a fuel.
biome — A large region defined by its climate and by the kind of life that grows there — tropical forest, thorn scrub, mangrove, alpine meadow.
biophysical — The living and non-living parts of the world, counted in physical units — cubic metres, kilograms, joules — rather than in rupees.
bioregion — An area with its own natural boundaries and its own community of life: a river basin, a mountain range, the Western Ghats.
bioremediation — Using living things, usually microbes or plants, to clean up contaminated soil or water.
biosolids — Treated sewage sludge, stabilised far enough to be put back on land as a nutrient.
biosphere — The thin skin of the planet where life is found — air, land, surface rock and water — and which life itself has altered.
biotic — The living part of a place: plants, animals, fungi, microbes. The opposite of abiotic.
biotic potential — The fastest a population could breed if nothing at all held it back. Something always does.
birth rate — Live births per 1,000 people in a year.
blackwater — Household wastewater carrying toilet waste.
bluewater — Rain that runs off roofs and hard ground into drains, streams and rivers, or sinks down to the groundwater. It is the water you can catch, store, pipe and sell.
boreal — The cold conifer forests of the far north, where the year averages below freezing. Russia, Canada, Scandinavia; India has none.
bottom up approach — Building something out of small parts that grow into a larger system, rather than designing the whole from above. It starts quickly and can end as a tangle. The opposite of a top down approach.
broadacre farming — Short for broadacre farming: cropping a large area, usually mixed and usually rainfed, rather than working an intensive plot.
Brundtland Commission Report — The UN report Our Common Future, which put the phrase sustainable development into circulation: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”

C

calorie — A unit of energy: the heat needed to warm one gram of water by one degree Celsius, about 4.184 joules. Food labels use the big Calorie, which is a thousand of them.
calorific value — How much heat a fuel gives out when it burns completely. It is why dry firewood is worth more than wet.
cancer — A disease in which cells grow past their normal limits, invade the tissue around them, and can spread to other parts of the body.
capillary action (wicking) — Water climbing through a narrow space on its own, pulled by surface tension — up a wick, up a brick wall, up through soil to the surface.
car pooling — Sharing a ride so that fewer cars make the same journey.
carbon budget — A tally of carbon in and carbon out for an activity, a company or a country.
carbon credit — A tradable permit to emit one tonne of carbon dioxide equivalent. Emitters that stay under their cap sell what they have not used to emitters that go over, so the cheapest cuts get made first. Whether the total actually falls is the argument.
carbon cycle — The path carbon takes as it moves between living things, rock, water and air.
carbon dioxide — CO2: the gas given off whenever carbon burns, and the greenhouse gas at the centre of climate change.
carbon equivalent (C-e) — Written C-e. A greenhouse gas figure expressed as the weight of carbon alone rather than of carbon dioxide: multiply the CO2-e by 12/44.
carbon footprint — The greenhouse gas released across the whole life of a product or service, from raw material to disposal, counted as carbon dioxide equivalent.
carbon labelling — Putting a product's greenhouse gas figure on the product itself, the way a food label carries fat and sugar.
carbon neutral — Carbon in equals carbon out, so nothing is added to the air on balance. Burning wood is neutral if as much is grown back as is burnt, and is not if it isn't.
carbon pool — A store of carbon: a forest, a soil, the ocean, a coal seam.
carbon sink — Anything taking in more carbon than it gives off — a growing forest, a living soil, the sea.
carbon source — Anything giving off more carbon than it takes in. A drained wetland, a burning field, a coal plant.
carbon stocks — How much carbon a pool is holding at a given moment.
carbon taxes — A charge on fossil fuels, set so that burning them costs more and less of them gets burnt.
carcinogen — Anything that causes cancer or helps it along — a chemical, a radioactive substance, a kind of radiation.
carrying capacity — The largest population a place can keep going without wearing itself out.
catchment area — The land that drains into one place: a tank, a dam, a river, or the roof that feeds a rainwater pit.
cell — The smallest unit that counts as alive, and the unit every living thing is built from.
CFC — Chlorofluorocarbon: a gas once standard in fridges, air conditioners and sprays. It tears holes in the ozone layer and is a powerful greenhouse gas besides. Phased out under the Montreal Protocol.
chlorinated hydrocarbon — A hydrocarbon with chlorine atoms attached — DDT and PCBs among them. Many are long-lived, dissolve in fat and are toxic. Also called organochlorines.
chlorofluorocarbons — The full name for CFCs: hydrocarbons carrying both chlorine and fluorine, one family of the haloalkanes.
circular metabolism — A system that feeds its own outputs back in, so water, materials and nutrients are reused rather than discharged. The opposite of linear metabolism, which is take, use, throw.
Class A pan — A standard open pan of water used to measure how fast water evaporates. Fixing the size and the setting is what makes one place comparable with another.
cleaner production — Cutting the pollution, energy, water and material a process uses without cutting what it makes. The saving comes from redesign, not from slowing down.
clearcutting — Felling every tree in a block at once.
climate — What the weather in a place does over decades. Weather is today; climate is the pattern today belongs to.
climate change — A lasting shift in temperature, rainfall and wind patterns. It can happen naturally, but the change now underway is ours.
coercion — Forcing people into a policy instead of persuading them. Amartya Sen's standing example is the birth rate: China compelled, Kerala educated, and Kerala got there anyway.
cogeneration — Making electricity and useful heat from the same fuel in one go, instead of throwing the heat away. A sugar mill burning its own bagasse does it.
cohousing — Houses built as a cluster around shared space — a kitchen, a hall, a garden — so that less has to be duplicated in every home.
coir — Coconut husk fibre. Rope, matting, doormats, and a growing medium in nurseries.
commercial and industrial waste — Waste from businesses, offices, schools and institutions. Counted apart from household waste and from building rubble.
commingled materials — Recyclables collected mixed together — bottles, tins and glass in one bag. Somebody has to sort them afterwards, and the mixing is what makes some of them worthless.
commune — A group who choose to live together and share property, work and income.
compensation point — The light level at which a plant's photosynthesis exactly matches its respiration. Below it, the plant is running itself down.
compost — Organic matter rotted down with air until it is dark, crumbly and stable.
composting — Rotting organic matter down with air on purpose. It gives off heat and carbon dioxide and leaves compost behind. Worms do the same job in vermicomposting.
confined aquifer — An aquifer sealed beneath a layer water cannot cross. It refills slowly or not at all, so a borewell into one is spending a fixed stock.
conflict resolution — The work of ending a conflict by agreement rather than by force.
conspicuous consumption — Buying in order to be seen to have bought.
construction and demolition waste — Rubble: soil, brick, concrete, asphalt, timber and fittings from building and pulling down. Heavy, mostly inert, and mostly recyclable.
consumer — In ecology, anything that lives by eating something else. Energy passes through it and leaves in a lower-grade form. The opposite of a producer.
consumer democracy — Voting with your money: buying, or refusing to buy, as a way of pushing a company to change.
consumption (ecology) — A living system taking in resources and running energy through them. The energy arrives usable and leaves as heat.
consumption (economics) — The part of income that is spent rather than saved: what households buy, what the government buys on their behalf, and what businesses use up in the course of producing.
contour ploughing (contour farming) — Ploughing across a slope, along the contour, so that each furrow holds the rain back instead of letting it run downhill and take the soil with it.
controlled burning — Lighting a fire deliberately, under chosen conditions, to clear fuel before an uncontrolled one does it.
Corporate Social Responsibility — A company carrying social and environmental obligations as part of its ordinary business. In India, large companies are required by law to spend on it.
covenants — Binding agreements — an industry signing up to a packaging standard, a landowner agreeing to keep a patch for wildlife in perpetuity. Voluntary to enter, enforceable once entered.
crop coefficient (Kc) — A multiplier that converts the water use of a standard reference crop into the water use of the crop actually in the field.
crop evapotranspiration (ETc) — How much water a crop uses in a day: what it transpires plus what evaporates off the soil around it.
crop rotation (crop sequencing) — Growing different crops on the same land in sequence, so pests and diseases lose their host and the soil is not asked for the same thing twice. Wheat after a pulse; paddy, then anything but paddy.
crude oil — Oil as it comes out of the ground — a mixture of hydrocarbons, before refining.
cullet — Crushed glass ready to be melted into new glass. Glass is one of the few materials that can go round without losing quality.
cultural eutrophication — Eutrophication sped up by us. Sewage, detergent and fertiliser deliver in a decade what a lake would have taken centuries to accumulate.
cultural services — What an ecosystem gives that cannot be weighed: somewhere to walk, a sacred grove, something to paint, something to know.
culture jamming — Turning mass media against itself — rewriting a hoarding, spoofing an advertisement — as a form of protest.
culvert — A pipe or channel carrying water under a road or path.
cut and fill — Moving earth from where there is too much of it to where there is too little, to make a level site or a graded slope.
cyanobacteria (Cyanophyta, or blue-green algae) — Bacteria that photosynthesise, once called blue-green algae. They put the first oxygen into Earth's air, and they are what turns a nutrient-loaded lake green and toxic.
cyclone — An intense low-pressure storm, winds spiralling inward: anti-clockwise north of the equator, clockwise south of it. In the Bay of Bengal and the Arabian Sea these are cyclones; the same storm is a hurricane in the Atlantic and a typhoon in the western Pacific. The wind is not usually what kills. The storm surge is.

D

DDT — An insecticide, and a chlorinated hydrocarbon that stays in soil, water and body fat for decades. Banned from farming in most places, still used in some against malaria mosquitoes.
debt-for-nature swap — A debt-for-nature swap: part of a poorer country's foreign debt is written off, and in exchange the country spends the equivalent on conservation at home.
decomposers — The organisms, mostly bacteria and fungi, that break dead matter back down into minerals and heat. Without them nothing would rot, and nothing new would grow.
deforestation — Clearing forest for farmland, building, mining or a road, and not putting it back.
dematerialisation — Getting the same service out of less material.
desert — Land receiving less than 250 mm of rain a year, or losing more water than it receives. The Thar is India's.
desertification — Dry land losing what productivity it had — partly through drought, mostly through overgrazing, over-cropping, tree-felling and salt.
detritivore (detritus feeder) — An animal that eats dead and rotting matter — an earthworm, a termite, a dung beetle — and speeds up decay by doing so.
detritus — Dead organic matter in pieces you can see, as against dissolved in the water.
developing countries — Countries with low average incomes, widespread poverty and little accumulated capital, grouped together by measures like the Human Development Index. The term carries an assumption worth noticing: that there is one path, and that the rich industrial economies are the end of it.
dietary energy supply — The food available for people to eat, counted as kilocalories per person per day.
dioxin — A family of long-lived, cancer-causing compounds formed mainly when material containing chlorine is burnt at too low a temperature. Burning plastic in the open makes them.
distributed water — Water delivered to a user and paid for — a mains connection, a canal running to a farm, a tanker.
diversion rate — The share of recyclable material actually kept out of the landfill.
divertible resource — The part of a region's runoff and recharge that can be taken for human use at all.
do no harm — The rule doctors swear to, borrowed by relief and development work: an intervention can leave a place worse than it found it, and nobody is exempt from checking whether theirs has.
downcycling — Recycling that loses quality each round. A clear bottle comes back as fibre, then as filler, then as nothing.
downstream — Everything that happens after the step you are looking at — the product leaving the factory, the packaging reaching the bin. The opposite of upstream.
drainage — The part of rain or irrigation that runs off the surface or sinks below the reach of roots.
drawdown — The drop in water level in a well or borewell as water is pumped out. If it does not come back up, more is being taken than is arriving.
dredging — Digging material out of a river, harbour or lake bed and putting it somewhere else.
drift net — A wall of net left hanging in the water to catch whatever swims into it. What it catches besides the fish it was set for is the objection.
drinking water — Potable water: water fit to drink.
drip irrigation — Water delivered drop by drop at the root through a pipe, so almost none is lost to evaporation or to the soil below the roots.
driver — In ecology, anything that changes an ecosystem. A direct driver acts on the system itself and can be measured; an indirect one works through the direct ones.
drop-off centre — A drop-off centre: a fixed place where people can leave sorted material for recycling.
drought — A shortfall of water long enough that supply no longer meets need — usually rain that failed, sometimes demand that grew.
dryland salinity — Salt building up in soil and groundwater on unirrigated land, usually after the deep-rooted trees that held the water table down have been cleared.

E

e-cycling — Recycling electronic waste.
e-waste — Discarded electronics: phones, televisions, computers, chargers, batteries. Valuable metals inside, poisons alongside them. Much of India's is taken apart by hand — Seelampur in Delhi is the largest of these markets.
eco- — A prefix stuck on almost anything to signal concern for the environment — ecohousing, ecolabel, ecotourism. It carries no guarantee.
ecolabel — A mark on a product saying it has met a stated environmental or social standard. The standard is the thing to check.
ecological deficit — The gap when a place's Ecological Footprint is larger than what its own land and water can supply. The difference is made up from somewhere else.
Ecological Footprint — The area of productive land and water it takes to supply what a person, a city or a country consumes, and to absorb the waste. It puts consumption into units of area.
ecological niche — The particular way a species makes its living — what it eats, where it shelters, when it is active — not simply where it is found.
ecological succession — The orderly way one community of life replaces another on a site over time: bare ground, then weeds, then scrub, then forest.
ecological sustainability — An ecosystem keeping its processes and its variety of life going indefinitely, without being run down.
ecological thinking — Thinking about a thing in terms of what it is connected to and what happens next, rather than the thing on its own.
ecologically sustainable development — Development that uses and improves resources in a way the natural processes underneath can carry indefinitely.
ecology — The study of living things in relation to each other and to their surroundings: what lives where, in what numbers, and why.
economic globalization — Trade, money and production organised across borders rather than within them, with governments holding less control over their own economies.
ecoregion — An area defined by natural boundaries and the community of life inside them. The same idea as a bioregion, one size down from a realm.
ecosystem — Plants, animals and microbes together with the air, water and soil they live in, working as a single unit.
ecosystem boundary — The line drawn around an ecosystem, usually where the organisms and the physical setting visibly change.
ecosystem services — The work nature does that nobody is billed for: pollination, clean air, soil, flood control, fresh water, shade. Grouped as supporting, provisioning, regulating and cultural.
effective rainfall — The rain that actually gets into the soil and reaches a crop — what is left after runoff, evaporation, and what never makes it past the leaves.
effluent — Liquid or gas discharged as waste, from a factory, a sewage works or a dyeing unit.
embodied energy — All the energy that went into making a thing and getting it to you — mining, processing, transport — before you have used it at all.
emergent property — A property the whole has and no part has. A flock turns; no bird does.
emergy — Energy memory: all the energy used, directly and indirectly, to make something, converted into units of one kind of energy so that it can be added up.
emission standard — The legal ceiling on what may be released.
emissions — What is released into the air — gases and particles, from a chimney, an exhaust, a burning field or a cow.
emissions intensity — Emissions per unit of output or per rupee of value. A measure of how dirty the production is, not of how much of it there is.
emissions trading — Buying and selling the right to emit, inside a cap. See carbon credit.
endangered species — A species at real risk of dying out: too few left, or losing its habitat, or being killed faster than it breeds.
energetics — The study of how energy moves through an ecosystem — where it enters, where it is stored, how fast it flows, where it is lost.
energy — The capacity to do work, measured in joules. The word is qualified in many ways: primary energy comes straight from nature and secondary energy is what we convert it into; embodied energy is what went into making a thing; potential and kinetic are energy stored and energy moving; solar, wind, hydro, tidal, geothermal and nuclear name the source.
energy accounting — Costing something by the energy it took rather than by the price it fetched.
energy audit — A systematic look at where a building or a business uses energy, and where it wastes it.
energy efficiency — Getting the same service from less energy: the same light, the same cold room, the same tonne moved.
Energy Footprint — The area of land and sea it would take to supply a population's energy and absorb the carbon dioxide from burning it.
energy management — Running a building or a business so that energy use, energy bills and emissions all come down, and stay down.
energy recovery — Getting heat or electricity out of waste that would otherwise be buried.
enhanced greenhouse effect — The natural greenhouse effect made stronger by the gases we have added. This is the part that is warming the planet.
environment — Everything around an organism that it has to deal with: conditions, resources, other living things.
environmental flows — Water deliberately left in a river instead of taken out of it, to keep the river itself alive.
environmental indicator — A measurement that stands in for the health of something larger — dissolved oxygen for a river, PM2.5 for city air.
environmental movement (environmentalism) — The broad movement — scientific, social and political — arguing that resources be used in a way that lasts and that nature be looked after. It treats people as part of the ecosystem rather than visitors to it.
environmental science — The study of how the physical, chemical and biological parts of the environment act on one another.
epidemiology — The study of what makes whole populations sick or well, and the ground on which public health decides what to do.
erosion — Soil, sand and rock carried off by water, wind or ice, or sliding downhill. One bare field in the first heavy rain can lose the layer that took centuries to build.
estuary — Where a river meets the sea and fresh water mixes with salt.
ethical consumerism — Buying on the basis of how a thing was made — who was paid, who was harmed, what it cost the land — and not only what it costs you.
ethical living — Ordering your life, and your spending, around the harm it does and the good it does.
eutrophication — Water loading up with nutrients, mainly nitrogen and phosphorus, until algae and weed take off. What follows is a bloom, then no oxygen, then dead fish.
euxinic — Water with no oxygen at all, and hydrogen sulphide instead. Worse than anoxic, and it smells like it.
evaporation — Water turning to vapour and leaving.
evapotranspiration (ET) — The water a field loses altogether: what evaporates off the soil plus what the plants transpire.
extended producer responsibility (EPR) — The rule that whoever makes a product has to take it back at the end of its life and deal with it. It puts the cost of disposal on the person who chose the design, which is an argument for designing things to be repaired, reused or recycled. India applies it to e-waste.
external water footprint — The water used to grow or make the things a country imports — spent somewhere else, on somebody else's rivers.
externality — A cost somebody else pays. The factory saves on the effluent plant; the village downstream drinks it.
extinction — A species gone: the last one dead, and no more coming.
extinction event — A short stretch of geological time in which a large share of the world's species disappear at once.

F

family planning — Deciding when and whether to have children, and having the means to act on the decision.
feedback — When the result of an action loops back and changes the action. Warming melts ice, bare ground absorbs more heat than ice did, warming increases: that is a feedback.
feedlot (feedyard) — A pen where cattle are fattened on brought-in feed before slaughter, at density and out of the field.
fertigate — To feed a crop fertiliser dissolved in its irrigation water.
fertility rate — Live births per 1,000 women of childbearing age in a year.
fertilizers (also spelled fertilisers) — Compounds fed to plants to make them grow, through the soil or sprayed on the leaves. Urea and DAP are the common ones here.
flyway — The route migrating birds follow, year after year. The Central Asian Flyway crosses India.
food co-op — A food co-op: a shop owned by the people who buy from it, or by the farmers who supply it, rather than by an outside owner.
food desert — A neighbourhood with nowhere to buy fresh food, usually poor and usually badly served by transport, so that the only food within reach is packaged.
food miles — How far food travelled to reach the plate, and what that journey cost in fuel and emissions.
food security — Having enough food, reliably, to live an active and healthy life. It turns on production, on access and on what the food does once eaten — a country can hold a surplus and still have hungry households.
Footprint — Short for Ecological Footprint, or for any measure of impact stated as the area of productive land it would take to make good.
forage — The leaf and stem that grazing animals eat.
forest — Land under a tree canopy. How much canopy, and how large a patch, is a line each forest survey draws for itself — which is why two forest figures for the same country rarely agree.
fossil fuel — Coal, oil and natural gas: the remains of living things, buried and cooked over geological time. Burning them puts back carbon that had been out of circulation for millions of years.
fossil water — Groundwater that has sat in a sealed aquifer for thousands of years with nothing recharging it. Pump it and it is gone. It is a mineral, not a crop.
freegan — Someone living as far outside the ordinary economy as they can manage — sharing, salvaging, and famously taking food out of the bins behind shops.
freon — DuPont's trade name for its CFC and HCFC refrigerants, once standard in every fridge and air conditioner.
freshwater — Water with little salt in it: river, lake, rain or groundwater. Fresh is not the same as safe to drink.
front — In weather, the boundary where a warm air mass meets a cold one. Fronts are where the weather happens.
froogle — A play on frugal: someone living deliberately small — making, mending, bartering, growing and catching what they can, and buying only what they must.
fugitive emissions — Gas that escapes on the way rather than at the point of burning: leaking from a well, a pipeline, a storage tank, or a coal seam being mined.
full-cost pricing — Full-cost pricing: setting a price that covers not only what the producer paid, but what the production cost everybody else — the pollution, the water, the health.

G

Gaia hypothesis — James Lovelock's idea that the living and non-living parts of Earth work together so closely that the planet behaves like one self-regulating organism.
garden organics — Prunings, grass clippings, leaves and the rest of the garden. All of it compostable; most of it burnt or binned.
gene — A stretch of DNA carrying one instruction, passed from parent to offspring.
gene pool — All the versions of every gene present in a population. A small pool is a fragile one.
genetic diversity — The variety within a species — one of the three levels of biodiversity, and the one that decides whether a crop or a herd can survive a new disease.
genetic engineering — Cutting and joining DNA in the laboratory to give an organism genes it would not have acquired on its own.
genome — The whole of an organism's genetic material.
geosphere — The solid Earth: crust, mantle and core. The lithosphere is the crust plus the upper mantle — the rigid shell the continents ride on.
geothermal energy — Heat from inside the Earth, reached as hot rock, hot water, brine or steam, and used for warmth or for electricity.
global culture — The pull towards one worldwide set of habits, tastes and expectations — the same brands, the same films, the same assumptions — carried along with trade and media.
global dimming — Less sunlight reaching the ground because pollution and haze scatter it back. It has been masking part of the warming.
global hectares — A hectare adjusted for how productive it is against the world average, so that land in different countries can be added together. One global hectare is one hectare of world-average productive land.
global warming — The rise in Earth's average temperature, caused by the greenhouse gases we have added trapping heat that would otherwise have left.
global warming potential — A multiplier that puts every greenhouse gas on the same scale as carbon dioxide, so a tonne of one can be compared with a tonne of another.
globalisation — The world working as one system — trade, money, technology, culture, politics — with everyone in it more dependent on everyone else.
glyphosate — The active ingredient in the weedkiller Roundup.
governance — Who decides, how they decide, and on what information. It covers government and everyone else with a hand on the decision.
green — Like eco, a word attached to almost anything to claim environmental credit — green plumbing, green purchasing. Capitalised, the Greens are a political party.
green architecture — Designing a building to run as far as possible on what falls on it and to reuse what leaves it: sun, rain, air, wastewater.
green design — Designing a thing so that it can be made, used and got rid of without doing damage.
green living — Living so that what you use, eat, wear and travel in takes less from the world than it used to.
green manure — A crop grown to be ploughed back in rather than harvested — dhaincha, sunn hemp — to put nitrogen and organic matter into the soil.
green power — Electricity from renewable sources, delivered through the same grid as everything else.
green products and services — Products that do less harm than the ones they replace: less packaging, less energy, less toxicity, more recycled content. Less harm, not none.
green purchasing — Buying with the environmental and social cost of the purchase treated as part of the price.
Green Revolution — The switch to high-yielding wheat and rice grown with heavy fertiliser and assured irrigation. It took hold first in Punjab and Haryana and it ended the fear of famine; the bill has come in since as spent groundwater and tired soil.
greenhouse effect — The atmosphere absorbing heat radiating off a planet and sending some of it back down, so the surface stays warmer than it otherwise would. Without it, Earth would be frozen.
greenhouse gas — A gas in the atmosphere that traps heat.
greenhouse gases — The gases that hold heat in the atmosphere: water vapour, carbon dioxide, methane, nitrous oxide, ozone, and a set of manufactured fluorinated gases. Some are natural, some are entirely ours, and they differ enormously in how hard they hit and how long they last.
greenlash — A sudden, large change in how an ecosystem is built and how it behaves — the system flipping rather than drifting.
greenwashing — A company spending more on looking green than on being green.
greenwater — Rain that soaks into the soil and leaves again through plants and evaporation. It cannot be piped, metered or sold, so water planning tends to leave it out — and it is the water that grows the food.
greywater — Household wastewater from baths, basins, washing machines and kitchen sinks. Everything except the toilet.
gross primary productivity — The total carbon plants take out of the air, before any of it is spent on staying alive.
groundwater — Water held underground in the gaps between grains of soil and in cracks in rock. It is what the borewell is looking for.
growth — Getting bigger. Worth keeping separate from getting better.

H

household collection — Collecting recyclables from where people live — each household putting out its own, or a building sharing common bins.
household hazardous waste (HHW) — The dangerous things in an ordinary home: paint, thinner, solvent, pesticide, batteries, tubelights. Small amounts, and they should not go into the same bin as the vegetable peel.
hydrogeology — The study of groundwater and of the rock and soil it moves through.
hydrology — The study of water: where it is, where it goes, how fast.

I

impermeable — Not letting water through. Clay, sound concrete and an unbroken sheet of plastic are impermeable — the spaces inside them do not connect, so there is no route across.
improved water source — A water source built in a way that can keep the water clean: piped supply, a borewell or tubewell, a protected dug well, a protected spring, rainwater, or packaged water. Built to keep it clean is not the same as tested and found clean.
industrial waste — Whatever an industrial process throws out — liquid, sludge, solid or hazardous.

L

leachate — The liquid that trickles out of the bottom of a heap of waste, carrying whatever it dissolved on the way down. From a landfill it is strong stuff, and it goes into the groundwater.
litter — Waste dropped where it stands, outside the collection system altogether.
localised pathway — A short cut by which dirt and microbes get into a well or borewell from right beside it: down the outside of the casing, through the soil a metre away, or straight in over the lip.

M

maintenance — Keeping a thing working. The handpump installed and never serviced is the standing example of what happens without it.
management — Deciding how something is run, and answering for it. Water management is deciding who gets water, how much, and when.
mandatory recycling — Recycling required by law rather than left to choice. In India the Solid Waste Management Rules require households to separate their waste.
membrane — A thin sheet that lets some things through and holds others back. It is how an RO filter works.
methane — CH4: a colourless, flammable gas made when organic matter rots without air. The main component of natural gas, and a greenhouse gas far more powerful than carbon dioxide for as long as it lasts.
microbial growth — Microbes multiplying — bacteria, algae, fungi. In a stored tank or a standing pipe, it is what turns the water bad.
mixed municipal solid waste — Municipal waste that arrives mixed, with nothing separated at source. Once wet waste has been through it, most of the rest can no longer be recycled.
mixed paper — Waste paper collected without sorting — newspaper, magazines, cartons and office paper together.
mixed plastic — Waste plastic collected without sorting by type. Different plastics do not melt together, so either somebody sorts it or nobody recycles it.
municipal solid waste (MSW) — The ordinary waste of a town: from homes, shops and small industry. It excludes hazardous waste, building rubble, sewage sludge, medical waste and scrap metal, all of which are handled separately.

O

organic — Made by, or coming from, living things. In farming the word carries a second and stricter sense: grown without synthetic fertiliser or pesticide.
over-abstraction — Over-abstraction: taking groundwater out faster than rain and rivers put it back, so the water table falls year on year. Punjab does this.

P

permeability — How easily water moves through a material — a question of whether the gaps inside it connect. Sand is permeable; clay is not.
policy — A settled set of principles for making decisions, written down so that they get made the same way each time.
pollutant — Anything that, added to water or air or soil, makes it unfit for use.
pollution — Changing what water, air or soil is made of, so that it becomes harmful.
population density — How many people live on a square kilometre.
porosity — How much of a rock or a sediment is empty space. Porosity says how much water it can hold; permeability says whether the water can get out again.
precipitation — Water coming out of the sky in any form: rain, snow, hail, sleet.

R

recharge — Water going back into an aquifer — rain soaking in, a river leaking downward, or a recharge pit built to make it happen faster.
reservoir — A body of water held behind a dam.
run off — Rain that flows over the ground instead of into it, and reaches a drain, a stream, a river, the sea.
rural — Of the countryside rather than the town. The opposite is urban.

S

sanitary — Clean in the sense that matters for health — above all, free of human faeces and of what lives in them.
saturated zone — The ground below the water table, where every gap is full of water. This is what a well draws from.
sedimentation — Suspended material settling out of still water and coming to rest as a layer on the bottom.
soil — The top layer of the land: broken rock and mineral grains mixed with dead organic matter and the living things working on it. Centuries to make, one monsoon to lose.
stakeholder — Anyone affected by a decision, or carrying responsibility for it. For a village water source that means the people who drink from it, the people who maintain it, and the officials who answer for it.
sustainable — Able to keep going at the same rate, on the same inputs, without breaking down or running anything out.

T

toxic substance — A chemical, or a mixture of them, that can injure health or damage the environment.
toxic waste — Waste that can harm whoever breathes it, swallows it, or gets it on their skin.
transpiration — Water pulled up by a plant's roots and released as vapour from its leaves. A large tree moves a great deal of water this way, which is part of why it is cooler underneath one.
turbidity — How cloudy water is, from the particles floating in it. Clear is not proof of safe, but cloudy is a good reason for caution.

U

ultraviolet light — Sunlight at wavelengths shorter than the eye can see. It burns skin, and it kills microbes — which is why it is used to disinfect water.
unsaturated zone — The ground between the surface and the water table, where the gaps hold both air and water. Roots can draw on it; a well cannot.

V

vapour — Water as a gas, its molecules loose and moving freely.
vermicomposting — Letting earthworms eat organic waste and turn it into castings: dark, crumbly, and richer in plant nutrients than what went in.

W

waste — Material left over and unwanted, from a process or from a household. Nothing is waste by any property of its own — it is waste because somebody stopped wanting it.
waste characterization waste — A waste-to-energy plant burns municipal waste to produce heat or electricity. Waste characterisation is the separate job of sorting a sample to find out what the waste is actually made of — and that is what decides whether burning it makes any sense.
wastewater — Used water on its way out of homes, businesses and industry, carrying whatever was dissolved or suspended in it.
water quality — What is in the water — chemically, physically and biologically — judged against what the water is for. Water that is fine for irrigation may be unfit to drink.
water scarcity — When there is not enough water for the people, the animals and the land that depend on it. Demand above supply.
waterbody — Any sizeable body of standing or flowing water: a lake, a tank, a river, a sea.
weathering — Rock, wood and metal breaking down where they stand, worked on by air, water, heat, cold and living things. It is the first step in making soil.

Z

zero waste — Designing products and systems so that nothing is left over to burn or bury: everything discarded becomes raw material for something else.

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