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129 Environment Trivia Questions and Answers

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Easy Environment Trivia Questions

  1. Which emissions chiefly cause acid rain?

    Sulfur dioxide and nitrogen oxides

    Sulfur dioxide and nitrogen oxides react with water and oxygen in the atmosphere to form sulfuric and nitric acids, which fall as acid rain. These pollutants can travel long distances before returning to Earth.

    Easy · Also offered: Carbon monoxide and volatile organic compounds, Ozone and particulate matter, Ammonia and hydrogen sulfide · Source: U.S. Environmental Protection Agency, What is Acid Rain?

  2. Which form of pollution was blamed for dying lakes in Scandinavia and dying forests in central Europe through the 1970s and 1980s?

    Acid rain

    Sulfur dioxide and nitrogen oxides from coal burning and vehicle exhaust turn into sulfuric and nitric acid in the air and come down in rain and snow. The acid stripped nutrients from forest soils and pushed lake water acidic enough to kill the fish, until emissions limits cut the pollutants back.

    Easy · Also offered: Photochemical smog, Ozone depletion, Greenhouse effect · Source: U.S. EPA

  3. Which greenhouse gas from human activity drives the most warming, by sheer volume released?

    Carbon dioxide

    Atmospheric CO2 has climbed from about 280 parts per million before the Industrial Revolution to over 420 ppm today. Charles David Keeling began recording it continuously at Mauna Loa Observatory in Hawaii in 1958, producing the rising trend line now known as the Keeling Curve.

    Easy · Also offered: Methane, Nitrous oxide, Sulfur hexafluoride · Source: NASA, The Causes of Climate Change

  4. A reef with hundreds of species scores highly on which ecological measure?

    Biodiversity

    Biodiversity is the variety of life in a place, or across the planet as a whole. The word is a contraction of biological diversity and only entered wide use in the late 1980s.

    Easy · Also offered: Biomass, Endemism, Carrying capacity · Source: National Park Service

  5. Which carbon sink is turning more acidic because of the CO2 it absorbs?

    The ocean

    The ocean has taken up roughly a quarter of the carbon dioxide people have released. Dissolving that gas makes seawater more acidic, which makes it harder for corals and shellfish to build their skeletons and shells.

    Easy · Also offered: Forests, Soils, Permafrost · Source: NOAA Ocean Service, Ocean Carbon Uptake

  6. Which carbon-cycle process lets growing plants take in carbon dioxide?

    Photosynthesis

    Photosynthesis lets growing plants absorb carbon dioxide and use sunlight to turn its carbon into sugars for growth. Oxygen is released as a byproduct.

    Easy · Also offered: Respiration, Decomposition, Ocean uptake · Source: NASA Earth Observatory, The Carbon Cycle

  7. What term measures climate-warming emissions linked to an activity or person?

    Carbon footprint

    A carbon footprint measures the greenhouse-gas emissions caused directly and indirectly by an activity or person. It includes gases beyond carbon dioxide, expressed together as carbon dioxide equivalents.

    Easy · Also offered: Water footprint, Ecological footprint, Material footprint · Source: U.S. EPA

  8. Which poisonous gas is produced by incomplete combustion?

    Carbon monoxide

    Carbon monoxide is a colorless, odorless gas produced when fuels burn incompletely.

    Easy · Also offered: Carbon dioxide, Sulfur hexafluoride, Nitrous oxide · Source: U.S. EPA, Basic Information about Carbon Monoxide (CO) Outdoor Air Pollution

  9. Which class of older industrial chemicals became closely associated with damage to the ozone layer?

    chlorofluorocarbons (CFCs)

    CFCs are ozone-depleting substances. In the stratosphere, their breakdown releases chlorine or bromine atoms that deplete ozone.

    Easy · Also offered: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6) · Source: U.S. Environmental Protection Agency: Phasing Out Ozone-Depleting Substances

  10. What economic model emphasizes reuse, repair and recycling to reduce waste?

    Circular economy

    A circular economy keeps products and materials in use and aims to reduce waste and resource extraction.

    Easy · Also offered: Subsistence economy, Command economy, Linear economy · Source: European Parliament, Circular economy: definition, importance and benefits

  11. Building flood defences and switching to heat-tolerant crops are examples of which response to climate change?

    Adaptation

    Adaptation means adjusting to effects that are already happening or expected: flood defences, different crop varieties, heatwave plans. Mitigation is the other half of the pair: cutting the emissions that cause the warming in the first place.

    Easy · Also offered: Mitigation, Decarbonisation, Offsetting · Source: IPCC, SROCC Glossary

  12. What soil amendment can be made from recycled food scraps and yard trimmings?

    Compost

    Compost is produced by recycling organic materials such as food scraps and yard trimmings into a soil amendment.

    Easy · Also offered: Mulch, Manure, Biochar · Source: U.S. EPA

  13. What marine ecosystem forms from colonies of tiny animals with hard skeletons?

    Coral reef

    A coral reef forms from colonies of tiny coral animals called polyps, which build hard calcium carbonate skeletons. Over time, these skeletons accumulate into the reef structures that support thousands of marine species.

    Easy · Also offered: Oyster reef, Mussel bed, Sponge reef · Source: NOAA Ocean Service

  14. What term means converting wooded areas to another land use?

    Deforestation

    Deforestation is the conversion of forest to another use, such as cropland, cattle pasture or building. Thinning or damaging a forest that remains a forest counts as degradation instead.

    Easy · Also offered: Forest degradation, Habitat fragmentation, Desertification · Source: Food and Agriculture Organization, Global Forest Resources Assessment

  15. What prolonged weather pattern brings unusually little precipitation?

    Drought

    A drought is a stretch of unusually low precipitation long enough to draw down soil moisture, rivers and reservoirs. It is measured against what a place normally gets, so a wet region can be in drought on rainfall a desert would call a good year.

    Easy · Also offered: Monsoon, El Nino, Rain shadow · Source: National Weather Service

  16. What kind of energy does Earth emit to space after absorbing sunlight?

    Infrared radiation

    The Sun is hot enough to radiate mostly visible light, while Earth's cooler surface radiates at longer, infrared wavelengths, the same reason a hot stove element glows red rather than white. Gases in the atmosphere trap part of that outgoing infrared and send it back down, keeping the surface warmer than it would otherwise be.

    Easy · Also offered: Ultraviolet radiation, Microwave radiation, Gamma radiation · Source: NASA, Climate and Earth's Energy Budget

  17. What is the practice of assisting the recovery of a degraded or destroyed ecosystem called?

    Ecological restoration

    Ecological restoration is the practice of helping a degraded, damaged or destroyed ecosystem recover: replanting native species, pulling out invasives, re-flooding drained wetland, reopening a river blocked by a dam. The aim is a system that sustains itself without further intervention.

    Easy · Also offered: Ecosystem management, Habitat conservation, Watershed management · Source: Society for Ecological Restoration, International Principles

  18. Old phones, screens and computers are kept out of ordinary landfill mainly because they contain what?

    Heavy metals such as lead and mercury

    Discarded electronics carry lead in old solder and screens, mercury in backlights and switches, and cadmium in batteries. Buried in ordinary landfill these leach into soil and groundwater, so e-waste is collected separately, which also makes it possible to recover the gold, copper and rare earths inside.

    Easy · Also offered: Radioactive isotopes, Asbestos fibres, Formaldehyde · Source: U.S. EPA, Cleaning Up Electronic Waste (E-waste)

  19. What coastal area forms where freshwater mixes with seawater?

    Estuary

    An estuary is a coastal area where freshwater mixes with seawater.

    Easy · Also offered: Delta, Lagoon, Fjord · Source: NOAA

  20. What is a single straight-line sequence of organisms, each one eaten by the next, called?

    Food chain

    A food chain runs in one line, grass to rabbit to fox, each link passing on a fraction of the energy it took in. Because most animals eat more than one thing, real chains interlock into a branching food web.

    Easy · Also offered: Food web, Energy pyramid, Biomass pyramid · Source: National Geographic Society

  21. In a forest, what layer is formed by the crowns of its trees?

    Canopy

    The canopy is the upper forest layer formed by the crowns and branches of trees. It intercepts much of the sunlight and rainfall and provides habitat for many forest organisms.

    Easy · Also offered: Emergent layer, Understory, Shrub layer · Source: U.S. Forest Service, Forest Canopy

  22. Which ecosystem locks up the most carbon per hectare on land?

    Forests

    Forests act as terrestrial carbon sinks because trees absorb carbon dioxide through photosynthesis and store the carbon in trunks, branches, roots, and soil. Much of a forest’s carbon can remain locked away for decades or centuries if the ecosystem is not disturbed.

    Easy · Also offered: Grasslands, Wetlands, Tundra · Source: FAO, Global Forest Resources Assessment

  23. Coal, oil, and natural gas are collectively called what?

    Fossil fuels

    Coal, oil, and natural gas are fossil fuels, formed from the remains of ancient plants and organisms over millions of years. Because they take so long to form, they are considered nonrenewable energy sources.

    Easy · Also offered: Biofuels, Nuclear fuels, Synthetic fuels · Source: U.S. Energy Information Administration

  24. What ecological term names an organism's usual living environment?

    Habitat

    A habitat is the natural environment where an organism lives. The National Park Service identifies habitat as essential to organisms' survival.

    Easy · Also offered: Ecosystem, Niche, Biome · Source: National Park Service

  25. In the Atlantic, what is a tropical cyclone called once its sustained winds reach 74 mph (119 km/h)?

    Hurricane

    An Atlantic tropical cyclone becomes a hurricane at sustained winds of 74 mph; below that it is a tropical storm. The same storm would be called a typhoon in the north-west Pacific and simply a cyclone in the Indian Ocean and around Australia.

    Easy · Also offered: Typhoon, Cyclone, Willy-willy · Source: National Weather Service

  26. What is a harmful non-native species called?

    Invasive species

    Invasive species are introduced organisms that establish and spread while causing environmental, economic, or human-health harm.

    Easy · Also offered: Endemic species, Indicator species, Umbrella species · Source: U.S. Fish and Wildlife Service, Invasive Species

  27. What engineered site is used to bury solid waste?

    Landfill

    A landfill is an engineered site where solid waste is placed and covered.

    Easy · Also offered: Incinerator, Transfer station, Composting yard · Source: U.S. EPA

  28. Which metal in old paint and old plumbing is especially harmful to children's developing nervous systems?

    Lead

    Lead damages the developing brain, affecting learning and behaviour, and young children take up far more of it through the gut than adults do. Lead paint and lead water pipes are the classic sources, which is why both were phased out of new building.

    Easy · Also offered: Mercury, Cadmium, Chromium · Source: World Health Organization, Lead poisoning and health

  29. What collective name is given to the salt-tolerant trees and shrubs that form tropical coastal wetland forests?

    Mangroves

    Mangroves are the roughly seventy species of trees and shrubs, drawn from many unrelated plant families, that grow in the salty tidal zone of tropical and subtropical coasts. They either filter salt out at the roots or push it back out through their leaves, and their tangled aerial roots trap sediment, shelter young fish and blunt storm surges.

    Easy · Also offered: Saltmarsh, Seagrass, Reedbed · Source: NOAA Ocean Service

  30. What are fragments of manufactured polymers under 5 millimetres commonly called?

    Microplastics

    Fragments of manufactured polymers smaller than 5 millimetres are called microplastics. They can form when larger plastic items break down or be released directly from products such as synthetic clothing and cosmetics.

    Easy · Also offered: Nanoplastics, Microbeads, Microfibres · Source: U.S. National Oceanic and Atmospheric Administration, What are microplastics?

  31. Which international agreement phases out ozone-depleting chemicals?

    Montreal Protocol

    The Montreal Protocol is the global agreement designed to protect the ozone layer by phasing out substances that deplete it.

    Easy · Also offered: Ramsar Convention, Basel Convention, Paris Agreement · Source: UN Environment Programme Ozone Secretariat, The Montreal Protocol

  32. In which atmospheric layer is most of Earth's ozone found?

    Stratosphere

    The ozone layer is a region of the stratosphere containing relatively high ozone concentrations.

    Easy · Also offered: Troposphere, Mesosphere, Thermosphere · Source: NASA, Ozone

  33. Ozone, the gas that shields the Earth from ultraviolet radiation, is made of which element?

    Oxygen

    Ozone is oxygen wearing a different hat: three atoms bonded together as O3, rather than the two-atom O2 we breathe. High in the stratosphere, ultraviolet light constantly splits ozone apart and the fragments recombine, and it is that endless breaking and remaking that soaks up the radiation before it reaches the ground.

    Easy · Also offered: Nitrogen, Carbon, Hydrogen · Source: NASA

  34. In a food web, what is an animal that kills and eats other animals called?

    Predator

    A predator is an animal that hunts and eats other animals.

    Easy · Also offered: Decomposer, Producer, Pollinator · Source: National Geographic Society

  35. Which water-collection method do some drought-prone places now require every new building to install?

    Rainwater harvesting

    Roof runoff is guttered into a rain barrel or underground tank and reused for watering, washing and flushing, cutting demand on the mains. Bermuda has no natural springs or rivers, so its building code requires every roof to be shaped and guttered to catch rain for storage on site.

    Easy · Also offered: Fog harvesting, Dew harvesting, Groundwater harvesting · Source: U.S. EPA

  36. What term describes a polluted haze often found over cities?

    Smog

    Smog is a blend of the words smoke and fog, coined for the coal hazes that used to settle over British cities. The modern kind is photochemical: sunlight reacts with exhaust fumes to make ground-level ozone, which is why it peaks on hot, still, sunny afternoons.

    Easy · Also offered: Fog, Mist, Vog · Source: U.S. EPA

  37. What process carries soil away by wind or water?

    Erosion

    Erosion is the process in which wind or water wears away and carries off soil and rock. The material moved by erosion can later settle elsewhere as sediment.

    Easy · Also offered: Weathering, Deposition, Mass wasting · Source: U.S. Geological Survey

  38. What process lets bacteria make atmospheric N₂ usable by plants?

    Nitrogen fixation

    Bacteria convert atmospheric N₂ into forms plants can use through nitrogen fixation. The other choices are real nitrogen-cycle processes but describe different conversions.

    Easy · Also offered: Nitrification, Denitrification, Ammonification · Source: FAO, Soil biodiversity and nitrogen fixation

  39. What power source generates electricity as coastal waters move in and out?

    Tidal energy

    Tidal energy generates electricity from the regular movement of ocean water as tides rise and fall.

    Easy · Also offered: Biomass energy, Wave energy, Solar energy · Source: U.S. Energy Information Administration

  40. What is a violently rotating column of air extending from a thunderstorm to the ground?

    Tornado

    A tornado must touch both the base of a thunderstorm and the ground. The strongest ones descend from the broad rotating updraught inside a supercell, and the same vortex over water is called a waterspout.

    Easy · Also offered: Waterspout, Mesocyclone, Downburst · Source: National Weather Service

  41. What urban approach uses vegetation, soils, and natural processes to manage stormwater?

    Green infrastructure

    Green infrastructure uses plants, soils, or permeable substrates to capture and infiltrate or reuse stormwater.

    Easy · Also offered: Greywater recycling, Industrial symbiosis, Desalination · Source: U.S. EPA, Green Infrastructure Installation, Operation and Maintenance

  42. What area of land drains precipitation to a common outlet such as a river, lake, or ocean?

    Watershed

    A watershed is an area in which water and sediment drain to a common outlet such as a river, lake, bay, or ocean.

    Easy · Also offered: Aquifer, Estuary, Water table · Source: U.S. EPA, Your Coastal Watershed

  43. What is the highest air temperature ever officially recorded on Earth?

    56.7°C (134°F)

    The reading came from Furnace Creek in Death Valley, California, on 10 July 1913 and is still recognised by the World Meteorological Organization despite some modern meteorologists questioning whether the 1913 equipment and methods were fully reliable. A higher claim of 57.8°C from Libya in 1922 stood as the record for 90 years until the WMO formally disqualified it in 2012 over measurement errors.

    Easy · Also offered: 54.4°C (130°F), 57.8°C (136°F), 50°C (122°F) · Source: Science/AAAS, Move over, Death Valley: these are the two hottest spots on Earth

Medium Environment Trivia Questions

  1. What term describes members of one species living in the same area?

    A population

    A population is a group of individuals of the same species living in the same area.

    Medium · Also offered: A community, An ecosystem, A biome · Source: National Park Service, Ecosystems

  2. What is it called when an animal takes in a pollutant faster than it can break down or excrete it?

    Bioaccumulation

    The classic case is DDT, which built up in fish and then moved further up the food chain into birds of prey. It thinned their eggshells so badly that bald eagle and peregrine falcon numbers collapsed, before the United States banned the pesticide in 1972.

    Medium · Also offered: Biodegradation, Bioremediation, Bioconversion · Source: U.S. EPA, Exposure Assessment Tools for Aquatic Biota

  3. What is the rising concentration of a pollutant at each successive level of a food chain called?

    Biomagnification

    Biomagnification is the step-by-step rise in a pollutant's concentration up a food chain, because each predator takes in everything its prey has already stored. DDT and mercury are the classic cases, which is why top predators such as ospreys and tuna carry the heaviest loads.

    Medium · Also offered: Bioaccumulation, Biodegradation, Bioremediation · Source: U.S. EPA, Toxics in the Food Web

  4. Which cleanup method uses bacteria and fungi to break down contaminants?

    Bioremediation

    Bioremediation uses microorganisms to degrade organic contaminants in soil, groundwater, sludge, or solids.

    Medium · Also offered: Pump-and-treat, Soil vapour extraction, Thermal desorption · Source: U.S. EPA, Remediation Technology Descriptions

  5. What term describes capturing and storing CO₂ in natural or geologic reservoirs?

    Carbon sequestration

    Carbon sequestration is the capture and long-term storage of carbon dioxide in natural systems or underground geologic formations. In geologic sequestration, CO₂ can be injected deep underground into formations such as saline aquifers or depleted oil and gas reservoirs.

    Medium · Also offered: Carbon leakage, Carbonization, Radiative forcing · Source: U.S. Geological Survey, Geologic and Biologic Carbon Sequestration

  6. Which environmental term means a net removal of atmospheric CO₂?

    Carbon sink

    A carbon sink absorbs more atmospheric CO₂ than it releases, reducing the amount of CO₂ in the atmosphere. Oceans, forests, and soils are major natural carbon sinks.

    Medium · Also offered: Carbon budget, Carbon flux, Carbon footprint · Source: IPCC, SROCC Glossary

  7. At the annual climate summits, what does COP stand for?

    Conference of the Parties

    The Conference of the Parties is the decision-making meeting of the countries that signed the UN climate convention, which is why the summits are numbered COP26, COP27 and so on.

    Medium · Also offered: Climate Objectives Programme, Council on Pollution, Convention on Preservation · Source: UN Framework Convention on Climate Change

  8. What stress most commonly triggers coral bleaching?

    Abnormally warm water

    Water even a degree or two above the usual summer maximum, held for weeks, makes corals expel the algae living in their tissues that supply most of their food and all of their colour, leaving the white skeleton showing through. Bleached coral is not dead and can recover, but it starves if the heat does not break.

    Medium · Also offered: Heavy coastal runoff, Intense sunlight exposure, Extreme low-tide exposure · Source: NOAA Ocean Service, What Is Coral Bleaching?

  9. Which process returns the nutrients locked in dead plants and animals to the soil?

    Decomposition

    Decomposition breaks down dead organisms and returns simpler compounds and nutrients to the environment.

    Medium · Also offered: Photosynthesis, Respiration, Weathering · Source: National Park Service, Decomposition and Nutrient Cycling

  10. What is land degradation in dry areas that reduces biological productivity called?

    Desertification

    Desertification is the degradation of land in dry areas that reduces its biological productivity. It can be driven by factors such as unsustainable farming, overgrazing, drought, and climate change.

    Medium · Also offered: Soil salinization, Groundwater depletion, Climate aridification · Source: UN Convention to Combat Desertification, About Desertification

  11. Roughly what share of the energy at one level of a food chain passes to the level above it?

    About 10%

    Most of the energy an animal takes in is spent on movement, warmth and everyday upkeep, or lost as waste, and only a small slice ends up as body mass a predator can eat. Ecologists use about 10% as a rule of thumb rather than a fixed constant, and it is why food chains rarely run beyond four or five links.

    Medium · Also offered: About 1%, About 50%, About 90% · Source: OpenStax Biology 2e, Energy Flow through Ecosystems

  12. In ecology, which term covers a species' whole way of making a living: what it eats, where it feeds, and what conditions it can tolerate?

    Ecological niche

    A species' ecological niche is its whole way of making a living: what it eats, where and when it feeds, what preys on it, and the range of temperature, moisture and light it can tolerate. Two species with identical niches cannot coexist indefinitely in one place; one out-competes the other.

    Medium · Also offered: Habitat, Biome, Trophic level · Source: U.S. EPA, Introduction to Watershed Ecology

  13. What adjective describes a species found naturally only in one geographic area?

    Endemic

    An endemic species occurs naturally in a particular geographic area and nowhere else.

    Medium · Also offered: Invasive, Indicator, Keystone · Source: Encyclopaedia Britannica, Endemic species

  14. What formal process examines a proposed project's likely ecological effects before approval?

    Environmental impact assessment

    An environmental impact assessment evaluates a proposed project’s likely effects on the environment before approval. It can also identify ways to avoid, reduce, or mitigate those effects.

    Medium · Also offered: Strategic environmental assessment, Environmental risk assessment, Environmental health assessment · Source: UNEP, Environmental Impact Assessment

  15. In an ocean dead zone, decomposing algae strip the water of what fish need to survive. What is the resulting condition called?

    Hypoxia

    When a nutrient-fed algal bloom dies, the bacteria decomposing it consume the dissolved oxygen in the water. What is left is hypoxia: oxygen too low to keep fish alive, so they either flee or suffocate. The Gulf of Mexico dead zone can spread across several thousand square miles.

    Medium · Also offered: Acidification, Salinization, Turbidity · Source: U.S. EPA, The Effects: Environment

  16. What process can cause algal blooms when waters receive excess nutrients?

    Eutrophication

    Eutrophication is nutrient enrichment of water that can stimulate excessive algal and plant growth.

    Medium · Also offered: Desertification, Salinization, Acidification · Source: U.S. Environmental Protection Agency, Nutrient Pollution

  17. Which pollutant forms when nitrogen oxides and VOCs react in sunlight?

    Ground-level ozone

    Ground-level ozone is formed in the atmosphere when nitrogen oxides and volatile organic compounds react in sunlight.

    Medium · Also offered: Stratospheric ozone, Sulfur dioxide, Carbon monoxide · Source: U.S. EPA, Ground-level Ozone Basics

  18. Which renewable source has long generated more of the world's electricity than any other?

    Hydropower

    Hydropower supplies roughly a seventh of all the electricity generated worldwide, more than any other renewable source, by letting falling or flowing water spin turbines. China, Brazil, Canada and the United States produce the most of it.

    Medium · Also offered: Solar, Wind, Geothermal · Source: U.S. Energy Information Administration

  19. Conserving a species in the place it naturally lives, rather than in zoos or seed banks, is called what?

    In situ conservation

    In situ means in place: national parks, reserves and habitat protection, keeping viable populations where the species already lives. Its counterpart, ex situ conservation, holds a species away from its habitat in zoos, botanic gardens and gene banks.

    Medium · Also offered: Ex situ conservation, Assisted migration, Species reintroduction · Source: Convention on Biological Diversity, Article 2

  20. What kind of species has an ecosystem impact much larger than its abundance suggests?

    Keystone species

    A keystone species has a disproportionately large effect on its ecosystem relative to its abundance.

    Medium · Also offered: Indicator species, Pioneer species, Flagship species · Source: National Park Service, Keystone Species

  21. Which climate pattern brings cooler-than-usual sea-surface temperatures to the central and eastern equatorial Pacific?

    La Niña

    La Niña is the cool phase of the El Niño-Southern Oscillation. Strengthened trade winds push warm surface water towards Asia and let cold water rise along the coast of South America, shifting rainfall and storm tracks worldwide.

    Medium · Also offered: El Niño, Pacific Decadal Oscillation, North Atlantic Oscillation · Source: NOAA Pacific Marine Environmental Laboratory: What is La Nina?

  22. Which gas makes up about half of landfill gas and can be used as fuel?

    Methane

    Methane makes up about half of landfill gas and can be captured and burned as a fuel. It is also a potent greenhouse gas, so using it for energy can help prevent its release into the atmosphere.

    Medium · Also offered: Ethane, Propane, Butane · Source: U.S. Environmental Protection Agency, Basic Information about Landfill Gas

  23. Which gas makes up the largest share of Earth's atmosphere?

    Nitrogen

    Nitrogen makes up about 78 percent of Earth's atmosphere, more than any other gas.

    Medium · Also offered: Oxygen, Argon, Carbon dioxide · Source: NOAA National Centers for Environmental Information, Earth's Atmosphere

  24. Which process do corals use to build their hard skeletons?

    Calcification

    Corals lay down a skeleton of calcium carbonate, a process called calcification. As the ocean absorbs carbon dioxide from the air its water turns slightly more acidic and carbonate ions become scarcer, so building and holding that skeleton costs the animal more energy.

    Medium · Also offered: Silicification, Ossification, Photosynthesis · Source: NOAA Ocean Service, Ocean Acidification

  25. What compound forms as seawater absorbs CO₂?

    Carbonic acid

    The reaction lowers ocean pH by releasing hydrogen ions, a process called ocean acidification that makes it harder for corals, oysters and other marine organisms to build calcium carbonate shells and skeletons.

    Medium · Also offered: Carbolic acid, Formic acid, Acetic acid · Source: NOAA Ocean Service, What Is Ocean Acidification?

  26. What treatment breaks oil slicks into smaller droplets?

    Dispersant

    Dispersants contain surfactants that break petroleum oil into small droplets that disperse into the water column.

    Medium · Also offered: Sorbent, Solidifier, Bioremediation agent · Source: U.S. EPA, Dispersing Agents

  27. Which principle calls for action when serious environmental damage remains uncertain?

    Precautionary principle

    The precautionary principle calls for protective action when serious or irreversible environmental harm is possible, even if scientific certainty is incomplete. It is enshrined in Principle 15 of the 1992 Rio Declaration.

    Medium · Also offered: Polluter pays principle, User pays principle, No-harm principle · Source: United Nations, Rio Principles Study

  28. Who wrote the environmental warning book Silent Spring?

    Rachel Carson

    Rachel Carson wrote Silent Spring, the 1962 book that documented the ecological dangers of pesticides.

    Medium · Also offered: Jane Goodall, Sylvia Earle, Dian Fossey · Source: U.S. National Park Service, Rachel Carson

  29. What shallow planted hollow, dug beside a downpipe or driveway, is designed to let runoff soak into the ground?

    Rain garden

    A rain garden is a shallow dish of ground, planted up and fed by roof and paving runoff, that holds a downpour and lets it drain away into the soil over a day or so instead of surging into the sewers. Deep-rooted plants keep the soil open and the soil strips out grit and oil on the way through.

    Medium · Also offered: Green roof, Soakaway, Retention pond · Source: U.S. EPA

  30. Which international agreement focuses on conserving wetlands?

    Ramsar Convention

    The Ramsar Convention is an international treaty dedicated to the conservation and wise use of wetlands.

    Medium · Also offered: Montreal Protocol, Basel Convention, Antarctic Treaty · Source: Convention on Wetlands, Signage at Ramsar Sites

  31. Which term describes re-establishing tree cover on land that was forest until recently?

    Reforestation

    Reforestation puts trees back where a forest recently stood, after logging, fire or clearance for farming. Afforestation is the neighbouring term for planting forest on ground that has carried no trees for a very long time, or never has, such as grassland or moor.

    Medium · Also offered: Afforestation, Agroforestry, Rewilding · Source: U.S. Forest Service

  32. What practice uses vegetation between harvests to protect soil from erosion?

    Cover crops

    Cover crops such as rye, clover or vetch are sown between cash crops to keep the ground covered when it would otherwise sit bare. The canopy takes the impact of the rain, and the living roots hold the soil in place through the winter.

    Medium · Also offered: Crop rotation, Strip cropping, Contour farming · Source: USDA Natural Resources Conservation Service

  33. What term describes the fraction of sunlight a surface reflects?

    Albedo

    Albedo is the reflectivity of a surface; bright snow and ice generally have higher albedo than dark land or ocean.

    Medium · Also offered: Emissivity, Conductivity, Humidity · Source: NASA, Earth Observatory: Albedo

  34. Which forestry method harvests individual trees instead of whole stands?

    Selective logging

    Selective logging harvests individual trees or small groups while leaving much of the surrounding forest standing. When carefully managed, it can preserve more of the forest’s structure and habitat than removing an entire stand.

    Medium · Also offered: Clear-cutting, Shelterwood cutting, Seed-tree cutting · Source: FAO, Sustainable forest management

  35. Which biome forms a broad belt of coniferous forest across Canada and Siberia?

    Taiga

    The taiga, or boreal forest, is a vast belt of mainly coniferous woodland across the far north.

    Medium · Also offered: Tundra, Chaparral, Temperate deciduous forest · Source: National Park Service, Boreal Forests

  36. Why can a temperature inversion worsen smog?

    It traps polluted air near the ground

    A temperature inversion places warmer air above cooler surface air, preventing normal upward mixing and trapping pollutants close to the ground. The pollution can build up until wind or changing weather disperses it.

    Medium · Also offered: It increases vehicle and factory emissions, It stops rain from washing out particles, It speeds sunlight-driven ozone formation · Source: U.S. EPA, What is Particle Pollution?

  37. Which water-cycle process releases water vapor from plant leaves?

    Transpiration

    Transpiration is the release of water vapor from plants, mainly through tiny openings in their leaves.

    Medium · Also offered: Evaporation, Condensation, Infiltration · Source: U.S. Geological Survey, Water Science School: The Water Cycle

  38. Which biome is typically treeless and underlain by permafrost?

    Tundra

    Tundra is a cold, mostly treeless biome whose soils commonly include permafrost.

    Medium · Also offered: Taiga, Savanna, Temperate rainforest · Source: National Park Service, Arctic Tundra

  39. What phenomenon makes built-up areas warmer than nearby less-developed areas?

    Urban heat island

    An urban heat island occurs when buildings, roads, and other paved surfaces absorb and re-release more heat than natural landscapes, making cities warmer than nearby less-developed areas. The effect is often strongest at night, when those surfaces slowly release the heat they stored during the day.

    Medium · Also offered: Urban canyon effect, Temperature inversion, Heat dome · Source: US EPA, Heat Island Effect

  40. In the waste hierarchy, what is the term for preventing waste from being created at all, rather than dealing with it afterwards?

    Source reduction

    Source reduction sits at the top of the waste hierarchy, above reuse, recycling and energy recovery, because waste that is never made costs nothing to collect, sort or burn. Thinner packaging and refillable containers are everyday examples.

    Medium · Also offered: Material reuse, Waste recycling, Energy recovery · Source: U.S. EPA, Sustainable Management of Construction and Demolition Materials

  41. Which wastewater stage uses microorganisms to remove most dissolved organic matter?

    Secondary treatment

    Secondary treatment uses biological processes to remove biodegradable dissolved and suspended organic matter.

    Medium · Also offered: Primary treatment, Screening, Sludge dewatering · Source: U.S. EPA, Wastewater Treatment Fact Sheet

  42. Which atmospheric gas is Earth's most abundant greenhouse gas?

    Water vapor

    Water vapor is the most abundant greenhouse gas; its amount in the atmosphere is strongly influenced by temperature, making it an important feedback.

    Medium · Also offered: Carbon dioxide, Methane, Nitrous oxide · Source: NASA, Water Vapor

  43. A marsh holds back storm water and lets it out slowly over the following days. What is this wetland service called?

    Flood attenuation

    Flood attenuation is the flattening of a flood peak. A wetland stores a surge of rain and releases it over hours or days, so the water reaching towns downstream arrives lower and later than it otherwise would.

    Medium · Also offered: Groundwater recharge, Water purification, Sediment trapping · Source: U.S. EPA, Why Are Wetlands Important?

  44. The Great Barrier Reef, the Galapagos Islands and Yellowstone all hold which international designation?

    Natural World Heritage site

    UNESCO's World Heritage List has a natural strand alongside the cultural one, and a place joins it by showing what the convention calls outstanding universal value: exceptional geology, ecosystems, natural beauty or habitat for threatened species. Yellowstone was on the very first list in 1978.

    Medium · Also offered: UNESCO Biosphere Reserve, Ramsar Wetland of International Importance, UNESCO Global Geopark · Source: UNESCO World Heritage Centre, Natural sites

  45. What is the diameter of the largest hailstone ever officially verified in the United States, which fell near Vivian, South Dakota, in 2010?

    20.3 cm (8.0 in)

    The stone also set the U.S. weight record at 0.88 kg (1.94 lb) and had reportedly measured even larger before part of it melted ahead of being officially measured. It was found by a local resident after a severe thunderstorm and validated by the National Climate Extremes Committee.

    Medium · Also offered: 17.8 cm (7.0 in), 16.3 cm (6.4 in), 23.6 cm (9.3 in) · Source: NPR, S.D. hailstone hailed as largest ever in U.S.

Hard Environment Trivia Questions

  1. What is contaminated land formerly used for industry or commerce called?

    A brownfield

    A brownfield is previously developed property whose reuse may be complicated by actual or suspected contamination.

    Hard · Also offered: A greenfield, A landfill, A wilderness · Source: U.S. Environmental Protection Agency, Brownfields

  2. What is the name for a sudden release of dissolved gas from deep lake water, as at Lake Nyos?

    A limnic eruption

    A limnic eruption is the sudden release of dissolved carbon dioxide from deep lake water, producing a dangerous gas cloud.

    Hard · Also offered: A phreatic eruption, A lahar, A seiche · Source: Encyclopaedia Britannica, Limnic eruption

  3. What term describes a set of local populations linked by occasional dispersal?

    A metapopulation

    A metapopulation consists of separate local populations of the same species connected by occasional movement of individuals.

    Hard · Also offered: A community, A guild, An ecotype · Source: Encyclopaedia Britannica, Metapopulation

  4. What is the vegetated area alongside a river or stream called?

    A riparian zone

    A riparian zone is the strip of land and vegetation directly alongside a river, stream, or other flowing waterway.

    Hard · Also offered: A watershed, A floodplain, An estuary · Source: U.S. Environmental Protection Agency, Riparian Areas

  5. Which naturally occurring contaminant is a major groundwater concern in Bangladesh?

    Arsenic

    Arsenic contamination of groundwater is a major public-health problem in Bangladesh and other regions.

    Hard · Also offered: Aluminum, Chloride, Calcium · Source: World Health Organization, Arsenic

  6. Which British ecologist introduced the term ecosystem in a 1935 paper?

    Arthur Tansley

    Arthur Tansley introduced the term ecosystem in his 1935 paper The Use and Abuse of Vegetational Concepts and Terms.

    Hard · Also offered: Eugene Odum, Charles Elton, G. Evelyn Hutchinson · Source: A. G. Tansley, The Use and Abuse of Vegetational Concepts and Terms (1935)

  7. Which treaty regulates transboundary movements and disposal of hazardous wastes?

    Basel Convention

    The Basel Convention governs shipments of hazardous waste between countries. It was adopted in 1989 after a run of scandals in which toxic waste from industrialised nations was dumped in poorer ones, and its central aim is to stop that trade rather than to manage chemicals or pollutants in general.

    Hard · Also offered: Rotterdam Convention, Stockholm Convention, Minamata Convention · Source: Basel Convention Secretariat

  8. What measure estimates organic matter breakdown by microbes in water?

    Biochemical oxygen demand

    Biochemical oxygen demand measures how much dissolved oxygen microbes use while breaking down organic matter in water. A standard test often measures this oxygen use over five days at 20°C.

    Hard · Also offered: Chemical oxygen demand, Dissolved oxygen concentration, Total suspended solids · Source: U.S. EPA, Water Quality Standards Handbook: Biochemical Oxygen Demand

  9. The Convention on Biological Diversity describes biodiversity at which three levels?

    Genetic, species, and ecosystem diversity

    The 1992 Convention on Biological Diversity defines biodiversity as variety within species, between species and of ecosystems, which is to say genetic, species and ecosystem diversity. Nearly every country has signed it, so those three levels frame most national conservation targets.

    Hard · Also offered: Genetic, species, and functional diversity; Species, ecosystem, and phylogenetic diversity; Genetic, functional, and phylogenetic diversity · Source: Convention on Biological Diversity, Biodiversity Levels

  10. Which UNESCO designation has core, buffer, and transition zones?

    Biosphere reserve

    UNESCO biosphere reserves use core, buffer, and transition zones to combine conservation with research and sustainable local activity.

    Hard · Also offered: World Heritage site, Ramsar site, Global Geopark · Source: UNESCO, What Are Biosphere Reserves?

  11. Which engineered system uses planted beds of gravel, soil and reeds to clean wastewater or runoff?

    Constructed wetland

    A constructed wetland is a man-made bed of gravel, soil and water plants where bacteria growing on the roots and grains strip nutrients, solids and pollutants out of water as it passes slowly through. They treat sewage for small communities, mine drainage and stormwater at a fraction of the running cost of a mechanical plant.

    Hard · Also offered: Rain garden, Oxidation pond, Vegetated swale · Source: US EPA, Constructed Wetlands

  12. What is the term for a species whose condition is used to gauge the health of an environment?

    Bioindicator

    A bioindicator is a species or biological response used to read environmental conditions directly. Lichens thin out where the air carries sulphur dioxide, and mayfly larvae vanish from streams fouled by sewage or farm runoff, so counting them reveals the state of the air or water without a single chemical test.

    Hard · Also offered: Keystone species, Umbrella species, Foundation species · Source: U.S. EPA, ROE Glossary

  13. How much disturbance an ecosystem can absorb before it flips into a different state is called what?

    Ecological resilience

    The idea was introduced by ecologist C.S. Holling in 1973. A clear lake that tips into a permanently algae-choked state after nutrient runoff, or a coral reef that flips to algae-covered rubble after a bleaching event, is a classic example of an ecosystem crossing that threshold.

    Hard · Also offered: Ecological resistance, Ecological succession, Ecological adaptation · Source: National Park Service, Ecological Resilience

  14. In habitat restoration, what is an intact or historical site used as the benchmark for what a damaged site should become called?

    Reference ecosystem

    A reference ecosystem is a nearby intact site, or a picture assembled from historical records and old surveys, showing what a damaged habitat could realistically become. Restoration teams use it to set targets and to judge, years later, whether the work took.

    Hard · Also offered: Baseline survey, Control plot, Climax community · Source: Society for Ecological Restoration, International Principles and Standards

  15. What is the name for a transition zone between two neighboring ecosystems?

    Ecotone

    An ecotone is an area of gradual transition between two or more ecosystems.

    Hard · Also offered: Biome, Estuary, Trophic level · Source: IUPAC Gold Book, Ecotone

  16. What environmental policy assigns end-of-life impacts of goods to the businesses behind them?

    Extended producer responsibility

    Extended producer responsibility makes producers responsible for managing or financing a product’s impacts at the end of its life. It can encourage businesses to design products that use fewer materials and are easier to reuse or recycle.

    Hard · Also offered: Deposit-refund system, Pay-as-you-throw, Landfill tax · Source: OECD, Extended Producer Responsibility

  17. Which two recurring events stop grasslands from turning into forest?

    Fire and grazing

    Regular fire and heavy grazing kill tree seedlings, while grasses survive both because they regrow from growing points at or below ground level. That is why prairies and savannas stay open instead of closing over into woodland.

    Hard · Also offered: Drought and flooding, Erosion and sedimentation, Frost and snowmelt · Source: National Park Service, Patch-Burn Grazing

  18. What process splits one continuous natural area into smaller, isolated patches?

    Habitat fragmentation

    Habitat fragmentation divides a once-continuous habitat into smaller patches that are often separated from one another.

    Hard · Also offered: Habitat loss, Ecological succession, Species migration · Source: U.S. Fish and Wildlife Service, Habitat Fragmentation

  19. Which method measures a product's environmental impact across its whole existence, from raw materials to disposal?

    Life-cycle assessment

    A life-cycle assessment adds up a product's environmental burden at every stage: extracting the raw materials, manufacturing, transport, years of use, and final disposal or recycling. It is often called a cradle-to-grave study, and it is why an electric car is judged on battery mining and end-of-life recycling as well as on what comes out of the tailpipe.

    Hard · Also offered: Environmental impact assessment, Material flow analysis, Environmental risk assessment · Source: U.S. EPA, Greener Products A-Z List

  20. What term covers carbon stored by mangroves, marshes, and seagrass beds?

    Blue carbon

    Blue carbon refers to carbon captured by ocean and coastal ecosystems and stored in biomass and sediments.

    Hard · Also offered: Black carbon, Grey carbon, Mineral carbon · Source: NOAA Ocean Service, What Is Blue Carbon?

  21. What conservation term describes a zone that bans fishing and resource removal?

    A marine reserve

    Inside the boundary, breeding fish and shellfish are left undisturbed long enough for numbers and body size to recover, and some of that surplus drifts or swims across the line into waters that are still fished. Studies of reserves such as California's Channel Islands have measured this spillover increasing biomass in the fished waters just outside the boundary.

    Hard · Also offered: A marine sanctuary, A marine park, A marine buffer zone · Source: National Oceanic and Atmospheric Administration, Marine Protected Areas

  22. What term describes the smallest group expected to persist for a stated period despite normal risks?

    Minimum viable population

    A minimum viable population is the smallest population size expected to survive for a specified period with an acceptable level of certainty. It is not a universal number because it depends on the species, environment, and persistence goal.

    Hard · Also offered: Carrying capacity, Effective population size, Population bottleneck · Source: IUCN Species Survival Commission, Population Viability Analysis

  23. Which step of the nitrogen cycle converts nitrate in soil back into nitrogen gas?

    Denitrification

    Denitrification is carried out by bacteria in waterlogged soils and sediments where oxygen is scarce. They strip oxygen from nitrate and step it down through nitrite and nitrous oxide to plain nitrogen gas, which escapes to the air. It is the return leg of the cycle, balancing the fixation that pulls nitrogen out of the atmosphere in the first place.

    Hard · Also offered: Nitrification, Nitrogen fixation, Ammonification · Source: U.S. EPA, N-STEPS nutrient overview

  24. What long-term change in seawater is caused by absorbing excess atmospheric CO2?

    Ocean acidification

    Ocean acidification is the long-term decline in seawater pH caused mainly by the ocean absorbing additional carbon dioxide.

    Hard · Also offered: Eutrophication, Hypoxia, Salinization · Source: NOAA Ocean Service, Ocean Acidification

  25. Which class of chemicals, including DDT and PCBs, is banned worldwide by the Stockholm Convention?

    Persistent organic pollutants

    The Stockholm Convention took effect in 2004 and initially listed twelve substances, nicknamed the 'dirty dozen', including DDT and PCBs. These chemicals accumulate in fatty tissue and become more concentrated at each step up the food chain, building up to high levels in top predators.

    Hard · Also offered: Volatile organic compounds, Endocrine-disrupting chemicals, Hazardous air pollutants · Source: United Nations Environment Programme, Persistent Organic Pollutants

  26. Which major plant nutrient cycles mainly through rock, soil, water and living things, with no significant gas phase in the air?

    Phosphorus

    Unlike carbon, nitrogen and sulfur, phosphorus has no meaningful atmospheric stage: it moves from weathering rock through soil, water and organisms and back into sediment.

    Hard · Also offered: Carbon, Nitrogen, Sulfur · Source: Encyclopaedia Britannica, Phosphorus cycle

  27. What cleanup approach uses plants to remove or contain contaminants?

    Phytoremediation

    Phytoremediation uses vegetation as a cleanup or containment technique for contaminants in soil or groundwater.

    Hard · Also offered: Incineration, Dredging, Vitrification · Source: U.S. EPA, Phytoremediation of Contaminated Soil and Ground Water

  28. The plastics industry ships its raw material as lentil-sized pellets, which spill in transit and wash up on beaches. What are those pellets nicknamed?

    Nurdles

    Nurdles are pre-production plastic pellets, melted down at factories and moulded into bottles, packaging and car parts. Trillions are shipped each year, and losses at sea and in handling scatter them along coastlines worldwide, where they rank among the largest single sources of microplastic pollution and are swallowed by seabirds and fish that mistake them for food.

    Hard · Also offered: Regrind, Masterbatch, Flake · Source: NOAA Marine Debris Program, Pre-production Plastic Pellets

  29. What ecological term describes the rate at which producers convert energy into organic matter?

    Primary productivity

    Primary productivity is the rate at which plants, algae, or other autotrophs produce biomass, usually through photosynthesis.

    Hard · Also offered: Secondary succession, Carrying capacity, Respiration rate · Source: NOAA Ocean Service, Primary Productivity

  30. Which treaty targets persistent organic pollutants?

    Stockholm Convention

    The Stockholm Convention requires measures to eliminate, restrict, or reduce releases of persistent organic pollutants.

    Hard · Also offered: Rotterdam Convention, Cartagena Protocol, MARPOL Convention · Source: Stockholm Convention Secretariat

  31. What name is given to the fertile, charcoal-rich dark soils created by ancient communities in parts of Amazonia?

    Terra preta

    Terra preta, or Amazonian dark earth, is unusually fertile soil enriched by charcoal and other materials left by past human activity.

    Hard · Also offered: Laterite, Loess, Terra rossa · Source: Encyclopaedia Britannica, Terra preta

  32. Which region includes the seafloor and organisms living on or in it?

    The benthic zone

    The benthic zone consists of the ocean floor and the organisms that live on or within its sediments.

    Hard · Also offered: The pelagic zone, The photic zone, The neritic zone · Source: NOAA Ocean Service, Ocean Zones

  33. What measure compares human demand on nature with Earth's capacity to regenerate resources?

    The ecological footprint

    An ecological footprint estimates the biologically productive area needed to provide resources and absorb waste for a population.

    Hard · Also offered: The carbon footprint, The carrying capacity, The biodiversity index · Source: Global Footprint Network, Ecological Footprint

  34. Which model explains why larger, less isolated landmasses tend to support more species?

    The theory of island biogeography

    The theory of island biogeography relates the number of species on an island to its area and its isolation from a source of colonists.

    Hard · Also offered: The theory of ecological succession, The theory of trophic cascades, The theory of demographic transition · Source: Robert MacArthur and Edward O. Wilson, The Theory of Island Biogeography

  35. What term describes ground that collapses into irregular hollows as permafrost thaws?

    Thermokarst

    Thermokarst is irregular terrain formed when thawing ground ice causes permafrost surfaces to subside and collapse.

    Hard · Also offered: Karst, Sinkhole terrain, Glacial outwash · Source: National Park Service, Thermokarst

  36. What food-web effect links a change at one level to indirect changes at others?

    Trophic cascade

    A trophic cascade is a series of effects in which a change in predators or prey indirectly alters organisms at other feeding levels.

    Hard · Also offered: Founder effect, Island biogeography, Niche partitioning · Source: National Park Service, Cycles and Processes

  37. Which conservation term describes a species chosen for protection because the sheer size of the range it needs shelters many others?

    Umbrella species

    An umbrella species needs a very large area of habitat, so setting aside enough ground for it automatically protects the smaller species living inside that range. Tigers and grizzly bears are used this way.

    Hard · Also offered: Flagship species, Pioneer species, Keystone species · Source: U.S. Fish and Wildlife Service, Thunder Basin Grasslands Conservation Strategy

  38. What ocean process brings cold, nutrient-rich deep water to the surface?

    Upwelling

    Upwelling carries cold, nutrient-rich water from depth toward the ocean surface, supporting high productivity.

    Hard · Also offered: Downwelling, Thermohaline circulation, Coastal erosion · Source: NOAA Ocean Service, Upwelling

  39. Which wastewater stage mainly removes settleable solids by physical processes?

    Primary treatment

    Primary wastewater treatment uses physical processes such as screening and settling to remove solids.

    Hard · Also offered: Secondary treatment, Tertiary treatment, Disinfection · Source: U.S. EPA, Wastewater Treatment Fact Sheet

  40. What water-rights doctrine is commonly summarized as 'first in time, first in right'?

    Prior appropriation

    Prior appropriation is the doctrine that gives priority to the earliest users who put water to beneficial use. During shortages, those “senior” rights generally take precedence over later claims.

    Hard · Also offered: Riparian doctrine, Public-trust doctrine, Rule of capture · Source: U.S. Geological Survey, Human Factors in Upper Colorado River Water Supply

  41. Which renewable source is intermittent rather than dispatchable?

    Wind energy

    Turbine output rises and falls directly with wind speed, so grid operators typically pair it with batteries or backup generation that can ramp up quickly when the wind drops.

    Hard · Also offered: Hydroelectric energy, Geothermal energy, Biomass energy · Source: U.S. Energy Information Administration

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