163 Fun Facts About Environmental

On what date is Earth Day held every year?

April 22 was picked for the first Earth Day in 1970 because it fell on a weekday between spring break and final exams, when the most students could join the campus events.

Which US senator proposed the nationwide environmental teach-in that became the first Earth Day in 1970?

Gaylord Nelson, a Wisconsin Democrat, borrowed the idea from the campus teach-ins against the Vietnam War and hired the young activist Denis Hayes to organise it.

Julian Koenig, the ad man credited with naming Earth Day, also wrote which carmaker's 'Think Small' campaign?

Volkswagen's 'Think Small' Beetle ads of 1959 made Koenig's name; he said 'Earth Day' came easily because the event fell on his birthday and the two words rhyme.

Which climate accord was opened for signature at the United Nations on Earth Day in 2016?

The Paris Agreement was signed by 175 parties in New York on its first day, and enough countries then ratified it for the deal to take legal effect that November.

Earth Day 1990, the first held worldwide, is credited with giving a huge boost to which green habit?

Recycling got a huge lift from Earth Day 1990, which drew some 200 million people in 141 countries and helped pave the way for the UN Earth Summit two years later.

Rachel Carson's Silent Spring first reached readers in 1962 as a serial in which magazine?

The New Yorker ran it before the book came out; chemical companies tried to discredit Carson, but a presidential science panel backed her findings the following year.

In 2018 the European Union banned outdoor use of three neonicotinoid pesticides to protect which insects?

Bees were the reason: an EU food-safety review found the three chemicals a risk to honeybees and wild bees wherever they were used outdoors, which left greenhouses as the only place for them.

What prompted Silent Spring, according to its author's account?

A friend's letter about dead birds reached Carson in 1958: Olga Owens Huckins wrote that a plane spraying DDT against mosquitoes had killed the songbirds around her Massachusetts home.

Which Apollo mission took 'Earthrise', the 1968 photograph of our planet rising over the Moon's horizon?

Apollo 8 was the first crewed flight to orbit the Moon; Bill Anders shot the picture on Christmas Eve, hours before the crew read from Genesis in a live broadcast from lunar orbit.

Which US president posthumously awarded the author of Silent Spring the Presidential Medal of Freedom in 1980?

Jimmy Carter gave Rachel Carson the medal sixteen years after her death; chemical firms had once tried to dismiss her as a hysterical woman or a Communist.

Which Swiss chemist won a Nobel Prize in 1948 for discovering DDT's insecticidal power?

Paul Hermann Müller won the 1948 Nobel Prize in Physiology or Medicine for discovering DDT's insecticidal power in 1939; the compound itself had been synthesised in 1874 by Othmar Zeidler.

Which US agency banned DDT on farms in 1972?

The EPA, opened in December 1970, cancelled almost all uses of DDT in June 1972 after months of hearings, though the pesticide could still be made for export.

A 2001 treaty banned DDT on farms but still allows it against the mosquitoes that spread which disease?

Malaria is the exemption: the treaty on persistent organic pollutants lets health agencies spray DDT inside homes, where it kills the mosquitoes that carry the parasite.

John Steinbeck's The Grapes of Wrath follows a farming family uprooted by which environmental disaster?

The Dust Bowl was partly man-made: farmers had ploughed up millions of acres of the native grass that held the Plains soil, so drought and wind carried the topsoil away in vast dust storms.

Which predator was brought back to Yellowstone National Park in 1995, about seventy years after being wiped out there?

The grey wolf returned when fourteen animals trapped in Alberta were released in the park; without wolves, elk numbers had boomed and stripped the vegetation that beavers relied on.

Which president signed the first US Clean Air Act in December 1963?

Lyndon B. Johnson signed it on December 17, 1963, 25 days after Kennedy's assassination; a 1955 law had only funded research, while this one set up a federal programme to control air pollution.

Which president signed the Endangered Species Act on December 28, 1973?

Richard Nixon signed it into law; five years later the Supreme Court used the act to halt a nearly finished Tennessee dam in order to save the snail darter, a three-inch fish.

Which two federal agencies administer the Endangered Species Act?

The Fish and Wildlife Service and Marine Fisheries Service split the work between land and sea, so sea turtles answer to both: one agency on nesting beaches, the other in the water.

Which bird of prey, once near extinction, left the US endangered list in 2007?

The bald eagle recovered after DDT was banned and its nests and habitat were protected by law; it moved from endangered to threatened in 1995, then off the list altogether.

Which Ohio river caught fire in June 1969 and became a symbol of America's polluted waterways?

The Cuyahoga had burned more than ten times before, far worse in 1952; the 1969 blaze was out in under half an hour and at first drew little notice.

Which Ohio city does the river that famously burned in 1969 bisect?

Cleveland is split into east and west sides by the river; the day after the 1969 fire its mayor, Carl Stokes, led reporters to the scorched railway bridge to draw attention to the pollution.

Love Canal, the neighbourhood built beside a buried chemical dump, is part of which city?

Niagara Falls, New York, saw homes and a school go up beside a canal filled with chemical waste; in 1978 a federal emergency was declared and hundreds of families were moved out.

For how much did Hooker Chemical sell the Love Canal dump site in 1953?

$1 was the price in 1953, when Hooker Chemical covered the dump with earth and sold it; a school and a neighbourhood of homes were then built on and around the buried waste.

The Love Canal scandal led Congress to pass which law in 1980?

Superfund (CERCLA) taxed the oil and chemical industries to pay for cleaning up abandoned dumps and made whoever left the waste liable for the bill.

Which small US state has the most sites on the federal toxic-waste cleanup list?

New Jersey has more National Priorities List sites than any other state, a legacy of its industrial past: the factories that helped build America left contaminated land behind.

How many UN member states have never ratified the Montreal Protocol on protecting the ozone layer?

Zero: it and its parent convention were the first treaties in UN history to be ratified by every country, and with CFCs phased out the ozone layer is on course to recover across most of the world by about 2040.

In what year was the Montreal Protocol agreed?

The Montreal Protocol was agreed in Montreal on 16 September 1987 and entered into force on 1 January 1989.

The 2016 Kigali Amendment targets which gases, used in fridges after CFCs were phased out?

Hydrofluorocarbons spare the ozone layer but trap heat thousands of times better than carbon dioxide; phasing them down could avoid up to half a degree of warming this century.

British scientists reported in 1985 that a seasonal hole in the ozone layer was opening over which continent?

Antarctica's ozone hole, found by Joe Farman's team, was far deeper than anyone had predicted; the shock pushed governments to agree the Montreal Protocol two years later.

Who calculated in 1896 that doubling atmospheric carbon dioxide would warm Earth's surface by several degrees?

Svante Arrhenius published the estimate in 1896 and saw no cause for alarm: he expected a warmer world to bring milder climates and bigger harvests, especially in cold regions.

CFCs were first banned in 1978, years before the ozone hole was found, from which everyday product?

Aerosol spray cans came first: the United States and a few other countries dropped CFC propellants in the late 1970s, while fridges and air conditioners kept theirs for years longer.

Which trade name became the household word for the CFC gases used in fridges?

Freon made fridges and air conditioning commonplace from the 1930s and for decades seemed harmless; it was later banned for destroying the ozone layer.

Which General Motors engineer invented both leaded petrol and the first CFC refrigerants?

Thomas Midgley Jr. found the lead additive in 1921; three years later, to calm fears, he washed his hands in it before reporters, though he had recently recovered from lead poisoning himself.

Clair Patterson, who later exposed lead pollution, reported in 1956 that the Earth is how many years old?

4.5 billion years was his answer, read from the lead in a meteorite; stray lead kept spoiling his samples, which set him on a long campaign that helped get lead out of petrol.

Which country was the last to stop selling leaded petrol for cars, in July 2021?

Algeria used up its last stocks in July 2021, ending almost a century of leaded petrol; the UN estimates the worldwide phase-out prevents more than 1.2 million early deaths a year.

Which device, fitted to most new US cars from 1975, required unleaded petrol?

The catalytic converter cleans exhaust gases but is ruined by lead, so unleaded petrol had to reach the pumps along with it.

Which two emissions react in the atmosphere to cause acid rain?

Sulfur dioxide and nitrogen oxides, mostly from burning fossil fuels, react with water and oxygen in the air to form sulfuric and nitric acids, which winds can carry far from the chimneys that made them.

Which city did the Great Smog of December 1952 smother for five days?

London's smog was so thick that it seeped indoors and cinemas closed because audiences could not see the screen; the outcry led to the Clean Air Act of 1956.

The Great Smog of 1952 was caused mainly by smoke from homes and power stations burning which fuel?

Coal fires burned day and night during a cold snap while windless air trapped the smoke at street level; officials counted 4,000 deaths, but later studies put the toll nearer 12,000.

In 1661 John Evelyn sent Fumifugium, his plea against the capital's smoke, to which king?

Charles II, newly restored to the throne, was urged to move the smokiest trades out of town and plant fragrant gardens; the pamphlet is among the earliest works on air pollution.

Which gas leaked from the Union Carbide plant in Bhopal in December 1984?

Methyl isocyanate, used to make pesticide, escaped overnight after water got into a storage tank and set off a runaway reaction; thousands died in what is often called the world's worst industrial disaster.

Which chemical giant bought Union Carbide in 2001, inheriting survivors' demands over the Bhopal disaster?

Dow bought the company twelve years after Union Carbide settled with India for $470 million, a fraction of the $3.3 billion the government had sought.

Minamata disease, first identified in Japan in 1956, is poisoning by which metal?

Mercury in a chemical factory's wastewater built up as methylmercury in the bay's fish and shellfish, and the fishing families who ate the catch were poisoned.

Between which two countries did the Aral Sea lie?

Kazakhstan and Uzbekistan shared the lake until Soviet irrigation drained it into separate pools; a dam finished in 2005 has since let the northern, Kazakh part partly refill.

Soviet planners shrank the Aral Sea by diverting its rivers to irrigate fields of which export crop?

Cotton was meant to become a major Soviet export; it took so much river water that the lake split into shrinking remnants, leaving fishing boats stranded on dry seabed.

In which Alaskan body of water did the Exxon Valdez run aground in March 1989?

Prince William Sound was fouled after the tanker left its shipping lane to dodge icebergs and failed to turn back in time, hitting Bligh Reef and spilling about 11 million gallons of crude.

Which island nation held a cabinet meeting underwater in 2009 to dramatise the threat of rising seas?

The Maldives' president and ministers signed a call for carbon cuts on the seabed, talking with hand signals and whiteboards, weeks before the Copenhagen climate summit.

For which oil company was the Deepwater Horizon rig drilling when it exploded in April 2010?

BP did not own the rig, which belonged to its contractor Transocean; a US court still ruled in 2014 that the oil company's gross negligence was chiefly to blame for the blowout, which killed 11 workers.

Into which body of water did the Deepwater Horizon well pour oil for 87 days in 2010?

The Gulf of Mexico took millions of barrels before the well was capped that July, and the oil reached the coasts of five US states, from Texas to Florida.

Roughly how much did the Deepwater Horizon disaster cost its oil company in the record 2016 US environmental settlement?

$20.8 billion is the largest environmental settlement in US history; more than $8 billion of it was set aside to restore the damaged coast and its wildlife over fifteen years.

The supertanker Torrey Canyon struck rocks in 1967 off the far tip of which English county?

Cornwall's beaches were coated in oil from the wreck on the Seven Stones reef; ships sprayed the slick with detergents that failed to disperse it and did much damage of their own.

How did Britain try to get rid of the wrecked tanker Torrey Canyon and its oil?

Bombing it from the air was a last resort to sink the wreck and burn off its oil; a quarter of the 42 bombs first dropped missed the stationary ship.

Where did a 1969 oil-platform blowout foul miles of American coast and help to inspire the first Earth Day?

The Santa Barbara Channel blowout sent up to 100,000 barrels of crude onto California beaches; the outrage also helped bring about the National Environmental Policy Act.

The Great Pacific Garbage Patch lies between California and which Pacific islands?

Hawaii and California bracket its best-known part, but there is no island of rubbish to see: most of its pieces are tiny fragments spread so thinly that satellites cannot pick the patch out.

Charles Moore stumbled on the Great Pacific Garbage Patch in 1997 while sailing home from what?

A yacht race had just ended when Moore steered home through a remote stretch of ocean; scientists had predicted the patch years earlier, but it took a racing skipper to stumble on it.

The Ocean Cleanup, which trawls plastic from the Pacific, was founded by a teenager from which country?

The Netherlands: Boyan Slat was 16 when he saw more plastic bags than fish on a diving holiday in Greece and asked why nobody was cleaning it up; two years later he started the group.

Which country did a 2021 study rank first for river-borne plastic entering the ocean?

The Philippines accounted for more than a third of the total, as small rivers drain crowded cities such as Manila; the study overturned the view that a few giant rivers like the Yangtze carry most of the plastic.

Which flood-prone country became the first in the world to ban thin plastic bags, in 2002?

Bangladesh banned thin polythene bags in 2002 after discarded bags were blamed for blocking drains and waterways and worsening floods in the low-lying country.

Which BBC series is credited with a lasting surge of attention to plastic pollution in 2017?

Blue Planet II, narrated by David Attenborough, was the UK's most-watched programme of 2017, drawing over 14 million viewers; after it aired, the BBC pledged to ban single-use plastics across its operations by 2020.

The recycling symbol won a 1970 student design contest run by what kind of company?

A cardboard-box maker: Container Corporation of America, a big user of recycled paper, ran the contest to promote paper recycling, and student Gary Anderson won it with his three chasing arrows.

The recycling symbol's three chasing arrows together form which mathematical figure?

A Möbius strip: the folded arrows make a one-sided loop with a twist. The symbol was never trademarked, so anyone may use the design free of charge.

What is the archaeological term for the ancient piles or pits of waste that predate landfills?

Middens are old refuse heaps of shells, bones and broken pots; archaeologists prize them because what people threw away shows what they really ate and used.

In which city did Greenpeace open its first office?

Greenpeace began in Vancouver in 1971 as a small group opposed to nuclear testing in the Pacific; its offices around the world are now coordinated from Amsterdam.

What was Greenpeace's forerunner group called?

The Don't Make a Wave Committee set out to stop a US nuclear test under the Alaskan island of Amchitka, which protesters feared could set off an earthquake and tidal wave; it later took the name of its protest boat, Greenpeace.

Which Canadian singer performed at the 1970 benefit concert that funded the first Greenpeace voyage?

Joni Mitchell played the 16 October 1970 show at the Pacific Coliseum and asked for her then boyfriend, James Taylor, to join the bill; Joan Baez could not appear but helped line up the acts.

In which harbour did French agents sink Greenpeace's Rainbow Warrior in July 1985?

French DGSE agents mined the Rainbow Warrior at Marsden Wharf in Auckland harbour on 10 July 1985; photographer Fernando Pereira drowned.

What became of the wrecked Rainbow Warrior two years after French agents bombed it in 1985?

Scuttled as a dive reef: judged beyond repair, the ship was sunk in Matauri Bay in December 1987, where it now shelters marine life and draws divers.

Which Greenpeace board member was ousted and went on to found Sea Shepherd?

Paul Watson was voted off the Greenpeace board in 1977 because his confrontational tactics clashed with its commitment to non-violence; he founded Sea Shepherd the same year.

Chi Chi, the zoo star who inspired a famous conservation logo in 1961, was what kind of animal?

A giant panda: Chi Chi reached Britain in 1958 and became its best-known zoo animal, so when WWF was founded three years later Sir Peter Scott drew its logo from her.

In which country was WWF conceived, and its first office opened, in 1961?

Switzerland: WWF was conceived in the town of Morges in 1961 and opened its first office there, inside the headquarters of the conservation union IUCN, whose work it was set up to help fund.

Which organisation runs Earth Hour?

The World Wildlife Fund, known worldwide as WWF, started Earth Hour in 2007; landmarks such as Big Ben go dark for the hour as a show of support for the planet.

In which city did Earth Hour begin as a lights-off event in 2007?

Sydney held the first Earth Hour on 31 March 2007, planned under the working title 'The Big Flick'; that October San Francisco copied it with its own 'Lights Out', and the event soon went worldwide.

Who founded the Sierra Club in San Francisco in 1892?

John Muir founded the Sierra Club in 1892 and led it until his death in 1914, a year after the club lost its long fight to stop Yosemite's Hetch Hetchy Valley being dammed.

In which country was the 'Father of the National Parks' born?

Scotland: the 'Father of the National Parks' was born in Dunbar in 1838 and left for a Wisconsin farm as a boy in 1849; his magazine articles of 1890 helped persuade Congress to create Yosemite National Park.

Which president signed the act creating Yellowstone, the world's first national park, in 1872?

Ulysses S. Grant signed the Yellowstone act on 1 March 1872, but poaching went on unchecked until the US Army took charge of the park in 1886 and ran it for three decades.

Which Kenyan founded the tree-planting Green Belt Movement and won the 2004 Nobel Peace Prize?

Wangari Maathai's movement helped Kenyan women plant more than 20 million trees, and in 1989 her protests stopped a skyscraper planned for Uhuru Park, Nairobi's main public space.

Which children's-book character 'speaks for the trees' as a greedy factory owner chops them all down?

The Lorax pleads for the Truffula trees in Seuss's 1971 book until the last one falls, then lifts himself away, leaving a pile of rocks bearing a single word, 'UNLESS'.

What does 'Chipko', the name of India's 1970s forest movement, mean in Hindi?

Hugging, or clinging: villagers wrapped their arms around trees so loggers could not fell them, and in 1980 the protests won a 15-year ban on commercial felling in their Himalayan forests.

Who led the women of Reni village in facing down loggers during the Chipko movement's key stand-off of 1974?

Gaura Devi rallied the women after officials had drawn the village men away with a promise of compensation; they stood their ground among the trees until the loggers gave up and left.

Julia Butterfly Hill lived for two years in the late 1990s in which kind of tree to save it from loggers?

A redwood: Hill spent 738 days in the 1,000-year-old California tree known as Luna, coming down in December 1999 only after Pacific Lumber agreed to spare it.

Where did 15-year-old Greta Thunberg hold the 2018 solo school strike that inspired Fridays for Future?

Outside the Swedish parliament: Thunberg sat there every school day for the three weeks before the 2018 general election, then kept striking each Friday, which gave Fridays for Future its name.

Which utility did Erin Brockovich help build a groundwater-contamination case against in 1993?

Erin Brockovich helped build the case against Pacific Gas & Electric over hexavalent chromium in the groundwater of Hinkley, California; PG&E settled for $333 million in 1996, and Julia Roberts played her in the 2000 film.

The 2014 Michigan water crisis began when one city switched its supply to which source?

Flint switched its supply from Detroit's Lake Huron water to the Flint River in April 2014; officials failed to add corrosion inhibitors, so lead leached from old pipes.

In which Ukrainian plant did reactor 4 explode on 26 April 1986?

Reactor 4 at the Chernobyl plant near Pripyat exploded during a botched safety test; it is one of only two accidents rated level 7, the maximum on the International Nuclear Event Scale.

Radiation from the 1986 Soviet reactor explosion was first detected abroad at a plant in which country?

Alarms at Sweden's Forsmark nuclear plant, over 1,000 km from the stricken reactor, went off on 28 April 1986; once the fallout was traced abroad, Moscow was forced to admit the accident.

Near which Pennsylvania city did the Three Mile Island partial meltdown occur in 1979?

Three Mile Island sits in the Susquehanna River near Harrisburg; about half the reactor core melted, yet regulators found no detectable health effects from the small radioactive releases.

Which nuclear accident shares the maximum level 7 rating with the 1986 Soviet reactor explosion?

Fukushima was rated level 5 within a week, the same as Three Mile Island, but a month after the 2011 tsunami regulators raised it to the maximum 7 as the scale of its radioactive releases became clear.

Which country left the International Whaling Commission in 2019 and resumed commercial whaling?

Japan quit the commission in 2019 and restarted commercial hunts in its own waters, ending three decades of 'research' whaling in the Southern Ocean carried out under the commission's ban on commercial catches.

The wildlife-trade treaty CITES is also known by the name of which city?

CITES is also called the Washington Convention because delegates from 80 countries agreed its text in Washington, DC, on 3 March 1973, a date the UN now marks as World Wildlife Day.

The Ramsar Convention on wetlands is named after a Caspian Sea resort in which country?

Ramsar is a resort in northern Iran where the wetlands convention was adopted on 2 February 1971, a date now marked each year as World Wetlands Day.

As of 2024, which country had designated the most Ramsar wetland sites?

As of 2024 the United Kingdom had designated 175 Ramsar sites, more than any other country, with Mexico second on about 140.

On the IUCN Red List in 2023, which of these animal groups had the highest share of threatened species?

Amphibians: a 2023 global assessment found about 41% of species threatened, against 27% of mammals, 21% of reptiles and 13% of birds, with climate change now the biggest driver of new declines.

Which three IUCN Red List categories are collectively called 'threatened'?

Critically Endangered, Endangered and Vulnerable are the Red List's 'threatened' categories; the Iberian lynx improved from Endangered to Vulnerable in 2024 after breeding and reintroductions rebuilt its numbers.

The founders of the Environmental Defense Fund linked DDT to what problem in large birds?

The Environmental Defense Fund's founders traced collapsing osprey numbers on Long Island to DDT, which caused thinning of egg shells; their lawsuits won a local ban, then a state ban, then a national one.

On which date is the UN's World Environment Day celebrated?

World Environment Day is 5 June; the first, in 1973, had the theme 'Only One Earth' and the day is led by the UN Environment Programme.

Which 1972 UN gathering established World Environment Day?

The Stockholm Conference of June 1972 was the UN's first world conference on the environment; besides World Environment Day, it led to the creation of the UN Environment Programme.

Which US environmental charity, founded in 1951, is best known for protecting land by buying it?

The Nature Conservancy made its first deal in 1955, helping neighbours buy 60 acres of hemlock forest in New York's Mianus River Gorge; it has since protected more than 100 million acres.

How many greenhouse gases does Kyoto Protocol Annex A list for its second commitment period?

Annex A covers seven gases for the 2013-2020 second commitment period: the original six (carbon dioxide, methane, nitrous oxide, HFCs, PFCs and sulfur hexafluoride) plus nitrogen trifluoride, added by the 2012 Doha Amendment.

Which country withdrew from the Kyoto Protocol, effective December 2012?

Canada announced its withdrawal in December 2011, a day after the Durban climate talks; environment minister Peter Kent said staying in would cost $14 billion in penalties for missing its target.

What preferred limit on global warming does the Paris Agreement set?

The Paris Agreement's binding aim is to hold warming 'well below 2 °C' while 'pursuing efforts' to limit it to 1.5 °C, the preferred figure pushed by small island states.

Which two UN bodies set up the Intergovernmental Panel on Climate Change in 1988?

WMO and UNEP, the UN's weather and environment agencies, set up the panel in 1988; it does no research of its own, relying on volunteer scientists to assess thousands of published studies.

With whom did Al Gore share the 2007 Nobel Peace Prize?

The IPCC, the UN's climate-science panel, split the prize equally with Gore 'for their efforts to build up and disseminate greater knowledge about man-made climate change'.

Which media mogul co-created the 1990 eco-superhero cartoon Captain Planet and the Planeteers?

Ted Turner created Captain Planet with producer Barbara Pyle and aired it on his TBS network, with stars such as Whoopi Goldberg, Sting and Meg Ryan voicing the Earth spirit and the villains.

Which set of 17 global goals did all UN members adopt in 2015, with a 2030 deadline?

The Sustainable Development Goals replaced the eight Millennium Development Goals, which had targeted developing countries only; the 17 new goals apply to every nation, rich and poor alike.

Which country holds about a fifth of the world's forest, more than any other nation?

Russia had over 800 million hectares of forest in the FAO's 2020 count, a fifth of the world total and well ahead of second-placed Brazil; forests cover about 31% of Earth's land overall.

Which activity directly caused nearly 90% of global deforestation between 2000 and 2018?

Agriculture: an FAO satellite survey found cropland expansion caused about half of the forest loss and livestock grazing almost 40%; logging counts as deforestation only when the land is put to another use.

As of 2024, which single renewable source generated the most electricity worldwide?

Hydropower supplied about 14% of the world's electricity in 2024, ahead of wind at 8% and solar at 7%; solar output, though, had doubled in just three years.

Under whose mentorship did Jane Goodall begin studying chimpanzees at Gombe Stream in 1960?

Louis Leakey sent Jane Goodall to Gombe in 1960 and later got her into Cambridge, where she earned a PhD in ethology without ever having taken an undergraduate degree.

Dian Fossey studied mountain gorillas in which country until her murder in 1985?

Rwanda: Fossey began in the Congo in 1967, but soldiers forced her out within months, so she founded the Karisoke Research Center just across the border and worked there until she was killed in 1985.

In 2016, more than 100 Nobel laureates signed a letter urging Greenpeace to end which campaign?

Its opposition to GMOs: the letter singled out Golden Rice, bred to fight the vitamin A deficiency that blinds up to 500,000 children a year, and asked how many must die before this counted as a 'crime against humanity'.

Which city hosted the UN Conference on Environment and Development in June 1992?

Rio de Janeiro hosted the 1992 'Earth Summit', which produced the UN climate convention behind the annual COP meetings and a sister treaty on biodiversity.

The Keeling Curve of rising CO2 rests on measurements begun in 1958 at which observatory?

Mauna Loa, Hawaii: Keeling's first reading there in March 1958 was 313 parts per million, and the record soon showed a yearly zigzag as plants draw down CO2 each growing season, like the planet breathing.

Which forester's 1949 essay collection A Sand County Almanac introduced the idea of a 'land ethic'?

Aldo Leopold died fighting a neighbour's grass fire in 1948, so his son Luna saw the essays into print the following year; more than two million copies have since been printed.

The Great Green Wall, a belt of trees planned across Africa, is meant to hold back which desert?

The Sahara is the desert the African Union set out to contain with a wall of trees stretching from Dakar in Senegal to Djibouti. The original plan ran 7,775 km long and 15 km wide.

Which planet's runaway greenhouse effect makes it the hottest in the solar system, at about 464 °C?

Venus may once have had liquid surface water before its greenhouse effect ran away and evaporated it. The air there now presses down 92 times harder than Earth's does at sea level.

Which rainforest, spread across nine nations, makes up over half of Earth's remaining rainforest?

The Amazon holds an estimated 390 billion individual trees belonging to about 16,000 species. Brazil has 60% of the forest, followed by Peru with 13% and Colombia with 10%.

Which island nation gets almost all of its electricity from hydropower and geothermal plants?

Iceland draws about 70% of its power from rivers and nearly 30% from underground heat. That same hot water warms roughly nine in ten of the country's homes through district pipes.

Lonesome George, dubbed the rarest creature in the world, was the last of a subspecies of which animal?

Giant tortoise Lonesome George was the last of the Pinta Island subspecies, first seen alone there in 1971. Eggs laid by his female companions in 2008 all proved inviable.

Where is most of Earth's fresh water held, dwarfing the amount in every lake and river combined?

Ice caps and glaciers lock up about 69% of the planet's fresh water, and groundwater holds most of the rest. All the lakes, rivers and swamps together account for only about 0.3%.

Martha, who died at the Cincinnati Zoo in 1914, was the last known member of which bird species?

Passenger pigeon flocks once numbered three to five billion birds, making the species the most abundant in North America. One 1866 flock over Ontario was said to take 14 hours to pass.

Which voice of Life on Earth and Planet Earth has won BAFTAs in black-and-white, colour and 3D?

David Attenborough is the only person to have won BAFTA Awards in black-and-white, colour, high-definition, 3D and 4K. His 1979 series Life on Earth set a benchmark for wildlife film-making.

Which animal, cut from about 60 million to 541 by 1889, became the US national mammal in 2016?

American bison went from vast herds before the 1870s to near extinction in the 1880s. Recovery efforts brought the wild population back to roughly 31,000 by 2019.

Which vast wetland did Marjory Stoneman Douglas recast as a slow 'River of Grass' in a 1947 book?

The Everglades is a shallow river about 60 miles wide that creeps south from Lake Okeechobee to Florida Bay at roughly half a mile a day. That sheet of moving water gave it the nickname.

The ozone layer that blocks most of the Sun's ultraviolet rays sits in which part of the atmosphere?

The stratosphere holds the ozone layer roughly 15 to 35 km above the ground. There it soaks up 97 to 99% of the Sun's medium-frequency ultraviolet light, which would otherwise harm life at the surface.

Which greenhouse gas, the main ingredient of natural gas, is belched out by cattle and seeps from landfills?

Methane traps about 80 times as much heat as carbon dioxide over a 20-year period. Belching cattle and other ruminants account for roughly 22% of the amount the United States emits each year.

Which term did zoologist Robert Paine coin after an experiment in which he removed starfish from a rocky shore?

Keystone species was Paine's 1969 name for an animal whose effect on its surroundings far outweighs its numbers. He took it from the wedge atop an arch, which bears the least pressure yet holds every other stone up.

Which process, fed by fertiliser washing down the Mississippi, creates a summer 'dead zone' in the Gulf of Mexico?

Eutrophication is an overdose of nutrients that feeds vast algal blooms, and the decay of those algae strips oxygen from the water. Autumn storms break the Gulf's dead zone up, and it re-forms each spring.

Which process makes top predators such as swordfish far more toxic than anything lower in their food chain?

Biomagnification raises the concentration of a long-lived pollutant at every step up a food chain. That is why ospreys and eagles can carry far more of a poison than direct exposure would explain.

Which biome of pines, spruces and larches covers about 11.5% of Earth's land in a belt across the far north?

Taiga, also known as boreal forest or snow forest, is second in area only to the world's deserts and dry shrublands. Its eastern Siberian stretch is one vast forest of larch.

Which salt-tolerant trees line tropical coasts, blunting storm surges while young sharks shelter among their roots?

Mangroves have a salt filtration system and tangled roots that let them survive conditions that kill most plants. Their swamps shield coasts from erosion, cyclones and tsunamis.

Which crusty growths on rocks and tree bark are used as cheap living gauges of air pollution?

Lichens, each a partnership of fungus and algae, are so sensitive that very badly polluted air can leave none at all. A few tough kinds do cling on to city pavements and walls.

Which ocean life produces at least half of the oxygen made on Earth, despite being about 1% of plant biomass?

Phytoplankton are microscopic drifters that carry out about half of all the photosynthesis on Earth. They take in carbon dioxide as they do it, just as land plants do.

Which waterlogged landscapes cover about 3% of the globe yet store more carbon than all the world's forests?

Peatlands are the largest natural carbon store on land, holding over 600 gigatons in their soils. They form where waterlogging starves dead plants of oxygen, so the litter never fully rots.

Which phrase did ecologist Garrett Hardin make famous in an essay about shared resources ruined by self-interest?

Tragedy of the commons was the title of Hardin's 1968 essay, whose chief worry was overpopulation. Economist Elinor Ostrom, a later Nobel laureate, is seen by some as having refuted his claims.

Which chemist named his theory of a self-regulating Earth after a Greek goddess, on novelist William Golding's advice?

James Lovelock formulated the Gaia hypothesis in the 1970s with microbiologist Lynn Margulis. Early critics attacked it for implying that Earth keeps itself fit for life on purpose, a reading he rejected.

Which US president put about 230 million acres under public protection and created the first 51 federal bird reserves?

Theodore Roosevelt also founded the US Forest Service, signed five national parks into being and proclaimed 18 national monuments under the Antiquities Act of 1906.

Which book records Henry David Thoreau's two years in a cabin he built on woodland owned by Ralph Waldo Emerson?

Walden covers two years, two months and two days beside a pond near Concord, Massachusetts. Thoreau even ran experiments to measure the depth of the supposedly bottomless water.

Which wonder off Queensland, the biggest single structure built by living organisms, can be seen from outer space?

The Great Barrier Reef is made up of over 2,900 individual reefs built by billions of tiny coral polyps. Studies found that it lost more than half of its coral cover between 1995 and 2017.

Which scaly mammals, poached for armour made of the same keratin as fingernails, are the world's most trafficked?

Pangolins are rated as threatened in all eight species the IUCN has assessed. International trade in every one of them is banned under the strictest listing of the wildlife treaty CITES.

Which bird, the widest-winged in North America, numbered just 27 when the last wild ones were captured in 1987?

California condor numbers fell so low that every remaining wild bird was taken into captivity to breed. Their descendants have since been released in California, Arizona, Utah and Mexico's Baja California.

Which ocean giant, the largest animal known ever to have existed, was hunted almost to extinction?

Blue whale hunting was banned outright by the International Whaling Commission in 1966. The biggest confirmed animals reached about 30 metres long and weighed up to 200 tonnes.

Which measure of how much sunlight a surface reflects is about 0.9 for fresh snow and 0.04 for charcoal?

Albedo drives a vicious circle in a warming Arctic: when bright sea ice melts, the dark ocean beneath it absorbs more sunlight, which melts even more ice.

Which Brazilian rubber tapper and union leader was assassinated in 1988 after fighting to save the rainforest?

Chico Mendes had just stopped a rancher from logging land that rubber tappers wanted as a protected reserve. Brazil's federal conservation agency, ICMBio, is named in his honour.

Which flightless bird of Mauritius vanished less than a century after Dutch sailors first recorded it in 1598?

The dodo was last reliably sighted in 1662. Its swift disappearance first drew attention to a problem nobody had recognised before: that people could wipe out an entire species.

Which animal, brought to Queensland in 1935 to eat crop beetles, had multiplied to over 200 million by 2011?

Cane toad poison kills native predators that try to eat the newcomers, and northern quolls and water monitors have crashed wherever they arrive. The invasion began with a single shipment of just 102 animals.

Which Asian plant, handed out by the US government to stop soil erosion, is now nicknamed 'the vine that ate the South'?

Kudzu arrived from Japan at the 1876 Centennial Exposition in Philadelphia. Officials later distributed 85 million seedlings to hold slopes in place, and plantings on abandoned farms ran wild.

Which shellfish from the Caspian Sea region reached the Great Lakes in ships' ballast water and now clogs water intakes?

Zebra mussel larvae are microscopic, so intakes suck them straight into water plants, where the adults grow densely enough to block pipelines. The name comes from the stripes on the shell.

Which proposed geological epoch, popularised by chemist Paul Crutzen in 2000, was voted down as a formal unit in 2024?

Anthropocene was meant to mark humanity's impact as a new chapter after the Holocene, and Crutzen suggested it began with the Industrial Revolution. The two bodies that rule on geological names turned it down.

What term from a 2004 paper by marine biologist Richard Thompson covers debris under 5 mm from bottles and tyres?

Microplastics either start out tiny, like the particles added to cosmetics, or wear off larger things such as drinks bottles, fishing nets, tea bags and car tyres.

Forests in Indonesia and Malaysia have been cleared for vast single-crop plantations producing which vegetable oil?

Palm oil goes into far more than food: by 2018 half of Europe's imports were being turned into biodiesel. The IUCN has noted that the crop needs much less land and water than rival oils.

Which fish did a 1992 ban protect off Newfoundland after stocks fell to 1% of historic levels?

Atlantic cod had been overfished for decades, and the closure cost about 37,000 fishermen and plant workers their jobs. A pause meant to last two years was made indefinite in 1993.

Which dam, the world's largest power station, forced more than a million people to move when its reservoir filled?

Three Gorges Dam on China's Yangtze displaced between 1.13 and 1.4 million people, depending on the estimate. By the end of 2008 more had been spent on relocating residents than on construction.

Which Asian capital, sinking partly because of groundwater pumping, did a 2022 law set out to replace with Nusantara?

Jakarta faces worsening coastal floods as groundwater extraction and the sheer weight of its buildings pull the land down. Indonesia chose a site in East Kalimantan for the new capital.

Which English river, declared biologically dead in 1957, now supports salmon, seahorses and hundreds of seals?

The Thames smelled so foul in the Great Stink of 1858 that Parliament hung lime-soaked curtains at its windows and discussed moving out of London. Seals are now seen as far upriver as Richmond.

Which African lake, shared by four countries, shrank from 25,000 to 2,000 square kilometres of open water by 1980?

Chad is both the lake and one of the four nations on its shores, with Nigeria, Niger and Cameroon. Climate change and water diversion shrank it, and it has since swung between 2,000 and 5,000 square kilometres.

Which tiny Pacific island nation had about 80% of its land stripped and devastated by a century of phosphate mining?

Nauru's phosphate was found in 1900 and dug until the viable reserves ran out in the 1990s. The mining left its central plateau a barren terrain of jagged limestone pinnacles up to 15 metres high.

Itai-itai disease, whose Japanese name means 'it hurts, it hurts', was mass poisoning by which metal washed from mines?

Cadmium released into rivers by mining companies in Japan's Toyama Prefecture softened victims' bones and made their kidneys fail. The companies were successfully sued for the damage.

Which aquifer beneath eight Great Plains states would need over 6,000 years of rain to refill once pumped dry?

The Ogallala supplies about 30% of the groundwater used for irrigation in the United States. Heavy pumping began after World War II, helped by centre-pivot sprinklers and car engines adapted to drive wells.

In which city did chemist Arie Haagen-Smit trace eye-stinging smog to car exhaust reacting in sunlight?

Los Angeles smog first drew Haagen-Smit in because it was damaging crops. He cracked it with techniques from his research on plant essential oils, and became known as the father of air pollution control.

Which country's oil wells, more than 600 of them, were set alight by retreating Iraqi troops and burned for months?

Kuwait did not see the last of its burning wells capped until 6 November 1991, months after the first were lit. Astronauts aboard the Space Shuttle Atlantis photographed the smoke plumes from orbit.

Which US range has had more than 500 mountains destroyed by coal mining that blasts away their summits?

The Appalachians hold coal seams that mountaintop removal reaches by taking off the ridge above, mostly in West Virginia and eastern Kentucky. The rubble has buried about 2,000 miles of streams.

Which hatchlings head the wrong way up the beach when artificial lights outshine the natural glow of the horizon?

Sea turtles rely on their senses to find the ocean after hatching and can mistake a lamp for the horizon's natural light. It is a common misconception that the hatchlings are drawn to the moon.

Which predator was reintroduced to Yellowstone in 1995, almost seventy years after the last ones there were killed?

Gray wolf numbers in the park hit zero in 1926, and without them elk multiplied until aspen and cottonwood were overgrazed. The park service spent more than 30 years trapping and killing elk instead.