In January 2019 social media filled with the #10YearChallenge: people posted a photo of themselves from 2009 next to a recent one to show how much, or how little, they had changed. The trend was fun, though some critics called it vain, and privacy campaigners wondered whether it was quietly training facial-recognition systems.
Within days, environmental groups, scientists and celebrities turned the format around. Instead of faces, they posted before-and-after pictures of glaciers, coral reefs, sea ice and rainforest. Greenpeace, the Chasing Coral team, Leonardo DiCaprio, UN Environment and Gisele Bündchen were among those who joined in. Some posts were alarming, a few were hopeful, and several stretched the ten years quite a bit.
Below are the most widely shared examples, with what each one actually shows, when the pictures were taken where that is known, and where a caption needed correcting. Before-and-after images are powerful, but they are most useful when the dates, places and sources are clear, so each caption tries to supply that context.
Arctic glaciers: Greenpeace's Svalbard pair
Greenpeace International's post, shared on 17 January 2019, described the pictures as the Arctic "100 years ago" and today. The glacier is Blomstrandbreen, on the west coast of Spitsbergen in Svalbard, Norway. The black-and-white image is an archive photo from 1928, and Swedish photographer Christian Åslund took the colour image for Greenpeace in 2002, so the gap is 74 years, not a century.
The pair at the top of this page shows how far the ice front has moved: the wall of ice that once rose behind the small boat has been replaced by open water and bare mountains. Studies published in 2018 found that Blomstrandbreen has retreated more than 2 km since 1928. Åslund returned to Svalbard aboard the Greenpeace ship Witness in August 2024 to photograph the glaciers again and described seeing the same pattern of retreat at many of them.
Coral reefs and the speed of bleaching
Chasing Coral, the team behind the 2017 Netflix documentary of the same name, made a different point: some changes take weeks, not years. Their images, credited to The Ocean Agency and the XL Catlin Seaview Survey, show a reef in December 2014 and again in February 2015, by which time the colourful coral had bleached white. Bleaching happens when water stays too warm for too long and corals expel the algae that feed them; if the heat lasts, many die.
This widely shared 2008 versus 2018 coral comparison shows a vivid, branching reef next to a dull, broken one. Its exact location and photographer were not given in the posts that spread it, so it is best read as an illustration rather than a record of one site. The decade it covers did include major global bleaching events, including the severe heat stress of 2016 and 2017.
Forests: the Amazon and beyond
Greenpeace USA reposted an image first shared by the activist network Rising Tide North America, with a caption suggesting the meme had finally found a meaningful use. The post helped push the environmental version of the trend into wider circulation in the United States.
Leonardo DiCaprio reposted a satellite comparison from his foundation showing Rondônia, a state in western Brazil, from around 2006 to 2018. Rondônia has long been one of the most heavily deforested parts of the Brazilian Amazon, where roads, cattle ranching and farming have pushed into the forest in a characteristic fishbone pattern visible from space.
This WWF-branded image contrasts dense green forest labelled 2009 with bare, eroded ground labelled 2019. The post did not name the location, so it should be read as a symbolic pairing. Forest loss is driven mostly by agriculture, logging and mining, and once soil is exposed, erosion can make recovery slow.
Sea ice, polar bears and global temperature
A user named Julien Geoffrion paired a healthy-looking polar bear labelled 2009 with a thin bear on a small ice floe labelled 2019. It is an emotional image, but the two photos show different animals in different places, and a single thin bear cannot by itself show what caused its condition. The broader concern is well founded: polar bears rely on sea ice to hunt seals, and less ice means less time to feed.
Shared under the tag #agingchallenge, this pair compares Arctic sea ice in September 1984 and September 2016, using a NASA visualisation that shows the age of the ice. The bright, thick multi-year ice that once covered much of the Arctic Ocean has shrunk sharply, leaving more thin ice that forms and melts within a single year.
Rajat Rai Handa shared NASA Goddard Institute for Space Studies maps of temperature differences across the globe, from the series covering 1884 to 2017, and urged people to act within the next ten years. At the time, NASA put warming since the late 19th century at roughly 0.9°C, with much of that coming in recent decades. Later NASA and international assessments put it above 1°C.
Mountain glaciers across a century
Former Formula E champion Lucas di Grassi posted a 1913 versus 2012 comparison of a mountain glacier, arguing that the challenge that mattered was a much longer one. His tweet encouraged home solar panels, eating less meat and driving electric. Repeat photography of this kind, taking a new photo from the exact spot of an old one, is one of the clearest ways scientists document glacier retreat.
The SDG Academy shared views of the Rhône Glacier in Switzerland in July 2008 and September 2018, with a meltwater lake appearing where ice had been. The glacier, the source of the Rhône river, has retreated about 1,300 metres over the past 120 years and has lost an estimated 60 per cent of its volume since 1850. Every summer, white fleece blankets are spread over part of it to protect the tourist ice grotto, which can reduce melting there by up to 70 per cent.
For the bigger picture, NASA's satellite measurements at the time reportedly showed Antarctica losing around 127 gigatonnes of ice a year and Greenland around 286 gigatonnes, adding to sea-level rise.
Not every story was bad news
UN Environment used the hashtag for a hopeful update from Iberá National Park in north-east Argentina, where jaguars had disappeared during the 20th century. Thanks to a breeding and rewilding programme run with Tompkins Conservation, two cubs had been born there, and in the following years jaguars began to be released back into the wild wetlands.
Gisele Bündchen used the challenge to describe the Água Limpa (Clean Water) project her family started around 2009 in her home town in southern Brazil. She wrote that more than 40,000 trees had been planted along river banks, improving water quality and creating a corridor that brought wildlife back. It is a reminder that restoration is slow, but it does work.
How to read before-and-after images
The environmental #10YearChallenge was effective because it took a playful trend and used it to make slow, hard-to-see changes visible. The examples above also show its weak points. A few things to check whenever you see a pair like these:
- Dates. Is it really ten years, or 74, or two months? The Greenpeace glacier pair was described as a century apart; the true gap was 74 years.
- Place. Are both photos of the same location, from the same viewpoint? Repeat photography and satellite pairs are strongest; mixed stock photos are weakest.
- Season. Glaciers, sea ice and forests all change through the year, so like should be compared with like.
- Source. A named photographer, archive or agency makes a picture far easier to verify.
For more images like these, see Murray Lowe's photographs of regrowth after the Australian bushfires.
Sources: Greenpeace International: Heartbreaking photos illustrate Arctic glaciers' retreat in the last century; Wikipedia: Blomstrandbreen; Wikipedia: Rhône Glacier; Wikipedia: Iberá National Park. Photographs and posts: Christian Åslund/Greenpeace and the Norwegian Polar Institute; The Ocean Agency/XL Catlin Seaview Survey via Chasing Coral; Greenpeace USA and Rising Tide North America; Leonardo DiCaprio Foundation; UN Environment and Tompkins Conservation; Gisele Bündchen; WWF; Julien Geoffrion; Andi Lee Carter; Lucas di Grassi; Rajat Rai Handa; The SDG Academy.
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