Mongabay’s journalism provides boundless visual storytelling opportunities that reach audiences who don’t consider themselves environmentalists or know much about conservation with information derived from our original news reporting. This year Mongabay videos included some of the most pressing environmental issues of 2021. These included video series about how climate change affects agriculture and food security and highlighted how the pandemic plays a part in the trade of natural resources, especially illegal ones. We reported on extractive projects in Africa, Asia and South America disturbing local communities, how new laws and old traditions help uphold environmental values everywhere, and the conflict between Indigenous peoples and corporations (and governments) in different countries.

We continued our hosted video series Candid Animal Cam, which showed rare footage of wild animals doing their thing uninterrupted. We expanded our explainer video series Mongabay Explains to provide background on the environmental issues that repeatedly appear in our reporting. In 2021 we introduced a new series: Problem Solved, where we explore major environmental problems and examine potential pathways to addressing them.

Here, we rewatch the ten top most watched videos of 2021 on Mongabay’s YouTube channel.

1. Rare buffy-headed marmosets in Brazil’s Atlantic Forest are disappearing

The buffy-headed marmoset is down to no more than 2,500 individuals scattered across dwindling patches of Brazil’s Atlantic Forest. It faces a range of threats, from yellow fever to climate change, but the biggest is hybridization with other marmoset species released into its habitat from the pet trade. Conservationists working to save the species warn that populations are declining rapidly, with little funding for studies or captive-breeding programs and a lack of political will under the current government to act urgently.

2. Seaweed farmers in Indonesia struggle with climate change

Seaweed farmers in Indonesia’s Latonro village are losing business because of climate change. The village in South Sulawesi Province lies near Bone Bay, where saltwater meets freshwater. The seaweed they cultivate (Gracilaria spp) thrives in brackish water. This cultivation has been the community’s leading source of income for 15 years. But increasingly erratic weather patterns make it harder to grow as much seaweed as before.

3. Did the world fix the hole in the ozone layer? | Mongabay Explains

When humans came together to fix the hole in the ozone caused by CFCs, we managed to shrink the hole, and in the next 40 years, it could disappear altogether. Scientists and conservationists hold this example up as a sign that we’re equally capable of tackling other environmental concerns like climate change on a global scale. So how did we fix the ozone depletion problem? The landmark Montreal Protocol on Substances that Deplete the Ozone Layer, such as CFCs, represents a story of practical global cooperation.

4. What are the planetary boundaries? | Mongabay Explains

In 2007, Johan Rockström and Will Steffen set out to answer a fundamental question: “What is the safe operating space for humanity on Planet Earth?” They suggested limits, called Planetary Boundaries — guardrails to keep us a safe distance from these catastrophic tipping points. Because as our population has grown, we’ve pulled more resources away from our life-support systems. We’ve diverted water, land, and minerals to agriculture, industry, and urban development. People began to wonder, “would these pressures eventually prove too much?”

5. Sumatran rhino poop may help save the species

Sumatran rhino dung could help researchers solve a decades-long mystery of how many Sumatran rhinos remain in the wild. Estimates suggest fewer than 80 of these critically endangered rhino species are left, which means there isn’t much genetic diversity left within the remaining population. Limited genetic diversity can have consequences for the successful and healthy breeding of future generations. But researchers hope to find more precise answers about how many Sumatran rhinos are left by digging through their droppings for DNA.

6. What’s going on in the Greater Mekong Region?

The global illegal timber trade generates up to $152 billion a year. This accounts for up to 90% of deforestation in tropical countries and attracts the world’s biggest organized crime groups. Today, illegal logging is responsible for 15% to 30% of global timber production. Estimates vary because complex international supply chains make it difficult to ensure the timber has been lawfully handled at every stage. Illegal logging is devastating forests in the Greater Mekong region, consisting of Thailand, Laos, Cambodia, Myanmar, Vietnam, and China.

7. What is a nurdle? | Mongabay Explains

Anything made of plastic, like our laundry baskets, buckets or water bottles, starts life as nurdles. They are the first step in the manufacturing process after oil. In October 2017, two container ships collided in the South African port of Durban during a severe storm, causing billions of nurdles to spill into the ocean. It was the first time most South Africans had ever heard the word “nurdle,”and suddenly these cute-sounding, lentil-size plastic pellets were the cause of a severe environmental disaster.

8. Can soil fight climate change? | Problem Solved

Can soil fight climate change? In the inaugural video of Mongabay’s new series, “Problem Solved,” Mike DiGirolamo breaks down how soil works, how it can be used as a climate solution, and the challenges that need to be overcome to harness its power.

9. ‘The river will bleed red’: Indigenous Filipinos face down dam projects

For more than five decades, Indigenous communities in the northern Philippines have pushed back against the planned construction of hydropower dams on the Chico River system. For Indigenous communities in Kalinga and Mountain Province, the river is of great importance. They call it their “river of life” and have depended on it for generations.

10. Does planting trees help with climate change? | Mongabay Explains

Planting trees is a strategy that several countries pursue to fight climate change. But how effective is this approach? Experts suggest that there are many factors to take into account when reforesting.

Banner image: A baby Sumatran rhino in Sumatra. Image by Rhett A. Butler / Mongabay.