Ecosystems like this are the unsung heroes of our planet. Absorbing huge amounts of greenhouse gases, they are one of the most effective tools we have in tackling the climate crisis.
Known as “carbon sinks,” mangroves, peatlands and boreal forests have helped cool the Earth for thousands of years.
By storing billions of tons of CO2 in their soil and vegetation, and locking it away underground, they protect us from the worst effects of global warming.
Now they are under threat from deforestation, agriculture and global warming, with the potential to release catastrophic amounts of CO2 into the atmosphere – putting us on a trajectory for devastating climate change.
Here’s the good news. Managed properly, these extraordinary ecosystems can recover and play a vital role in helping us turn the tide in the fight against climate change. Around the world people are working against the clock to protect and restore them. And they need your help.
Explore carbon sinks around the world
Mangroves
Known Mangroves locations
Covering just 0.1 % of the planet’s surface, mangroves flourish on the coastlines of countries in tropical regions.
Sources: Global Mangrove WatchCovering just 0.1 % of the planet’s surface, mangroves flourish on the coastlines of countries in tropical regions.
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Mangroves are small, hardy trees and shrubs that grow in brackish or saline water in coastal regions, where their complex root systems anchor them to withstand the tides. They are one of the best carbon sinks on the planet.
Mangrove soil worldwide holds 4.5 times as much carbon as the US emits every year.
Each acre can store up to twice as much carbon as tropical rainforests, like the Amazon, and three to four times as much as other terrestrial forests.
Mangroves are one of the most threatened ecosystems in the tropical region. Once the trees are destroyed, the carbon stored in the soil is released into the atmosphere as CO2, further adding to climate change.
Mangrove trees grow through photosynthesis, absorbing CO2 from the atmosphere with the help of sunlight and water.
When leaves and organic matter fall off the trees, they take their stored carbon with them. This organic matter builds up amongst the mangrove's roots, where the water slows down the rate of decomposition, locking much of the carbon in place.
Eventually this sediment builds up to create a dense soil, which stores the carbon until it is disturbed by extreme weather events (like tsunamis or hurricanes) or human activity.
Mangroves are an amazing buffer against coastal erosion, tidal surges and tsunamis, which are increasing due to global warming.
They provide an estimated $82 billion-worth of storm protection worldwide.
They support incredibly rich biodiversity both above and below the water, including fish, crabs, shellfish and octopuses.
They are also the main source of food and livelihoods for many coastal communities, benefiting hundreds of millions of people worldwide.
Despite their natural value, mangrove forests are being destroyed and degraded across the planet to make way for shrimp farms, agricultural land, coastal developments and charcoal production.
Recent studies show that manmade destruction of mangroves has dropped dramatically in the early 21st century, offering hope for conservationists. But mangroves aren’t out of danger yet – they are at increasing risk from sea-level rise due to climate change, making their preservation more important than ever.
BIRDS
Many native and migratory birds live in mangrove forests, aiding the mangrove pollination process by distributing seeds. Classified as endangered, the mangrove hummingbird is found along Costa Rica's coasts.
CROCODILES
The largest reptile on Earth, the saltwater crocodile can reach over 21 feet in length. They live along the coastal regions of India, Southeast Asia and northern Australia.
TIGERS
The endangered Royal Bengal tiger is found in Sundarban forest of the Ganges Delta, spanning India and Bangladesh. It lives on a diet of fish, frogs and lizards.
MONKEYS
The dense mangrove foliage in Borneo provides an ideal home for Proboscis monkeys. Their webbed hands and feet make them excellent swimmers and help them avoid hungry crocodiles.
CRABS
Found in the mudflats of mangrove forests, fiddler crabs ingest organic waste and bury it in the mud, filtering and redistributing nutrients, which helps mangroves to grow.
FISH
The colorful rainbow parrotfish is a prominent herbivore along the coast of south Florida. It lives between mangroves and coral reefs, helping to maintain healthy coral by keeping algae in check.
BIODIVERSITY
Mangrove forests have incredibly rich biodiversity and are home to many species of birds, insects, reptiles and mammals. The long, tangled roots of mangroves are important breeding grounds for fish.
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In Cispatá Bay, Colombia, mangroves grow along the edges of the Caribbean Sea, part of a forest that covers some 2,500 square miles.
Alongside storing carbon, the mangroves protect coastal communities from storm surges, and provide food and firewood. But illegal farming, fishing and logging, as well as unsustainable tourism and climate change, threaten this ecosystem.
Apple partnered with environmental NGO Conservation International on a project to protect and rebuild 42 square miles of mangrove forest here, which they hope will remove an estimated 1 million metric tons of carbon dioxide from the atmosphere in its lifetime.
The funding is helping field assistants to accurately measure the amount of carbon stored in the trees and soil. From this information, verified carbon offsets can be sold, where companies can balance out their carbon emissions with payments that will be used to conserve and restore the mangroves. If successful, it’s hoped the project will provide a model for similar initiatives around the world.
The biggest threat to mangroves worldwide is shrimp farming and aquaculture. Industrial shrimp farming involves diverting the natural flow of water through mangrove forests into large ponds, disrupting seed dispersal and changing the delicate balance of salt and freshwater essential to maintaining healthy mangroves.
The huge environmental cost to mangroves can make farmed shrimp more carbon intensive than beef pound for pound. Avoiding farmed shrimp or buying from sustainable sources can help protect mangrove forests worldwide. Check out these sustainable seafood guides from WWF and the Marine Conservation Society.
The biggest threat to mangroves worldwide is shrimp farming and aquaculture. Industrial shrimp farming involves diverting the natural flow of water through mangrove forests into large ponds, disrupting seed dispersal and changing the delicate balance of salt and freshwater essential to maintaining healthy mangroves.
The huge environmental cost to mangroves can make farmed shrimp more carbon intensive than beef pound for pound. Avoiding farmed shrimp or buying from sustainable sources can help protect mangrove forests worldwide. Check out these sustainable seafood guides from WWF and the Marine Conservation Society.
Peatlands
>50% peatlands
20-50% peatlands
This map shows known peatland locations. According to UNEP, “It does not reflect the true global extent of peatlands because of the challenges faced in finding and defining them. Recent modeling studies indicate that there could be three times more tropical peatlands than current estimates."
Sources: Global Peatland Database, 2020 - Greifswald Mire Centre in collaboration with UNEP and the Global Peatlands InitiativePeatlands cover around 3% of Earth’s land surface and are found in an estimated 180 countries across all continents.
This map shows known peatland locations. According to UNEP, “It does not reflect the true global extent of peatlands because of the challenges faced in finding and defining them. Recent modeling studies indicate that there could be three times more tropical peatlands than current estimates."
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>50% peatlands
20-50% peatlands
Sources: Global Peatland Database, 2020 - Greifswald Mire Centre in collaboration with UNEP and the Global Peatlands Initiative
Peatlands, which include bogs and fens, are waterlogged landscapes that hold vast stores of carbon in their soil. They can be open treeless areas or found beneath forests, grasslands and marshes.
Peatlands are the largest terrestrial carbon store, holding twice as much carbon as all the Earth's forests and more than all the rest of the world’s vegetation combined.
As well as absorbing CO2 from the atmosphere, peatlands also help to filter water and protect against flooding and drought.
Sphagnum moss is one of the most important plants in peatland ecosystems, absorbing huge amounts of water and preventing the decay of organic matter, helping peat to form and locking away carbon.
Active peatland, where plants grow on the surface, absorbs CO2 from the atmosphere and stores it in the roots and soil underground.
The large amount of water in the soil slows down the decomposition of dead plant matter, keeping much of the carbon from being released back into the atmosphere.
This partially decomposed material accumulates and compacts over time to form a layer of peat densely packed with carbon which, if undisturbed, can be locked away for millennia.
The biggest threat to peatlands worldwide is agriculture, where peatlands are drained and dried out to use as farmland. Infrastructure projects, commercial forestry and peat extraction for fuel and horticulture also cause extensive damage. Global warming increases the effects of drainage and risks of forest and peat fires.
Drained peatlands are also highly flammable and peatland fires can burn for months undetected underground, releasing huge amounts of CO2 and causing dangerous pollution for neighbouring areas.
Three months of peatland fires in Borneo in 2019 released more CO2 than the entire annual output of Australia. The fires also posed a grave threat to the island’s endangered orangutan population which lives in its peatland swamp forests.
REPTILES
The viviparous lizard or “common lizard” is found in peatland, moorland and grassland across Northern Europe, Eurasia and North Asia. It hibernates in colder months to preserve its body temperature.
BIRDS
The wood sandpiper is a migrant species, using peatlands in Northern Europe and tundra regions as a stopover. Along with other birds, it is under threat in Nordic regions due to peatland drainage.
BUTTERFLIES
The large heath butterfly has adapted to the wet, acidic conditions of peatlands. It feeds on a common peatland plant, hare’s-tail cottongrass, and its caterpillars can survive underwater for a short time if submerged.
MAMMALS
The mountain hare is found on Scotland’s blanket bogs – its grey-brown summer coat turns white in winter to allow it to blend in with the snowy landscape.
SPIDERS
A key plant species in peatlands, sphagnum moss provides protection for spiders such as the wolf spider, which lives amongst its stalks and enjoys the high humidity.
BIODIVERSITY
Peatlands are home to many rare plant and animal species that have adapted to their wet, acidic conditions. They are also an important feeding and breeding ground for many types of birds.
Rollover the image to discover more about this ecosystem's biodiversity
Tap the image to discover more about this ecosystem biodiversity
Peatlands make up a fifth of the Scottish landscape and store around 1.6 billion metric tons of carbon – equivalent to more than 140 years of the country’s greenhouse gas emissions.
Around 80% of that land has been degraded by activities including heavy grazing and draining the soil for agriculture and forestry. But the Peatland ACTION project is working to restore it.
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With funding from the Scottish government, 96 square miles of damaged peatlands – an area roughly the size of Edinburgh – has been put on the road to recovery since 2012. The restoration process includes blocking drains that have been cut in the peat to allow it to rewet.
In February 2020, the Scottish government announced it would invest £250 million ($320 million) in peatland restoration over the next 10 years. It is aiming to restore 965 square miles in that time.
As well as providing a significant carbon store, the Scottish peatlands are an important habitat for butterflies and owls, reduce flood risk and improve water quality.
The growth of the palm oil industry in Indonesia has caused vast swaths of peatland swamp forest to be cleared and burned for agricultural use. Indonesia now supplies over half of the world’s palm oil, with research showing 11,583 square miles of tropical peat swamp forests in Malaysia and Indonesia have been replaced by palm oil plantations.
Palm oil is used in many consumer products, from processed snacks like instant noodles, cookies, ice-cream and chocolate to shampoo, cosmetics and detergent. Avoiding products that contain palm oil could help protect peat swamp forests. Check out the World Wildlife Fund’s Palm Oil Buyers Scorecard to see how food, retail and manufacturing companies rate on sustainability. You can also help by avoiding fuel or horticulture products that contain peat or use peat-free alternatives.
The growth of the palm oil industry in Indonesia has caused vast swaths of peatland swamp forest to be cleared and burned for agricultural use. Indonesia now supplies over half of the world’s palm oil, with research showing 11,583 square miles of tropical peat swamp forests in Malaysia and Indonesia have been replaced by palm oil plantations.
Palm oil is used in many consumer products, from processed snacks like instant noodles, cookies, ice-cream and chocolate to shampoo, cosmetics and detergent. Avoiding products that contain palm oil could help protect peat swamp forests. Check out the World Wildlife Fund’s Palm Oil Buyers Scorecard to see how food, retail and manufacturing companies rate on sustainability. You can also help by avoiding fuel or horticulture products that contain peat or use peat-free alternatives.
Boreal Forest
Known Boreal forest locations
Boreal forest or “taiga” circles the Northern hemisphere, spanning Alaska, Canada, Russia and parts of Europe and Asia, and accounts for around one third of the Earth’s forests.
Sources: Map data @2020 INGEI Imagery @2020 NASA TerraMetrics/RESOLVE EcoregionsBoreal forest or “taiga” circles the Northern hemisphere, spanning Alaska, Canada, Russia and parts of Europe and Asia, and accounts for around one third of the Earth’s forests.
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Boreal forests store nearly double the carbon of tropical forests, mostly underground in carbon-rich soil and peatland. Boreal regions are also underlain by vast swaths of permafrost – continuously frozen ground – which contains huge amounts of carbon. There is now around twice as much carbon in permafrost as in the Earth’s atmosphere.
Permafrost in boreal regions depends on the thick blanket of soil, and shade from vegetation, to keep it from thawing during summer.
However, global warming and increased forest fires are causing permafrost to thaw and start releasing its carbon stores as CO2 and methane -- a greenhouse gas with around 30 times the heat-trapping ability of CO2 over a 100-year timespan.
Scientists fear boreal forests and permafrost may reach "tipping points" by the end of this century at the current rate of global warming – leading to irreversible changes.
As they release more stored carbon they will exacerbate global warming, which will in turn damage them further, making them potentially the biggest carbon source in the world.
Boreal ecosystems absorb CO2 from the atmosphere through trees and vegetation.
Over thousands of years, this carbon accumulates underground in the cold conditions, and high moisture levels help peat to form in some areas.
Many boreal regions also have underlying permafrost, where frozen soil locks huge amounts of carbon underground.
Logging, mining and oil and gas extraction threaten boreal forests, reducing the forest cover, disrupting habitat for wildlife and often introducing toxic chemicals into pristine water systems.
Boreal forests are particularly susceptible to climate change, with temperatures in the Arctic and boreal regions rising twice as fast as other parts of the world.
Scientists predict the increase in atmospheric CO2 from degraded forests, wildfires and permafrost thaw will encourage more plant growth, potentially offsetting some of these emissions, but it is unclear how much of a difference this will make in the long-term.
BIRDS
The snowy owl spends its summers in the Arctic and migrates south to boreal regions for winter. It hunts during the day, relying on its white feathers for camouflage against the snow.
CARIBOU
Reindeer by another name, woodland caribou are the only ungulate (hoofed mammal) with antlers on both the male and female of the species, which can grow up to 2.5cm per day.
WOLVERINE
These hardy, solitary mammals have large “snowshoe-like” feet and thick fur to withstand harsh conditions and can travel up to 15 miles a day in search of food.
LYNX
These large solitary cats hunt at night with the help of their keen eyesight. Canadian lynx prey on small mammals like voles and squirrels but their favourite meal is a snowshoe hare.
BIODIVERSITY
Boreal forests are some of the world’s last remaining tracts of wilderness, home to a wide array of animals. They are also breeding grounds for billions of birds that migrate from the Americas.
Rollover the image to discover more about this ecosystem biodiversity
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The ancient Dvinsky forest, in northwest Russia, is home to bears, flying squirrels, wolverines and more than 60 other species of rare animals and plants.
Part of the world’s largest boreal forest, it also stores almost 400 million metric tons of carbon in its biomass, soil and peatlands, according to WWF-Russia - the CO2 emissions equivalent to the annual energy used by almost 170 million US homes.
Decades of unsustainable logging mean much of the forest has been lost. WWF-Russia says that without conservation measures, the 4,000-year-old forest could disappear in just 15-20 years, and Russia could lose all its intact forests in 80 years, releasing their carbon stores into the atmosphere.
But after 17 years of negotiation between timber companies, the regional government and conservation groups including WWF and Greenpeace, a protected area has been agreed.
It will cover over 1,166 square miles – an area four times the size of New York City – around 40% of Dvinsky forest, and aims to balance the needs of the environment with those of the locals.
While no industrial logging will be allowed in the reserve, local communities will still be able to use the area for activities like mushroom and berry picking, fishing and hunting, which can be an important source of income.
Reducing global carbon dioxide emissions is vital to protecting boreal forests and the huge carbon stores they hold frozen underground. Changes to lifestyle, including diet, transport and energy use can help reduce your carbon footprint. Check out our guide to five ways you can reduce your carbon emissions.
Boreal forests provide up to one third of the wood and a quarter of the paper products used worldwide, so sustainable forest management is essential to their protection.
Reducing global carbon dioxide emissions is vital to protecting boreal forests and the huge carbon stores they hold frozen underground. Changes to lifestyle, including diet, transport and energy use can help reduce your carbon footprint. Check out our guide to five ways you can reduce your carbon emissions.
Boreal forests provide up to one third of the wood and a quarter of the paper products used worldwide, so sustainable forest management is essential to their protection.