Planting seedlings young plant in the morning light on nature background

1204031983

Planting seedlings young plant in the morning light on nature background

Photo by: sarayut Thaneerat

sarayut Thaneerat

Tree Planting and Reforestation Will Help Limit Global Warming

By: Robin Fearon

Planting new trees is one of the most effective ways to reduce atmospheric carbon dioxide (CO2) and limit global warming.

December 03, 2021

As forests grow they remove CO2 from the air through photosynthesis, working as a natural reservoir to store carbon. Planned projects worldwide will plant billions of trees and it is thought that forests will help protect the environment for future generations.

An estimated 420 million hectares (one billion acres) of forest have been lost since 1990, converted to farmland and other uses. But by planting new trees in existing forests (reforestation), and growing in areas with no previous tree cover (afforestation) nations are using nature-based solutions to tackle man-made industrial emissions.

Afforestation is seen as one of the best ways to store carbon. Data gathered by the United Nations (UN) shows that, by 2015, China had planted 79 million hectares (195 million acres) in an effort to stop farmland from turning into desert. Next was the US, which planted forest covering 26 million hectares (65 million acres), ahead of Russia with 20 million hectares (49 million acres).

Aerial view of deforestation in the Amazon caused by the expansion of agricultural areas. - Reserva Legal

1279550313

Aerial view of deforestation in the Amazon caused by the expansion of agricultural areas.

Photo by: Lucas Ninno

Lucas Ninno

Aerial view of deforestation in the Amazon caused by the expansion of agricultural areas.

The US Forest Service says it uses both afforestation and reforestation to restore forestland damaged by events like wildfire, climate change, and insect and disease damage. Benefits it lists from planting include creating new wildlife habitat, improving clean water supply, stopping soil erosion, and sequestering carbon.

Sadly, despite slowing in recent decades, deforestation losses worldwide still outweigh planting gains. Forest areas measuring 10 million hectares (25 million acres) were cut down and cleared every year between 2015 and 2020. That is roughly equal to the land area of Iceland or South Korea each year.

Clearing forest releases CO2 and has contributed 23 percent of all man-made greenhouse gas emissions. One study says it has caused hotter day temperatures in Asia, Europe, and North America. In these regions, where more than 15 percent of tree cover was removed, deforestation led to a third of the increase in average hottest day temperatures.

That impact comes on top of biodiversity and species loss – 80 percent of the world’s known terrestrial plant and animal species are found in forests. Regeneration and afforestation together create a healthier ecosystem for wildlife and plants to flourish. Other benefits include flood prevention, as tree roots absorb excess water, shade to stop soil from drying out, and increased cloud cover and cooling caused by water evaporation.

Research by ETH Zurich shows that there is room to plant an additional one trillion trees on Earth. Some 900 million hectares (2.2 billion acres) of land is currently unused by humans worldwide – similar in size to the land area of the US – that could be forest, storing 205 gigatons (billion metric tonnes) of carbon once the trees mature in 50-100 years.



1165777708

Photo by: Ricardo Lima

Ricardo Lima

Part of the UN’s strategic plan for forests is to increase their area worldwide by three percent by 2030. While it is undoubtedly true that planting trees sequesters carbon, it is a slow process. All trees are not likely to survive, plus the way they are managed and cultivated may emit carbon dioxide or other greenhouse gases. Other plants – hemp for example – could be more effective at sequestration.

Different types of trees and forests are definitely more effective at storing carbon than others, but opinion is split. Commercial fir plantations may be better because they grow quicker, while others highlight broadleaf and conifer mixtures, alongside the plant and animal biodiversity they foster below the canopy.

Charles Darwin’s observation that forests grow better when there is a mixture of different plants and trees, at different stages of growth, is influencing ideas about afforestation. Mixed species use different nutrients from soil and appear to have higher growth rates, partly due to decreased competition for the same food.

What scientists know for sure is that time is a factor, so drone technology is one of the seed dispersal methods being considered for rapid planting. Startups like Flash Forest aim to plant one billion trees using aerial drones by 2028. Projects in Saudi Arabia, India, and Croatia follow similar strategies.

NASA expert analysis of the trillion tree concept says that reforestation and afforestation alone cannot counter climate change: we also need a decrease in fossil fuel emissions. There are questions about how forests compete with farmland, the best places to plant them, and the overall cost.


Satellites are uniquely well placed to tell us more about how Earth reacts to changes in its ecosystems. Their instruments show how forests absorb and emit carbon dioxide, reflect or absorb heat, and alter the water cycle. And this vital data will tell us just how much forests are capable of tackling the tough climate challenges we face.

Next Up

Cutting Methane is Quickest Way to Limit Global Warming Before 2030

President Joe Biden has announced plans to tackle climate change by reducing emissions of the greenhouse gas methane by at least 30% by 2030. His pledge, agreed with the European Union, aims to raise ambitions for world leaders to combat global warming ahead of the critical COP26 climate summit in November.

There's a Biodiversity Crisis--Here's What You Need to Know

Despite the world slowing down during the pandemic and studies hailing the slowdown of pollution and positive benefits on the environment, there’s one thing that continued full throttle: the globe’s biodiversity crisis.

Meet the First Cloned Endangered Animal in North America

This black-footed ferret is not only cute, she is beyond special. Meet Elizabeth Ann, the first endangered animal to be cloned in North America.

Microplastic Pollution Stirs Urgent Worldwide Clean-Up

Microplastics are a toxic timebomb that could plague the planet for centuries if not tackled urgently.

Melting Glaciers Could Flood Society with Problems

Earth’s glaciers are both a precious resource and a fragile ecosystem that is disappearing quickly due to global warming. Scientists warn that glaciers will vanish from the mainland US within decades. And their rapid melting is dangerous to society and the natural systems we rely on.

Meet Dogor, Your 18,000-Year-Old Best "Friend"

Dogor may have died 18,000 years ago, but his body has remained perfectly preserved — all-the-way down to the whiskers.

Frozen Ice Sculptures Could Save a Himalayan Cold Desert

Ladakh, a Himalayan cold desert with stunning mountains and blue waters is no stranger to the impact of a changing climate. But could manmade glaciers save this landscape and its people?

Scientists Have Decoded the Universal Language of Honey Bees

Scientists just made a real-life breakthrough in understanding how bees talk to each other. Learn more about decoding the honey bee waggle dance.

How a Lizard Loses Its Tail (and More Importantly, Keeps it Attached)

Thanks to a complex internal structure, lizards can shed a tail in a pinch… yet keep their tails attached when they need them.

Narwhal: The One With Two Waggly Tails?

Meet Narwhal, an adorable pup with two tails. But how did this anomaly happen? Read on to learn more.