If we don’t take relevant actions to fight climate change, there will be severe consequences on the economy, society and nature. The only way to reduce these effects is to move towards net zero global emissions by 2050.
However, the current global carbon dioxide level in the atmosphere is 413.25 ppm1 (parts per million), the highest level in the past 800,000 years! Over the past years, the global growth rate of atmospheric CO₂ has been 2.3 ppm per year. According to NOAA, this rate is about 100 times faster than previous natural increases2!
So, it’s not surprising that we must work hard to reverse this situation. Although most people think that planting a few trees will magically solve the problem, the solution is far more complicated. In this article, you will learn why trees can’t solve climate change alone and what other alternatives we have!
What are Negative Emissions
As you may have noticed, we don’t have a healthy level of CO₂ in the atmosphere. It should be reduced to at most 350 ppm to be considered “safe”, according to the Yale School of the Environment3. Therefore, we also need to remove what’s already in the atmosphere - that’s where negative emissions come in!
Negative emissions are the opposite of emissions. It’s the act of absorbing CO₂ from the atmosphere and permanently storing it in a different way. This is what we need to reverse what we’ve done to nature! And it’s possible with CO₂ removal practices and technologies.
That said, it’s important to mention that carbon removal is not an excuse to avoid reducing emissions and deforestation. They should go hand in hand to fight climate change. There’s already too much CO₂ in the atmosphere and if we don’t reduce our emissions the conditions we have today will only stay the same or get even worse.
Trees are not the Silver Bullet for Climate Change
We all know that trees absorb CO₂ from the atmosphere and how important they are for nature. Unfortunately, we’ve put so much CO₂ in the atmosphere that trees can’t remove all of it by themselves. We must help them.
Right now, the global forest area is 4.06 billion hectares4, which covers 31% of the global land area. Likewise, this map5 shows there are approximately 3.04 trillion trees in the world. On the other hand, the rate of deforestation is estimated to be about 10 million hectares per year4!
Even though one study claimed that we could plant a trillion extra trees on 0.9 billion hectares6 to fight climate change, there are some inconsistencies:
Trees Grow Slow
New trees will need at least 10 years to have a good carbon sequestration rate and depending on the species, it could take more time. Additionally, trees will need decades or even centuries to reach maturity.
In an ideal scenario, worldwide reforestation could remove a maximum of 40-100 gigatons of CO₂7 by the time the trees reach maturity. It sounds like a lot, but that would reverse just one decade of our emissions! In other words, it would only remove 15-30 ppm from the current level of CO₂ in the atmosphere.
But more importantly, even if we start planting all those trees today (which we should), the reduction of CO₂ from the atmosphere would become relevant after 2050.
Environmental Challenges
You might be surprised to know that planting trees could warm the local climate in some areas7, particularly in snowy regions. Replacing native vegetation with trees would make the surface darker, so it would absorb more of the sun’s heat.
Likewise, replacing native vegetation with trees could release more carbon dioxide in some ecosystems7. Furthermore, they could affect local biodiversity, water supplies, and more.
Economic and Social Challenges
A world full of trees is an unrealistic target as we also need land for other social and economic activities, such as food production. Moreover, worldwide reforestation would need money, planning, and commitment from all countries.
In short, trees are a great and easy natural option to remove carbon dioxide from the atmosphere. But, we should combine it with other carbon removal methods, while decreasing current deforestation and emission rates.
Natural Carbon Removal Methods
When people think about natural carbon removal methods, they think trees are the only option available. However, there are other natural options, for example:
- Coastal Ocean Ecosystems: These ecosystems have significant carbon sequestration capacity, but they’re vulnerable to human activities. This method relies on the restoration and construction of ecosystems like mangrove forests, salt marshes, seagrasses, and algae.
- Carbon Farming: This method removes CO₂ from the atmosphere to increase the carbon content of the soil. This is possible with agricultural and land management practices that are well known by farmers.
- Biochar: Biochar is a product resistant to decomposition, so it can store original biomass carbon for a long time. It’s similar to charcoal, but it’s made through sustainable practices. Even though the potential of carbon sequestration through this method is high, it isn’t widely applied.
Non-natural Carbon Removal Methods
Nowadays, there are a few non-natural carbon removal methods that we must use to accelerate natural options, such as:
- Direct Air Capture and Carbon Storage: This method separates CO₂ from the air by using chemical or physical processes while using zero-carbon energy sources. Then, the CO₂ captured is turned into stones.
- Enhanced Weathering: This method accelerates a natural process known as weathering. This chemical reaction naturally removes CO₂ from the atmosphere and it’s accelerated by grinding silicate minerals to increase the surface area.
- Bio-oil: Bio-oil is a product made out of biomass waste to store captured CO₂ from the atmosphere. Then, the bio-oil is pumped into deep, geological forms to store the carbon dioxide.
Finally, let’s clarify that all these carbon removal methods have benefits and challenges. So, we can’t solve climate change by using just one method. We need to take advantage of each one of them to capture and store as much carbon dioxide as we can!
We should also focus on protecting existing forests to prevent future deforestation and replace fossil fuels with renewable energy sources to reduce new emissions.
- CO₂ levels ↩︎
- NOAA - Climate Change: Atmospheric Carbon Dioxide ↩︎
- Yale Environment - How the world passed a carbon threshold and why it matters ↩︎
- FAO - State of Forests ↩︎
- Mapping tree density at a global scale - T. W. Crowther ↩︎
- The global tree restoration potential ↩︎
- What role can forests play in tackling climate change? - Imperial College, London ↩︎
