Planting tree has long been seen as one of the simplest and most powerful solutions to climate change. Forests absorb carbon dioxide, cool the planet, and restore degraded landscapes. However, this well-intentioned climate solution comes with unintended consequences of hidden complexities?
Implementing such strategies to remove carbon are highly land-intensive. Planting trees, or growing energy crops that are used as alternative sources for energy production, would have to be done at massive scale – across millions of square kilometres of land. In turn, this could have serious implications for biodiversity – the very foundation of life on Earth – without careful planning.
Hidden Cost of Planting Trees to Remove Carbon: Why Carbon Removal Is Now Essential
The global efforts to limit climate change require deep and sustained cuts to carbon emissions. But despite growing awareness, emissions continue to rise, with approximately 42 billion tonnes of carbon dioxide released each year from fossil fuels and land-use changes. In spite of international commitments under the Paris Agreement, the world is still far from achieving the targets of limiting global warming to 1.5°C. Whereas to meet the goals of the Paris Agreement – especially the commitment to limit global warming to 1.5°C – reducing emissions alone will not be enough. It will require large-scale removal of carbon dioxide from atmosphere.
The longer the emission reductions are delayed, the greater our dependence on future carbon removal strategies becomes. Scientists agree that we must also remove carbon dioxide already present in the atmosphere. This is where carbon removal strategies come into play. These include:
- Planting trees (afforestation and reforestation)
- Growing energy crops for biofuels
- Restoring degraded ecosystems
While reducing emissions remains the top priority, it is no longer enough. Although necessary, these strategies for carbon removal do not come without trade-offs. The global land-use projections for carbon removal with biodiversity data to assess areas of overlap and potential ecological impact, remains a virtual challenge.
The Land Use Challenge: Competing with Nature
One of the biggest challenges of carbon removal is land availability. To significantly impact global carbon levels, tree planting and bioenergy production would need to cover millions of square kilometres. However, land is not empty or unused – it is home to ecosystems, wildlife, and communities.
Recent scientific research reveals how large-scale carbon removal projects often overlap with areas rich in biodiversity. In many places of overlap, carbon removal strategies may conflict with biodiversity conservation. These include the pristine ecosystems like savannas and grasslands, which do not naturally have much forest cover. Converting such landscapes into forests and energy crops or monoculture plantations can disrupt native habitats, reduce species diversity, and alter ecological balance.
Understanding Biodiversity Loss: Important biodiversity areas
Biodiversity refers to the variety of life on Earth – plants, animals, fungi, and microorganisms that sustain ecosystems. Healthy biodiversity is essential for pollinating crops, regulating water cycles, maintaining soil fertility, and supporting food systems.
Unfortunately, the world is losing biodiversity at an alarming rate of 2% to 6% per decade over the last 30-50 years. Intense resource extraction, climate change, environmental pollution and invasive species are some of the drivers. Biodiversity is critical for pollinating food crops and regulating water and nutrient cycles.
Recognizing this crisis, the global leaders adopted the Kunming-Montreal Global Biodiversity Framework, aiming to halt biodiversity loss by 2030.
Climate Refugia and Biodiversity Hotspots: Nature’s Safe Havens
Scientific findings could inform plans for how to achieve ambitious climate action and biodiversity conservation, but the framework does not clearly define areas of high biodiversity importance. Not all areas are equally important for biodiversity. Scientists identify certain regions, which are critical for conservation, including:
1. Climate Refugia
The so-called climate refugia are critical areas for biodiversity. These climate refugia areas were defined by a team of biodiversity experts as part of Wallace Initiative. These are areas where climate change occurs relatively slowly, and allow species to survive and adapt over time. They act as natural shelters for biodiversity, protecting animal, plant and fungal species from harm – at least to some degree.
2. Biodiversity Hotspots
These are the regions rich in rare and unique species, often under threat from human activity. Initiatives like the Wallace Initiative help map and protect these vital areas. However, research shows that up to 13% of climate refugia could be affected by land-intensive carbon removal strategies – a concerning overlap for both climate refugia and biodiversity hotspots, which require special policy attention.
When Tree Planting Can Harm the Environment
While planting trees sounds universally beneficial, but it is not always the right solution everywhere. It may result into:
1. Disrupting Natural Ecosystems
Grasslands and savannas are naturally treeless or sparsely forested ecosystems. Planting trees in these areas can:
- Destroy native plant species
- Disrupt wildlife habitats
- Alter soil and water systems
2. Monoculture Plantations
Energy crops like miscanthus or switchgrass are often grown in large monocultures. These lack biodiversity and can:
- Reduce habitat variety
- Increase vulnerability to pests
- Degrade soil health
3. Regional Impacts
In regions such as western Africa, studies show that expanding bioenergy crops may overlap with ecologically sensitive areas, threatening local biodiversity.
The Trade-Off: Climate Goals vs. Conservation
Balancing climate action with biodiversity protection is not easy. Strict conservation targets under the Kunming-Montreal Framework could limit available land for carbon removal by over 50% in some scenarios. This creates a difficult trade-off:
Use land for carbon capture, or preserve it for biodiversity. The reality is that both goals are essential, and must be pursued together.
A Better Approach: Biodiversity-Sensitive Climate Action
Encouragingly, carbon removal and biodiversity conservation do not always have to conflict. Careful choices about locating land-intensive carbon removal strategies may avoid negative impacts. There could even be benefits for biodiversity. With careful planning, they can support each other.
1. Restore Degraded Lands
Instead of converting natural ecosystems, restoring forests in degraded or abandoned landscapes can create ecological corridors, reconnecting fragmented habitats and supporting wildlife. This can:
- Increase carbon storage
- Improve soil quality
- Support wildlife recovery
2. Create Ecological Corridors
Reforestation can connect fragmented habitats, allowing species to move freely and adapt to climate change.
3. Protect Natural Ecosystems First:
Preserving existing forests, grasslands, and wetlands is more effective than replacing them.
4. Use Diverse Planting Strategies:
Avoid monocultures. Mixed-species forests are more resilient and better for biodiversity.
The Role of Smart Policy and Planning
Effective climate action requires policies that integrate environmental priorities. Effective carbon removal can help mitigate climate change, and indirectly protect biodiversity from warming-related threats. Ultimately, the success of these strategies depends on careful, and context-specific planning. Governments and planners must:
- Identify high-risk biodiversity areas
- Avoid harmful land-use changes
- Promote sustainable land management
- Invest in less land-intensive carbon removal technologies
Scientific tools and scenario modeling can help guide these decisions, ensuring that climate solutions do not come at the cost of nature.
The Ultimate Solution: Reduce Emissions First
The conclusion is clear: while carbon removal is important in addressing climate change, it should not become a substitute for reducing emissions. It must be implemented wisely. The best solution remains rapid and substantial reductions in greenhouse gas emissions. By prioritizing emission cuts, we can reduce our reliance on large-scale carbon removal and better safeguard our planet’s rich biodiversity. The most effective way to combat climate change is still:
- Transitioning to renewable energy
- Reducing fossil fuel use
- Promoting sustainable consumption
By cutting emissions quickly, we reduce the need for large-scale land-based carbon removal, and the risks it poses to biodiversity.
Conclusion: A Delicate Balance for the Future
Planting trees remains a powerful symbol of environmental action. But as science reveals, it is not a one-size-fits-all solution.
If done carelessly, carbon removal efforts can harm ecosystems, disrupt biodiversity, and create new environmental challenges. But identifying both potential conflicts and opportunities for synergy between carbon removal strategies and ecological protection could become a force for restoration and resilience. When guided by thoughtful and strategic planning, site selection and ecological understanding, the initiatives of carbon removal could even enhance biodiversity.
Using widely accepted decarbonisation scenarios of how energy systems, economies, and land-use patterns might evolve to meet ambitious climate targets, the path forward lies in balance – where climate action and nature conservation work hand in hand, and not against each other. The urgency of biodiversity conservation cannot be overstated, because in the fight against climate change, protecting biodiversity is not optional – it is essential.
