An international team of researchers from the United Kingdom and South Africa examined how offsetting greenhouse gas emissions through the creation of tree plantations actually performs in real-world climate mitigation. Their analysis concludes that这种 offset strategy is less effective than commonly assumed and can pose risks to local ecosystems if deployed without careful planning. The researchers published their findings in a peer‑reviewed journal, Ecology and Evolution Trends (TEV), contributing a cautious but data‑driven view to the ongoing dialogue about climate solutions.
Across the spectrum of ecosystem services already provided by tropical environments, society has tended to reduce their value to a single, carbon‑centric measure. The study argues that current and proposed policies should avoid driving ecosystem degradation by pursuing tree planting under a narrow lens of carbon sequestration alone, without considering broader ecological health, resilience, and social dimensions.
There is a widely held belief that planting trees to capture carbon carries automatic benefits for biodiversity and for social and economic well‑being. The authors of the study caution that these positive co‑benefits do not automatically materialize, and in many cases may not occur at all if planting choices and broader land‑use practices are not aligned with ecological realities and local needs.
Tropical ecosystems are renowned for their rich biodiversity and for delivering a suite of ecosystem services, including maintaining water quality, supporting soil health, aiding pollination, regulating microclimates, and sustaining cultural and livelihood systems for communities that depend on them.
By contrast, many carbon capture plantations are designed as monocultures, often dominated by a small set of tree species selected for timber, pulp, or other commercial uses. The most commonly grown species worldwide in these plantations tend to be teak, mahogany, cedar, sevilla, and black locust, which creates ecological simplification and reduces habitat complexity.
Although these plantations can deliver short‑term economic value, they typically support lower levels of biodiversity compared with diverse, native forests. For example, in Brazil’s Cerrado savanna, a 40% increase in tree cover has been associated with a roughly 30% decline in plant diversity and a corresponding drop in ant diversity, illustrating how tree planting can reshape community composition in unexpected ways.
Plantations may directly harm ecosystems by altering hydrological regimes, lowering river flows, depleting groundwater reserves, and acidifying soils, all of which can cascade into wider ecological and agricultural consequences. These effects highlight the importance of considering watershed health and soil processes when evaluating large‑scale planting strategies as climate solutions.
The report also points out that simply planting new trees to offset emissions would require enormous land areas. To compensate for humanity’s annual greenhouse gas emissions, an area equivalent to the combined expanse of Russia, China, the United States, and the United Kingdom would need to be entirely forested, a scale that raises questions about feasibility, social equity, and land use trade‑offs.
To address climate challenges effectively, scientists advocate prioritizing the preservation and restoration of intact ecosystems, including tropical grasslands and savannas, rather than relying primarily on new tree plantations. Maintaining the integrity of these ecosystems helps protect biodiversity, preserves critical ecosystem functions, and supports local communities who depend on them for resources and livelihoods.
The discussion closes with a reminder that even seemingly simple climate interventions require careful consideration of ecological dynamics. Arctic mosses and lichens, for instance, can shift from acting as carbon sinks to becoming carbon sources under changing environmental conditions, underscoring the need for adaptive management and long‑term monitoring across diverse biomes.