Will planting a tree save the planet? The role of nature-based carbon offsetting in net zero transitions
Addressing anthropogenic climate change demands urgent, multifaceted interventions across political, technological, and economic domains. From subsidising renewable energy systems and expanding electric vehicle infrastructure to developing carbon taxes, low-carbon materials, and direct air capture technologies, the global response has been diverse and uneven. Among these interventions, carbon offsetting, the practice of compensating for greenhouse gas (GHG) emissions by funding activities that reduce or remove emissions elsewhere, has become one of the most widely recognised and contested strategies in the climate mitigation toolkit. In particular, nature-based carbon offsetting, using ecosystems to absorb and store carbon dioxide, has gained traction, with tree-planting a common political, corporate, and individual strategy to demonstrate commitment to emission reduction or assuage guilt from fossil-fuel intensive lifestyles. How did tree-planting become such a ubiquitous method to offset emissions, how much carbon dioxide does a tree actually absorb, and what other nature-based solutions might also play a role?
The rise and challenges of carbon offsetting
Carbon offsetting gained traction during early international climate negotiations and was formalised in the 1997 Kyoto Protocol, which introduced market-based mechanisms to allow industrialised nations to meet emission reduction targets through international offsetting projects. Offset projects initially focused on reforestation, renewable energy, and methane capture. By the early 2000s, a voluntary carbon market emerged, enabling nations and corporations to buy carbon credits that each represent one tonne of carbon dioxide to offset emissions beyond regulatory requirements. Standards such as the Verified Carbon Standard (VCS) and American Carbon Registry were developed to verify credibility of offsetting projects. The 2015 Paris Agreement marked a shift by encouraging nations to align carbon markets with national climate commitments, emphasising actual emissions removals over avoided emissions. The voluntary carbon market has now become a multibillion-dollar global industry and expanded to include individual consumers. You may have seen, for example, the option to pay an additional fee to ‘offset’ the associated carbon emissions when purchasing a flight or certain products.
However, the offsetting landscape has been fraught with valid concerns. Some projects have exaggerated their benefits or lacked ‘additionality’, a requirement that the project results in emission reductions that would not have happened otherwise. There are documented instances of land grabs and displacement, such as in Uganda, where communities were evicted to make space for monoculture plantations. Critics also argue that offsetting can enable ‘climate delay’ by allowing emitters to buy credits rather than change emission-intensive behaviours. These critiques have spurred reforms aimed at tightening carbon offsetting verification standards, improving transparency, and incorporating social and biodiversity co-benefits.
Nature-based solutions: Beyond trees
Leveraging nature to absorb and store carbon dioxide is not a new concept, although one that has begun to dominate carbon offsetting markets. In 1976, physicist, Freeman Dyson, proposed tree planting as a way to counter greenhouse gas emissions. The offsetting potential of trees lies in their photosynthesis: trees absorb carbon dioxide and release oxygen, storing carbon in their trunks, leaves, and soil. Forestry-linked nature-based offsetting projects involve afforestation (planting trees where there were none before) or reforestation (restoring deforested areas). The Intergovernmental Panel on Climate Change (IPCC) has a global roadmap to restore up to one billion hectares of forest, a theoretically feasible target, considering that two-thirds of terrestrial land could support forest ecosystems.
However, trees are not a silver bullet. A typical single mature tree sequesters about 21 kilograms of carbon dioxide annually. A single return flight from London to New York emits approximately 1 tonne of carbon dioxide, requiring about 47 trees to offset just that journey. To meet rising corporate and consumer demands, many offsetting schemes have turned to monoculture plantations, often of fast-growing species like eucalyptus or pine. While efficient from a carbon offsetting perspective, these plantations reduce biodiversity, alter hydrological cycles, and may even exacerbate warming due to reduced albedo. As climate change worsens, we are seeing a decline in the global tree carrying capacity, for example, from desertification. Tree plantations are also vulnerable to wildfires that can instantly reverse decades of carbon storage, casting doubt on the permanence of some nature-based offsetting schemes. Additionally, operationalising tree planting, for example, in countries with the highest land capacity for reforestation (i.e., Russia, US, Canada, Australia, Brazil, and China) is challenged by geopolitical, social, and economic issues.
Despite these issues, tree planting has become a go-to climate gesture, visible, symbolic, and quantifiable. This symbolism often oversimplifies nature’s role, crowding out other vital ecosystems from climate conversations, such as native grasslands.
Grasslands: The undervalued carbon sinks
Grasslands, ecosystems dominated by grasses and herbaceous plants, cover vast areas of the globe and are remarkable carbon sinks, especially due to their below-ground biomass. Unlike forests, which store most of their carbon in trunks and branches, grasslands store up to 90% of their carbon in roots and soils, making them more resilient to fire and climate stressors. Grasslands are native to nearly every continent (excluding Antarctica), from the North American prairies and South American Pampas to the African savannas, Asian steppes, and Australian rangelands. It is estimated that grasslands store approximately 34% of the global terrestrial stock of carbon.
These ecosystems are under threat from overgrazing, agricultural conversion, urban expansion, and fire suppression. Fire is an essential part of grassland health. Many grassland species have evolved to survive and regenerate after fire, storing their nutrients underground. This unique adaptation makes grasslands less vulnerable to complete carbon loss during wildfires compared to forests. Given rising temperatures, prolonged droughts, and increasingly frequent wildfires, grasslands may prove more climate-resilient than forests in many regions, offering long-term carbon storage.
Grassland restoration projects have wider benefits than just carbon sequestration. Focusing solely on carbon dioxide, or ‘carbon tunnel vision’, reduces complex ecosystems to a single metric, and risks ignoring the ripple effects of habitat destruction. Native grasslands support vast biodiversity. Some grassland plants have cultural, medicinal, and ecological value that we have not even begun to understand. The cure for cancer might very well lie in an overlooked blade of grass. Grassland plants help stabilise soil, prevent erosion, and often thrive in nutrient-poor conditions where trees would struggle.
Grasslands remain chronically undervalued in climate policy and carbon markets. Part of this neglect is due to measurement difficulties; the carbon benefits of grasslands are less visually apparent and more complex to verify. Unlike forests, where trees can be counted and measured, grasslands require soil sampling, ecological knowledge, and long-term monitoring to accurately assess carbon sequestration. Their biodiversity value is also overlooked, with restoration efforts often dismissed in favour of high-profile tree planting schemes.
Grassland restoration in practice
Despite these challenges, several grassland restoration initiatives are leading the way in demonstrating the potential of these ecosystems. In North America, the Northern Great Plains Grasslands Project and Canada’s prairie conservation efforts use tools like the Climate Action Reserve to protect native grasslands and their carbon-rich soils. In Argentina, the Pampas restoration effort seeks to restore overgrazed lands while integrating carbon measurement protocols. Australia’s Carbon Farming Initiative incentivises regenerative grazing to preserve native rangelands. Meanwhile, Kenya’s Northern Rangelands Trust has created a model for community-led rangeland management that supports both biodiversity and carbon sequestration, earning credits through Verra and reinvesting in local livelihoods. These examples illustrate how grassland restoration can deliver climate mitigation, ecological resilience, and social equity, especially when designed with local contexts in mind.
Should we plant grasslands instead of trees?
Not necessarily. Grasslands are not a universal alternative to forests; both ecosystems play complementary roles. Mismanaged grasslands, particularly those overstocked with livestock, can lead to soil degradation, biodiversity loss, and methane emissions. The focus should be on ecosystem-appropriate restoration. In areas where grasslands are the natural biome, planting trees can do more harm than good. Conversely, in forested zones, restoring tree cover can bring profound benefits. The goal should not be to choose one over the other, but to protect and restore ecosystems in line with their ecological potential and context.
The bottom line
Nature-based solutions, including forests and grasslands, are indispensable in the fight against climate change. But they are not a license to maintain business-as-usual. Planting trees, or restoring grasslands, will not cancel out carbon-intensive lifestyles or geopolitical and structural inefficiencies. These strategies must be integrated with deep systemic transformations in how we produce, consume, travel, and govern. Additionally, ecosystems should not be commodified solely for their carbon content. Protecting nature must go hand-in-hand with safeguarding biodiversity, cultural values, food security, and community rights. Policymakers must strengthen regulatory frameworks, expand public financing, and support scientific research to ensure that nature-based solutions deliver genuine, lasting benefits, not just carbon accounting fixes.
Ultimately, while you should not just outsource your emissions to a patch of pine saplings and feel better about that long-haul flight, if you are still riddled with eco-guilt after that flight, plant those 47 trees. Just make sure they are not all eucalyptus. And while you are at it, do not forget the grasslands.
