The “Global Warming of 1.5 degree C” report determined “afforestation” (planting new forests) and “reforestation” (replacing forests on deforested or recently harvested lands) as essential strategies to remove greenhouse gases (GHGs) from the atmosphere. Likewise, the role of trees in addressing the climate change problem has received much attention in the Intergovernmental Panel on Climate Change’s (IPCC) special report on “Climate Change and Land”. However, planting trees is not a silver bullet against climate change and it should be a part of an inclusive action plan to address the climate crisis.
Planting trees is no substitute for natural forests. A recent study published in “Frontiers in Forests and Global Change” shows that growing existing forests intact to their ecological potential—termed “Proforestation”—is a more effective, immediate, and low-cost approach for removing and storing GHGs in the long-term. Proforestation signifies protecting and stewarding intact forests/ecosystems—largely free from human interventions except primarily for trails and hazard removals—and restoring natural forests. This approach could be implemented across suitable forests of all types.
Proforestation serves a crucial service by maximising co-benefits such as nature-based biological carbon sequestration—the removal of carbon dioxide from the atmosphere by plants to then be stored in vegetation and soils—and unparalleled services to the ecosystem. It also provides long-term benefits for biodiversity, climate resilience, and human benefits. Proforestation has the potential to provide additional carbon sequestration to reduce net emissions in the US by much more than the 11 percent that forests provide currently, according to research.
Afforestation and reforestation face significant challenges. Afforestation requires an enormous amount of additional land, which would be a considerable barrier to feed nine billion people by 2050. Besides, neither strategy can remove sufficient carbon by growing young trees during the critical next decade(s), a study indicates.
“Natural climate solutions”—conservation, restoration, and improved land management actions—have the potential to increase carbon storage and avoid GHGs. However, existing proposals for natural climate solutions do not consider explicitly the potential of proforestation.
A more recent paper in the journal Science, entitled “The global tree restoration potential”, explains that the restoration of trees remains among the most effective strategies for climate change mitigation. “A trillion trees could be planted” to address the changing climate problem, the paper estimates.
The “Climate Change and Land” report summarised that while some response options have immediate impact such as the conservation of high-carbon ecosystems: peatlands, wetlands, rangelands, mangroves and forests; other options, such as afforestation and reforestation as well as the reclamation of degraded soils, take decades to deliver measurable results. These examples indicate that restoring and protecting the existing ecosystems are more effective than tree plantations, in terms of getting adaptation and mitigation benefits within a short time.
The concept of “nature-based solutions” can be misinterpreted by prioritising and investing in more tree plantations (either through afforestation and reforestation), which is one of the popular initiatives for addressing climate change, taken by the government. According to Science, the primary climate solution is the “protection”, “stewardship” and “restoration” of carbon-rich intact ecosystems/natural forests.
Natural forests (including soils) store more carbon than is found in the atmosphere. Their loss and degradation would trigger emissions that would cause global warming to exceed 2 degree C, crossing the 1.5 degree C threshold. Mature forests can adapt to changing conditions and store more carbon than young, degraded or plantation forests.
The latest IPCC report sheds light on the Sundarban’s present condition. The report mentions that, “large areas of the Sundarban mangroves have been converted into paddy fields over the past two centuries and more recently into shrimp farms.” They warn coastal land erosion could be expedited as a result of the destruction of mangrove forests and wetlands.
Deforestation is the conversion of forest to non-forest land and can result in land degradation. In some areas, emissions from degradation can exceed those of deforestation, studies indicate. Once damaged, natural ecosystems are more exposed to further impacts from climatic and non-climatic stressors.
Avoiding further loss and degradation of natural forests and intact ecosystems, and allowing degraded forests to regrow naturally, would reduce global carbon emissions annually by about one gigaton (Gt), and reduce another two to four Gts of carbon emissions through just allowing natural regrowth, one study estimates.
A study published in the Nature journal estimates that increasing canopy cover through natural regeneration of degraded forests could have superior climate benefits over the course of the century than establishing new plantations.
Restoring natural forests have, therefore, received huge attention from scientists and policymakers. The German government and the IUCN launched the Bonn Challenge, which aims to restore 350 Mha of forest by 2030.
Under this challenge and other national schemes, 43 countries in the tropics and subtropics have pledged to restore forests to sequester carbon. For instance, Vietnam is allowing 14.6 Mha to return to natural forest, which is the world’s most substantial commitment of this nature.
Proforestation provides the most effective solution to the dual global crises of climate change and biodiversity loss. It does not require additional land beyond what is already forested and provides new forest related opportunities along with quantifiable ecosystem services. However, effective actions are indispensable to make the most of it.
Politicians have to recognise that proforestation is a better means of GHGs removal than other options. Our government must identify suitable (public) forest lands for protection and reservation for proforestation. Our government must also realise that implementing (and reorienting) existing forest regulations are a sine qua non of growing intact forest ecosystems. Proforestation requires explicit support of the (updated) “Bangladesh Climate Change Strategy and Action Plan.” It is a practical, economical, and effective mechanism of GHGs removal. Without revamping forest governance, however, it will be hard to implement it.
Ranjan Roy, Ph.D, is an Associate Professor at the Department of Agricultural Extension and Information System, Sher-e-Bangla Agricultural University.