Air Pollution Endangers Mangrove Forests: New Study Warns

    Seema Agarwal
    May22/ 2024
    Last Updated:

    Mangroves: Anchors of Marine Ecological Integrity; The study reveals significant levels of toxic heavy metals like lead, chromium, and cadmium in Kolkata's air, directly affecting the Sundarbans Delta's mangrove forests.

    Mangroves Forest visuals

    Recent research by scientists from Bose Institute, Kolkata, and the Indian Institute of Technology, Kanpur, has revealed that rapidly increasing air pollution in metropolitan cities is becoming lethal for mangrove ecosystems. They noted that harmful air pollutants are consistently rising in the air over the Sundarbans Delta, known for its mangrove forests, leading to a contraction of the mangrove forest area.
    The air in regions around Kolkata contains significant quantities of toxic heavy metals such as lead, chromium, and cadmium, affecting the atmosphere and, consequently, the mangrove forests. Several factors contribute to the rising pollution levels in the delta region, many of which need urgent control. For instance, local boatmen in the Sundarbans still use old diesel-powered motors for their boats, which emit thick, black smoke laden with toxic metals. This polluted smoke directly affects the forested areas.
    Additionally, the per capita income in areas adjacent to mangrove forests is very low. As a result, people still rely on solid fuels like wood, coal, and cow dung cakes for their daily needs, increasing black carbon levels in the air and posing a significant threat to the mangrove forests. Due to low income and poor infrastructure, residents of these regions use kerosene lamps for lighting instead of electric bulbs. Clean fuels like solar light and liquefied piped gas are not available, leading to increased air pollution levels, which destroy the mangroves.
    Mangroves, which are tropical trees and shrubs found in tidal areas along coastlines, saline swamps, and muddy shores, play a crucial role in combating climate change, protecting biodiversity, and mitigating the risks of natural disasters like tsunamis and cyclones. They provide numerous benefits to the environment, economy, and communities. According to the United Nations Framework Convention on Climate Change (UNFCCC), about 67 percent of mangrove habitats worldwide have been destroyed. In India, the Sundarbans, Bhitarkanika, Pichavaram, Chorao, and Baratang are some well-known mangrove regions, but they are among the most endangered mangrove belts today.

    The Forest Survey Report 2021 states that the total mangrove area in India is 4,992 square kilometers. While there has been an increase of 17 square kilometers in the mangrove area compared to the 2019 assessment, this growth is minimal compared to the scale of destruction. The Centre for Science and Environment found that a reduction in mangrove forest areas could lead to a 30-fold increase in carbon emissions by 2050. At COP-27 in 2022, it was highlighted that mangroves can absorb four to five times more carbon emissions than other tropical forests.

    Experts assert that mangrove ecosystems not only provide habitats for numerous species of fauna and flora but also play a significant role as carbon sinks and support the livelihoods of coastal communities. Mangroves are the only species of trees that can tolerate saline water, making them a unique ecological system that supports hundreds of species of fish, reptiles, amphibians, insects, microorganisms, algae, birds, and mammals. They also act as buffers against tidal waves and help prevent soil erosion by stabilizing sediments with their tangled roots.

    Thus, protecting and conserving mangrove forests is of utmost importance. The destruction of these forests not only disrupts environmental balance but also has severe impacts on local livelihoods and global climate.

    Mangroves emerge as indispensable sentinels, safeguarding the sustenance of marine life. Revered as pivotal constituents within the intricate web of marine environmental dynamics, they hold profound significance, particularly in nations of modest economic means. These nations reap manifold benefits, availing themselves of diverse ecological services and livelihoods bestowed by mangrove ecosystems.

    Recent studies unveil a distressing trend: over the past two decades, the relentless incursion of agriculture and urban sprawl has wrought havoc upon mangrove expanses. Consequently, the vaunted carbon reservoirs have witnessed a staggering depletion of 15.84 million tons, while carbon emissions have surged unabated.

    Alarming statistics proffered by Greenpeace India underscore the exacerbation of atmospheric pollutants such as PM 2.5, PM 10, and nitrogen oxides in coastal metropolises adjoining mangrove hinterlands like Chennai, Mumbai, Kolkata, and Kochi. These pollutants far exceed benchmarks set by the World Health Organization, painting a dismal picture of air quality in these urban enclaves.

    Degraded air quality triggers a cascade of deleterious effects upon mangrove ecosystems. The presence of black carbon and particulate matter impedes sunlight penetration, throttling photosynthetic rates within mangrove flora. Consequently, these vital organisms, deprived of sustenance, languish and perish, plunging the ecological equilibrium into disarray.

    Asphyxiating pollutants in the air precipitate respiratory afflictions among denizens of mangrove ecosystems, engendering a slow and inexorable demise. Moreover, the surge in greenhouse gases, such as nitrogen oxides, augurs ill for the delicate balance of marine ecosystems, exacerbating temperature rise and oxygen depletion, hastening the demise of mangrove habitats.

    Experts concur that a confluence of factors—rampant urbanization, unbridled coastal development, industrial expansion, rampant deforestation, invasive species, and climate vagaries—have conspired to imperil the very fabric of mangrove ecosystems.

    In the face of escalating climate vagaries and global warming, concerted global efforts have been marshaled to shield mangrove ecosystems from impending peril. Foremost among these endeavors stands the Mangrove Alliance for Climate, unveiled during COP 27, garnering pledges from nations large and small to proactively identify and mitigate threats to mangrove habitats. Coastal zones are slated for transformation into sanctuaries conducive to the flourishing of mangrove ecosystems.

    India has assumed a proactive stance within this alliance, delineating ambitious goals aimed at ameliorating the condition of its mangrove forests. Inclusion in the National Red Plus Program signifies a commitment to fortify mangrove ecosystems, with a pledge to sequester 2.5 to 3 billion tons of carbon from forested regions by 2030, underscoring a resolute intent to preserve mangrove habitats.

    Per counsel from experts at IIT Kanpur, the Indian government stands enjoined to address ten pivotal points to ameliorate air quality in the Sundarbans region.

    Recommendations from the esteemed Bose Institute advocate the expeditious deployment of solar and wind energy in the region. Environmental cognoscenti advocate the proliferation of solar and wind energy sources to curtail reliance on fossil fuels, thereby mitigating black carbon emissions and ameliorating air quality. Policy initiatives such as the Solar Rooftop Scheme and the Kusum Scheme warrant fervent propagation.

    A paramount imperative beckons: ensuring equitable access to subsidized LPG cylinders for every household in the region, thereby obviating impediments to LPG supply. Endowed with a cornucopia of biodiversity, mangrove forest regions serve as coveted tourist destinations. Stringent regulation of tourism holds the potential to mitigate air pollution while safeguarding mangrove habitats.

    To stem the ingress of toxic heavy metals such as lead and chromium into the atmosphere, the proscription of antiquated vehicles is warranted. In their stead, provision of electric boats at subsidized rates or on credit offers a viable alternative. By fostering novel avenues for employment in mangrove-rich regions, India can nurture these invaluable ecosystems, thereby fostering a symbiotic relationship between economic development and ecological preservation.

    In alignment with the wisdom of mangrove experts, unwavering adherence to land use regulations and legislation in locales such as Kolkata, Chennai, Visakhapatnam, and the coastal reaches of Bangladesh offers a beacon of hope in preserving these irreplaceable ecosystems.

    To safeguard the biodiversity of the Sundarbans Delta, the closure of brick kilns and pollutant-emitting factories is imperative. Mangrove forests stand as veritable bulwarks in coastal and saline ecosystems, and India can ensure their sustainable stewardship through the implementation of robust conservation policies.