Unesco World Heritage forests: India’s Sundarbans among 5 sites with highest ‘blue carbon’ globally

Heritage forests release rather than sequester more carbon due to human activities, says Unesco

By DTE Staff
Published: Thursday 28 October 2021
A herd of Chital (Axis deer) in the Sundarbans. Photo: istock

India’s Sundarbans National Park is among five sites that have the highest blue carbon stocks globally, according to a new assessment of greenhouse gas volumes emitted from and absorbed by forests in Unesco World Heritage sites.

Also, such ‘World Heritage forests’ are now releasing more carbon than they are absorbing, primarily due to human activity and climate change, according to the assessment.

Researchers at Unesco, the World Resources Institute and the International Union for Conservation of Nature estimated the gross and net carbon absorbed and emitted by Unesco World Heritage forests between 2001 and 2020.

They did this by combining satellite-derived data with monitoring information at the site level, according to a statement by the organisation. They found that Unesco World Heritage forests in 257 sites absorbed approximately 190 million tonnes of carbon dioxide (CO2) from the atmosphere each year.

This figure, according to the study, was comparable to roughly half the United Kingdom’s annual CO2 emissions from fossil fuels.

The study added that World Heritage forests also stored substantial amounts of carbon in addition to absorbing CO2 from the atmosphere.

The total carbon stored till now by these forests is approximately 13 billion tonnes of carbon. If all this stored carbon were to be released into the atmosphere as CO2, it would be akin to emitting 1.3 times the world’s total annual CO2 emissions from fossil fuels.

The study described blue carbon as organic carbon that is mainly obtained from decaying plant leaves, wood, roots and animals. It is captured and stored by coastal and marine ecosystems.

Unesco lists 50 sites across the globe for their unique marine values. These represent just one per cent of the global ocean area. But they comprise at least 15 per cent of global blue carbon assests.

These 50 sites have carbon stores estimated at 1.4 Gigatonne Carbon (Gt C). The Sundarbans National Park has stores of 60 million tonnes of carbon (Mt C).

The other four sites besides the Sundarbans National Park in India are the Bangladeshi portion of the Sundarbans (110 Mt C), Great Barrier Reef in Australia (502 Mt C), Everglades National Park in the United States (400 Mt C) and the Banc d’Arguin National Park in Mauritania (110 Mt C).

Worrying scenario

The researchers found that 10 of 257 forests emitted more carbon than they captured between 2001 and 2020 due to different anthropogenic disturbances and pressures.

The reasons for emissions to be greater than sequestration included clearance of land for agriculture, the increasing scale and severity of wildfires due to drought as well as extreme weather phenomena such as hurricanes.

The 10 sites are:

  1. Tropical Rainforest Heritage of Sumatra (Indonesia)
  2. Río Plátano Biosphere Reserve (Honduras)
  3. Yosemite National Park (US)
  4. Waterton Glacier International Peace Park (Canada, US)
  5. Barberton Makhonjwa Mountains (South Africa)
  6. Kinabalu Park (Malaysia)
  7. Uvs Nuur Basin (Russian Federation, Mongolia)
  8. Grand Canyon National Park (US)
  9. Greater Blue Mountains Area (Australia)
  10. Morne Trois Pitons National Park (Dominica)

The report urged strong and sustained protection of Unesco World Heritage sites and their surrounding landscapes to ensure their forests could continue to act as strong carbon sinks and stores for future generations.

It recommended rapidly responding to climate-related events, as well as maintaining and strengthening ecological connectivity through improved landscape management. 

It also called for integrating the continued protection of Unesco World Heritage sites into international, national and local climate, biodiversity and sustainable development strategies.

This should be in line with the Paris climate agreement, the Post-2020 Global Biodiversity Framework and the Sustainable Development Goals, it said. 

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