Mangroves help protect coastal areas against sea level rise

Blue & Green Tomorrow: Mangrove forests could play a crucial role in protecting coastal areas from sea level rise caused by climate change, according to new research involving the University of Southampton. A joint study between researchers at the University of Southampton along with colleagues from the Universities of Auckland and Waikato in New Zealand used leading-edge mathematical simulations to study how mangrove forests respond to elevated sea levels.

Taking New Zealand mangrove data as the basis of a new modelling system, the team were able to predict what will happen to different types of estuaries and river deltas when sea levels rise. They found areas without mangroves are likely to widen from erosion and more water will encroach inwards, whereas mangrove regions prevent this effect – which is likely due to soil building up around their mesh-like roots and acting to reduce energy from waves and tidal currents.

Coastal estuaries and recesses in coastlines that form bays receive the run-off from erosion on steep catchments, which give them the tendency to fill in over time. As they infill, the movement of the tidal currents over the shallow areas create networks of sandbanks and channels. The sand banks grow upward to keep pace with water-level changes, while the channels get deeper to efficiently drain the excess water out to sea.

The researchers’ latest work shows that mangroves can facilitate this process, by adding leaf and root structures into the accumulating sediment, which increase the elevation while enhancing the trapping of new sediment arriving from the catchment.

Dr Barend van Maanen from the University of Southampton explains: “As a mangrove forest begins to develop, the creation of a network of channels is relatively fast. Tidal currents, sediment transport and mangroves significantly modify the estuarine environment, creating a dense channel network. Within the mangrove forest, these channels become shallower through organic matter from the trees, reduced sediment resuspensions (caused by the mangroves) and sediment trapping (also caused by the mangroves) and the sea bed begins to rise, with bed elevation increasing a few millimetres per year until the area is no longer inundated by the tide.”...

Mangroves in Zanzibar, shot by Fanny Schertzer, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Malaysia moves against coastal erosion crisis

Sohail Rahman in Al-Jazeera.com: ...Malaysia and Denmark ... have been working on environmental projects for over a decade. Both recognise the importance of their coastline and Denmark has years of experience in dealing with water levels and rising seas.

...So fast forward to Penang, coastal erosion and fresh water fishermen. They have a huge problem of coastal degradation. Is global warming the reason for the way typhoons have hit Asia Pacific these past few years, or the terrible floods that hit Malaysia in December 2014?

It could be a factor if the bigger global environmental jigsaw puzzle is worked out Here, though, the government, local and national is working with local nongovernmental organisations, acknowledging there is a need to support the livelihoods of over 200 fisherman on the island that locals call Pulau Pinang.

Together they identify vulnerable areas, work out which of the 150 species of hmangrove will be best suited to binding the land, grow quickly and feed the natural wildlife that depends on the plants. Keeping salt water away and encouraging freshwater wildlife that can sustain communities, such as fish, prawns and lobster to return.

...It is working yet we hear very little about it. Some NGOs such as The Consumer Association of Penang say the government need to do more and quickly. It is an easy statement to make but no government official likes to be told what to do. Yet Malaysia will be doing that soon enough. Telling its neighbours or the international community at the UN what they think and what needs to be done....

Karachi's mangroves, defence against storms and tsunamis, threatened

Space Daily via AFP: Thick mangroves have long protected Karachi, southern Pakistan's sprawling metropolis, from battering by the Arabian Sea, but pollution, badly managed irrigation and years of illegal logging have left this natural barrier in a parlous state.

Experts fear that loss of the natural barrier formed by the mangroves could put the city of nearly 20 million people at greater risk from violent storms and even tsunamis. Close to Karachi, the mighty Indus river ends its long journey from the Himalayas in the sea.

The river delta is home to the shimmering green mangrove, a delicate ecosystem that thrives in the mingled salt and fresh water....But the mangrove is a shadow of its former self -- from 600,000 hectares in the early 20th century now barely 130,000 hectares remain, according to marine biologist Mohammad Moazzam Khan.

The rest has fallen victim to illegal loggers, pollution from nearby industry and changes to the river flow caused by irrigation upstream on the agricultural plains of Sindh and Punjab provinces. The fishermen, who make a livelihood from the fish and shellfish that shelter in the mangroves, have warned about their decline for years....

NASA image of the Indus River delta

210 million people benefit from mangroves-associated fisheries

Wetlands International: Some 210 million people live in low elevation areas within 10 km of mangroves and many of these directly benefit from mangrove-associated fisheries. Yet, these people are often unaware of the key role mangroves may play, especially if the associated fisheries are offshore.

A new study by Wetlands International, The Nature Conservancy and the University of Cambridge, launched today at World Fisheries Day, concludes that mangrove conservation and restoration in areas close to human populations will render the greatest return on investment with respect to enhancing fisheries.

The fisheries value of mangroves is site specific as it depends on how many fish a mangrove produces, how many fish are subsequently caught by humans, and then what the fisheries value is, both in economic terms, as a food supply or through the livelihoods that they support.

As demands for fish continues to rise with the increase of coastal populations and rapidly growing economies, understanding where mangrove-associated fish productivity is highest is critical. Well-known species that rely on mangroves in one way or another include crabs, prawns, mullet, herring, anchovy, snappers and groupers….

Mangroves in Cuba, shot by Manuel Dohmen, Wikimedia Commons, under the Creative Commons 3.0

New UN report warns of ‘devastating’ effects from ongoing destruction of mangrove forests

UN News Centre: The world is losing its mangroves at a faster rate than global deforestation, the United Nations revealed today, adding that the destruction of the coastal habitats was costing billions in economic damages and impacting millions of lives.

In a new report launched today at the 16th Global Meeting of the Regional Seas Conventions and Action Plans, held in Athens, Greece, the UN Environment Programme (UNEP) warned that the deforestation of the planet’s mangroves was exceeding average global forest loss by a rate of three to five times, resulting in economic damages of up to $42 billion annually and exposing ecosystems and coastal habitats to an increased risk of devastation from climate change.

“The escalating destruction and degradation of mangroves – driven by land conversion for aquaculture and agriculture, coastal development, and pollution – is occurring at an alarming rate, with over a quarter of the earth’s original mangrove cover now lost,” said UNEP Executive Director Achim Steiner.

“This has potentially devastating effects on biodiversity, food security and the livelihoods of some of the most marginalized coastal communities in developing countries, where more than 90 per cent of the world’s mangroves are found,” he added.

The Executive Director noted that mangroves – which are found in 123 countries around the world – provide ecosystem services worth up to $57,000 per hectare per year, storing carbon that would otherwise be released into the atmosphere and providing the over 100 million people who live in their vicinity with a variety of goods and services such as fisheries and forest products, clean water and protection against erosion and extreme weather events....

A mangrove forest in Brazil, Shot by Ulf Mehlig, Wikimedia Commons, under the Creative Commons 2.5 license

Mangroves help shield coastal areas from storm surge

Butch D. Enerio in the Business Mirror (Philippines): Close to a thousand civil servants from different national and local offices, employees from private companies and students trooped to the shore of Taytay, El Salvador City in Misamis Oriental, on Thursday for their unified gesture to celebrate the World Environment Day (WED). They planted mangroves.

This year’s celebration, which is anchored on the theme, “Small Islands and Climate Change,” with the slogan—“Raise Your Voice, Not the Sea Level”—aims to promote worldwide awareness and action for the environment.

“It intends not only for people to realize their shared responsibility in taking care of mother earth, but for them to become agents for positive environmental change,” said Ruth M. Tawantawan, Department of Environment and Natural Resources (DENR) regional director for Northern Mindanao.

The Wednesday celebration was spearheaded by the DENR and the Philippine Information Agency in Northern Mindanao.

...The DENR said mangroves protect coastal communities from future typhoons and storm surges and other extreme weather events that may occur because it serves as buffer-shielding the coastal areas—as it also provides nursery grounds for fish, prawns and crabs that support fisheries production. Originally, the Philippines has 500,000 hectares of mangrove forest, but due to coastal development, land conversion and reclamation, only less than 100,000 hectares are visible in the country today....

Bamboo bridge and Mangroves at Bakhawan Eco-park and Research Centre,  shot by Paolobon140 , Wikimedia Commons, under the Creative Commons 3.0 license

Climate change in coastal areas of Pakistan

Syed Muhammad Abu Baker in the Nation (Pakistan):
...According to German Watch Institute, Pakistan was not included in the Long-Term Climate Risk Index (1993-2012) which clearly shows that it wasn’t a disaster hit country but the Climate Risk Index (CRI) for 2012 ranked Pakistan at number 3 as the most affected country by climate change revealing that inappropriate decision making of the government, ineffective planning and over-exploitation of natural resources causing billions of dollars in damage and driving the economically unstable country further into poverty.

...Scientists have commented that floods in Pakistan (2010, 2011, 2012) are the result of climate change but if proper adaptation measures had been taken, their devastation could have been reduced greatly. It has been observed that Pakistan was never a disaster-prone country and received adequate rainfall and seasonal temperatures throughout the year, but as time passed the frequency of natural calamities increased, which highlights the fact that human activities have led the whole country to this point.

...It has been observed that people adjoining northern and coastal areas of Pakistan are witnessing the worse impacts of climate. Unawareness, ignorance and over-exploitation of natural resources are some causes and deforestation is one of the major causes for increasing climate change impacts. Over the past few years deforestation in Pakistan has increased at a fast pace of 2.1% per annum, the highest in Asia, followed by mangrove forest depletion at an alarming rate of 2.3 % annually.

Pakistan is blessed with one of the largest semi-arid mangroves in the world but has ignored their ecological importance for long which has caused great damage. Mangrove cover helps in protecting coastal communities from harsh climatic conditions as they serve as a shield from storms and floods and also serve as a potential habitat for shrimps and marine life, also economically supporting fishermen communities. Using mangroves for fuelwood for domestic and commercial purposes, camel grazing, pollution from industrial effluents and reduced fresh water supply to the forests are some of the main reasons for reduced mangrove cover in Pakistan. Fast depleting mangrove forests have made the coastal areas of Pakistan vulnerable to harsh climatic conditions especially cyclones, floods, sea level rise and the impacts of change...

Mangroves in Port Qasim, Karachi, shot by Ismail.sultan, Wikimedia Commons, under the Creative Commons CC0 1.0 Universal Public Domain Dedication 

Mangroves in Florida expanding due to climate change

Nature World News: Fewer cold snaps in Florida are helping mangroves extend their territory, according to a new study. Mangroves thrive in warm, salty areas and are known to form complex ecosystems. Their presence in the Sunshine State was limited due to freezing temperatures during winter. However, from the past few years, there has been a decline in the number of days that see temperatures dipping below negative 4 degrees Celsius (25 degrees Fahrenheit).

Fewer cold days have led mangroves to getting a foothold in the region. "Before this work there had been some scattered anecdotal accountsand observations of mangroves appearing in areas where people had not seen them, but they were very local," said study lead author Kyle Cavanaugh, a postdoctoral researcher at Brown University and at the Smithsonian Institution, according to a news release. "One unique aspect of this work is that we were able to use this incredible time series of large scale satellite imagery to show that this expansion is a regional phenomenon. It's a very large scale change."

The study team didn't just document the rise of the mangroves in Florida, but even tried to assess the factors that helped these forests thrive. The team, along with researchers at the University of Maryland, ruled out major contributors such as rise in the annual mean temperature, land use and rainfall.

Researchers then focused on cold snaps, the days that see a brief dip in temperature. Daytona Beach experienced just 1.4 fewer cold snaps between 1984 and 2011 while Titusville had just 1.2 days a year that saw the mercury levels drop below freezing point. The scientists found that these subtle changes were enough to explain the doubling of mangrove in these areas....

US Fish and Wildlife service photo of a mangrove swamp in Florida

Mangroves help Guyana defend against changing climate

Desmond Brown in IPS: Theola Fortune can recall how residents of Victoria would ridicule her and others every time they went into the east coast village to warn residents about the importance of mangroves and the need to protect them.

“They would accuse us of breeding mosquitoes in the community,” Fortune said. Yet scientists say that mangrove trees, which grow mainly in tropical and subtropical regions, can shield cities and towns from rising seas and storm surges by creating a natural barrier where the ocean meets the land.

Approximately 90 percent of Guyana’s population lives on a narrow coastline strip a half to one metre below sea level. That coastal belt is protected by seawall barriers that have existed since the Dutch occupation of the country. In recent times, however, severe storms have toppled these defences, resulting in significant flooding, a danger scientists predict may become more frequent.

After huge waves breached the seawalls on more than one occasion this year alone, Fortune said, “residents are finally beginning to realise that mangroves could help to protect their community” from destruction, in addition to saving lives.

Fortune, Avnel Wood and Kene Moseley are among the women who, as part of the Guyana Mangrove Restoration Project (GMRP), are combining commercial activity with spreading the word on the importance of protecting coastal mangroves.

...Wood does not doubt what is causing the unusually high waves and frequent topping of the seawalls. “This is a product of climate change,” she told IPS. “There is nothing in that [coastal] area to break the energy of the waves because there are no mangroves at that part of the seawall.” Scientists say that mangroves also play an important role in combating climate change because they store ten times more carbon than any other tree in Guyana’s forests....

Mangroves bring wildlife back to Senegal coast

Terra Daily via AFP: Crabs scuttle among mangrove roots in a dense riverbank forest in southern Senegal, where a major reforestation project is reviving wildlife and boosting the west African country's lukewarm economy.

"Everything you see here has been replanted. Before 2006, there wasn't a single tree," said Senegalese environmental activist and government minister Haidar El Ali in Tobor, a village near Ziguinchor, the main city of the Casamance region.

He gestured toward mangroves tied to stilts bordering the Casamance river, planted by his Oceanium environmental organisation to boost an area that experts said was severely depleted by deforestation, drought and increased salt levels in the water.

...The habitat was destroyed through decades of illegal logging in mangrove forests for firewood and building. "There has been nothing here since the 1960s and 70s. Replanting is bringing back the mangrove," said Simeon Diatta, the chief of Diakene Diole village near the Guinea-Bissau border, pointing at riverside vegetation.

Since 2006, reforestation has revived 12,000 hectares (30,000 acres) of mangrove in Senegal -- an area larger than the city of Paris -- mainly in Casamance but also in the north and centre of the country, according to official figures...

Mangroves in Casamance, in Senegal, shot by Ji-Elle, public domain

Well-managed mangroves 'can survive rising sea levels'

Richa Malhotra in SciDev.net: The prevailing idea that sea-level rise will inevitably wipe out mangrove forests — fragile ecosystems that protect nearby communities from natural hazards such as floods and storms — is challenged by a recent report.

Mangroves in some areas will be able to survive climate change-induced sea-level rise as they can slowly increase the level of soil in which they thrive, but only if they are managed and protected, according to 'The response of mangrove soil surface elevation to sea level rise' report.

Activities such as building dams on rivers and converting mangrove areas into shrimp farms may have a stronger impact on the health of mangroves than sea-level rise, the report adds. Once weakened by such changes, mangroves will be less able to adapt to changes in sea level.

University of Cambridge "A lot of the rivers [that feed mangrove areas] are being dammed, and by doing that we reduce the freshwater flow and sediment flow to mangroves. Both can be very deleterious for mangroves," says Anna McIvor, lead author of the report and a researcher at the University of Cambridge, United Kingdom.

"Once mangroves are degraded, they are much less likely to keep up with sea-level rise," McIvor tells SciDev.Net...

Two false-color Landsat images showing the growth of the shrimp farming industry in Honduras from 1987 (lower image) to 1999 (upper image) and the corresponding removal of mangrove swamps.

When mangroves no longer protect the coastline in Guyana

Institut de recherche pour le developpement media centre: The mangroves of Guyana, in South America, are gradually disappearing. Contrary to the coastline of its near neighbour, French Guiana, which is still relatively protected, that of Guyana has been largely developed. In order to develop agriculture and aquaculture, earth dikes were built, destroying the greater part of the mangrove forest.

A study conducted by IRD researchers and the University of Aix-Marseille shows that the reduced protection provided by mangroves against the swell will lead to the large-scale erosion of 370 km of the country's coastline. Only one ecosystem restoration programme will help contain this phenomenon.

...The mangrove forests in the Guyanas (French Guiana, Surinam and Guyana), which spread across the Orinoco and Amazon deltas, are among the most extensive in the world. This particular ecosystem, between the earth and the sea, plays a major role in protecting the particularly unstable muddy coastline against erosion. However, most of the Guyana mangroves have been destroyed to develop the coastal plain. The retreating mangrove wall will result in large-scale coastal erosion, threatening populations and their economic activities, as demonstrated in a study conducted by researchers from IRD and the University of Aix-Marseille.

Although the French Guiana coastline remains protected by human developments for the time being, that of Guyana is already highly disrupted. The entire coastal strip is now inhabited*. In order to conquer this space and subsequently develop the aquaculture and agriculture - mainly rice cultivation - the coastal swamp areas have been transformed into polders. To this end, dikes have been built, reducing the 1km mangrove strip to just a few dozen metres wide. More than three quarters of Guyana's 450 km of coastline along the Atlantic are currently diked up. Coastal stability now depends on these earthen dikes.

...However, these dikes do not provide the same level of protection as mangroves against the swell, which is the main cause of erosion. Moreover, they would not withstand the strength of the waves if the mangroves were to disappear completely. Yet, they prevent the sedimentation of mud coming from the Amazon, which enables forest regeneration...

Mangrove losses raising risks in South Asia

Amantha Perera in AlertNet: Rapid destruction of South Asia’s mangroves, which act as a buffer against extreme weather conditions such as storm surges and rising sea levels, is endangering lives and livelihoods in the region, experts say.

Asia is home to 41 percent of the world’s mangroves, but in countries including Sri Lanka, Pakistan, Bangladesh and India they are fast disappearing. Ajanta Dey, a project director at the Nature, Environment and Wildlife Society, a Kolkata-based organisation that works on environmental and sustainable livelihood issues in eastern India, says her organisation believes at least 40 percent of Asia’s mangroves have been lost in the last 50 years.

...Preserving mangroves is important because they can act as a natural shield against storm surges and other severe weather. Most are also rich biodiversity hotspots, harbouring fish, shellfish and other animals that can provide food and income for people in the area.

But in Pakistan, over 80 percent of the mangrove cover has been lost in the last 80 years, according to the Pakistan office of the International Union for the Conservation of Nature (IUCN).  Mangrove forests that once covered over 600,000 hectares are now reduced to around 86,000 hectares. And such mangrove losses are now spreading increasingly across South Asia, including to India and Bangladesh’s coastal Sundarbans region, and to regions of Sri Lanka undergoing rapid development after years of conflict....

Mangroves in the Sundarbans, shot by Ashif Anam Siddique (Ruesho), Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Restoring mangroves may give Suriname carbon credits

Marvin Hokstam in Alertnet: The seawall that is supposed to protect the muddy coastline of coconut district Coronie, in the country's north, is almost complete. Standing some 10 meters above sea level, the wide dam provides a scenic drive, with virginal land on both sides and fish-filled channels cutting through it - a dream habitat for wildlife.

But this idyllic situation may not last long. According to University of Suriname professor Sieuwnath Naipal, much of the land on the ocean side of the 15-km-long dam will disappear in 20 years, abandoned as unsalvageable as the country focuses on forming a barrier against the waves that are eroding Coronie District’s coastline.

The dam, which contractors started building two years ago, sits about 100 meters inland; everything between it and the sea is sacrificed to the waves. Already, about 50 meters of the road to the dyke has disappeared, chewed away by the constant barrage of salt water. “That’s a part of our country we already lost,” Naipal says, shaking his head.

The solution to preventing similar losses, Naipal says, is his mangrove reintroduction project, which he believes will save the land that others have given up on. As it does so, the project could also turn out to be a groundbreaking money-earner for Suriname, potentially making the country tens of millions of dollars from the carbon-compliance market....

Mexican fisherwomen organise against climate change

Emilio Godoy in IPS: Every night, Adlemi Marrufo goes out to catch bait crabs used to fish for octopus in this small seaside town and others along Mexico's Yucatan Peninsula, as part of a women's cooperative that is working to adapt to and fight climate change. The longnose spider crab (Libinia dubia), known locally as the "maxquil" crab, is fished from August to December in San Felipe, where Marrufo, who everyone calls "Doña More", has been mayor since 2010.

"We haven't received support, and I think it would be difficult to get any. Even in our community, we have problems with the men, who wonder how we can do their work," Marrufo tells IPS as she gets her fishing gear ready on her boat, "Rebeca". In 1999, she was one of the founders of the Mujeres Trabajadoras del Mar cooperative, currently made up of 13 fisherwomen. The women's cooperative emerged as a collective effort to adapt to climate change, the effects of which are increasingly being felt on the coast of the Gulf of Mexico, which bathes the shores of this fishing village at the top of the Yucatan Peninsula in southeast Mexico.

San Felipe, which has a population of 1,850, is one of the 25 coastal towns in Mexico most exposed to the effects of global warming, in the form of stronger hurricanes, heavier and more frequent flooding and increasing changes in the availability of seafood species, which has caused problems for fishing, the town's main economic activity.

...The women in the cooperative, who were trained in "mangrove ecology" a year after the hurricane, have played a key role in restoring the mangroves, which are vital to keeping water temperatures from climbing too high in the lagoon, an important breeding ground for species ranging from lobsters to the longnose spider crab....

A burst of colour lights the shallow waters of the Gulf of Mexico off the Yucatan Peninsula. The swirls of tan, green, blue, and white are most likely sediment in the water. From NASA

Mangroves among the most carbon-rich forests in the tropics

EurekAlert: Coastal mangrove forests store more carbon than almost any other forest on Earth, according to a study conducted by a team of U.S. Forest Service and university scientists. Their findings are published online in the journal Nature Geoscience. (www.nature.com/naturegeoscience.com)

A research team from the U.S. Forest Service's Pacific Southwest and Northern research stations, University of Helsinki and the Center for International Forestry Research examined the carbon content of 25 mangrove forests across the Indo-Pacific region and found that per hectare mangrove forests store up to four times more carbon than most other tropical forests around the world.

"Mangroves have long been known as extremely productive ecosystems that cycle carbon quickly, but until now there had been no estimate of how much carbon resides in these systems. That's essential information because when land-use change occurs, much of that standing carbon stock can be released to the atmosphere," says Daniel Donato, a postdoctoral research ecologist at the Pacific Southwest Research Station in Hilo, Hawaii.

…This high-carbon storage suggests mangroves may play an important role in climate change management. Aside from the main greenhouse gas contributor of fossil-fuel burning, the forestry sector can play a part—especially carbon-rich forests that are being cleared rapidly on a global scale, such as mangroves….

Rhizophora mangle (red mangrove) forest, Caeté estuary, Bragança, Pará, Brazil, shot by Ulf Mehlig, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

Putting people over money in El Salvador

Dahr Jamail in Al-Jazeera.net: While debate about whether climate change is real or not continues in the US, the world's leading producer of CO2 emissions per capita, those already living with the effects, like Jose Domingo Cruz in El Salvador, don't have time to debate.

"Our storms are increasing in number and intensity," Cruz, a member of his community Civil Protection Committee that responds to community needs during natural disasters, told Al Jazeera while standing on a levy that ruptured during Tropical Storm Agatha last year. "All of us attribute this to climate change."

…Against the backdrop of these dire predictions, the people are, however, forming a movement that is learning to protect and sustain itself in the increasingly chaotic world of global climate change and its severe ramifications on people, the environment, and local economies.

In addition to climate change, El Salvador faces environmental issues that include deforestation, soil erosion, water pollution, and soil contaminated from decades of cotton and sugar cane production using toxic herbicides and fertilisers. El Salvador is the 2nd most deforested country in the Western Hemisphere, second only to Haiti. Only two per cent of primary forest that existed 50 years ago remains today.

In response to increasing natural disasters related to climate change - and as an effort to promote environmental protections and sustainable living - a group known as The Mangrove Association was birthed in 1999. Members of the group are primarily subsistence farmers and fisher-folk whose livelihoods depend on the viability of local ecosystems now threatened by climate change and unsustainable farming practises like those practised by the sugar cane industry.

…In what has become a major grassroots social movement that aims to increase diversified sustainable farming, organic foods, food security, and all of this via environmentally friendly methods, many people living in this area are actually seeing their lives improve, despite the challenges. Yet, the challenges are many, and are not going away….

Fair trade coffee growers in Tacuba in the Parque Nacional El Imposible, El Salvador, shot by Adam C. Baker, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Cancun's vanishing mangroves hold climate promise

Patrick Rucker in Reuters, in Cancun: This famous beach resort, which will next week host international climate change talks, was itself born from the destruction of a potent resource to fight global warming. Thick mangrove forests lined the canals and waterways here before developers dredged the land to make way for the upscale hotels that now draw several million tourists every year.

In the 40 years since Cancun was founded, countless acres of mangrove forests up and down Mexico's Caribbean Coast have been lost -- and the destruction continues. Now many scientists say that mangrove forests can help slow climate change, and are desperate to save them.

"We still have a lot to learn but the potential is huge for mangroves," said Gail Chmura, a climate change researcher at McGill University in Montreal who studies how much carbon is stored in these knobby, tidal forests.

As they process sunlight into food, mangroves suck an uncommon amount of industrial carbon out of the atmosphere and bury it deep within their underground network of roots. As nations looks desperately for "carbon sinks" that can capture and store carbon linked to climate change, mangroves are increasingly seen as a resource worth saving….

A mangrove stand in Chacahua, Mexico, photo by Bernardo Bolaños, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Mangrove forests protect Bangladesh

ReliefWeb: On the first day of her official visit to Bangladesh, UNDP Administrator Helen Clark traveled to the remote island of Char Kukri-Mukri on the southeast coast. This island, with a population of around 20,000, is on the frontline of Bangladesh's work to adapt to climate change.

Sea levels on the coast of Bangladesh are expected to rise up to 23cm, directly affecting the lives of 38 million Bangladeshis living in coastal areas. Char Kukri-Mukri is already experiencing a marked increase in both the frequency and intensity of cyclones and accompanying tidal surges, disrupting agriculture and fishing, and also causing massive erosion. With about 70 percent of the population subsisting on crop agriculture and fishing, these changes are threatening a community already struggling below the poverty line.

To reduce the vulnerability of these communities to climate change and to help them adapt to its effects, UNDP began working with Bangladesh's Ministry of Environment and Forest on an innovative project. Char Kukri-Mukri was one of four sites chosen for this project which is establishing 6,100 hectares of mangrove plantations and 935 hectares of timber species and fruit trees. Women in Char Kukri-Mukri have been trained to grow mangrove saplings, as well as trees used for timber, such as bamboo, and in forest management. Mangrove saplings will soon be planted along the coastline to create mangrove forests containing over 2.5 million trees over the four sites.

Mangrove forests act as extremely effective carbon sinks, able to absorb 97.57 tons of carbon per hectare, or more than three times the absorptive capacity of non-mangrove forests. More importantly for Bangladesh's coastal communities, mangroves also provide physical protection, trapping sediment in their intricate root structure at such a high rate that they can potentially reverse the effects of sea level rise. Every year, millions of tons of sediment are washed through Bangladesh's river delta near Char Kukri-Mukri, offering one of the few natural lifelines the country can harness to protect itself against the impacts of climate change and combat coastal erosion…..

A mangrove forest in the Sundarbans, Bangladesh, shot by bri vos, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

New satellite data reveals true decline of world's mangrove forests

Science Daily: New satellite imagery has given scientists the most comprehensive and exact data on the distribution and decline of mangrove forests from across the world. The research, carried out by scientists from the U.S Geological Survey and NASA, is published in Global Ecology and Biogeography, and reveals forest distribution is 12.3% smaller than earlier estimates.

Mangrove forests are among the most productive and biologically important ecosystems of the world, including trees, palms and shrubs which grow at tropical and subtropical tidal zones across the equator. Now scientists can use the world's most definitive map of the Earth's mangrove forest to reveal that approximately 53,190 square miles (137, 760 km2) of mangroves exist, substantially less than previous estimates.

"Our assessment shows, for the first time, the exact extent and distribution of mangrove forests of the world at 30 meters spatial resolution, the highest resolution ever," said Dr Chandra Giri from USGS. "This reveals that 75% of the remaining forest is found in just 15 countries, out of which only ~6.9% is protected under the existing protected areas network."

…"The current estimate of mangrove forests of the world is less than half what it once was, and much of that is in a degraded condition," said Giri. "It is believed that 35% of mangrove forests were lost from 1980 to 2000 which has had an impact on the coastal communities that use mangrove forests as a protective barrier from natural disasters such as hurricanes and tsunamis."

Using data from the NASA satellite Giri and an international team, including 30 student interns and visiting scientists from across the world, analysed more than 1,000 'Landsat' scenes using digital image classification techniques. This enormous task allowed the team to slowly piece together the world's most accurate map of mangrove distribution.

This work represents the most comprehensive global database of mangrove forests ever created and has revealed that the world's remaining mangrove forests are spread across 118 countries and territories. Asia has 42% of the world's mangroves, followed by 21% in Africa, 15% in North and Central America, 12% in Oceania and 11% in South America…..

Mangrove in Jozani Forest, Zanzibar. Shot by Fanny Schertzer, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license