Tropical wetlands are among the most productive ecosystems on Earth, containing unique aquatic and terrestrial communities high in biodiversity (Posa et al. 2011). Wetland forests occurring on organic soils –mangroves and freshwater peat swamp forests– are ubiquitous along coastlines and on coastal plains throughout the tropics. Inland peat swamp forests also occur within river basins at higher watershed positions (Anshari et al. 2010). Page et al. (2011) estimated that there were 441,025 km² of tropical peatlands globally, distributed throughout 61 countries in Africa, Asia, Central America and the Caribbean, South America, Australia and the Pacific. The majority of tropical peat...

The tropical peatlands of Borneo, Sumatra and peninsular Malaysia have developed on low-lying coastal plains and interior basins over the last 1000–13000 years largely because waterlogged conditions slow decomposition (Dommain et al. 2011). Disturbance and land-use changes of intact peat swamp forests result in large net carbon losses, especially as atmospheric carbon dioxide flux from the peat soil (Hergoualc’h and Verchot 2011). A pulse of CO₂ emissions from biomass and peat burning occurs with deforestation, and land-use changes expose upper peat layers to air and increased surface temperatures, which accelerate oxidation of organic matter.

Long-term CO₂ emissions from peat...

Historically, wetlands have been valued for their numerous ecosystem services and hydrological, ecological and habitat functions. Since the early 1980s, a small number of wetland scientists have also recognised their additional value as global carbon sinks (De la Cruz 1982, 1986, Maltby and Immirzi 1993, Sorenson 1993, Page et al. 2011). Recently, tropical wetlands have entered into international policy dialogue for their important role in the global carbon cycle and climate adaptation and mitigation strategies.

When wetlands are drained, aerobic conditions stimulate organic matter decomposition and former wetland carbon sinks can emit large amounts of stored carbon into the atmosphere...

Modelling is essential for enhancing our understanding of the functioning of tropical wetland ecosystems, and for simulating future trajectories and testing for system thresholds. Anthropogenic activities such as drainage and land-use change can be integrated in models and their impacts on fluxes of greenhouse gas concentrations simulated. Models can also be used to test the response of peatlands and mangroves to climate extremes, variability and change, and to estimate reference levels and greenhouse gas emissions scenarios in the framework of climate change mitigation projects such as REDD+. In coastal settings, models are used to explore wetland resilience to sea-level rise....

Remote sensing approaches are of fundamental importance in monitoring wetlands status, dynamics and changes. For the majority of developing countries, the analysis of remotely sensed data from satellites and other platforms is often the only practical and objective approach for measuring change in forests and wetlands. The earth observation community advocates this approach and has provided technical guidance on how to use space-based earth observations for studying trends and patterns in tropical land-use change and associated carbon emissions (GOFC-GOLD 2010). In particular, remote sensing offers unique monitoring opportunities, in the assessment and comparison of historical and future rates of change...

The Intergovernmental Panel on Climate Change (IPCC) has developed guidelines for parties to the United Nations Framework Convention on Climate Change (UNFCCC) to report their national greenhouse gas emissions (IPCC 2006). Annual reporting of greenhouse gas emissions is mandated for the developed (or Annex 1) countries, whereas non-Annex 1 countries can report less frequently.

In June 2010, the 32^nd session of the Subsidiary Body for Scientific and Technical Advice (SBSTA) invited the IPCC to hold an Expert Meeting to explore the need for and ways to clarify methodological issues related to the reporting on harvested wood products, wetlands and nitrous...

The ecosystem services provided by wetlands are often unrecognised or remain undervalued in land-use practices, leading to their conversion and over-exploitation. Both tidal and freshwater wetlands are vulnerable to anthropogenic activity, as well as climatic pressures such as temperature shifts, sea-level rise, droughts, floods and changes to seasonality (MEA 2005). These pressures are predicted to become more variable and/or intense with climate change, potentially leading to severe cumulative effects. In Indonesia, communities that are heavily dependent on these wetlands are already struggling to maintain their livelihoods in an environment of increasing climatic variability and competition for resources; and in doing...

The large carbon stocks found in tropical wetland ecosystems are the result of net positive carbon balance accumulated over thousands of years. The carbon pools of tropical peatland and mangrove ecosystems can be over twice the amount found in upland tropical and temperate forests. What gives particular importance to these ecosystems is the fact that a great proportion of the carbon stocks are stored in belowground organic-rich soils, which can release significant amounts of greenhouse gases if disturbed.

Studies have demonstrated that even small anthropogenic and/or environmental influences can cause considerable impacts and feedback loops in tropical wetland ecosystems. For...