Wetlands, Climate Change Impact and Adaptation

The term global climate change conjures up different images to each of us, depending on a variety of factors such as our geographic location and our lifestyle. Based on its research, the IPCC concludes that "human activities, including the burning of fossil fuels, land-use change and agriculture, are increasing the atmospheric concentrations of greenhouse gases (which tend to warm the atmosphere) and, in some regions, aerosols (microscopic airborne particles, which tend to cool the atmosphere), are projected to change regional and global climate and climate elated parameters such as temperature, precipitation, soil moisture and sea level."

While currently the number one driver of wetland loss and degradation is habitat change as a result of human development, climate change effects are already being felt across the world. As our understanding of climate change increases, there is a new sense of urgency about the state of wetland species and ecosystems: clearly, climate change will become one of the major drivers of ecosystem loss during this century and will intensify the impacts of the other drivers.

In general, wetlands found in prairies, tropical and boreal forests, arctic and alpine ecosystems, and coral reefs and mangroves are thought to be especially vulnerable to climate change because they have a limited capacity to adapt to change - damage to these ecosystems may be irreversible.

Expected increases in sea surface temperature of about 1-3°C are likely to result in more frequent coral bleaching events and widespread mortality of corals.  Coastal wetlands including salt marshes and mangroves are likely to be negatively affected by sea-level rise, especially where there are physical barriers on their landward side; increased damage from coastal flooding through storms and tidal surges will take place in many areas.

Changes in the timing and volume of fresh water run-off from inland wetlands will affect salinity, nutrient availability, and moisture regimes in coastal ecosystems – all of which will have an impact on coastal ecosystem functions. Many low-lying islands, particularly those in the Pacific, Indian and Atlantic Oceans and the Caribbean Sea, are likely to be at risk of being submerged.

Changes in rainfall intensity and variability are expected to increase flooding and drought in many areas. In general, precipitation increases are expected in high latitudes and parts of the tropics and decreases in some sub-tropical and lower mid-latitude regions (some of these latter areas are already water stressed). Some climate models predict that by 2050, annual average river runoff and water availability are projected to increase by 10-40% at high latitudes and in some wet tropical areas, and decrease by 10-30% over some dry regions at mid-latitudes and in the dry tropics. Higher water temperatures and extreme weather events (such as floods and droughts) are projected to affect water quality and to intensify many forms of water pollution – pollutants such as high nutrient levels, pathogens, pesticides, salt, etc.

Nearly 2 billion people already live in areas of high flood risk, often as a result of destruction of floodplain wetlands and reclamation for agriculture and urban development; further losses of wetlands in these areas, along with the impact of climate change in certain latitudes, increases this vulnerability. The impacts of floods are many – quite aside from the immediate effects of human mortality there is the risk of infectious diseases, and there is evidence of equally negative impacts of climate-related effects on mental health, resulting in long-term depression and anxiety.

Around 50% of the world’s people live along the coast and the density of populations in coastal area is three times higher than the global average. Many of the world’s poorest communities are coastal dwellers and rely on mangrove and reef-based fisheries for food security.

In developing countries, coral reefs contribute about a quarter of the annual fish catch, providing food for about one billion people in Asia alone; in Indonesia, for example, some 60% of the population is dependent on marine and coastal fishing resources for food and livelihoods. The Great Barrier Reef contributes a total of US$ 4.5 billion to the Australian economy, with US$3.9 billion from tourism, US$469 million from recreation, and US$115 million from commercial fishing, collectively generating 63,000 jobs.

Broadly there are a number of key responses that can be made to resolve the loss of wetland biodiversity and the additional impacts of climate change on those losses:

·         Maintain the health of our intact wetlands;

·          Redouble efforts to address the key drivers of wetland loss and degradation (habitat loss, pollution, excessive water withdrawals, invasive species, overexploitation, etc.);

·         Continue to identify vulnerable species and ecosystems, and plan and implement species and ecosystem action plans for recovery;

·         Priorities and plan wetland management and restoration programmes for a changing and more variable climate; managers will have to adapt their planning to take account of these changes with the aim of maintaining as far as possible the delivery of ecosystem services;

·         Continue to restore degraded wetlands, since healthier wetlands are more resilient than degraded ones; and  urgently address the additional impact of climate change on wetland species and ecosystems through:

·         Climate change mitigation actions;

·         Appropriate climate change adaptation strategies.

Mitigation requires us to reduce greenhouse gas emissions and to encourage the removal of such gases already in the atmosphere, ‘trapping’ them in soils and vegetation. There is no question that the key culprit globally in CO2 emissions is our use of fossil fuels. But we can also have a real impact on emissions by the way we manage our environment. Especially significant are the continuing rapid rates of deforestation of wetland and other forests and the draining of peat lands. Peat lands, though covering only 3% of global land area, have long been recognized as an important carbon sink, and their drainage and conversion for other uses as an important source of emissions. There is also increasing evidence of the role of mangroves, salt marshes and other wetlands as carbon sinks, and thus there is an urgent need to restore and secure the management of these wetlands as well.

For this Ecosystem-based adaptation is the best to climate change delivers this holistic approach. For inland wetlands, it requires actions to:

·         Reduce the degradation of river basins by deforestation;

·         Increase afforestation;

·         Maintain and restore riparian wetlands and floodplains along rivers so that they can provide better protection from flooding;

·         Improve management of wetlands and water at the basin level;

·         Restore “green infrastructure” wherever possible: the natural flood defense system provided by inland wetlands will help to ensure that the other ecosystem services provided by wetlands are maintained.

Ecosystem-based adaptation in coastal ecosystems requires actions to:

·         Reduce the loss and degradation of, mangroves, salt marshes, sand dunes, coral and shellfish reefs and other coastal wetlands, and restore them where possible, to produce ecosystems more resilient against sea level rise;

·         Minimize “hard” infrastructure developments against coastal floods in favor of green infrastructure wherever possible;

·         Remove artificial barriers on the landward side of mangroves and salt marshes so that they may be able to migrate landwards as sea levels rise.