WETLANDS FOR CLIMATE CHANGE ADAPTATION AND MITIGATION
You may be wondering why this fuss about climate change never seems to end, with environmentalists on one hand telling you the world is at risk if we do not take care of our natural resources, while sceptics on the other hand tell you not to worry, that we are currently going through an inevitable natural warming cycle and should expect natural disasters here and there.
The South African National Biodiversity Institute (SANBI) and the Working for Wetlands Programme are taking part in the events surrounding COP17, with the aim of highlighting how the conservation of biodiversity and rehabilitation of ecosystems can contribute significantly to reducing the impacts of climate change and helping humans adapt to these impacts. Working for Wetlands has invested heavily in labour intensive wetland rehabilitation on a national scale for the past nine years, rehabilitating over 800 wetlands and in the process creating over 15 000 work opportunities under the Expanded Public Works Programme. If you choose to believe the sceptics, or if you are wondering how Working for Wetlands' investment is relevant to our national response to climate change, below is information that will explain in simple terms how wetlands fit into the climate change picture and why we have to take good care of them.
DID YOU KNOW THAT?
Over 200 000 wetlands, covering 2.9 million hectares, or 2.4% of South Africa's surface area, have been mapped to date. Of this, it is estimated that peatlands cover 29 500 hectares, or 1% of the country's total wetland area, and contain about 280 million cubic metres of peat. Peatlands are wetlands containing a special type of soil, called peat, which is found only in wetlands. Peat enhances normal wetland functions, making peatlands particularly efficient at carbon and water storage and highly effective as filters.
HOW IS PEAT FORMED?
Permanently saturated conditions in some wetlands inhibit the decomposition of dead plant and animal matter. Instead of decomposing, some of this material accumulates over time and becomes peat, which is the first step in the formation of coal. Although at least 30% of the world's wetlands are peatlands, most are concentrated in the northern hemisphere. Southern hemisphere peatlands are generally small, shallow and sparsely distributed. It is estimated that peat accumulates at a rate of about 0.5 mm per year in South Africa, compared to the global average of 1–2 mm per year. Peatlands are also used for subsistence farming, grazing, harvesting of plant material and water collection.
WHAT IS THE ROLE OF WETLANDS IN MITIGATING CLIMATE CHANGE?
Wetland ecosystems help regulate climate by capturing and storing carbon. Peatlands, in particular, influence the global balance of three main greenhouse gases—carbon dioxide, methane and nitrous oxide. In their natural state, peatlands remove carbon dioxide from the atmosphere via peat accumulation. Although peatlands also emit methane, the long-term negative effect of methane emissions is smaller than the positive effect of carbon dioxide removal. After oceanic deposits, peatlands are the world's most important carbon stores, even though they only cover 3% of the world's land surface. If left undisturbed, peatlands can store this carbon for thousands of years and as a result are called 'carbon sinks'.
A range of human activities impact negatively on the ability of peatlands to store carbon. When peatlands are disturbed and peat is exposed to air, the decomposition process resumes and stored carbon is released back into the atmosphere. Degraded peatlands can thus become significant sources of carbon dioxide. Draining and burning of peatlands releases about 3 billion tons of carbon into the atmosphere every year. This is equivalent to more than 10% of global fossil fuel emissions.
A 2008 assessment identified 7 100 hectares, or 25%, of South Africa's remaining peatlands as being degraded, which resulted in about 300 000 tons of carbon dioxide being released into the atmosphere in 2008 alone. It is estimated that a further 194 million tons of carbon dioxide could still be released into the atmosphere if the remaining healthy peatlands in South Africa were to be degraded. Experts estimate that many of our other permanently saturated wetlands also contain soil carbon, although not in sufficient concentrations to qualify as peat. This stored carbon could amount to a further 2 200 million tons of carbon dioxide that could be released into the atmosphere if these wetlands become degraded.
HOW DO WETLANDS HELP US ADAPT TO CLIMATE CHANGE?
Many wetlands are able to improve water quality, reduce flood impacts, control erosion and sustain river flows. In providing these services to people, they also help us to adapt to the impacts of climate change. Wetlands are important for reducing the impacts of extreme weather events like floods and droughts that we are already experiencing. Changes in rainfall intensity and variability due to climate change are expected to increase flooding and drought in many areas. Wetlands can therefore play a more important role than ever before in mitigating the impacts of such extreme events, but they can only do this if they are in a healthy state.
WHAT WILL HAPPEN IF WETLANDS ARE AFFECTED BY CLIMATE CHANGE?
Many wetlands in South Africa are likely to be affected in some ways by changes in temperature and rainfall brought about by climate change:
• Some wetlands with a limited capacity to adapt to rapid change may be especially vulnerable to climate change. Damage to these ecosystems could be irreversible.
• Coastal wetlands including salt marshes and mangroves are likely to be negatively affected by sea level rise.
• Certain invasive species may expand their ranges.
• Higher water temperatures and extreme events like floods and droughts are projected to decrease water quality and increase erosion in many of our wetlands.
The recently completed Millennium Ecosystem Assessment, the most thorough examination of the health of the planet's ecosystems, points out that the continued loss of wetlands will further reduce human health and well-being, especially for the poor. Although we all benefit from wetlands in some way, wetland-derived goods and services are especially important for the poorest and most vulnerable sectors of our population.
WHAT CAN WE DO?
It is vital to understand and pay attention to wetlands in South Africa and how they can form part of our response to mitigating and adapting to climate change. We can:
• Keep our remaining wetlands healthy and resilient. Let's celebrate our wetlands as vital natural infrastructure, because healthy wetlands provide a robust and resilient mechanism for managing our scarce water resources under conditions of uncertainty.
• Target the main activities that are responsible for ongoing wetland loss and degradation.
• Focus on actions that support both the health of wetlands and the health of people, since there is a direct link between the two.
• Rehabilitate degraded wetlands, since healthier wetlands are more resilient than degraded ones. Rehabilitation and good management of our wetlands can generate multiple benefits including poverty alleviation, combating of land degradation, maintaining biodiversity and mitigating climate change.
• Place particular emphasis on protecting and rehabilitating our peatlands. Because of the large emissions from degraded peatlands, rewetting and rehabilitating them is one of the most cost-effective ways of reducing greenhouse gas emissions. Recognising this, although peatlands make up only a fraction of South Africa's wetlands, 40% of all current and previous rehabilitation projects undertaken by the Working for Wetlands Programme have targeted peatlands or their catchments.
For more information:
• GRUNDLING, P-L. & DADA, R. 1999. Peatlands of South Africa. Wildlife & Environment Society of Southern Africa.
• JOOSTEN, H. 2009. The Global Peatland CO2 Picture: Peatland status and drainage related emissions in all countries of the world. Report for the UN-FCCC conference in Copenhagen, December 2009. Wetlands International.
• PARISH, F., SIRIN, A., CHARMAN, D., JOOSTEN, H., MINAYEVA, T., SILVIUS, M. & STRINGER, L. 2008. Assessment on Peatlands, Biodiversity and Climate Change: Main Report. Global Environment Centre, Kuala Lumpur and Wetlands International, Wageningen. http://www.imcg.net/media/download_gallery/books/assessment_peatland.pdf
• RAMSAR CONVENTION ON WETLANDS. 2009. Caring for wetlands: an answer to climate change. Leaflet produced for World Wetlands Day 2010. www.ramsar.org/pdf/wwd/10/wwd2010_aa_leaflet_e.pdf .