Temps de lecture :4 minutes
There is clear interlinkage between biodiversity and climate change in many ways and at many scales. At global policy level there is increasing focus on the twin axes of mitigation against climate change, and also adaptation to it. For both mitigation and adaptation to the effects of climate change, biodiversity has a key and important role. Increasing commonality of purpose and approaches between the Multilateral Environmental Agreements, the UNFCCC on one hand and the family of biodiversity related conventions represented by the CBD on the other, means science behind both climate change and biodiversity needs to work together more effectively.
As some of you may know, we have our own day, world wetlands day, on February 2. Normally this is celebrated around the world in our Parties, with various local events. This year the theme was “fish for tomorrow?” – attempting to point at the issue of fishing down our resources. Next year will be “healthy wetlands, healthy people”, focusing on the intricate links between having healthy wetlands and the values that has for promoting human well being.
But both of these issues, important as they are for wetlands, are also likely to be impacted by the energized demon we call climate change. Hotter, more acidic seas, and freshwater lakes with temperature and physico-chemical changes we can expect but not forecast exactly, will add pressures to those from over-fishing. Hotter and drier conditions will also impact on the form and function of wetland systems, which in turn will not be able to deliver the full range of ecosystem benefits to people. So everywhere we turn there are problems and issues between climate change and wetlands and their component biodiversity. And it is the range of synergistic processes we add to the pressures of climate change, like salt to a recipe, which is increasing uncertainty. Indeed the only future certainty is greater uncertainty!
Of course, wetlands are shaped by their biodiversity, in literal as well as metaphoric, sense. So amid all the gloom and doom and dire warnings, are there any positive ideas we can take? Well yes it seems there are. Wetlands are keys to managing the global water cycle, above ground where we are used to seeing it, but also below ground, where much water flows, and is stored. So well managed wetlands can actually help in the protection and purification of water, as well as in the production of water.
Wetlands are also critical to mitigating climate change. They have an important and underestimated role in both carbon storage and Greenhouse Gas regulation. Where they have been degraded wetlands are already a significant additional source of atmospheric carbon and wetlands restoration/rehabilitation offers a return on investment up to 100 times that of alternative carbon mitigation investments. Burning peat forests in the south-east of Asia of course are graphic examples of where wetlands, badly managed, can add to our woes.
And yet, in terms of adaptation, soft engineering approaches can utilise especially wetland systems on the coastline where it is being eroded by rising seas, and in terms of helping mitigate against our worst excesses.
In many parts of the world wetlands are now seen as potential “instant” ecosystems which can add a whole host of benefits. In countries from the temperate humid regions of the world to the hot and arid Arabian gulf, constructed wetlands have a new role in helping treat sewerage to remove the nutrients of nitrogen and especially phosphorous, which can cause eutrophication if discharged without a final living filter. The biomass from these wetlands has a future as bio-energy, either through fermentation to produce ethanol, or as pelleting for solid fuel burning. In the face of climate change, then, wetlands can really help return the world to elements of stability and sustainability.
We know, though, that significant impacts of CC on wetlands related species include:
* Increase of wetlands productivity, with uncertain results;
* Proliferation of invasive species;
* Loss of endangered or endemic biodiversity.
Among wetlands, Peatlands alone store twice the carbon present in forest biomass of the world and that their storage is a very long term, contrary to forests. However, precise information concerning the storage-capacity of other types of wetlands is missing. One thing is sure: degradation of wetlands by drainage and fire has severe impacts on carbon emissions in the atmosphere. Therefore, reducing climate change is possible through the conservation, restoration or creation of wetlands but becomes even more difficult if their degradation is not prevented. Here our obsession with the idea that forests are the main way to sequester carbon would seem less sure. Of course forested ecosystems are important, but the lemming-like rush to use forests as the only way to manage carbon in an ecosystem way ignores the power and potential of the worlds wetlands.
So, including wetlands in landscape level planning for ecosystem services will reduce costs in climate change adaptation responses. And it is clear that there is a critical need for greater awareness of the role of wetlands in carbon storage by policy makers within UNFCCC and other international processes and for this awareness to follow through to relevant policy development. Communication of existing science and policy activity in our conventions to the broader public is becoming more critical than simple acquisition of more knowledge.
It is assumed that conservation of what we have must be a key priority. And yet, if the IPCC and the Millennium Assessment are correct, even in general direction, we face serious problems if we rely simply on conservation. We must become more effective biodiversity managers, which means using adaptive management and the ecosystem approach to manipulate biodiversity towards outcomes resilient under climate change. While we certainly don’t want to encourage invasion of aliens, we may need to be proactive in moving species around our land- and sea-scapes to enhance our potential response to change.
And our protected areas? These may well have additional roles to keeping what we have, including being sites for the evolution of new species and new ecosystems, capable of responding more effectively to the excesses of climate change.
Speech by Peter Bridgewater, Secretary General, Ramsar Convention
International Day for Biological Diversity
22 May 2007