In the months that led up to December’s UN Climate Change Conference in Copenhagen, reports forecasting the environmental and socio-economic impacts to come from climate change were sobering. The future for our coasts and oceans? Rising sea levels and coastal flooding. Increased acidification of seawater. Coral bleaching. Poleward shifts in ocean habitats and species ranges. Conceivably, a hundred years from now, our coasts and oceans could look quite different from today.
This poses a challenge for resource managers. Faced with what amounts to a shifting playing field, they must develop ways to manage effectively both for today’s world and for tomorrow’s. It requires planning ahead: anticipating the changes that may come, assessing vulnerable areas, and working to mitigate the impacts of climate change – or to adapt to them. In this issue of MEAM, we examine several aspects of climate change as they impact ecosystem-based management, and how managers can be proactive in a changing world.
Managing shifting ecosystems
Over the past four decades, many fish stocks in the Northwest Atlantic Ocean have been shifting northward, with some stocks nearly disappearing from US waters as they move farther offshore. This finding, from a new study by US National Oceanic and Atmospheric Administration scientists, shows the impact of changing coastal and ocean temperatures on fisheries in the region, says lead author Janet Nye. The shifting species, including several commercially important ones like yellowtail flounder and hake, are seeking waters that are cooler than what their traditional habitats have become, says Nye.
“Whether stocks depart from the region – due to changing thermal or oceanographic conditions brought about by climate change – is ultimately beyond human control,” she says. “What we can recommend are robust management strategies that account for potential effects of climate change. Stocks facing pressures from overfishing are usually more susceptible to other pressures like climate change. Therefore, managing fisheries so they are sustainable, and thereby allowing for resiliency of individual stocks and the ecosystem, is an excellent start.”
Knowing what level of fishing to recommend in order to avoid overfishing, and continually adapting that level to changing conditions (including the movement of species into and out of the region), will require constant and careful evaluation of stock dynamics, says Nye. “Robust management measures, procedures, and processes for today’s ecosystems will be germane for future ecosystems,” she says. “Managing sustainably [for today’s ecosystems] sets us up to do so for future ecosystems, too.”
She imagines a future in which the regional fishery management council that oversees US fisheries in her study area could be managing a different suite of species. “The stocks in our region today are a mix of species that are at the southern, middle, and northern extent of their ranges,” she says. “It seems likely that if poleward movements of species continue as predicted and observed, then the ratio of southern to northern species will increase in this region.” (Nye’s study “Changing spatial distribution of fish stocks in relation to climate and population size on the Northeast United States continental shelf” was published in Volume 393 of the journal Marine Ecology Progress Series.)
Marine protected areas normally have fixed boundaries and are designated to protect certain species or habitats. As a result, they may be particularly impacted over time by climate-related shifts in those species and habitats. MEAM’s sister newsletter MPA News (mpanews.openchannels.org) has documented several MPA-related strategies for addressing these shifts, including:
Protecting north-south corridors with networks of MPAs – In the March 2005 issue (MPA News 6:8), biologist Satie Airame explained how plans to designate a system of no-take marine reserves up and down the California state coast could be critical to species and habitats currently protected within the Channel Islands National Marine Sanctuary in Southern California. Protected species and habitats may eventually migrate northward out of the sanctuary to cooler waters, said Airame. “Because the scale of global warming is much larger than the Channel Islands region, complementary regulations that cover a much larger area – the entire state of California – are likely necessary,” she said.
Adjusting protection regimes as species shift – In the same March 2005 article, David Obura of CORDIO, an international research program to respond to coral reef degradation in the Indian Ocean, said comprehensive marine zoning could be managed to follow shifting species and habitats of concern. In other words, protective measures in various zones could be up- or downgraded as needed over time. “If done cleverly, the boundaries of zones within such a system may not need to be changed – just the management regime,” he said. He added this might be preferable to creating new MPAs to follow shifting species, or expanding the boundaries of existing MPAs, as those measures could be viewed by resource users as governmental “land grabs”.
Protecting geologic features rather than specific habitats or species – In the March 2008 issue (MPA News 9:8), Joe Uravitch of the US National Marine Protected Areas Center cited a need to protect “important geological and persistent oceanographic features” with MPAs. These features, such as canyons and seamounts, are often areas of high biodiversity, he noted. “We can logically assume that ecosystems and species assemblages in these particular locations will change as species move poleward or die off,” he said. “But we can also reasonably assume that the geologic features upon which these MPAs were established are the most likely places around which new species assemblages and ecosystems will form over time.”
Policy options for sea level rise: Protect, redesign, rebuild, elevate, relocate, or retreat
In 2007, when the UN Intergovernmental Panel on Climate Change released its forecast for sea level rise by the year 2100 (18-59 cm over current levels), it based the projection primarily on the natural expansion of water as it warms. This was because it was unclear at that time how large a role the gradual melting of polar ice sheets (in Greenland and Antarctica) would play. Since then, melting of these sheets has occurred at faster-than-expected rates, leading some scientists to project sea level rise of a meter or more by next century.
For low-lying coastal and island nations, the math is grim. Several small island nations like the Maldives are little more than 1 m above sea level, and may have to abandon their country eventually. Even in Australia, where there is enough land to allow for inward migration, sea level rise is already affecting planning and financial decisions. Last year, an administrative tribunal in the state of Victoria ruled that a project to build homes along the coast could not proceed in light of estimates that sea level rise could flood the site over time. In this case, the Victorian Civil and Administrative Tribunal applied the precautionary principle that although there was uncertainty about the magnitude of sea level rise to come, it was evident that such rises were to be expected.
Alan Stokes of the National Sea Change Taskforce, which represents the interests of coastal councils and communities in Australia, also cites a 2008 decision by the South Australian Supreme Court in which subdivision permits were refused because a developer had not adequately addressed the expected effects of sea level rise. “These cases are setting precedents that will no doubt be followed elsewhere in Australia,” says Stokes. “We believe this is a positive step because they help to highlight and emphasize the need to factor projected sea level rise and other climate change impacts into coastal planning decisions.”
The taskforce is encouraging its member councils to implement climate change adaptation and mitigation considerations in all coastal planning, undertake vulnerability assessments at regional and local scales, and even consider the carbon footprint of future land use and development. (The recommendations are in the taskforce report Planning for Climate Change: Leading Practice Principles and Models for Sea Change Communities in Coastal Australia, available at www.seachangetaskforce.org.au/Publications/PlanningforClimateChange.pdf.)
A report this year by an Australian House of Representatives committee on climate change spelled out the policy options available to coastal communities in addressing sea level rise: protect, redesign, rebuild, elevate, relocate, or retreat. The report (www.aph.gov.au/house/committee/ccwea/coastalzone/report.htm) described the uncertainties local planning councils will face in deciding which policy would apply best in each circumstance. While some vulnerable coastal communities could be protected by sea walls and levees, there will be areas where it is not physically or financially possible to introduce an engineering-based solution. In the latter cases, a policy of “planned retreat” inland may become the only choice.
In the Netherlands, planned retreat is not an option, says Leo de Vrees, water manager for the country’s Rijkswaterstaat North Sea Directorate. “We are a very densely populated country where almost half the population lives below sea level,” says de Vrees.
The Dutch have a long history of defending against the sea. “We know from experience and research that it is possible to keep pace with sea level rise, even with higher scenarios,” says de Vrees. “Presently, we supply 12 million m3 of sand per year [to maintain the Dutch coastline]. With a sea level rise of 130 cm, which is the higher scenario according to the Delta Committee [a Dutch government advisory committee], this would increase to approximately 85 million m3 per year.” He says the main challenge is to balance the maintenance of the coast with the cost of doing so, which is now approximately 60 million euros annually.
Does building up a country’s coastline count as ecosystem-based management? De Vrees says it does. “The Dutch coast is a natural dune coast with high natural values,” he says. “Most of the coast, including the shallow waters, consists of designated Natura 2000 areas under the European Birds and Habitats directives. Beach nourishment and underwater nourishment as a method of maintaining the coast have been chosen, among other reasons, because of the benefit to the ecosystem. We call it ‘building with nature’. Without this nourishment, the coast would erode whereby natural values would be lost. If hard structures were constructed [to defend against sea level rise], natural values would be lost as well.”
Sand mining for the coastal maintenance work is even included in Dutch marine spatial planning: the country has dedicated a zone in its North Sea to that activity. “Because of the increased demand for sand and because of the increasing demand for space for other functions (especially offshore wind farms), it was necessary to safeguard certain areas for sand mining,” says de Vrees. The sand mining zone extends from the 20-meter depth contour out to 12 nautical miles, covering roughly 5000 km2. The Netherlands is expected to require at least 9 billion m3 of sand over the next 100 years for nourishment (beach and underwater) and commercial purposes. “The sand mining zone is certainly large enough to supply that amount,” says de Vrees.
Protecting ecosystems, protecting ourselves
A relatively new concept in the marine and coastal management field is ecosystem-based adaptation. It consists of the sustainable management, conservation, and restoration of ecosystems, with the goal of allowing those ecosystems to continue providing vital services to help people adapt to climate change. Take coral reefs and mangrove forests, for example. They can play a crucial role in protecting shorelines from flooding, erosion, and extreme weather events. By protecting and restoring these ecosystems, managers increase ecosystem resilience and allow coastal communities to adapt better to a changing world.
In a new IUCN report The Ocean and Climate Change: Tools and Guidelines for Action, authors Dorothée Herr and Grant Galland strongly recommend the adoption of ecosystem-based adaptation (EbA or EBA) strategies. They also note the distinctions between EbA and ecosystem-based management. “Ecosystem-based management is one of the critical means of delivering EbA, especially for building ecosystem resilience and when considering the needs to reduce other non-climate stressors such as overfishing or pollution,” says Herr, of IUCN. “However, since EbA is applied in the context of responding to new situations brought about by climate change, specific EbA interventions might not be directly apparent from an EBM point of view.”
To illustrate, she cites mangroves. Under an EBM approach, timber harvest from mangroves could be sustainably managed at a certain level. But from an EbA point of view, says Herr, a reduction in that harvest level might make sense to maintain a higher stand density and reduce the impacts of increased storm surges due to climate change. “While EBM is an overarching approach to protect ecosystem function and key processes as well as to manage natural resources, EbA involves a set of activities that specifically increase resilience and reduce vulnerability of ecosystems and people to climate change,” she says.
Galland, a Ph.D. student at Scripps Institution of Oceanography, says an EbA approach might not fit the needs of all coastal communities. “It would be naïve to think that the people of Manhattan Island could dedicate the time and space required to restore riparian zones and coastal wetlands in response to the threat of rising sea levels,” says Galland. “Also, they can afford large-scale, industrial fixes – including walls, water pumps, etc. – to keep their city safe. Those tactics are complementary to EbA and, under some circumstances, more appropriate than it.” A new IUCN guide Ecosystem-Based Adaptation: A Natural Response to Climate Change provides several case examples of how EbA has been incorporated in terrestrial and coastal resource management (http://cmsdata.iucn.org/downloads/iucn_eba_brochure.pdf).
Christian Nellemann of the UN Environment Programme (UNEP) says that protection of coastal and marine ecosystems is now more critical than ever. This is in light of findings that seagrass beds, mangrove forests, and salt marshes serve as major carbon sinks for the world – meaning they store or sequester carbon dioxide, effectively removing it from the atmosphere. In the new UNEP report Blue Carbon: The Role of Healthy Oceans in Binding Carbon, Nellemann cites that over half of the biological carbon captured in the world is captured by marine living organisms, and that the above-mentioned habitat types are responsible for most of what is actually stored. By preventing the further degradation of these ecosystems and working to restore them, humans can help offset 3-7% of current fossil fuel emissions over two decades, according to the report. (The report is available at www.grida.no/publications/rr/blue-carbon.)
“We know that improved coastal management will benefit biodiversity, food security, health, and coastal livelihoods,” says Nellemann. “But it has not been brought to public attention how crucial many of these ecosystems are for binding and storing carbon, or how large the potential is for sequestration through restoration of these habitats.”
Nellemann would like to see the creation of a global “Blue Carbon Fund”, as suggested by UNEP, to support and generate investments in the protection and restoration of seagrasses, mangroves, and salt marshes. He says such activities would generate jobs, development, protection of biodiversity, and climate mitigation – all at the same time. “It is an extraordinary win-win opportunity,” he says.
Ross Sea: An ideal site for studying climate change?
David Ainley has studied Adélie penguins in the Ross Sea of Antarctica since the late 1960s. Over that time, he has watched climate changes affect penguin populations – sometimes in beneficial ways, sometimes not. Owing to increased winds, nearshore waters have become ice-free earlier in spring (or even in winter), making it easier for the penguins to reach the sea to gather food. On the other hand, the increased winds lead to thinner sea ice in general, which is a problem for nearby Emperor penguins whose colonies depend on the ice to stay in place longer.
Ainley says the Ross Sea ecosystem serves as a particularly useful site for studying climate change. The reason, he says, is that it remains relatively pristine. Due in part to the fact it is completely ice covered for seven months of the year (and partially so for the remaining months), the Ross Sea has historically experienced low levels of exploitation from fishing and whaling. As a result, the sea still has a full suite of top predators.
“Having an oceanic ecosystem available that has not been exploited – one in which whole functional groups have not been removed – is a marvelous opportunity to investigate food web processes and the effects and responses of species interactions,” says Ainley. “This allows us to understand how food webs once were structured and how these intact food webs once responded (or not) to climate cycles and change.” He compares the Ross Sea to other parts of the Southern Ocean, where there was little data collection before most of the whales were gone and huge expanses were fished out of demersal species. “A number of trends in top predators in those areas, thought initially to be related to climate, can be explained as responses to the exploitation of competitors or, more recently, the competitors’ recovery,” says Ainley.
The Ross Sea is not completely free of exploitation. Since 1996, an industrial fishery for Antarctic toothfish has targeted the sea, with a catch of roughly 3000 tons/year. Before the region entices more fleets to its severe waters, Ainley would like to see the entire Ross Sea set aside as a no-take marine reserve. He is science director of a project, The Last Ocean (www.lastocean.com), which champions that idea. “The Ross Sea covers 3.2% of the Southern Ocean,” says Ainley. “Viewing the Southern Ocean as a whole, it would be wise to set aside portions where there would be no exploitation, thus to benefit the science that is the hallmark of international cooperation under the Antarctic Treaty.” He adds a Ross Sea reserve could also help restore depleted species in neighboring areas of the Southern Ocean.
For more information:
Janet Nye, Northeast Fisheries Science Center, Woods Hole, Massachusetts, US. E-mail: janet.nye@noaa.gov
Alan Stokes, National Sea Change Taskforce, Sydney, Australia. E-mail: stokes@bigpond.net.au
Leo de Vrees, Rijkswaterstaat North Sea, The Netherlands. E-mail: leo.de.vrees@rws.nl
Dorothée Herr, IUCN-USA, Washington, DC, US. E-mail: Dorothee.Herr@iucn.org
Grant Galland, Scripps Institution of Oceanography, University of California, San Diego, US. E-mail: ggalland@ucsd.edu
Christian Nellemann, UNEP, Lillehammer, Norway. E-mail: christian.nellemann@nina.no
David Ainley, The Last Ocean, Sausalito, California, US. E-mail: dainley@penguinscience.com
BOX: More information sources on climate change and EBM
MEAM has compiled a list of 20 useful reports and websites on climate change – from general overviews, to sources that focus on specific aspects (sea level rise, ocean acidification, coral bleaching, etc.). See it here.