News•April 14, 2010
Managers Face the 'Coastal Squeeze'
Average sea level at Tomalas Bay in Marshall, Ca has risen about 8 inches in the last 100 years.
It was late February and at a training workshop in Marshall, California, a group of fleece-clad public and private coastal and marine resource managers were being inundated with yet more bad news about climate change — rapid sea level rise, increased erosion and more intense storm events.
“We needed Paxil at the end of the first day,” joked Lauren Wenzel, the National Marine Protected Area system coordinator, and one of the workshop participants.
But this workshop was not all doom and gloom. Rather, managers were learning how to prepare for a future altered by climate change. This approach is what scientists call climate change “adaptation.”
It wasn’t too long ago that “adaptation” was considered a dirty word among those concerned with climate change, due to a fear that talking about adapting to climate change would detract from efforts to reduce greenhouse gas emissions. Scientists now generally believe that we have to do both: prepare for the changes to climate that are already in the pipeline, while continuing to curb our carbon emissions habit.
Since 1880, the planet has warmed about 1.3°F. It is projected to warm another 6 to 10°F this century if we don’t slow our carbon emissions. But, here is the kicker: Even if we ceased emitting all greenhouse gases tomorrow, which is an absurdity given how much we rely on fossil fuels today, the planet will still warm at least another degree or two, and the seas will still continue to rise much faster in this century than the last.
One reason for this is that, like a sponge, the oceans are still absorbing heat resulting from increased concentrations of greenhouse gases in the atmosphere. The deeper, colder layers of water respond especially slowly. With time, as these layers warm, less heat will disappear into the oceans — the sponge will saturate — causing the atmosphere to get warmer. The slow response of the oceans also means that sea level will keep on rising for a long time too, due to continued thermal expansion of the waters.
Also, even if greenhouse gas concentrations were stable, melting of the massive land ice sheets in Greenland and Antarctica would continue, contributing to an extended period of increasing sea levels.
The workshop, which was organized by a collection of federal and state government and private marine and coastal agencies, focused on re-thinking management policies to ensure that vital infrastructure such as roads and airports, as well as public parks, residential development, and wildlife refuges will all still be protected in the face of higher seas, more erosion, less rainfall and fog, as well as more intense storm events and higher temperatures — all related to climate change.
The San Francisco Bay and similar urbanized estuaries are particularly vulnerable to sea level rise. In the last century, sea level in S.F. Bay rose by 7 inches, similar to the global average. It is projected to rise by as much as 55 inches this century. If this occurs, low elevation highways will flood more frequently. Beaches and public coast access will disappear. Wetlands, which provide all kinds of benefits — from buffering of storms, to providing kidney-like filtering of pollutants, to habitat for fish and wildlife — may drown.
A report by the Pacific Institute estimates that $62 billion worth of shoreline development around the San Francisco Bay is at risk from flooding.
This is where adaptation comes in: What we do now — how we build protections, where we situate new development, how we restore habitat — will determine the impacts and costs of climate change on our communities.
Rachel Kamman, a hydrologist, eloquently described the link between restoration and adaptation. At the Giacomini Wetlands Restoration, at the edge of Point Reyes National Park north of San Francisco, she asked the workshop participants to look out across the landscape of grasslands, marshes and open water that until just 2 years ago had been a dairy farm. “This is your sea level rise happy place,” she said.
The Giacomini Wetlands Restoration site at the mouth of Tomalas Bay.
The Giacomini land is the headwaters of the Tomales Bay, where three rivers converge and feed fresh water to the estuary. It had been diked and drained in the 1940s by the Army Corp of Engineers. The complex salt and freshwater marshlands all but disappeared, degrading the function of the entire bay system. Since the dikes were removed in 2007, water has been allowed once again to ebb and flow over the land. The sea can creep in and the marsh can migrate inland over time. This is what makes Kamman so excited: The restoration provided the necessary space for the ecosystem to adapt.
Two years after restoration, biologists found a breeding population of endangered red-legged tree frogs this pond.
We don’t think about it much, but space for a marshland to migrate and respond to rising seas is a rare luxury in the United States. Many marshes abut dense development. As the sea rises, those marshes will not be able to move inland, and if nothing is done to protect them, they will disappear. How to save marshes and simultaneously protect development is one of the more vexing issues coastal managers face. Experts think what it boils down to is that we have to engineer totally new solutions.
“We have to turn ideas on their head,” Will Travis, the executive director of San Francisco Bay Conservation and Development Commission told me.
At the workshop, the familiar “hold-the-line” strategy of armoring shoreline was presented as yesterday’s methodology. Levees would need to be built bigger and taller to handle higher seas and more powerful waves. And counter intuitively, levees can increase community vulnerability over time, because they encourage development directly behind them, and cause the erosion of storm-buffering habitat, like beaches and wetlands, on the seaward side.
“The task now is to enhance or use natural systems processes to create a solution. This will be the state of the process in five years,” said David Revell, a senior associate at the engineering firm Phil Williams and Associates.
Following the workshop, a new inter-agency team formed to incorporate adaptation planning into the update of the Marin County Local Coastal Program. For the California Coastal Commission and other workshop organizers, this is good news.
According to Travis, one of the biggest hurdles to action on climate change is moving it to the top of agencies’ agendas so that the impacts are factored into today’s decision-making processes.
“The problem is not managers figuring out what to do. The hard part is taking the future crisis and getting prepared for it now.”
Brian Aviles, in blue, and other workshop participants interview a Marshall homeowner about his concerns over climate changes and sea level rise in his community.
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