While Gary Griggs has lived near the coast of California most of his life, visits to the coasts of 46 nations helped shape his latest book, Coasts in Crisis: A Global Challenge. The distinguished professor of Earth sciences at the University of California, Santa Cruz, writes on how coral reefs provide shelter, food and breeding grounds for about one-third of the world’s species of marine fish, as well as coastal protection from major weather events. Most coral reefs are now besieged by pollution, overfishing, sedimentation, coastal construction, tourism and global warming.
Approximately 3 billion people—nearly half our planet’s total population—live in coastal areas. He cites that hurricanes have caused more U.S. fatalities than any other natural hazard, and the driving forces behind rising sea levels will increase future vulnerabilities unless effective actions are taken now.
Griggs, who also wrote Introduction to California’s Beaches and Coast and Living with the Changing California Coast and co-wrote The Edge, today recaps the history and assesses the current status of coasts worldwide. He suggests ways in which current negative trends might be reversed or improved.
How can we better deal with rising sea levels?
There are now about 200 million people living within three feet of high tide. Both mitigation and adaptation will be required. We need to do everything possible to cut back on greenhouse gas emissions, but that’s not going to stop rising sea levels anytime soon. We need to start adapting right away.
We can elevate structures, but that’s limited. Historically, we’ve used armoring, including seawalls, levees and rock revetments, which work for awhile, but have endpoints. Ultimately, it’s going to take relocation, or what we call “planned retreat”, moving back when the sea nears our front yard. The more we reduce or mitigate the emission of greenhouse gases, the less adaptation will be needed to cope with climate change.
Why are coral reefs so vital to the global ecosystem?
In the tropical latitudes, coral reef ecosystems have formed the basic biological, geological, economic and cultural framework of area coastlines and island nations for centuries. Today, fisheries and tourism anchor those economies. Millions of people depend on these local ecosystems for their protein supply.
About 50 percent of coral reefs are in poor or fair condition, and most are in decline. Whether from pollution, dredging, filling or overfishing, virtually all of those reefs are under significant threat.
Have researchers seen any overfished species rebound?
A 2013 report by the Natural Resources Defense Council found that about two-thirds of U.S. commercial fish species that had been seriously depleted had made significant recoveries—28 of 44 fish stocks, including Atlantic bluefish, flounder and black sea bass—primarily due to better management practices. We now have fisheries restrictions and marine-protected areas in place. To realize some long-term success, we need to limit fisheries in certain areas and for certain species.
California’s Monterey Bay Aquarium publishes a Seafood Watch Consumer Guide card specific to regions; it color codes which species are safe to eat and which ones no longer can provide a sustainable harvest, so we know which ones to ask for at grocers and restaurants.
What might mitigate the environmental impact of what you term “coastal megacities”?
Eight of the largest metropolitan areas worldwide—Shanghai, Mumbai, Karachi, Tokyo, Dhaka, Jakarta, New York/New Jersey and Los Angeles—are along shorelines. Coasts in Crisis looks at the hazards of hurricanes, cyclones, typhoons and tsunamis that their residents are exposed to—along with long-term sea level rise.
These incredible concentrations of people not only fish heavily, they discharge large volumes of waste and wastewater. You can’t put 10 million people on a shoreline and not expect impacts. We need to get all of these discharges cleaned up and under control. Shorelines are very delicate biological environments.
We also must get global population under control to make a much softer footprint on the planet. It would take four planet Earths to support the present global population if everyone indulged in America’s current consumption habits (FootprintNetwork.org).
Sustainability is what we must work toward, whether it’s food, water or energy. Currently, we’re mining the planet for all its resources, which can’t go on for much longer. We need to recognize this and return to equilibrium with what the planet can supply.