What to Do When the Oceans Rise

This summer, Americans are experiencing climate change as record-breaking heat and drought. Our new normal, with its massive wildfires and severe storms, has given the whole nation a sense of the economic and social consequences of global warming that coastal communities around the world have been experiencing for decades. If you live near the sea, you’re probably witnessing the consequences of too much carbon dioxide in the atmosphere as rising sea level, coastal flooding, and eroding shorelines. In the western Pacific and Indian Oceans, low-lying islands are being engulfed. Meanwhile, in some parts of the Arctic, the rate of erosion has doubled to tens of meters per year due to thawing and the loss of sea, which increases wind fetch. Rising seas also ruin coastal farmland and fresh water aquifers and can destroy biologically rich habitats like marshlands and mangroves. The costs of either rebuilding or relocating in response are enormous but unavoidable. Furthermore, since the economies of many coastal communities are based on fisheries and tourism, the impacts of anthropogenic climate change threaten their long-term sustainability [1]. Given their vulnerability, coastal communities are on the front line of global warming. But do they have the capacity to adapt to so much environmental change? Do their responses to past challenges suggest strategies for coping with future change? Can we predict which communities are most vulnerable and help them to become more resilient? To answer these questions, scientists like Tim McClanahan and Joshua Cinner are merging marine and climate change ecology with modern social science. Their goal is to figure out what aspects of coastal communities facilitate social adaptation and how these traits can be promoted. McClanahan is a renowned coral reef ecologist who lives in Kenya and works for the Wildlife Conservation Society. Cinner, a Research Fellow based at James Cook University in Townsville, Australia, is at the forefront of a revolution in the social sciences. He’s leading the way to replace the traditional descriptive case study approach with a sort of human macroecology [2], where relationships between societies and their environment are explored by assembling geographic databases of social and ecological traits. This new approach is inherently large scale and statistical as opposed to the traditional local-qualitative method. McClanahan and Cinner’s new book, Adapting to a Changing Environment: Confronting the Consequences of Climate Change, is a primer and also an application of this emerging holistic science. The book is concise, accessible, and written for students, scientists from other disciplines, and policy makers. The authors use coastal east Africa as a case study to develop their model of estimating the ‘‘social adaptive capacity’’ of communities. Unlike temperate and polar coasts, the shorelines of much of the tropics are fringed by coral reefs that buffer coastal communities from waves and storms, provide productive fisheries, and are the base of a tourism economy. The downside is that corals are quite sensitive to ocean warming, and their ongoing global disappearance [3] is both depriving people of their livelihoods and simultaneously increasing erosion as their buffering function is lost [4]. In other words, the vulnerability of this threatened ecosystem is passed on to its human dependents. (Such interconnectedness is a recurrent theme in the book.) The book contains thorough but understandable introductory chapters on marine fisheries, climate change, and coral reefs. McClanahan and Cinner highlight the challenges of effective fishery management and describe actions taken on international and national levels to more effectively and sustainably manage marine resources. A chapter on coral reef resilience explains what a coral is (a coelentrate, related to jellyfish), how corals form reefs, and the role of the microscopic zooxanthellae that form a crucial symbiosis with their coral hosts. The authors explain how this symbiosis can be disrupted by small temperature increases, leading to the eviction of the zooxanthellae and the ‘‘bleaching’’ and death of the coral if