Mcle Self Study Article: Climate Disruption and Sea Level Rise: Legal Issues for Coastal Land Use in California

• Publication year: 2017
• Author: Tim Duane, J.D., Ph.D.

MCLE Self Study Article: Climate Disruption and Sea Level Rise: Legal Issues for Coastal Land Use in California

Check the end of this article for information on how to access one MCLE self-study credit.

Tim Duane, J.D., Ph.D.

Tim Duane is a California attorney and consultant specializing in climate, energy, environmental, land use, water, and natural resources law. He is also Visiting Professor of Law at the University of San Diego School of Law and Professor of Environmental Studies at the University of California, Santa Cruz. He holds a J.D. from Boalt Hall School of Law (UC-Berkeley) and a Ph.D. in Civil Engineering (Energy and Environmental Planning) from Stanford University. Duane was a member of the UC-Berkeley faculty from 1991-2009.

I. INTRODUCTION

Climate change threatens California in multiple ways, and sea level rise is one pathway for climate change to cause significant disruption of settled property and land use along the California coast. This article summarizes the key findings of climate change science for projected sea level rise on the California coast, identifies common law principles that will influence initial conflicts over property boundaries as the sea level rises, summarizes California's sovereign property interests in the coast through the Public Trust Doctrine, discusses relevant statutes under the California Coastal Act and their implementation by the California Coastal Commission and California Coastal Conservancy, and analyzes where implementation of state and local regulatory policies to protect the state's interests could generate takings claims under the Fifth Amendment of the U.S. Constitution. It concludes with recommendations for responding to sea level rise through legal adaptation.

II. CLIMATE DISRUPTION AND SEA LEVEL RISE IN CALIFORNIA

A. Climate Change Science

The global climate is changing and there is no serious scientific dispute about the general direction of those changes and the primary causes.¹ However, there are varying levels of uncertainty associated with projections of specific types of change, their timing, and degree. In particular, forecasts of likely sea level rise are uncertain at the high end: the rate of sea level rise is projected to be fairly predictable and modest based on thermal expansion alone, but global warming could cause positive feedback loops that result in rapid loss of the Antarctic and Greenland ice masses. Rapid and extreme sea level rise could then occur if the continental ice now locked on Antarctica and Greenland were to melt quickly.

The United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO) established the Intergovernmental Panel on Climate Change (IPCC) in 1988 for the purpose of assessing the causes and impacts of climate change. Since 1990, the IPCC has released five Assessment Reports (AR). Each AR is a peer-reviewed synthesis of existing literature conducted by scientific experts in each of the sub-fields under review. Over time, the IPCC has established a standard language for expressing the scientific uncertainty associated with each element in its assessment.² The confidence of the IPCC in attributing human emissions of greenhouse gases (GHGs) as a primary cause of global warming has also increased with each AR.³ The most recent AR, released in 2013-2014, has projections of global sea level rise with some regional variation to reflect other geologic forces affecting sea level rise. Even within California, local geology plays a role in affecting the likely local increase in sea level rise.

[Page 12]

California has been a leader in climate change science and climate change policy responses because it is particularly vulnerable to the effects of climate change.⁴ The state is highly dependent on climatic conditions due to its reliance on water transfers from snow stored in the Sierra Nevada and Colorado River basins as well as agriculture's sensitivity to changes in temperature. Moreover, California's energy demand and supply are directly affected by temperature. Finally, the state's coastline is the primary location for population and investment that would be vulnerable if sea level rise is significant:

If sea levels rise as predicted, over 156,000 Southern Californians will be living in areas vulnerable to a 100-year coastal flood by 2100.⁵ Low-income populations, the elderly, minority communities, and other vulnerable populations in Southern California may be disproportionately exposed to adverse impacts. The increased storm-related flooding, inundation, and erosion associated with sea-level rise have the potential to damage health care facilities, businesses, homes, and other privately owned structures in vulnerable coastal areas. The estimated replacement value of Southern California building stocks that will be impacted by coastal flooding is 26.1 billion dollars.⁶

The San Francisco and Monterey Bay Areas in northern California are also vulnerable to sea level rise.⁷ Natural resources, wetlands, and coastal infrastructure throughout the coastline (including streets, roads, highways, sewers and wastewater treatment systems, water supplies, railroads, airports, public transportation, and power plants) are all threatened.

B. Climate Disruption

The term "climate change" implies a gradual set of changes in the climate. Although the buildup of GHGs has been occurring steadily since the Industrial Revolution, it has accelerated in recent decades and climate change will generate major disruptions to social and economic systems that have been built around historic conditions. There may also be sudden, non-linear changes in natural systems, including collapse of the Antarctic and Greenland ice sheets. "Climate disruption" is therefore a more accurate term than "climate change:" some of the anticipated changes will cause dramatic disruption in California.

C. Sea Level Rise

Sea level rise will not occur evenly across the planet or even along the California coast. California's geology is characterized by its position at the interface of the Pacific Plate and the North American Plate. From the Salton Sea north to Cape Mendocino, the San Andreas Fault is a strike slip fault where the two plates slip past each other: the Pacific Plate, to the west, is sliding north along the North American Plate to the east. However, the relationship between the two plates changes north of Cape Mendocino. There, the Pacific Plate is subducted under the North American Plate, pushing the latter up while also giving rise to the volcanically active Cascade Mountains due east of this subduction zone. The relative increase in sea level rise will therefore be less north of Cape Mendocino, because the land is "rising" there relative to a stable sea level. Sea level rise appears smaller in relative terms north of Cape Mendocino. The greatest sea level rise will therefore occur along the most populated areas of the California coast: a 1.5 feet increase forecast for Crescent City in 2100 under one scenario will be matched by a 2.5-2.6 feet increase at the Golden Gate and in La Jolla.⁸

Sea level has risen roughly eight inches at the Golden Gate since 1854.⁹ The primary cause of sea level rise to date has been thermal expansion of the oceans: warmer water takes up more volume, so the oceans' absorption of the energy generated by global warming¹⁰ literally makes the sea level rise as the warmer ocean expands its volume, even in the absence of any increased melting of continental snow or ice. Future sea level rise due to this thermal effect is therefore fairly reliably predicted as a function of GHG emissions, accounting for the saturation of the oceans with thermal energy already—the oceans now appear to be less able to absorb thermal energy than before. However, increased global temperatures are now projected to increase the relative contribution of melting ice and snow on sea level rise.¹¹ In particular, the potential rapid melting and collapse of the Antarctic and Greenland ice sheets could generate dramatically higher sea level rise.

Until recently, mainstream scientific projections of sea level rise for California have estimated that there is at least a 50% probability that sea level rise would increase 0.4 feet (Crescent City) to 0.9 feet (La Jolla) by 2050—independently of whether global GHGs are reduced.¹² Estimates for 2100 range from 0.7 feet in a low-emissions future to 1.5 feet in a high-emissions future (for Crescent City) and from 1.7 feet in a low-emissions future to 2.6 feet in a high-emissions future (for La Jolla).¹³ A report from the California Coastal Commission found that "on a relatively flat beach, each centimeter of sea-level rise will result in the mean high tideline migrating 40 centimeters inland."¹⁴ This 40:1 ratio means that the Pacific Ocean would move from roughly 28 to 104 feet inland from its current location. "The California Coastal Commission reports that, as a rule-of-thumb, one foot of sea-level rise corresponds to 50 to 100 feet of beach loss,"¹⁵ suggesting a 50:1 or 100:1 ratio for beach loss. It does not seem like much, but the loss of beach affects the most valuable real estate in California.

[Page 13]

The loss of beach also understates the likely impact of sea level rise, because the shifting shoreline will change the reach of low-frequency events such as storm surges and "king" tides (extreme high tides that occur naturally) that coincide with high precipitation (and therefore high runoff) events. Most of the property damage and human health risk associated with sea level rise will come from just a few events each year or decade. The Dutch now assume that the 100-year-flood (i.e., a flood with a 1% probability of occurring each year) is now a 10-year flood (i.e., a flood with a 10% probability of occurring each year).¹⁶ That means the 1000-year flood is now assumed to be ten times as likely to occur as before. These extreme events could therefore cause much greater damage with very little sea level...