Global sea level rose during the 20th century, and projections suggest it will rise further and at a higher rate during the 21st century. Dr. Suzanne Moser, a Social Science Research Fellow at the Woods Institute for the Environment at Stanford University and a Research Associate at the University of California-Santa Cruz, Institute for Marine Sciences, has warned that “the impacts of sea level rise are already being felt widely.” So why are sea levels rising? Simply stated, the climate is warming, and a warming climate causes sea level to rise primarily by water expanding in a warming oceans and melting land ice, transferring water to the ocean.
The warming climate is commonly referred to as “climate change.” The most general definition of climate change is a change in the statistical properties of the climate system when considered over long periods of time, regardless of cause. Accordingly, fluctuations over periods shorter than a few decades, such as El Niño, do not represent climate change. The term sometimes is used to refer specifically to climate change caused by human activity, as opposed to changes in climate that may have resulted as part of Earth’s natural processes. In this sense, the term climate change has become synonymous with anthropogenic (the influence of human beings on nature) global warming. Whether or not climate change is a reality should not be confused with the uncertainty associated with climate change science, particularly the magnitude and timing of impacts from climate change, such as the amount of sea level rise and how it will unfold over time.
The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change and the most regularly referenced authority on the subject. The IPCC is a scientific body with a membership of 194 countries. This intergovernmental body was established to provide the world with a clear scientific view on the current knowledge surrounding climate change and its potential environmental and socio-economic impacts. Thousands of scientists from all over the world contribute to the work of the IPCC on a voluntary basis. Other scientific bodies are using the IPCC’s global sea level rise predictions to make regional assessments. Sea-level rise is uneven and varies from place to place depending on, for example, the global mean sea level rise and regional factors like ocean and atmospheric circulation patterns, melting of modern and ancient ice sheets and tectonic plate movements.
Focusing on the U.S. west coast, the National Research Council predicts the sea level off most of California’s coast will rise about one meter (over three feet) over the next century, an amount slightly higher than projected for global sea levels, and will likely increase damage to the state’s coast from storm surges and high waves. Sea levels off Washington, Oregon, and northern California will likely rise less, about 60 centimeters over the same period of time. However, an earthquake of magnitude 8 or larger in this region could cause sea level to rise suddenly by an additional meter or more. Furthermore, coasts subsiding due to natural or human-induced causes will experience larger relative rises in sea level. The National Research Council’s projections for the California coast south of Cape Mendocino are slightly higher than its global projections because much of the coastline is subsiding.
The West Antarctic Ice Sheet, which holds enough water to raise global seas by several feet, is thinning. Scientists have been warning of its collapse, but with few firm predictions or timelines. A study published May 16, 2014 in Science details how University of Washington researchers used topography maps and computer modeling to show the collapse of the West Antarctic Ice Sheet may have already begun. Eric Rignot, a glaciologist at the University of California, Irvine, and NASA’s Jet Propulsion Laboratory in Pasadena, California has said, “A large sector of the West Antarctic Ice Sheet has passed the point of no return” in terms of its retreat. Researchers say that the fast-moving Thwaites Glacier will likely disappear in a matter of centuries, raising sea level by nearly 2 feet. That glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet of global sea level rise.
The public has heard mostly about climate change driven sea level rise impacts on economies and infrastructure, and to a lesser extent on habitat, but not much on recreational resources. Surfing is ideally suited as a key recreational resource to consider as one potentially significantly impacted by sea level rise. Of course, many surfers actually live in the coastal zonenand have to worry about issues more serious than the surf quality, like the potential inundation of their home, roadways, schools and businesses. Broader climate change impacts stand to affect surfing in a myriad of ways. To pick one example, changes in rainfall patterns will affect transport of pollutants to the line-up in urban areas and also affect the delivery of sediment to the coast which will subsequently affect the health of beaches and sandbars. Of these broader impacts, surfers seem to have been mostly focused on how climate change will impact wave climates, or the average condition of waves at a particular place, over a period of years. Climate change will result in changes in average wave heights, periods, and directions. But what will the beaches at which those waves will be arriving look like? Sea level rise alone stands to be the most significant impact to surfers, combined with the other broader climate change impacts affecting surfers.
Surfers are going to be on the front line of climate change driven sea level rise impacts, both via recreational impacts realized directly and wider impacts experienced as users of coastal infrastructure. In many cases those that live near the beach, impacts experienced as coastal dwellers. Surfers’ access and entry pathways to the surf will be affected: the beach, parking lots, access roads, staircases, etc., not to mention our homes, schools and places of business. Regional examples help illustrate. The Pacific Institute report The Impacts of Sea-Level Rise on the California Coast concludes that sea-level rise will inevitably “change the character of the California coast.” The Pacific Institute has a web based tool that shows populations and critical infrastructure at risk under various sea level rise scenarios. The available maps show coastal flood and erosion hazard zones under sea level rise scenarios.
Under the 2100 sea level rise scenario, my home near the beach in Oxnard, California will be threatened by inundation, as well as a lot of important infrastructure around my house. Of course, this won’t happen instantaneously, but rather on a continuing and increasing basis, with irregular spikes in impacts and inundation along the timeline. Correspondingly, the impacts are likely to be felt much sooner than the scenario offered by this image eight decades into the future.
Needless to say, adding one to three feet of water over our coastal ocean and surf spots in the next couple of decades to three quarters of a century is going to affect the surf quality. To illustrate in simplistic terms, take the example of a reef where the surf is highly tide dependent. A spot that currently breaks properly only on a high tide will in the future break on what is now the low tide once sea level rise is superimposed on its current condition. More critically, a surf spot that currently breaks only on a low tide will cease to break. Of course, beach breaks will be affected in potentially numerous ways, too. Coastal erosion will likely accelerate surf zones will become narrower and, as in the reef example, surf-tide relationships will change. All of our surf spots will be affected by the phenomena of coastal squeeze.
Coastal squeeze occurs as follows. As sea levels rise, coastal habitats like salt marshes, if in an entirely natural situation, would respond by migrating landward or “rolling back” to adjust their position to the best ecological fit for the new sea level. Rising land, development, or fixed man-made structures such as seawalls prevent or severely limit this landward movement, restricting the ability for beaches to adapt to rising sea levels. The coastal habitats, if present, are therefore squeezed between rising sea levels and fixed defense lines or higher land, therefore there is a risk the beach and adjacent coastal habitat may be lost altogether.
A significantly worrisome specter will occur along our urban beaches where people surf most: an unknown but foreseeable human response will unfold as sea level rises. Along these urban coastlines where significant infrastructure exists, communities will take action in response to sea level rise as valuable infrastructure is threatened; seawalls, probably the most likely short term human response and the one that stands to cause the most damage to coastal access, beaches, and surf quality, will proliferate. The human response to sea level rise also has large uncertainty associated with it in relation to timing, location, extent, and feedback loops. Sea level rise therefore presents both a direct and an indirect threat to our beaches, our surf, and our ability to access the surf.
What can you do as a surfer? Firstly, educate yourself on climate change and sea level rise and take actions that address the big problem: climate change. Reduce your environmental footprint through conservation, recycling and changing consumption patterns. Focus on your ability and approach to changing laws; for example, campaign for low carbon public transport and organize to elect officials who protect the environment. Secondly, be aware of the potential local impacts. In your coastal communities, educate decision makers and citizens and be a voice for decisions that have a long term view, account for sea level rise, preserve beaches and allow for shoreward migration of coastal habitat, decisions such as managed retreat of threatened infrastructure rather than placing seawalls to protect poorly located infrastructure.
“In the U.S., you have the best data set on what’s happening in the world, and yet it’s not used in public policy,” observed Robert Nicholls, professor of coastal engineering, University of Southampton, England. It’s a paradigm we surely need to reverse.