Commission staff is now seeking input on the Draft Sea-Level Rise Policy Guidance. The Draft Sea-Level Rise Policy Guidance document provides an overview of best available science on sea-level rise for California and recommended steps for addressing sea-level rise in Coastal Commission planning and regulatory actions. Click the link for the Coastal Commission's Public Review Announcement.
Opportunities to learn more about the draft guidance document:
In the long run, sea-level rise will be one of the most serious consequences of global warming. But how fast will sea levels rise? Model simulations are still associated with considerable uncertainty – too complex and varied are the processes that contribute to the increase. A just-published survey of 90 sea-level experts from 18 countries now reveals what amount of sea-level rise the wider expert community expects. With successful, strong mitigation measures, the experts expect a likely rise of 40-60 cm in this century and 60-100 cm by the year 2300. With unmitigated warming, however, the likely range is 70-120 cm by 2100 and two to three meters by the year 2300.
Predictions of sea level rise could become more accurate, thanks to new insight into how glacier movement is affected by melting ice in summer. Scientists led by the University of Edinburgh gathered detailed GPS ice flow data and ice surface melt rates along a 115 km transect in west Greenland and compared ice motion from an average melt year, 2009, with the exceptionally warm year of 2012.
Read the full article here.
There have been many news stories, features and blog posts regarding the recently released IPCC 5th Assessment Report (The Physical Science Basis) and what it says about sea level rise. The summary for policymakers is a great resource, and is available here. Two other interesting stories regarding this assessment are described below.
What the New IPCC Report Says About Sea Level Rise
This blog post from the European Climate Foundation examines the new projections of global sea level rise from the latest Intergovernmental Panel on Climate Change (IPCC) assessment report, the changes since the last assessment in 2007, and the data used to support the projections.
Read the full blog post here.
IPCC “Conservative” on Sea Level Rise
The international scientific community’s new assessment of the estimated sea level rise caused by global warming is a significant development, but experts say the projections for higher sea levels in the Intergovernmental Panel on Climate (IPCC) assessment report (AR5) are still on the low side. The new estimates are between 28cm and 98 cm by 2100, depending on the amount of carbon dioxide emitted and efforts to mitigate its effects.
Read the full article here.
New research led by the National Center for Atmospheric Research (NCAR) shows that when three atmospheric patterns came together over the Indian and Pacific oceans, they drove so much precipitation over Australia in 2010 and 2011 that the world’s ocean levels dropped measurably. Unlike other continents, the soils and topography of Australia prevent almost all of its precipitation from running off into the ocean. The 2010-11 event temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets.
Read the news release from NCAR here.
Global sea levels will rise about 7 feet over the next several thousand years for every degree Celsius the planet warms, a U.S. study estimates. Researchers at Oregon State University combined analyses of four major contributors to potential sea level rise into a collective estimate, and compared it with evidence of past sea-level responses to global temperature changes, to arrive at their conclusion. The major contributors to sea-level rise on a global scale will be melting of glaciers, melting of the Greenland ice sheet, melting of the Antarctic ice sheet and expansion of the ocean itself as it warms, the researchers said.
Natural habitats such as dunes and reefs are critical to protecting millions of U.S. residents and billions of dollars in property from coastal storms, according to a new study by scientists with the Natural Capital Project at the Stanford Woods Institute for the Environment. The study, published in the journal Nature Climate Change, offers the first comprehensive map of the entire U.S. coastline that shows where and how much protection communities get from natural habitats such as sand dunes, coral reefs, sea grasses and mangroves. In our changing climate, extreme weather, sea-level rise, and degraded coastal ecosystems are placing people and property at greater risk of damage from coastal hazards. The likelihood and magnitude of losses can be reduced by intact ecosystems near vulnerable coastal communities.
Improved satellite measurements and computer simulations of ice sheets are creating a more accurate picture of the current and future rise in global sea level, according to an international team of climate experts including Slawek Tulaczyk, a professor of Earth and planetary sciences at UC Santa Cruz.
The team's study, published in today’s issue of Nature, found that Antarctic ice loss might be only half of what has previously been reported. But the researchers also confirmed a major loss of mass from the Greenland Ice Sheet, calculated to be twice as large as the Antarctic contribution to global sea-level rise.
Read the article here.
A new study of glaciers worldwide using observations from two NASA satellites has helped resolve differences in estimates of how fast glaciers are disappearing and contributing to sea level rise.
The new research found glaciers outside of the Greenland and Antarctic ice sheets, repositories of 1 percent of all land ice, lost an average of 571 trillion pounds (259 trillion kilograms) of mass every year during the six-year study period, making the oceans rise 0.03 inches (0.7 mm) per year. This is equal to about 30 percent of the total observed global sea level rise during the same period and matches the combined contribution to sea level from the Greenland and Antarctica ice sheets.
Read the NASA news release here.
Read the Science article here.
The summary report for the Third Biennial Ocean Climate Summit, held February 20, 2013 in San Francisco, is now available. The goal of the summit was to connect information, resources, and people across disciplines to collaboratively sustain North-central coast and ocean ecosystem health through fostering awareness, promoting action, and advocating climate smart conservation. OCOF staff presented at the Summit, and announced the release of the beta version of the outer coast decision support tool.
Workshop materials, including a summary report, are available for the Beyond Bathtub: Modeling and Responding to Sea Level Rise and Shoreline Change workshop, held December 19, 2012 in Costa Mesa, California. OCOF staff presented at the workshop as a modeling case study to address shoreline change impacts.
A team of researchers in Singapore and the United States has proposed a simple method to identify areas that are vulnerable to sea-level rise. The method uses a simple, low-cost tool, and is financially and technically accessible to every country with coastal wetlands, say its inventors. The study, led by Associate Professor Edward L. Webb of the National University of Singapore (NUS) and involving researchers from the United States Geological Survey, was published this week in the journal Nature Climate Change.
Read the full article here.
Ongoing glacier loss in the Canadian high Arctic is accelerating and probably irreversible, new model projections by Lenaerts et al. suggest. The Canadian high Arctic is home to the largest clustering of glaciar ice outside of Greenland and Antarctica - 146,000 square kilometers (about 60,000 square miles) of glaciar ice spread across 36,000 islands.
Read the full article here.
In this featured story from NASA's earth observatory, extreme storms such as Hurricane Sandy, Snowmageddon, and the tornadoes of 2011 are considered in the context of whether climate change is affecting the intensity of weather. Satellites, statistics, and scientific models are teaching scientists a lot about what is known of severe storms, and it is becoming more clear that global warming may be priming the earth's atmosphere to produce fewer, but stronger, storms.
Read the full feature here.
Rutgers University and the National Oceanic and Atmospheric Administration recently released an online mapping tool that provides visualization of communities in New Jersey that are vulnerable to severe flooding if sea level rise continues as expected. By illustrating the risk posed by the combination of future severe storms and sea level rise, the project hopes to help towns and counties prepare for rising sea level.
Both this mapping project and Our Coast - Our Future are funded through the National Estuarine Research Reserve Science Collaborative.
This blog post examines the uncertainty surrounding sea level rise projections and examines a novel approach developed by Mahe Perrette and colleagues for modeling sea level rise by combining simple models with general circulation models to take advantage of the benefits of both in predicting future change.
Researchers from Italy's University of Urbino and the UK's University of Bristol have shown in the journal Geophysical Research Letters how sea level rise will affect some regions of the world more than others. Modeling projections indicate that parts of the Pacific will see the highest rates of sea level rise, while some polar regions will experience falling sea levels. These regional differences in patterns of sea level change are due to the interaction of sea, land and ice.
Kelly Higgason and Michael Fitzgibbon presented at the Third Biennial Ocean Climate Summit (February 20, 2013), announcing the Beta release of the Our Coast Our Future decision support tool for sea level rise and storms.
Our Coast Our Future was highlighted in FEMA's Coastal Beat newsletter recently in an article written by Kris May (California Coastal Analysis and Mapping Project or CCAMP) and Marina Psaros (OCOF), comparing and contrasting these two projects focused on coastal flood hazards. "CCAMP and OCOF are both unprecedented in scale with a shared goal of increasing community awareness and preparedness with respect to coastal flood hazards. These two studies will complement each other in situations where a community wants to understand both current (CCAMP) and projected (OCOF) risks associated with coastal flooding."
Amy C. Foxgrover and Patrick L. Barnard have published a seamless, 2-meter resolution digital elevation model (DEM) of the north-central California coast using the most recent high-resolution bathymetric and topographic datasets available. The DEM extends approximately 150 kilometers along the California coastline, from Half Moon Bay north to Bodega Head. Coverage extends inland to an elevation of +20 meters and offshore to at least the 3 nautical mile limit of state waters. This report describes the procedures of DEM construction, details the input data sources, and provides the DEM for download in both ESRI Arc ASCII and GeoTIFF file formats with accompanying metadata.
For more information, please see this USGS publication online.