Independent study calls for action against the projected effects of sea level rise
As ocean temperatures rise and ice caps melt, sea levels rise. But what happens then? The National Research Council (NRC) recently released a 250-page report on the precise projections of how California, Oregon and Washington will be affected.
According to Gary Griggs, director of the Institute of Marine Sciences at UC Santa Cruz (UCSC) and the voice of the committee that published the report, previous sea level data was based on worldwide averages. Tide gages showed that global sea level is rising at double the rate that it did in the last century.
The NRC report, which was made possible through the participation of a number of state and federal agencies and a committee of scientists, focuses specifically on the West Coast, which is unique due to its geological composition and active coastline. California from San Diego to Cape Mendicino is sinking, while California north of Cape Mendicino, Oregon, and Washington, are rising.
This will eventually lead to a foot difference in sea level rise by the turn of the century, according to the report.
In the region south of Cape Mendicino, the report projects an average sea level rise of six inches by 2030, 12 inches by 2050 and 36 inches by 2100.
The report does provide a range, proving that the actual values, of course, are likely to vary.
“There are many uncertainties [like] global temperature, coal consumption, and geologic activity,” says Griggs. He adds that the projections further in the future face greater uncertainties.
For example, while the north is rising and the relative sea level rise is lower, a high magnitude earthquake has the potential to reverse the effect and inundate the area.
The report was designed to provide policy makers and city planners with objective data to help them cope with these uncertainties and to make future decisions.
Even if global climate initiatives achieve a best-case scenario, and the sea level reaches only the lowest projections, the report asserts that sea level rise should still be taken into account in land development, planning, and infrastructure reinforcement.
“What’s really going to be driving the impact for sea level rise will be winter storms … that’s when you’ll be experiencing your damages,” says Jeanine Jones, Interstate Resources Manager for the California Department of Water Resources. She adds that when sea level rises, the potential for flooding increases during winter storms.
In addition to melting ice caps and rising sea levels, the study suggests that climate change may also affect the magnitude and frequency of winter storms, which makes them less predictable and therefore harder to prepare for.
Santa Cruz County adopted a Local Hazard Mitigation Plan (LHMP) in 2007 to help prevent and mitigate extreme damages, like what was seen during the 1982 El Niño year.
“The water levels reached during these [winter storms] have exceeded mean sea level projections for 2100,” says Griggs.
The threat of inundation and flooding is greater in coastal communities at lower sea levels, especially during winter storms. The San Francisco Wetlands are at great risk, and the San Francisco International Airport, which was built only a few feet above sea level, is expected to be affected within the next several decades.
The study calls for action to be taken by coastal communities to offset the potential damages that sea level rise will predictably cause. Because of the regionalization of the issue, it will be up to state and local governments to adopt guidelines regarding sea level rise.
“Coastal communities need to begin to understand … what the sea level rise indicates to them and plan accordingly,” Griggs said in a summary video released with the study.