The repeated scenes of flooded streets and half-submerged homes this month have literally brought the issue of rising seas home to millions of people along the Gulf and Atlantic Coasts. The threat is no less real here on the West Coast, as  marine scientist Gary Griggs points out in his new book, “Coasts in Crisis: A Global Challenge.”

Griggs, who for 26 years, headed the UC Santa Cruz Institute of Marine Sciences, has advised state and local governments in California to plan for:

  • 6 inches of sea rise by 2030
  • 12 inches by 2050, and
  • 36 inches (3 feet) by 2100

Griggs  spoke with KQED Science Editor Craig Miller.

Craig Miller: Let’s put that in some perspective, because this seems to be the problem with trying to get people to engage with sea level rise —  that it is a sort of slow-motion train wreck. Six inches by 2030 might not sound like a lot. What would that actually look like in a place like the Bay Area?

Gary Griggs: There are places now that are already what has been called nuisance flooding, but it’s really high tides: these El Niños, when sea level can rise a foot or two over two or three month at a time, or a king tide when it can be six inches or so higher than normal, or the combination of storm waves and high tides. The sea level is a ramp that all these are on top of, so everything’s going to get progressively worse as we go on.

Miller: I find it interesting that you say “progressively,” because seas are rising faster now than they used to.

Griggs: Yeah. The last century was, along the California coast, maybe seven or eight inches. Right now, the rate is just about twice that high. The last 20-plus years we’ve been measuring sea level from space through satellites. Previously, it was done by averaging global tide gauges, and some of those the land is going up, some of those it’s going down. Now that we’re measuring it very precisely from space, which takes out the land component, the rates are maybe 13 and-a-half inches per century, or roughly twice as fast as it was, say in the last century. That’s significant.

Map shows estimated extend of flooding with 16-and-55 inches of sea rise.
Map shows estimated extent of flooding around San Francisco Bay with 16-and-55 inches of sea rise. (BCDC via UC Press)

Miller: Okay, so we now have Miami, where people are wading around certain streets, not just after Hurricane Irma but anytime there’s a high tide. How long before that’s the case on the Embarcadero in San Francisco?

Griggs: We could see much more problematic conditions by 2030, in 10 or 15 years. But again we’re on this curve, and the rate of increase is not completely known. What’s going to happen to Antarctica — which is where the biggest amount of potential rise is — where you have these massive glaciers or ice sheets, but they’re held in place by these floating ice shelves. They’re starting to crack and break loose. That then, is like taking the cork out of the champagne bottle, so a big pulse could happen.

Miller: The Bay Area may be the exception. We’ve seen some ambitious initiatives, and even a new tax recently, to prepare for encroaching seas. But do you think that Northern California as a whole is paying enough attention to this threat?

Griggs: You know, as I look around the country and I see what’s happening in places like Florida, North Carolina, where you either outlaw it or don’t talk about it, I’d say we’re way ahead. I think the fact that that tax passed [Measure AA in 2016] is a good indication of people’s awareness and concerns.

I think talking about it is one thing, and getting something done is a much bigger step. The Bay has somewhere between 400 and 500 miles of shoreline. What many people don’t realize is, from the Golden Gate all the way to Sacramento — which is sea level because Sacramento’s an ocean port — it’s 100 miles inland. So not only is the Embarcadero a problem, but we’ve got a problem 100 miles inland.

Miller: Well, there’s a lot of critical infrastructure — airports, freeways, treatment plants — sitting almost right at sea level, with no place to move them really. What do we do about those? Are we looking at a future of ever rising sea walls?

Griggs: You know, that’s the solution we’ve used in the short term. I think if you look at something like San Francisco International or Oakland, they weren’t thinking about sea level rise. You can imagine a levee or a wall for a while, but at some point that doesn’t work anymore.

Griggs' book, "Coasts in Crisis: A Global Challenge," takes on multiple threats to coastal regions, including sea rise, seismic threats, and pollution.
Griggs’ book, “Coasts in Crisis: A Global Challenge,” takes on multiple threats to coastal regions, including sea rise, seismic threats, and pollution. (UC Press)

We also have most of our power plants around the Bay which are right at sea level, to pump in cold sea water for cooling. Those are not a parking lot or a bike trail, they are multi-million dollar facilities, and there are dozens and dozens of those. I will say boldly that sea level rise is going to be the biggest challenge human civilization has ever faced.

Miller: If there’s one big takeaway from your book that you want to get out there, what would it be?

Griggs: We’ve got to start acting now. We have to start acting collectively, because I think our entire human future depends on it. I think traditionally what we’ve done — and we’re still doing now — is, whenever a conflict comes up, we draw a line and you get on that side and I get on this side and we punch it out. I think what we have to do is come to the realization finally that it’s a circle and we’re all inside of it.

Californians Must Change Thinking to Meet Challenge of Rising Seas, Says Author 17 October,2017Craig Miller

  • What a crock of alarmism. Everyone should look at SF’s tidal gauge record There has been about a 2.2mm/year rise on average since 1900. Since 1980, there has been absolutely no increase in SF’s sea level.

    • Ormond Otvos

      Denialist BS.

      • Osmond, I suggest you (and everyone else) download the SF tide gauge from the PSMSL website TO an EXCEL file.

        hen create a trend line starting with 1980. You can deny the evidence and choose to engage in name calling, but facts are facts. There has been absolutely no increase in SF’s sea level for the last 37 years. NONE!

  • mbrenman

    I’m not seeing that California or the Bay Area has done all that much preparation. Heck, the leaning Millenniium Tower was built on landfill with only 80 foot pilings. As long as bonehead mistakes like that are made and approved by the City of San Francisco, there’s no particular indication of progress being made in planning.

  • MikeW

    The Global Warming of Doom hysteria about sea levels is total nonsense. At any location, the local sea level is dominated by land movements, not climate change. And worldwide, coastal land areas over the past 30 years have actually increased (e.g. from river silting and land uplift) more than they have decreased (e.g. from subsistence), as revealed from actual satellite observations. If global warming were a significant factor in local sea levels, the coastal land areas worldwide would be decreasing, not increasing.

    • Mikey P

      If you like his comment here, MikeW’s profile is full of other great common sense proclamations such as:

      “In addition, coal burning is part of the natural carbon cycle, which is sustainable since it is powered by the sun.”
      “Go Donald! ”
      “Global Warming of Doom cultists like Pope Francis have caused much suffering for people by causing unaffordable energy prices and loss of jobs.”
      “Global tropical cyclone counts and total energy (hurricanes+typhoons) have been declining in recent years.”

      A sad shill for the coal lobby with a particular dislike of wind energy.

    • Ormond Otvos

      More denialist BS.

  • Ormond Otvos

    The May 2011 Scientific American covered proposals to put tidal gates on the Golden Gate. Make the Bay Fresh water, solve the water problem.


Craig Miller

Craig is KQED’s science editor, specializing in weather, climate, water & energy issues, with a little seismology thrown in just to shake things up. Prior to his current position, he launched and led the station’s award-winning multimedia project, Climate Watch. Craig is also an accomplished writer/producer of television documentaries, with a focus on natural resource issues.

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