This is a podcast of Scripps Institution of Oceanography at UC San Diego.
To learn more about how you can support scripts visit us online
at scripps.ucsd.edu.
Of
all the manifestations of climate change, sea level rise might become the
most obvious to Californians in coming decades.
The beach is at the heart of the state's tourist economy could shrink
or even disappear as erosion accelerates. The Northern California
levies that channel much of the state's water supply could breach
under the onslaught of the ocean, especially if combined with Sierra
Nevada
floods. Scripps scientists are attempting to create the most
accurate scenarios possible to help state lawmakers plan,
especially for events when rising sea level
combines with El Nino and high tides to produce perfect
storms of destruction. I guess to start with I should say that sea-level
along this coast has been rising historically and over the past 100 years
we've seen right out here
at Scripps pier and the San Diego tide gauge
an increase of about seven inches
over the last century. What we find is that
we might expect a range
of sea level rise here along the California coast
of probably at least a half a meter
that's something like a foot-and-a-half
and upwards to
about a meter and a half that's
something like five to six feet.
These are projections. They're not forecasts.
There's a lot of impersonation. There's a lot of uncertainty,
so all we feel we can do right now is to kind of guesstimate
the range potential sea level rise
over the future. We know that the most catastrophic damages from sea level
rise will happen
when the rise in sea level
is accompanied by high tide, probably El Ninos
and big storms so when those things
all come together, when they coincide,
we can expect the greatest affects.
Let's put this in context, suppose there's no sea level rise
what might happen. Well if there was no sea level rise and the weather,
the waves stayed just the way they are now we already have beach erosion
so that no change scenario is
the beaches are going away. Rising sea level
is only going to make the problem worse.
We have a lot of our water supply transmitted through
from the Sacramento and San Joaquin Rivers
through the upper part of the the Bay Delta estuary. We pump
much of the freshwater that used to the south of Sacramento.
And that area is susceptible to
water rise problems because there are levees,
there are the islands, which
lie below water level in that area.
If if those levees are over- topped,
it will create a problem with that system,
which will be hard to repair. It won't be
a one or two week thing, it'll be several months to get it back
in order. Ironically what coastal oceanographers need to understand and
model the consequences of 21st century storms
is to witness storms in the present-day. Oceanographers, like Scripp's Bob Guza,
say what's needed is a rapid observational response to episodes
as they happen. The effort requires large investments of time and resources,
but Guza says there is at least one good reason for making them.
Money, if your metric of importance is money
then sandy beaches are a major factor in your equation. They provide tax dollars
and they provide a vast wealth of jobs up and down the coast
in service industries, basically: restaurants,
hotels, etc. It is true
that if sandy beaches no longer were available to tourists,
and this is a scenario that's possible 50 to 100 years out,
it's going to hurt coastal tourism in California.
Looking at what's happening now, I think is our best path forward
in terms of trying to improve the predictions of how beaches are going to
respond.
We simply lack the understanding to make
reasonable predictions about what will happen in conditions we haven't yet
experienced.
That's why we need to get observations during major storms,
temporary rises in sea level so that we can tune those models up.
We should be paying attention in the short run
to these episodes when all of these influences occur.
In the longer run, I think we should be prepared for
when we're making plans
that involve the coast
and the estuaries, we're gonna have to take that into account
in in our infrastructure and in policy.
It's an interesting problem in that it's changing rapidly and we're developing
not only a better understanding better, but a better understanding of
what we don't understand.
That's sort of the state of things right now.
This has been a presentation
of Scripps Institution of Oceanography at UC San Diego.