Water in the Balance: The Human Fingerprint on Global Freshwater Availability as Seen from Space


Welcome to this evening’s seminar on sustainability
it’s a real pleasure to introduce tonight Dr. Jay Famiglietti who’s a professor here
at Irvine in Earth System Science and School of Physical Science. He’s also a professor
of Environmental and Civil Engineering in the Samueli School of Engineering and director
of The Center of Hydrologic Modeling. His work recently gained a great deal of attention
as he’s been using remote sensing technologies to assess groundwater loses at strategically
located places of large populations around the world and his findings have really made
a substantial contribution to our understanding of the situation of groundwater today and
the trends that we may have to implement over the next few decades. Today he’s going to
share some of his findings in a talk entitled Water in the Balance: The Human Fingerprint
on Global Freshwater Availability and Water Cycle Change as Seen from Space. Please join
me in welcoming tonight Dr. Jay Famiglietti. [Applause]
Thanks for inviting me. It’s a pleasure to be here and to share some of this research
with you. As Professor Mathew said I think some of it fairly compelling and one of the
interesting things about it is that it’s based around a new satellite mission called GRACE:
Gravity Recovery and Climate Experiment and so we’re actually seeing this picture of what’s
happening with water and water availability unfold in front of our eyes. So I’ll share
some of that with you tonight and in fact some of the things that I’ll talk about tonight,
when I wrote the abstract of this presentation it [inaudible] fully formed, so I’m happy
to share some this stuff with you tonight because I think that it is quite compelling
and there’s some serious issues left to deal with in the coming decades.
So I will start off by talking about what I mean by water cycle change and in the research
side of things we refer to this as water cycle acceleration so I’ll talk about what I mean
by that and we’ll spend a fair amount of time talking about what the implications are for
that. I mentioned that a lot of the work is based on the satellite mission called GRACE,
the Gravity Recovery and Climate Experiment. So I’ll go through several slides and explain
how it works which is actually pretty cool and it’s allowed us to see some things that
we haven’t seen before. So we’ll picture water availability changing, it’s allowing us to
quote unquote see underneath the ground. When you think about remote sensing, the sensors
are usually optical and looking at the surface, and so what this mission does, because it
uses gravity, and I’ll explain this in more detail, it allows us to actually see what’s
going on underneath the ground rather than just on the surface. So then I’ll talk about
with respect to the water cycle change in a changing climate if the water cycle is actually
changing what we would expect to see versus what we actually see. And I will base a lot
of this on this new satellite data which really looks at the storage has changed, as the water
storage changes rather than a flux like precipitation or evaporation it really is looking at, sort
of weighing, how much water is underground and how that’s changing overtime. So that’ll
be more clear. Then the human fingerprint; we’re having a huge impact on water availability
and water storage how that changes over time. And as Professor Matthew mentioned many of
these locations that are under the greatest stress are of course the places where there’s
the biggest population and water needs. But these unfortunately are places that won’t
be receiving a lot of precipitation in the future, so these are place that are in the
arid or semi arid regions of the world. And so what’s being used today will not likely
be replaced anytime soon. So this becomes a sustainability issue.
Just a brief slide about how the water cycle changes in the future. And a lot of it is
actually unknown but I will show you figures that — just a conceptual figure — that I
want you to think about because it has huge implications across a spectrum of security
issues. So then we can finish up by talking about some implications that, actually just
today, coincidentally, was looking at this pile of stuff on our coffee table and I picked
up this report from US Geological Survey that I picked up in December at the American Geophysical
Union meeting at San Francisco and left it on the coffee table, it just sat there for
months, and I picked it up this morning and it’s actually all about water security and
so it’s actually some great information there that I put on my last slide. What should we
be doing about it? Well maybe that’s something we can save for the discussion period after
the talk. Most of my comments, and I actually took them out of the presentation, will very
much gear towards research and gear towards the development of simulation models that
we work on so not a particularly exciting thing to talk about with you guys, but just
to make a point that our computer models are not that great, not up to speed with respect
to some of the issues that we’ll talk about today and that we’re seeing very clearly from
space. Ok, so let’s talk about water cycle change,
and what I mean by water cycle acceleration. In a warming climate, the climate’s warming,
the atmosphere can hold more water. And the water holding capacity of the atmosphere is
temperature dependent, in fact it’s exponentially temperature dependent, so it goes way up with
each increase, each degree increase in temperature. So in a warming climate we can expect more
evaporation; and when I talk about the water cycle it’s just like you learned in elementary
school, so precipitation, evaporation, river flow and I’ll show you a box diagram on one
of the next slides. So in a warming climate we can certainly expect more evaporation and
therefore more precipitation. Evaporation, say from the ocean, precipitation not only
over the ocean but over land, that’s where most of the water comes from, from precipitation.
Bringing in more precipitation on land, raining more, we get more runoff more [inaudible].
So in a warmer climate we can expect bigger exchanges or more cycling of water, more evaporation
up more precipitation down, more runoff from the continent back to the ocean. So it’s a
cycle just like you learned about in school and if you took my hydrology class it’s something
you learn about in my hydrology class. Models suggest and my models here talking about the
IPCC climate models, suggest that observations are beginning to indicate that the magnitude,
the size, and the frequency of hydrological extremes of flooding and drought will also
increase. So we’re thinking about more precipitation, more evaporation in a warmer weather climate
and the actual timing of the delivery will change. So there’ll be more intense precipitation
and by definition really if you think about the volume of precipitation if more of it
is coming down in shorter bursts of time then there are going to be longer gaps without
precipitation, so more extremes of flooding and drought. And there’s a spatial side to
that as well because the models also suggest that there will be a redistribution of precipitation,
global precipitation patterns and who knows where most of the rain falls globally?Do you
know? Right, most of the rain falls in the tropics and so you know if you take a basic
geography or
a basic water cycle study most of the rainfall falls in the tropics and at 60 degrees north
and south latitudes you get most of the deserts as far as 15 degrees to 40 degrees north and
south latitude doesn’t rain. Well so those places are going to get even drier. So the
desert regions will be getting even drier and the tropics and the other rainfall belt
at 60 degrees north and south latitude will be getting more precipitation so the places
that are wet are going to get wetter and the places that are dry are going to get drier.
And so that’s with the increase in frequency of flooding and drought. So, you know, this
is the future and so the issues are how do we put this global picture together, are we
starting to see this, are there ways to quantify some of these changes.
So this GRACE mission is actually beginning to contribute to studies of water cycle change
and I’ll share some of that with you in the next few slides really for the rest of the
talk. The mission itself helps us, what we call, close the water budget, if you’ve taken
any science classes you know the conservation equation [inaudible] equals the change in
the storage, well, in water and water cycle science, in hydrology which is what I do,
we haven’t had before the GRACE mission a measurement of the storage change. We could
measure precipitation, we could measure evaporation, we could measure streamflow, we could measure
the water that comes into a system like a watershed or an aquafer and the water that
leaves it, but we couldn’t really measure the storage change and now we can. So that’s
provided, it’s opened up, it’s a whole new ballgame and so I’ll share some of that. Ok
so GRACE, the GRACE mission, what is it all about?It’s the Gravity Recovery and Climate
Experiment and so it’s these two satellites that actually look at each other, ok? It was
launched, sorry it doesn’t show up so well, but the blue, sort of, what do you call those
things? It’s the three dimensional term for–they’re not rectangles, they’re trapezoidal, something
like that. Does anybody want to help me out with that? Shape? It’s a trapezoid, is that
what you call it? Well, whatever. They’re about the size of a school bus and they’re
up there flying around at about 450 kilometers in the atmosphere and they’re separated by
about 220 kilometers. And, so what’s happening there, I mentioned that they are not really
optical satellites in the sense that they are looking at the ground they actually look
at each other. And so the measurement that is made is a very precise measurement, sub micron level
measurement of
the distance between the two satellites. So the accuracy of which, so the perturbations
the distance changes are very small [inaudible] but the accuracy is sub micron level which
is less than the thickness of a human hair. So it’s pretty incredible. So precise measurements
of the distance between the two satellites [inaudible] the foundation for a special breed
of [inaudible] called geodesis, people who study the shape of the earth and its gravity
field to make very very accurate maps of the earth’s gravity field at monthly and longer
timescales. And I’ll explain why that’s important in some of the next slides. The mission was
originally planned for a 5 year lifetime so it should have went down in 2007 but it’s
been going great and it’s still flying and it’s still giving us great information. So
it’s been flying for almost a decade, it is a NASA mission and the follow on this plan
[inaudible] so if the mission stopped today there’d be a gap and we would have to wait
until hopefully 2016 for the follow up mission, but if you read any of the stuff in the papers
you know the budget, the US budget is pretty tight and the 2012 budget has not been approved
yet, so it’s not clear if this 2016 date is realistic or not.
Ok, so how does it work?We have these two satellites and their chasing each other around.
They’re separated by 220 kilometers distance so how do we get gravity, how do we get water
out of this? And so these guys are moving around like this, looking at each other and
the distance is measured by microwave laser measuring the distance between the two satellites
and GPS giving geolocation time. So what happens is if you look at the top panel there this
first satellite approaches some sort of heavier mass anomaly, snow in the sierra for example.
It’s pulled down towards the mountain and it’s accelerated towards the mountain so the
pull of gravity is greater, there’s more mass there. So it gets pulled down and accelerates,
so the distance between the two satellites changes and after that satellite passes that
mass anomaly, it drifts back to its original position in the orbit. And then the second
one approaches that anomaly and it does the same thing. It gets pulled down and accelerated
towards the mass anomaly and then drifts back to its original position. So there’s been
a perturbation of the distance and so that’s happening all over the world and those distances
that are used to fit the parameters, fit the coefficients of the spherical harmonic expansion,
a mathematical function that represents the [inaudible]. So the mission does this on a
monthly basis and so over the long term it’s measuring the gravity field and on a monthly
basis it’s measuring the change in the gravity field. So here’s a look at how the GRACE mission
has improved the estimate of the, what they call the static part, the unchanging part
of the gravity field. Unchanging part of the, the static part of the gravity field is primarily
due to the tectonic and topographic features of the earth based on short time scales like
monthly time scales don’t really change. The position of the continent the position of
the major mountain changes [inaudible] and so on. So as you look from left to right across
this figure, I’m not sure it shows up that well here but this was before GRACE and this
is what we thought the gravity field, this was our understanding of earth’s gravity field
before the GRACE mission. And then after just about 100 days or so we got this sort of improvements,
you really see a sharpening up of all the features, and then after about a year of GRACE
data you get a gravity field that looks like this. So you can see as you go from left to
right there’s been a progressive sharpening of and orders of magnitude improvement of
our understanding of the gravity field. If we were to look at the gravity field today
and I don’t have the figure but the current 2010, 2011 version of the gravity field it
would look even better. So it’s good. Orders of magnitude improvement in our understanding
of what the gravity field looks like. Now imagine that you have one of these really
sharp maps here that you’re making one [inaudible] and that’s kind of how we get the water information
out of this gravity mission. The difference between two of those global gravity maps,
that’s what we call the time variable. GRACE’s first mission that was designed to measure
the time variable components of the gravity field, the time contributions in the gravity
field. The main contributions to time variations in gravity are changes in water; it’s the
one thing that’s moving all over the earth that’s really, really heavy. So water in the
oceans, water in the atmosphere, well the atmospheric moisture is not that much compared
to water in the ocean, water on land. And the reason is because water is really really
heavy. And you know if you go to Costco and you buy a case of bottled water it’s incredibly
heavy or if you walk back from the grocery store and you’ve got a bunch of orange juice
in your shopping bag it’s pretty heavy. So the GRACE time variable signal on land is
really dominated by changes in what we call terrestrial water storage, or the total water
storage. The little figure I have up here on the upper right a watershed, could be a
big watershed like, you know, the San Joaquin River basin or the Sacramento River basin.
So what GRACE helps us to see is the change in all of the water in that basin, all of
the snow, all of the surface water, all of the soil moisture, all of the groundwater.
So in case [inaudible] it gives us the total change in water storage it doesn’t tell us
the absolute amount, just change in the water storage, ok? One way to think of it is that
it is like a giant scale in the sky and it doesn’t tell you how much you weigh, it tells
you how much weight that you gained or lost. That’s what GRACE is doing and the mass, weight
gained or lost is dominated by changes in water storage, so it’s telling us how much
weight of water, how much water mass has entered or left a region. And with respect to accuracy,
it’s really designed to work at large scales both in space and in time. So monthly and
longer time periods, 150,000 square kilometers or larger, so for reference 150,000 square
kilometers maybe is about the size of Illinois, about the size of the Sacramento and San Joaquin
River basins together are about 150,000 square kilometers. So it’s a very useful tool for
regional, continental scale and global studies, it’s not particularly helpful if you want
to know if it’s going to rain or something tomorrow in Irvine. So it’s really more for
large scale and longer time scale climate related issues. And this figure in the lower
right shows you what some of the data look like. And that’s a time series of the change
in water storage and so the ups are when it rains more and the downs are when there’s
more evaporation so that’s a typical [inaudible] cycle of what water [inaudible] looks like,
and there’s a little bit, in this case, a little bit of
a trend with that solid line, so this is what
the data look like. I think I mentioned this already GRACE monitors
changes in all of the water stored on land; all the snow, the surface water, ground water,
and so on. We call that the total water storage. And it’s important to recognize that if you
want to isolate a component of the total water storage you wouldn’t use the GRACE mission
to look at groundwater storage changes, then you have to do something like this that’s
over here on the right hand side. The change in storage on land, change in all of this
water storage is really equal to the sum of the changes in the components that we see
here in the figure. So if you want to know the total change well you can look at the
change in the snow and the change in the soil moisture and surface water and groundwater,
and so on. And so conversely if you want to isolate say change in groundwater then you
get delta S from the GRACE data and you want to solve for the delta S GW, change in groundwater
storage, you have to come up with other data for the snow and for the soil moisture, and
for the surface water. And we do that by a variety of ways. Other remote sensing, other
ground based data and data from hydrological models, ok? And I’ll show you some examples
of those. Let’s see if we can get this thing to work,
clicking on it, no.. Here we go. This is what some of the data look like. So in this case,
and I’m unfortunately going to flip the color scale around on you a few times but in this
case the reds are wetter than usual and the blues are drier than usual. See, so they’re
very very blotty and this an early version of some of the data we’ve refined the resolution
somewhat. Ok, I am going to be very bold here and go off my show and try to show you something
here, Google Earth. So this is just going to loop for us, so this is showing you, so
I have changed the color scale on you already, so here red is drier than usual and blue is
wetter than usual, these are monthly data. So when you see something red getting redder,
it’s progressively drying. When you see something blue it’s getting progressively wetter. And
if you follow one place, just focus, the easiest to follow, you know look at India, or look
at the middle east or something, you’ll see that it’s up and down, it gets redder and
then it gets bluer and then it gets redder, it gets bluer but if you track that thing
over time there could be a trend so if you think about one of those plots that I showed
you, the ups and downs [inaudible], ok? So yes I’m not particularly efficient with Google
Earth or else I’d give you a wonderful tour, fly around and we could go to, I don’t know.
So, let’s go back to our [inaudible]. And I will say stop, nice. Ok, so if you have
a feeling for what the data look like. Here’s some pretty cool maps; on the right side some
of these trends that are emerging, and I have a map that is different that has a lot of
these trends annotated. In this map the blue areas are places, of the right hand side,
the blue ares are places that are getting drier, and so you see it India, Pakistan,
the middle east, Australia, this aquifer here, the Guarani Aquifer in South America, the
southeast US and of course the big ice sheets obviously they’re losing water so Greenland
and Antarctica. Glaciers like Alaska, [inaudible], the northern side of the Tibetan plateau.
So there’s a mix of things that are going on but in my title makes reference to the
human fingerprint and that’s really referring to some of these places where we’re seeing
a lot of groundwater [inaudible] Australia, India, Middle East, China, both sides of Beijing
south and north, so the north of China into Russia, across southern Europe. So these are
all areas where there’s been a huge amount of groundwater precipitation. If you take
this trend map and we can average it up to different regions, different regions like
watersheds. And many of these watersheds, many of the world’s biggest watersheds, river
basins are trans boundary. so we can make these plots of the ups and downs, the storage
change and then fit the trends which are just solid lines here’s the [inaudible] one that
I showed you earlier. We can do these from all the major river basins, we can do it for
the whole world, which I’ll show you later and we can do it for entire continents. And
so the point I want to make here in some of these places have increasing trends, some
of these places have decreasing trends. In places where they’re decreasing if
the trends are actually cold over time, like
Australia like the Maryborough Basin in Australia for example, it’s not a great situation and
one that is sort of very ripe for conflict because especially with the trans boundary
basins sharing water is not something that we do in that way. And when you think about
the future and I’ll get into some of these future slides, we are going to have to work
that out, because the future does not look particularly bright.
So, anyway from a scientific perspective it’s good to know the trends but what’s even better
is that we can for the first time start to see these ups and downs what we call the interannual
variations, the variations on an annual basis, up and downs over a year and how that varies
over time as increasing and decreasing. What is it driven by? A lot of it is probably driven
by El Nino and we’ll just have to wait and see until we get longer data sets to really
fully understand what’s going on. Of course there’s a very strong human component
here too, the human fingerprint. And you can imagine if you build a big reservoir in one
of these river basins that you’re going to be changing this storage pattern, that’s what
reservoirs are all about actually, about minimizing these storage changes so that you can have
a reliable water supply. And we’re starting to actually look at that [inaudible]. So just
let me underscore the scientific importance of these data, they give us the storage change
that I mentioned before we didn’t have, we can see the behavior we could never see before
and there are all these socio, political, economic implications for some of these trends
and for sharing water across the political boundary. And the cool thing about satellites
like GRACE or any satellite mission is that satellite missions do not know political boundaries,
so in many cases we’re getting information that we would not be getting otherwise. You
cannot pick up the phone and call Libya and say can you give me the data of the north
African aquifer system on your side of the aquifer. It doesn’t work. There’s a [inaudible]
in Tunisia who had this very conversation and wanted to collaborate with people there
on that particular [inaudible] boundary aquifer groundwater storage unit and asked them for
the data and they said you can’t do that and we can’t let these guys know how much water
we’re using and they don’t want us to know how much water they’re using, so satellites
allow us to see across those political boundaries. Sometimes the data aren’t even collected,
so this is the case here in California in many aquifers, perhaps I want to say aquifers
are made of groundwater, a geological unit that stores water in the ground, groundwater,
so many times we don’t even really have the monitoring water cycle monitoring globally
is far worse than you probably could possibly ever even imagine. You may think we have great
data on say groundwater extraction from the central valley here in California where we
grow so much food, right, we grow about 90 percent of the produce eaten in the United
States come from the central valley but the truth is it’s poorly monitored and in fact
if you are a farmer you do not have to report your groundwater withdrawal, ok? So it’s like
having a bank account but not keeping track of the withdrawals, that would be, maybe you
guys will feel it. Today, it’s a little different, right, because
it’s all done with computers. So it doesn’t even matter if you keep your ATM slip. Although,
as an aside, I will say for the first time today we found somebody stole our credit card
and we found out it was my son and he thought he ordered a seasons worth of, what’s that
show called? Rome, or something like that? And so my wife traced it back and some person
in Florida somehow got his name and our credit card number. Anyway, I digress, I wanted to
make the point that you would be crazy to not keep track of the inputs and outputs to
your checking account to keep track of the balance. So why is it that we would not keep
track of the extraction of groundwater from our aquifers that hold this really precious
resource, water? Well, we just do. And the water law was written
in times when we had a lot of water and the population was a lot less, and we also didn’t
have a full understanding of the water cycle. So if you use a satellite like GRACE to do
things like look at groundwater depletion in the central valley and other regions around
the world. So these are just a few slides that show the valley, I mentioned its importance
to the food, of course to the economy of California as well, and so you can see this picture in
the middle, those are all the wells that we can find where we can get data on the level
of water in the central valley in the aquifer in this time period that we have stated up
here, 2003 to 2010. That is not very many wells that is actually ridiculous if you’re
trying to look at the whole picture of the water level in the central valley aquifer.
So we use GRACE data shown here on the right I don’t think it shows up that well but just
like the data that I showed you pulled out some for California. What we have to do because
GRACE measures the change in total water storage if we want to just look at groundwater then
we have to subtract off other water, the snow, the other water that’s not groundwater. So
the snow, the soil moisture, the surface water, that’s what’s shown in the upper right so
we’ve got the total, you go up to the upper right, so this is the total storage change
and we subtract from this the snow we got from the national weather service, the surface
water which we get from the California database of all our reservoirs, the soil moisture which
we get from a NASA hydrological model. Subtract all these, one two three, from this and we
get this. This is the time series of groundwater storage for this time period 2003 to 2010.
The lines here show piece-wise trends, sort of no trend in this period, 2003 to 2006 then
the drought kicks in. We had major droughts start around 2006. What happened there is
that the farmers in the valley, in particular the southern part of the valley really rely
on surface water allocation from the delta. So snow melts, runs off into the rivers, flows
down to the delta and we got this huge water projects here in California that move water
all around through the [inaudible]. And so during the drought conditions, the farmers
particularly the southern part of the valley don’t get their surface water allocation,
in fact it was cut by 90 percent. And so they have to go and pump groundwater. So there’s
two things happening, there’s drought, so there’s no rainfall, and they’re using more
groundwater and so you see there’s this very very steep decline here shown with the red
line from 2006 to 2010 and that total amount of water loss was equivalent to about two
thirds the volume of Lake Mead so about twenty cubic kilometers lost in this time period.
It was about the third steepest decline in groundwater in the valley of the last 50 years.
If you know anything about the valley you’ve been pulling water out of there for 50 or
60 years, it’s subsiding, the level of the surface is actually land subsidence. We’re
running out of water, farmers are cutting back on their planting acreage. So we have
to think about the future, what happens when there is no more water left? What’s going
to happen to our agriculture, what’s going to happen to our economy here in California,
in the nation, because we supply a lot of food to the country.
This is a similar thing, a similar study in India. So if you look over here you see that
it’s a trans boundary issue, India and Pakistan. The same sort of study, you’ve got the GRACE
data, we looked at the change in the water storage and we remove the others, everything
else, all the other water that’s not groundwater, so the snow, the surface water, the soil moisture,
really not much snow in that part and we’re left with this groundwater decline which was
huge, about 109 cubic kilometers over about a 6 year period. So that’s about three times
the volume of Lake Mead. If you’re familiar with that area, the population is huge, right,
this is the whole Green revolution so all the food that’s being grown, just like the
central valley, a very intensely productive, highly productive agricultural region that
relies primarily on groundwater just in that region for food production. Water levels are
dropping precipitously and there’s news about Indian groundwater all the time. So this particular
paper, again this is an example of a region where it would be very tough to put together
this picture without satellite data. I have Indian graduate students, I have an Indian
graduate student who works back in India, at an Indian university, he could not get
that data himself, and he certainly can’t get it [inaudible]. So satellites allow us
to see what’s happening and to see across these political boundaries and this is one
that is a true tinderbox. Speaking of tinderboxes here’s the middle east. Same deal, I won’t
bore you with the details except to say there’s been a huge amount of groundwater depletion
there, even bigger than the India situation. So we’re talking about almost 150 cubic kilometers
of water, equivalent to the volume of the dead sea, or four times the volume of Lake
Mead. Some of the stuff that’s so bad that we’re actually a little bit concerned about
publishing it and really setting off some serious conflict. I would be remiss not to
mention the fantastic contribution that GRACE has made to monitoring ice sheets and ice
sheet change. So the first big papers that were written based on GRACE data were looking
at Greenland and Antarctica and for the first few years the trends were linear, but now
you can see they they curve down and that means that the melting is accelerating. The
melting is accelerating, it also means that the sea level rise is likely accelerating
as well. We do see that in the sea level data. So, this is very important stuff. This is
work that’s also done here at UCI by Professor Isabella Velicogna and then she and her husband
just published a paper last month that showed that the ice sheet are now contributing more
to sea level rise than all the other major factors, glacial melt one of the bigger ones.
This is a figure that I’ve shown to Professor Matthew a few times and one that I think has
huge implications for all sorts of international water policy and so this is the one that I
think really hits on the human fingerprint. So I’ve taken that trend map, so this is a
map from GRACE that shows all the trends, all the major trends all over the world in
water storage. This time the color scale is red is drier, blue is wetter. So we’ve got
the major trends, I pointed out before that the biggest ones are the ice sheets like Greenland
and Antarctica, after that probably the glaciers like the Alaskan glaciers, the Patagonian
glaciers, the [inaudible]. Then after that all these red spots are all groundwater depletions,
so China, China Russia, China plateau, this India, Pakistan it’s really almost one continuous
blob now. This one here in northwestern Australia we actually think this is related to mining,
the water requirements, the incredible water requirements of mining. A little aside, I
was at this meeting and I was talking to an Australian, a guy who identified himself as
an Australian, and I said and I always ask people who, you know it’s a global map, but
a lot of the hot spots are of course regional, it’s very difficult to get the data, you have
to do a lot of traveling to a lot of these spots on the map and so I was at the meeting
and the guy said oh I’m Oscar and I live in northwestern Australia and said hey, what’s
happening over here? I think it’s mining and I think that we’ve looked at all the climate
data and we can’t see any kind of precipitation signal and [inaudible] data sets but yeah
we think it’s got to be mining. He swore up and down it’s not mining, it can’t be mining
for this reason and that reason and all the water that’s used in the mining is basically
recharged locally, so it convinced me that it wasn’t mining. And so we finished our conversation
and I said are you at the University of Western Australia and he said no I work for a mining
company. [Laughter] So we look all across here, all across this dry region of the world,
what we call the sub tropics, the desert region, these are places that don’t get a lot of precipitation
where we rely on groundwater and so these spots basically all correspond to major aquifers,
places that we know are used for groundwater but we’re not able to quantify, so we’re in
the process of quantifying that now. And so it gets huge, and so that’s what I mean by
the human fingerprint. Even some of these that I at first didn’t think were groundwater
they actually are, so this sort of very characteristic S shape here and you go look at a map of aquifers
in Africa there’s this very characteristic snake-like S pattern down here in Southern
Africa. This is the Guarani aquifer that I mentioned. There are some inter annual signals
here like due to El Nino, but a lot of the blobs that we see here are groundwater. Now
I mentioned I was up in Tunisia trying to get this Libya Tunisia thing going and I couldn’t
but I’ll tell you I was really struck by the lack of water in that region. They drill a
mile and a half for water in Tunisia, in this particular aquifer and the quality of the
water is absolutely terrible. The hotel I was in had no water they wouldn’t even give
you a glass of water for free. I asked the bartender for a glass of water because I wanted
to take a couple of Advil and he just said no and I showed him, I was looking for a little
humane treatment, I just wanted to take these Advil, no he reaches down into the refrigerator
and pulls out a bottle of water and it’s whatever the local currency is [inaudible], I forgot
how much it was. But it’s equivalent to about five dollars. I swallowed it like a man.
I want to get into some of the water cycle acceleration stuff and what we would expect
to see versus what we are seeing. So this is a figure actually based on NASA satellite,
so it’s sort of a current view of what the water cycle, the global water cycle looks
like. So precipitation over land, units are in thousands cubic kilometers per year, so
precipitation and evaporation over land. And the difference is this streamflow. So for
all of the continents, the global streamflow or discharge into the ocean. And then we look
over the ocean, evaporation exceeds precipitation by the same amount. And this is the water
cycle, and so we’re putting numbers on the water cycle. And so if you think about trying
to figure out if the water cycle is changing then one of the things that has to change
basically the wheel that spins the water cycle is the vapor transport on land and the return
flow in the ocean. So the gap between ocean evaporation and ocean precipitation, if we’re
expecting the water cycle to change, that gap has to change, this vapor transport has
to change, and that would lead to changes here. In general these numbers are in rough
balance, the vapor transport versus the global river discharge and so what we’re trying to
figure out is if this stuff is increasing if the ocean evaporation increases, ocean
precipitation increases, is the difference between the two increasing or this vapor transport
to land increasing? Then that would lead to increased precipitation on land and increased
river discharge. One of the things we looked was do we see an increasing river discharge,
are we seeing increasing fluxes in precipitation, evaporation, and the discharge?
Maybe I can make this a little bit more clear. Here’s a box diagram for the global water
cycle. Storage in the ocean, storage on land. Here’s the arrows that just represent the
evaporation and precipitation over the ocean, the vapor transport that that 36 that I just
showed you, and then evaporation and precipitation over land and return flow or streamflow discharge.
So with changing water cycle, are we going to see changes in evaporation and precipitation
over the ocean, are we going to see this increasing vapor transport, are we going to see increasing
precipitation and evaporation over land, and are we going to see increasing discharge back
into the ocean? So it’s speeding up, it’s increasing magnitude of the water cycle, basically
the number’s going to get bigger, the cycle itself is going to be bigger or transport
larger amounts of water. So we put together many data sets and long story short this one
we’re looking at changes in ocean evaporation from multiple data sets and then averaging
them up and looking at the trends and there’s this pretty significant trend in ocean evaporation
in this time period from 1994 to about 2006. So we have increasing ocean evaporation. Here’s
precipitation, a little bit more of what we call interannual variability, it goes up,
it goes down, it goes up more, it goes down. And so we average it out over this time period
and we get these piece wise trends, we’ve got this big increase over this time period
and then trends for the whole time period from 1994 to 2006 of an increasing ocean precipitation
but not as much as the increase in the ocean evaporation. So we’ve got the evaporation
increasing, precipitation increasing over the ocean just like we thought we would in
a more energetic water cycle and the gap between the evaporation and precipitation getting
bigger, meaning more vapor transport, so that arrow that was the 36 in the other figure
would probably get bigger, so that means it’s going to push the water cycle to spin faster.
And bottom line what we’re tying to do was estimate if that return flow, the global river
discharge, was increasing as well. And so we were able to do that in this study using
GRACE data and other data so we did a mass balance on the ocean, where we’ve got this
number from GRACE and other data sources, evaporation and precipitation data I just
showed you, and so we get this global river discharge time series that looks like this,
and we average it out over the, these are monthly data if you look at it from an annual
perspective, we get this. This inset here I think shows the increase a little bit more
clearly. Bottom line is there’s an emerging trend there, there’s a lot of interannual
variability, but there’s an emerging trend that shows an acceleration of discharge, about
540 cubic kilometers per year. Which is about one and a half percent per year, which is
actually a lot. It sounds like a little, but, you know, over a ten year time period that’s
15 percent, that’s a lot. So this paper got a lot of attention as one that was an indicator
of water cycle acceleration, it’s happening now. It’s not far off in the future. What
else might we expect to see? One thing that GRACE has allowed us to see, is keep doing
this for the time traces of the storage, the ups and downs, right? So if you think about
the ocean and what the ocean storage time series raise, what the ocean storage data
would look like. When it rains more, it’s going to go up, when it evaporates, it’s going
to go down. And so it sort of happens in seasons, it goes through a rainy season and the storage
goes up and then there’s a dry season and the storage goes down and then it goes back
up. So if evaporation is going to be bigger, evaporation is small, precipitation is small
and the amplitude of the ups and downs are going to be small. If precipitation gets bigger
it’s going to go up more, evaporation gets bigger it’s going to go down more. So the
magnitude of the water cycle is actually measured by, the strength of the water cycle is actually
measured this amplitude of the time trace, the storage data, and any changes in that
amplitude, evaporation keeps increasing over time we expect the lows to get lower, if precipitation
keeps increasing over time we expect the highs to get higher. So we expect to see sort of
a envelope of the storage, of the highs and lows of the storage curve. I’ll show that
to you in the next couple of slides. So here’s one. This figure actually shows
all of the water in the world from GRACE, almost all of the water, we don’t have the
atmospheric water in here because there’s not much of it, so we plot it on here it wouldn’t
even really show up. So this shows the change in the water storage. The blue line is changes
in water storage in the ocean on a monthly basis, so you see it goes up and down, up
and down, precipitation increases it, evaporation decreases it. So it goes up and down from
2002 to almost up to the present. Completely out of phase with the land signal which is
shown in green. So what that is, that is the out of phase relationship is really an expression
of the water cycle. So evaporation lowers the mass in the ocean and moves that water
to land. And then conversely this discharge from the land and evaporation from land lowers
the land signal and returns the water back to the ocean. So basic water cycles. So we
see that out of phase relationship, and then the ice sheets are on there as well shown
in pink and [inaudible]. So it’s pretty cool to have all the water there to be able to
track what’s going on over time. But now the ups and downs represent the strength of the
water cycle and does it look to you like there might be a change in amplitude? I think that
there is. Oh, here it is. So we’re seeing this change in amplitude and so that is really
a metric of this change, over just this short time period is really a metric of change as
a change in the water cycle. And it’s going to go up more if there’s more precipitation,
it’s going to go down more if there’s more evaporation, and if it changes over time that
means that the water cycle is changing. So that’s it that we’re seeing from GRACE and
it’s quite powerful. Third thing that we have to talk about is
this redistribution of precipitation and I would say this is critical. This has been
about the wetter is getting wetter, the drier is getting drier and think back to that trends
map that I showed you. Well the groundwater depletion in the dry areas they’re not going
to get any more rain, it’s just going to get even worse, so ultimately we’re going to run
out of water in many places. Well again this is IPCC stuff and so the red ares these are
projections of precipitation and the red areas that are drying out and with the various other
places that are projected you get more precipitation and so the current thinking is that we will
see this redistribution of precipitation from the mid latitudes to the high and the low
latitudes. Dry areas get drier, more drought, wet areas get wetter, more flooding, more
water. And so we see this, we’re seeing this in the GRACE data. I’d like to put on my funny
colored goggles and say wow I think we are seeing this, look that’s kind of yellow, of
course I made these boxes kind of yellow to kind of fool you, and then no I think we are
seeing this redistribution from the mid latitudes to high and low latitudes so just kind of
put those question marks there. Ok, love this figure, drew it by hand before
a meeting, my students just embarrassed by it, actually even put it in a proposal, didn’t
have much time and so I just put it in a proposal and one of my students, it was so bad that
one of my students his wife actually saw it and said I can’t believe this guy put that
into a proposal and she made me like a really nice figure which of course I don’t use because
I like this one better. What I’m trying to show here and a lot of people think, they
take earth science classes they’ll say well why do we care about global change? Because
[inaudible] glacial period, we’re in the middle of this interglacial period and these glacial
and interglacial periods come 20,000 year intervals, 40,000 year intervals. You know,
we’re 10,000 years into this interglacial period it’s just going to get cold, so why
do we even care? So the temperature is going to go like this. And so in theory we’re right
here, and it’s just going to cool off so why should we care? Well you should forget that,
and I’ll tell you why you should forget that in a minute. This is just [inaudible]. So
one of the things I want to point out though is that what we’re seeing, what we’ve been
able to now recognize, this is supposed to be the amplitude of the storage, global land,
or global oceans. When it’s really cold all the water frozen, so there are no ups and
downs there’s not much precipitation, there’s not much evaporation so there is no up and
downs. This is sort of where we are right now, we’re seeing the ups and downs whether
it’s that ocean signal or land signal, it’s the water cycle, the water cycle gets stronger,
atmosphere gets warmer it can hold more water we have more precipitation, more evaporation.
So when it’s cold everything’s frozen, so everything is in the freezer, there’s no activity,
frozen solid, no water moving around. Starting to thaw out, more water moves around, this
storage is going up and down, whether you’re talking about the global ocean or all of the
land it’s going up and down. Why should we care? In theory we’re going to end up back
here and so the water cycle is going to calm down, it’s not going to get more intense and
everything’s going to be great but the reality of our era, the Anthropocene, the era dominated
by humans is that, that didn’t show up there there it is, this is not going to happen.
Temperature, we’re not going into another glacial period, the reason we’re not going
to go into another glacial period is that the greenhouse gas forces is greater than
the orbital forcing, changes in the earth’s orbit that would drive this. So we’re not
going back here, so we’re in a new zone and that’s why I put a dashed line because we
don’t know where we are going, that’s based on the temperature projection. Now do the
extrapolation from here to there to there, that amplitude is going to get bigger, and
that’s scary because that amplitude means more energy, more precipitation, it means
more evaporation, it means more ups and downs, it means more of all the stuff that I just
went through. More drought in the drier regions, more redistribution of precipitation, huge
amounts of energy required to, water’s heavy, it takes a huge amount of energy to move it
around. We have no idea, I think I’m starting to recognize El Nino is sort of the work force
of global climate change. Lots of things happen more rapidly during El Nino period. So the
energy required to do that it may come from much more intense, longer duration, more powerful
El Nino. It takes a lot of energy to move that amount of water up and down. So we’re
going off into the unknown. Ok, so let’s finish up with a couple of slides and then we can
talk. So we’re basically in the middle of rapid climate change, we’re experiencing,
we’re driving it. And with it I think we’re starting to see this major change in the water
cycle. What are the implications? I think that they’re just insane. I wrote a few of
them down now and only because of talking to people like Professor Matthew, starting
to think about what are the implications for this stuff? [Inaudible]. 80 percent of water
is used for, 70 to 80 percent of water is used for irrigation. Much of this occurs in
the arid and semi arid regions of the world and most of that water comes from groundwater.
I showed you all those red blobs on that map, where groundwater is being depleted at an
incredibly rapid rate, it’s incredible. So groundwater resources are in global decline.
What does that mean for food security? It probably does not mean good things and think
about California as an example. International security, people have been fighting over water
forever. Maps like this that I showed you, I don’t think they’re going to help. They
may help us drive policy, but I’m afraid that, the NASA people said that when we published
the paper on India that we almost started World War III, we were completely naive, we’re
just looking at bright spots on a map, like typical nerds oh wow a big bright spot on
the map let’s write a paper and worry about the consequences afterwards and then sort
of mature into it rather quickly. So the trend map shows many of those hot spots are trans
boundary. India, Pakistan, North Africa I mentioned my experience there, I did not mention
my middle east experience. The same thing, I was in Turkey and thought that I was going
to be talk to Iraq and Iran and that everyone would be really nice and that just didn’t
happen. US and Canada, and even within countries, like the United States, I didn’t talk about
that but the Southeast, I don’t know if anyone noticed the big southeastern [inaudible] that
spans Florida, South Carolina, Georgia, South Carolina, North Carolina. Is the pacific northwest
going to want to [inaudible] less water, I don’t know in the future. So legal and engineering
infrastructure to move water from where it is, this is the future, moving water from
where it is, this redistribution, the wet places are going to get wetter those countries
that have water and places like us, places like here in California, are not. So we’re
going to have to move water from where it is to where it’s not. Or do a lot more recycling,
or do [inaudible] do all of those [inaudible]. My point is the legal infrastructure is not
there and certainly not at the international level and the engineering infrastructure is
just not there. Economic security, let’s look at California for example. What will happen
to California’s economy as the snowpack decreases. We’re running out of snow, by the end of the
century, gone, no snow. And so all that means is that the groundwater is going to go even
faster. So we get 50 percent of our water here in Orange County from groundwater. Luckily
we have this fantastic recycling facility, we have precedent, the groundwater replenishment
system in Napa valley, you should absolutely go, it’s amazing. That’s part of the [inaudible].
But, anyway, as we run out of groundwater, say in the central valley, what is that going
to do to our economy as an agricultural industry, [inaudible]. Energy security, now two to five
percent of energy used is for water movement, water treatment, for water heating. On the
other hand we generate a lot of hydropower. If we do more and more desal and more recycling,
the energy requirements in particular of desal are huge. So hydropower will be decreasing
in places where snow is melting, like the western US, like the Tibetan Plateau, like
Europe. And more energy will be required for desal and for recycling. And climate security,
this has been about that last figure with the water cycle gone wild, that where I said
oh maybe the water cycle has spun out of control, I don’t know. But the energetics of that are
huge and we need to do a lot of work quantifying that jump that I showed there with the dashed
line to figure out what the energetic changes are going to be. By energetics I mean the
amount of energy that’s required to lift the water for evaporation, to vaporize the water,
well that’s huge. But that energy is released when the precipitation forms, so we’re talking
about a lot more energy, water and the energy cycle are intimately coupled. So there’s more
water moving in the water cycle, there’s more energy moving in the energy cycle and it gets
released in things like thunderstorms and severe storms. So the energetics are huge,
they’re phenomenal and they point to these big changes in the extremes which will lead
to more flooding, drought, let’s not forget about sea level rise an intimate part of this.
So there are major concerns ahead. Too much to read here but this is from the USGS. I’ll
leave this for Professor Matthew feel free to take a look at some of this information.
This is from the USGS report the one that I found on my coffee table this morning. It
integrates a lot of the stuff that I just mentioned. So they’re starting think about
water security, defining what it means and this is sort of a summary from that professional
paper and a lot of the same issues. How do develop trans boundary water-sharing, how
are we going to work out this inter-dependency between water, energy, ecosystems, agriculture,
biodiversity, how are we going to make sure that all these major pieces of our earth system
get their fair share of water. How can we start to plan, deal with policy, what are
the threats to water security? Population growth by the way, I didn’t mention, we could
solve many of the world’s water problems with an ambitious condom distribution, just saying.
So population growth is a huge, huge part of what we have to deal with. So I’ll finish
there, happy to take any questions, hope you guys are still awake. [Applause]

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