Securing our shared water future amidst climate disruption
[Music]
we all
inherently understand that water is
essential to life
we drink bathe cook and dispose of waste
with it
every day but water is critical to
society
in many ways you may not realize
you need water to make just about
anything
from growing food to making raw
materials like steel
cement paper or plastic to manufacturing
of
all goods including the clothes you’re
wearing
and the screen on which you’re viewing
this talk
for example a cup of coffee requires 140
liters of water
and a smartphone more than 12 000.
water is even needed to generate
electricity
because we use water for almost all
human activity
as society continues to develop our
demand for water
is going to skyrocket with water
being so vital it’s important to ask
where is
all the water on earth we are fortunate
to have a planet with a tremendous
amount of water on it
millions of billions of liters in total
but 97 of this is in the oceans
and you can’t use salt water to drink
or grow food or manufacture goods
of the three percent or so of the water
on earth that is fresh
more than half is locked up in the ice
caps and glaciers
inaccessible to us almost all of the
rest
is under our feet in aquifers so-called
groundwater
now we are heavily reliant on
groundwater
we withdraw it much more rapidly than
it’s naturally replenished
this creates an unsustainable dynamic
that will exhaust this resource before
long
both india and the united states get
more than half of our water for
irrigation from groundwater
how will all that food be grown once
those aquifers run dry
what about surface water lakes and
rivers well
all together those equal only about
0.007 percent
of the water on earth yikes right and
that tiny supply
is becoming even more stressed because
of climate change
precipitation patterns are changing in
many cases making
already dry regions even drier
water crises like the one that happened
in cape town south africa in 2017 or
chennai and 2019 will only become more
common
in the coming years as sea level rises
salt water will start to intrude into
coastal freshwater aquifers
and perhaps most alarmingly the glaciers
and snow whose melt water feeds river
systems
on which billions of peoples rely
are disappearing water crises are
perhaps
most pressing in south asia where india
the largest economy
faces severe shortages and almost
no consensus on what to do about it
water problems threaten to hinder
india’s economic growth
and slow its rise as a regional power
india is not alone many developing
countries face similar challenges
and water often crosses political
boundaries this forces governments to
try and work together
to figure out how much water each side
can use
water sharing has always been difficult
more than four thousand five hundred
years ago in ancient mesopotamia there
were two neighboring city-states of uma
and lagos and they bickered constantly
over a tributary from the euphrates
river
eventually a water sharing agreement was
brokered the
treaty of messily this was not only the
world’s
first water treaty it was actually the
first recorded treaty
of any kind this speaks to the
centrality of water in human
civilization
unfortunately however that peace between
uma and lagash
devolved into conflict just 50 years
later
starting the world’s first but certainly
not its last
water war today in a time of
accelerating economic change and climate
disruption
tensions like these are exacerbated
south asia is reliant on water from two
sources
ice and snow melt from the himalayan
plateau and the annual monsoon rains
both of these sources are destined to
become more unpredictable
and unreliable going forward
moreover there’s already a large
regional dependence on groundwater which
is unsustainable so this cannot be
expanded to provide additional supply
without significant reforms to the way
that south asian nations
use and manage water they and many other
regions around the world
will face deepening economic and social
turbulence
there just won’t be enough water to go
around for sanitation
and growing food and cooling machinery
the outlook feels pretty darn bleak
so what do we do fortunately
developing countries have some powerful
tools available to address water
scarcity and enable
sustainable economic development this
involves
combining two essential elements that
must come together
as an integrated solution the first of
these
is cooperation south asia is both a
model
of international water agreements and an
example of budding water conflict
the indus water treaty between india and
pakistan
and the mekong river commission in south
east south east asia
have both survived decades of interstate
conflict
but contrast that with the case of the
brahmaputra river
which starts in the tibetan area and
flows through china
bhutan india and bangladesh and there is
little agreement over its governance
so first we must build on the successive
agreements like the indus treaty
and strengthen these institutions that
govern transboundary rivers
this isn’t just about india there are
nearly 150
countries around the world that have
international river basins in their
territory
and i should mention many aquifers also
cross political boundaries
creating an impartial incredible forum
to address water disputes will go a long
way
toward reducing these political tensions
so first we must have cooperation but
governments must also bring the second
piece of the story which is
promoting more efficient water use and
this will be through the encouragement
of the development and adoption
of water saving and water recycling
technologies
an obvious step to take is to shift to
more water efficient irrigation methods
less flood irrigation and more drip
irrigation
but there are emerging opportunities for
novel ideas in water
there is an explosion of research
discovery
in new water technologies around the
world some of the most exciting of these
entail taking polluted waste water and
returning it to fit for purpose water
without relying on the slow natural
water cycle to do this
recycling water in this way represents a
complete
reimagining of the water cycle and maybe
the most sustainable impactful path to a
secure water future
now addressing water crises in the
developing world through technology
will require a change in perspective
from those of us in the scientific
community
low-cost highly scalable and distributed
systems will be the key
rather than the high-tech centralized
solutions that we employ so often in the
developed world
let me give you a few examples of some
of these new water technologies with
this different flavor of water
recycling the first example is called
solar steam generation
the idea here is that you take the light
from the sun you convert it to
thermal energy and you concentrate all
of that heat
right at the top of a bath of polluted
water this will dramatically
increase the rate of evaporation leaving
the pollutants behind
you can then just capture the steam
allow it to condense
and you’ve got clean water fit for
almost any use
all driven by a plentiful and carbon
free energy source
the materials for solar steam generation
cost almost nothing
and these devices can be deployed almost
anywhere as long as there’s enough
sunlight
another example comes from the world of
membrane technology membranes are
filters with tiny pores that allow the
water to pass but block the unwanted
substances
they’re a great way to clean water but
there is a pervasive challenge with
membranes
which is that those unwanted substances
will often block the pores
not allowing the water to pass a process
called fouling
here again we can turn to the sun for
help
researchers are developing specialized
coatings that you can apply to membranes
that are activated by
light it creates reactive species that
degrade those fouling substances washing
them off the surface
so your membrane when it gets dirty can
literally clean
itself as long as it’s exposed to light
these are just two examples among a
plethora of promising water technologies
emerging on the horizon it may sound
like i’m
asking you to rely on hope but we don’t
have to rely on hope
we have precedent there are dry places
on earth today
that have combined technology and water
sharing
to produce sustainable water management
in an era of growing regional tensions
and a changing climate
this integration of water cooperation
and technology research and development
as a coupled solution
is a powerful tool a smart investment
for a secure water future for south asia
for the rest of the developing world and
for us all
thank you