The Global Water Crisis: Addressing an Urgent Security - Unu-inweh ...

4. Climate Change and the Loss of Hydrological ‘Stationarity’
All these challenges to the current status quo will be compounded in one way or another by climate change, and it will
be important for decision-makers to understand why climate change will play such a crucial role. Aside from inducing
warmer temperatures, decision-makers will need to grasp exactly how climate change will affect water security.
We have known for some time that hydro-climatic hazards such as droughts and floods have the potential to trigger
or exacerbate social tensions that may lead to intra- and inter-state conflict (Vidaurre et al., 2011). While conventional
wisdom in water policy circles today has it that growing populations and climate change do not necessarily translate into
increased water wars, the same wisdom does not apply to temperature. Higher temperatures have already resulted in lower
precipitation in North Africa, for example, and this has led to diminished agricultural production, greater unemployment
and growing unrest, especially among younger males. Scientists have modelled the connection between temperature and
conflict to demonstrate that conflict increases in lockstep with temperature. When conflict analyses and climate model
data were assimilated, they projected a roughly 50% increase in armed conflict by 2030, with almost 400,000 additional
battle deaths in Africa alone (Cullen, 2010).
It is not only in already politically unstable regions, however, that climate change is expected to cause economic and social
disruptions. To understand why climate change is such a threat to established stability, it is important to understand the
central role that water plays in our planet’s weather and climate system.
The fundamental threat that climate change poses relates to what hydrologists call ‘stationarity’. Stationarity is the notion
that natural phenomena fluctuate within a fixed envelope of certainty, and implies stability. It is because of stationarity
that we have come to expect that winters will be so cold and summers so hot; that melt from winter snow will always
contribute roughly the same amount of water to our rivers; and that rivers will rise so high in the spring and fall so low
in autumn. Stationarity suggests that lightening will strike only so frequently, and that tornadoes will occur only at the
most extreme margins of the weather conditions we have come to expect. Stationarity provides the certainty that is
needed to build houses to withstand winds of a certain speed and snowfalls of a certain weight, and to what size to build
storm sewers because history has shown that rainstorms only last so long and only result in so much run-off. Stationarity
provides the foundation for the reliable functions of natural ecosystem processes that provide a stable and resilient
backdrop to human existence.
By assuming stationarity within a defined range, humankind has been able to create cities in which millions of people live
with security, to develop water treatment and delivery systems that provide safe drinking water to billions of people, and
to develop transportation systems that allow many people to travel anywhere in the world within a day. But the statistics
and the standards upon which these were based to create these modern miracles no longer apply. What is happening
now is that increased temperatures are altering the patterns of movement of water through the global hydrological cycle.
This means that the statistics from the past related to how surface, subsurface and atmospheric water will act under a
variety of given circumstances, and on which we have come to rely, are no longer reliable.
While it is well known that climate changes naturally over time, we have enjoyed a relatively stable period over the last
century. As a society, we have been lulled into complacency by this relative stability. During this period, we established
our own idea of the limited range of natural climate variability that we believed exists, and then built our society and
the vast infrastructure that supports it around that range. Our risk assessments were also built on these same notions of
relative stability that may now no longer exist. This mistake has made societies vulnerable, and this vulnerability is now
being compounded by climate change. The warming of our climate has altered the fixed envelope of certainty within
which we anticipated natural phenomena to fluctuate, the result of which we are seeing through increased droughts,
floods and other extreme climatic events affecting the way we live.
As of yet, there is no adequate replacement for stationarity statistics. Until a new way is found for substantiating appropriate
action in the absence of stationarity, risks will become increasingly difficult to predict or to price.
14 The Global Water Crisis: Addressing an Urgent Security Issue