impact on water resources. Solving the energy challenge could thus aggravate
pressures on water resources as well as putting pressure on food supplies.
This is a good example of the need to consider impacts on water resources as
part of the review of climate mitigation strategies.
Uncertainty and time horizons
Uncertainty pervades every aspect of climate change adaptation planning. This
is seen by many as good reason to postpone action. Most impacts are expected
decades in the future, and the scale of impacts could vary widely with a range
of factors – the success and scope of mitigation efforts, the accuracy of today’s
models, the potential for non-linear tipping points that cannot be modelled,
and so on.
But the timeframe for aligning water resources management responses is on
a similar time-scale. Major water resources infrastructure, such as large
reservoirs or pipelines, routinely takes over a decade to design and construct.
Moreover they are extremely long-lived. The structures built today
will still be standing – and hopefully operating – a hundred years from now.
Similarly, hydrological data and information collected today will provide an
invaluable basis for monitoring, understanding and managing the world’s
changing hydrology for decades to come.
While sequencing and prioritizing specific medium-term priorities is surely
complex, it is timely and wise to focus now both on building our understanding
of the challenges and our capacity to deal with them. It is equally
important to seize existing opportunities for intervention, whether by
enhancing river regulation and water storage options; by strengthening
hydrological information systems, particularly for those strategic water
resources we know little about, such as groundwater and glacier melt; and
by introducing the difficult ‘soft’ measures such as conservation programmes
and incentives to reduce pollution that will change our behaviour and make
us less vulnerable in the future.