Julian Caldecott - Water: The Causes, Costs, and Future of a Global Crisis

As I write this, Britain is having a crash course in water awareness. Many of this book's themes are suddenly becoming all too familiar. We have realised, for example, that our vulnerability to flooding is made worse by building on floodplains, by channelling rivers through narrow, artificial banks, and by covering ground with tarmac and concrete, thus preventing it from absorbing water. We've learned the irreplaceable value of clean drinking water, and we are coming to realise that climate change is steadily demolishing our expectations about a gentle English climate.

Water is an extraordinary substance that makes life on Earth possible. But almost all the world's water is salty, and for us on land a regular supply of fresh, clean water is uniquely precious. Such a supply is the most important service that an ecosystem can offer, yet is often allowed to lapse through abuse, or it is diverted from those who really need it, or destroyed by over-use or pollution. As a result, over a billion people now have no access to clean water and 2.6 billion have no effective sanitation system. One consequence is a huge waste of human energy in an endless quest for water, a burden that often falls hardest on women and children. Another is unnecessary illness, which every year claims the lives of nearly two million children. We are, in every sense, facing a global water crisis.

Yet, as Julian Caldecott explains here, this global crisis is in fact made up of tens of thousands of local water crises, each one due to decisions that affect local ecosystems. Water and ecosystems are linked, from the boundaries of each catchment to the streams, rivers, lakes, floodplains, swamps and estuaries created by water. Everything we do in a catchment affects what happens downstream, so logging, farming and grazing, applying fertilisers or pesticides, dumping garbage, releasing sewage or spilling chemical wastes all have an impact that's conveyed by the ultimate solvent, water. Meanwhile, we've taken to pumping water from the ground at rates far higher than it's being replaced, causing wells to run dry in region after region.

This book is about human decisions. Julian Caldecott draws stories from all over the world, and reveals the many ways in which our experience of water is a common one. He shows how different approaches can have different outcomes, some destroying ecosystems, some transforming them, some sustaining them. But there's also a bigger context. The viability of the biosphere depends fundamentally on water often in ways that we barely understand. Water, ecosystems and climate are inextricably linked, so we need to make wise decisions about all three. Local ecosystems determine whether or not there's water in your well, river or tap, and help dictate rain or drought, storm or famine. All the evidence is that the negative changes we make to our environment are contributing to mass extinction, local water crises, and further climate chaos.