Page 63 - BBC Wildlife Volume 36 #05

AGENDA OPINION

Mark Carwardine’s

ATAGLANCE...

28 F LO O D I N G

WHAT CAUSES FLOODING? the USA in August 2017, was ditched in favour of explosive
Quite simply, floods are the country’s wettest-ever growth, and the result
caused by a combination of tropical cyclone; and in is predictable.
too much rain and an inability September of last year,
of rivers and their catchment Mumbai experienced a SHOULD WE WORRY?
areas to cope with the deluge. deluge of 304mm in Yes. UN data records
Either moderate rainfall over 24 hours, the second an average of 171 major
an unusually long time, or highest figure for that worldwide floods per
heavy rainfall over a short month ever. year from 2005–2014,
period, can cause rivers up from 127 per year
to burst their banks and HOW ARE WE Worcester was hit in the previous decade.
cause flooding. INTENSIFYING by severe flooding In the past 30 years or
THEIR IMPACT? in 2014. Events like so, floods killed 500,000
this are becoming
IS IT AN ACT OF GOD? Normally, rainwater more frequent. people worldwide and
Yes and no. Rain is natural, is absorbed by soil and displaced a further 650
of course, and rivers have vegetation, which act like a million. It is already one of the
always flooded (that’s why the giant sponge and release it planet’s biggest environmental
surrounding land is called the gradually. But deforestation, issues, and it is getting worse.
floodplain). So, in one way, over-cultivation, the burning ` WE ARE
flooding could be described of grouse moors and other ENCOURAGED WHAT MUST WE DO?
as a natural disaster. That forms of habitat degradation Well, we should stop building
is what we are encouraged are destroying this sponge. TO BELIEVE on floodplains, and we need to
to believe, but the truth is Instead of being held back, THAT FLOODING invest properly in flood
that we are exacerbating rainwater is washing into defences wherever we have
the problem – through rivers so fast that they IS A SIMPLE already made that obvious
incompetence, ignorance simply cannot cope. We are ACT OF GOD, mistake. But building higher
and greed – by making making things even worse by walls is not a long-term
precipitation heavier and straightening and dredging BUT WE ARE solution – it’s just a sticking
intensifying its impact. the rivers, which accelerates EXACERBATING plaster. We need to reduce the
the flow of water and makes THE PROBLEM.” amount of water, and slow the
HOW ARE WE DOING THIS? flooding further downstream flow. That means replanting
Global warming. It may not even more likely; and we woodlands and nurturing other
cause storms per se, but it are building embankments natural sponges; leaving
certainly makes them worse: that disconnect them from natural obstructions in rivers to
warmer seas evaporate more their floodplains. impede their flow (beavers can
quickly, warmer air holds do this for nothing); and letting
more vapour, and the result is WHAT ABOUT them meander as they once
that more water gets dumped URBANISATION? did. We also need to tackle
more intensely. In many Urbanisation is a more global warming, of course, by
parts of the world, storms extreme example, because reducing our consumption of
are becoming more powerful we are replacing the natural MARK CARWARDINE fossil fuels and developing
during which several months’ sponges with completely is a frustrated and renewable energy sources.
worth of rain can fall in just a non-porous cities. Around frank conservationist. And to do all this, we need
Every month he
few hours. The British winter the world, as more and more demystifies some of the politicians who understand that
of 1 December 2013 to 19 people move from rural to most important issues flooding is not a simple act of
afecting the world’s
February 2014 was the wettest urban areas in search of wildlife and assesses god, after all.
Watson/naturep .com years ago, for example, with rapidly and unchecked – onto that protect it. + FIND OUT MORE
work, cities are expanding –
since records began 250
the organisations
devastating flooding affecting
marshlands, wetlands and
O Would you like to
Future of UK flood defence:
wildlifeletters@
Hurricane Harvey, which hit
Ecological sense is being
W huge swathes of the country; other flood-prone areas. comment? Email http://bit.ly/2ssy7YR
immediate.co.uk
Spring 2018 BBC Wildlife 63