The human ecology of climate change - Climate Change: Biological and Human Aspects - page 411

270 000 cases of diarrhoea) compounded the problem. The year 2004 was particularly
bad but floods in this region are common and in 1998 about 70% of the country was
under water for nearly 3 months. With around 65% of the population deemed by
the International Red Cross to live below the poverty line, the people affected were
typical of those the IPCC consider to be most vulnerable to extreme weather events
and other climate change impacts. The IPCC cites Bangladesh as an example of a
risk area because it is low-lying, hence the potential for exposure to sea-level rise,
and because its climate naturally features weather extremes (often monsoon-related).
Factors conspired synergistically to make the 2004 floods in the north-eastern region
of Bangladesh impact heavily on people. First, four flash floods came in quick succes-
sion and, second, unusually high tides slowed the water's discharge to the sea. But, in
addition, population pressures, to farm and other land development, had constrained
the waterways, so increasing their chance of failing during extreme events (Nature
News, 2004).
In 2007 some 20 million were displaced in monsoon floods in northern India,
Bangladesh and Nepal. In 2008 the monsoon rains were so severe that the number of
people displaced necessitated the establishment of 119 relief camps. In 2010 Pakistan
monsoon floods, the worst for over 80 years, displaced 20 million people with a death
toll of close to 2000, and saw outbreaks of cholera and other diarrhoea-related disease.
Some 6.9 million ha of farmland was flooded and the loss of the cotton crop alone
was valued at US$1.8 billion. In 2011, by comparison, just two million were affected
by monsoon floods in India. Across the border in Pakistan some 2600 villages were
flooded, more than 400 people died, with 5.3 million people displaced, and millions
more otherwise affected. The District Badin in Sindh province saw record rainfall of
615.3 mm during the monsoon spell, breaking the earlier record of 121 mm in Badin
in 1936. The area of Mithi too had record rainfall of 1290 mm during the spell, where
maximum rainfall previously had been 114 mm in 2004. The 2011 monsoon season
also saw record flooding in Thailand, Cambodia and Myanmar and heavy flooding in
Vietnam. In China rain-fed floods affected more than 36 million people and caused a
direct economic loss of some $6.5 billion.
But are rain-fed floods actually getting worse? The IPCC (2001a) stated that there
were no observable changes in tropical cyclones (hurricanes and typhoons), and peak
precipitation intensities were not found in the few analyses available to it. In the 21st
century it forecast that increases would in the future be likely in some areas. This all
changed with the IPCC's 2007 assessment that noted that intense tropical cyclones
have increased with warming since around 1970, and that there have been increases
in heavy precipitation events.
Indeed, research is revealing increases in rain-fed floods, although it is still unclear
whether these will persist: a longer time frame is required as 20th-century analyses
reveal flooding periods of different frequencies (albeit at a lower level) that last for
decades. For example, in 2001 a US team led by Stanley Goldenberg showed that the
years 1995-2000 experienced the highest level of North Atlantic hurricane activity
in the reliable record. Compared with the generally low activity of the previous
24 years (1971-94), the subsequent 6 years saw a doubling of overall North Atlantic
heavy-storm activity, a 2.5-fold increase in major hurricanes (with wind speeds of
more than 50 m s − 1 ) and a 5-fold increase in hurricanes affecting the Caribbean.