Dr. Claus Rink,
Geoscientist and Special correspondent for Pattaya Mail Media Group
The hydrologic cycle is a worldwide system powered by
energy from the sun in which the atmosphere is the transmission belt between
the oceans and the continents. Water evaporates from the oceans, the rivers
and much lesser from the continents into the atmosphere. Wind then
transports this special mixture of air and water through the atmosphere and
the water is condensed into clouds. The water then falls into the ocean or
to the surface of the worldwide glaciers in the form of precipitation. The
cycle is complete now and can start once more.
But
what is happening with the glaciers now? Normally, when precipitation falls
in very cold areas (glaciers or the icecap of Greenland) the water will
become a part of the snowfield. A lot of water is stored in the glaciers as
fresh water (68.7 % of all freshwater). If the present glaciers were to melt
and release their stored water, the sea level would rise - up to a tenth of
meter.
The glaciers in the Himalayas are already melting and by
2035 will have reduced their size to 1/5 of their previous surface. This
will have major negative consequences for the world, but mostly for South
East Asia.
First, there will be more water in the rivers, because of
the melting glaciers, which will reach this region, particularly through
major rivers such as the Mekong and Chao Phraya. At first this could cause
major floods, but later there will be too little fresh water, because
melting water from the glaciers will no longer supply the rivers.
By 2050, this scenario being played out in the river
basins in Southeast Asia will have a negative impact on more than one
billion people. Many people in the so-called LECZ (low elevation coastal
zones) will have to change their place of residence, as massive floods will
threaten their homes.
Several
studies, for example made by the Potsdam Institute for Climate consequences,
come to the result that more than 200 million people live in areas that will
be flooded in the coming years. 30 of the 50 largest cities in the world are
situated on a sea coast. Large cities such as Bangkok and Tokyo, which will
suffer for years under the rising water table, must then have solutions at
hand, which will allow them, despite the rising water table, which is
actually linked to the rising sea level, to continue to lead a normal life.
Additionally the salinization of groundwater will play a major role.
The risk of flooding on parts of the country - including
the capital Bangkok - is certainly the biggest challenge for Thai climate
change policy. A study shows that about 200 kmฒ of Thailand’s 2600 km long
sea coast has already been lost. Particularly affected by coastal erosion
are Bangkok and four other provinces that border the northern part of the
Gulf of Thailand. In recent years, each year the sea penetrates around 5-10
cm deeper into the interior. Bangkok is an average of half a meter above sea
level. This would mean that in fact of a sea level rise, a part of Bangkok
will have big problems and could even be flooded.
Various simulation models from various universities show
that 55 percent of land in Bangkok could be permanently flooded when the
water level rises by 50 cm. A rise of 100 cm will mean 72 percent of the
city will be under water.
Those who want to know more about this topic: Dr.
Nitichan Pleumarom at the Department of Urban and Regional Planning of the
Faculty of Architecture in Bangkok has written a scientific article,
entitled “Climate Change in Bangkok”.
