Water level rises in Calcutta, India

Problems

• Kolkata (Calcutta) is the capital of the Indian state of West Bengal, on the eastern bank of the Hooghly River 80 km west of the border with Bangladesh. 
  
  It is the primary business, commercial, and financial hub of Eastern India and the main port of communication for North-East India. 
  
  Kolkata (also known as Calcutta), built around the Hooghly River, is highly vulnerable to flooding from the monsoon rainfall between June and September.

• Causes of water level rises in Calcutta

  A less prominent yet imminent threat is that of sea level rise. 
  Sea levels may rise by about one meter by 2100 if carbon emissions continue unchecked, according to a recent survey of experts, and the effects on coastal cities could be devastating.
  
  The drainage system in Kolkata one of the oldest in India.The poor economic history of the city has led to poor infrastructure maintenance and city planning, leading to clogged and unsanitary sewage, and sub-optimal canal design. 

• Consequences of rising water levels

  As sea levels continue to rise, a normal flood’s impact will be amplified enough to cause serious real estate and infrastructural damage.
  
  A 1-in-100-year flood (whose intensity has a 1% chance of occurring in any given year), most probably driven by a storm surge, could kill hundreds if not thousands and majorly disrupt economic activity. 
  Earth.Org has modeled what a 1-in-100 year flood would look like by 2100 in the absence of preventive measures. 
  
  In 30 years, Kolkata could be the worst-hit among Indian coastal cities as sea levels rise due to global warming. 
  New research suggests that by 2050, all of the city and its suburbs will be at risk of annual flooding, affecting many more million people than previously believed. Unless, as the study points out, carbon emissions are slashed, global warming slows, and preventative measures such as coastal buffers are taken to reduce vulnerability. 
  
  Urbanization contribute to a rise in the city’s temperature, with more than 80 percent warming being generated within the city itself. 
  
  Urban centres and cities warmer than the surrounding rural areas due to the urban heat island effect.
  Urban heat island effect arises from several factors, including reduced ventilation and heat being trapped as tall buildings are closely packed in a small area; heat generated from human activities; heat-absorbing properties of concrete and other urban building materials; and limited amount of vegetation.
  Kolkata’s greenery quotient is one of the lowest in the country.