Covering the entire land by cemented concrete, asphalt, solid tiles or any impermeable material is called ‘concretization’. Pakistan is increasingly concretized, and this does not bode well for our wellbeing, nor and by extension, our natural environment.
While it is necessary to construct roads, pavements and buildings, we must also allocate reasonable space for greenery which is a key component of sustainable development. Excessive concretization has become a major environmental concern particularly in urban metropolises of poor and developing countries including Pakistan.
Subh-e-Nau: an Environment and Public Health Concern has been working for noble causes for decades. In 2018, we identified a patch of land in KMC Sports Complex Karachi and decided to ‘de-concertize’ it. We planted dozens of indigenous tree saplings after removing unnecessary concrete floors over the large area. The project was completed in collaboration with KMC administration. Although it proved to be successful with a reasonable tree survival ratio, the authorities did not show interest in expanding it to a large-scale level. Unfortunately, environmental issues still remain neglected in Pakistan and excessive concretization is one of the very important issues.
A very adverse effect of urban concretization is water shortage. Falling water table is not only causing water scarcity but it also is putting our cities at risk of ‘subsidence’; a phenomenon when the buildings begin to sink into the ground due to extreme drop in ground-water table. How does this happen? Because we are pumping groundwater for domestic and commercial use while excessive concretizing is preventing the aquifers from getting recharged and hence disturbing the water cycle. This not only results in water shortage during dry summer months but may also cause subsidence as shrinking water levels weaken the ground hydraulic barrier.
In addition, more water is run off than infiltrated into the ground when it rains in overly concretized cities. This intensifies urban flooding impacts and also hampers groundwater recharge as well.
‘Urban Heat Island’ effect is another serious environmental issue caused by concretization. The problem is that concrete absorbs and retains more heat and hence causes our cities to heat up when the temperature rises in summer. This becomes even more serious as Global Climate Change is causing more frequent and intense heat waves which become intolerable in cities because we have turned them into ‘concrete jungle’. Conversely, the areas with more trees and greenbelts remain cooler during intense heat waves. Areas with poor vegetation cover and more concrete become so intolerably hot forcing people to use more air-conditioning which increases greenhouse emissions and causes more pollution.
Therefore, we must now rethink our development approach; consider trees as an important part of our life, leave ample space for greenery and install rainwater harvesting and groundwater recharge systems for sustainability. The government must also enact and enforce necessary laws to mitigate these issues and make Pakistan green again!