What we are ignoring about our urban heat footprint - I

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Rapid urban expansion has buried healthy soil under thick concrete beds. This could have dire consequences for public health, writes Azal Zahir

2018-07-13T11:05:33+05:00 Azal Zahir
More than half of the global population resides in cities. It is estimated that by 2050, 66 percent of the global population (which is projected to reach 9 billion) will move into cities, as projected by United Nations statistics. As of today, cities contribute to 70 percent of Greenhouse Gas Emissions (GHGs) when they only cover four percent of the planet’s land mass. These emissions are in the form of greater energy demands, “waste heat” (the heat given off by cars, factories, even a single human jogging) and deforestation. Not only is this putting a strain on cities themselves, but it is making those within it all the more vulnerable.

Though Pakistan attributes to less than one percent of GHG emissions as compared to the rest of the world, there are alarming warning signs of its effects. A record breaking temperature worldwide in April this year was found in none other than our own country- at 50 degrees Celsius in Nawabshah. With death rates increasing every year due to heat-related stresses, and severe natural disasters such as floods and unpredictable weather patterns associated with climate change, we need to truly start worrying. We do not have the infrastructure, nor the financial means to protect or even rebuild our cities from these disasters. Point in case, Puerto Rico still has not restored its electricity to full capacity after hurricane Maria nearly nine months ago.
Without healthy soil, our land loses its potential to retain water, which vegetation relies on for growth. Without rain water retention, there is nothing replenishing underground aquifers or contributing to underground water bodies

Lahore, Karachi and Islamabad are the only three metropolitan cities in Pakistan that are growing at an average growth rate of over two percent. With this steady growth, urban expansion, whether upwards or outwards, is inexorable. To compensate for rural-urban migration, excessive development schemes have literally buried healthy soil under thick concrete beds. As a result these cities have become Urban Heat Islands (UHI), omitting more heat on a daily basis as temperatures rise from GHG emissions.

Urban heat islands have worse air and water quality compared to their rural neighbours. As more and more toxins pile up, there is less space for them to scatter and they are easily trapped in the insulated heat, thus mulling in city water and air. This breeds illnesses such as cancer, asthma and typhoid. For example, a recent typhoid epidemic in Pakistan caused serious alarm because it marked the first ever drug resistance in typhoid. Not to mention, excessive heat has dire consequences for surrounding ecosystems. Native species are delicately adapted to their environments and drastic changes such as excessive heat can result in mass extinctions.

The most offensive criminal act by cities towards the natural environment is fragmenting it. Removal of natural vegetation in place for more and more concrete has serious impacts on ecology. Water, energy, mineral and community cycles, that are networks within networks, are severely damaged. To explain it plainly, soil is like earth’s skin. As vegetation decreases, there is little interaction between the soil (which sequesters carbon) and bacteria/microbes in roots which make the soil healthy and increases its capacity to absorb carbon from the atmosphere.

Without healthy soil, our land loses its potential to retain water, which vegetation relies on for growth. Without rain water retention, there is nothing replenishing underground aquifers or contributing to underground water bodies via the process of through-flow. This decreases the availability of fresh water all around. When there is less vegetation, rainwater that falls hard seals or ‘caps’ the top layer of soil which prevents water from reaching to the healthier parts. Eventually this leads to the desertification of land. According to Founder of Combating Poverty and Climate Change Foundation (CPCCF) Ahsan Rashid, “As it stands, 75 percent of Pakistani land area is drylands, and it is safe to assume that in 20 years drylands will expand to 95 percent and from here the areas will simply desertify.” A view of the urban map of Pakistan, according to the 2017 census, will depict all major settlements around the Indus and its tributaries. What will happen when these dry up?

The city municipality can be a major player in the city’s health. They are closer to the issues and can act quicker, engage citizens more effectively and ensure strong implementation as opposed to a distant federal government. Pakistani cities have an even greater advantage – they are still developing. This means they have the upper hand to start out by building themselves more resiliently and sustainably. According to the 2017 census on urban centers, Pakistan has three metropolitan corporations (major cities) and 25 municipal corporations (smaller cities). As there are only three major cities in Pakistan, the expense to make them more climate resilient will not be as much as a state in America. However, in order to do this, local government officials need to begin projects and ensure that these projects are resilient enough to undergo changing governments and ultimately climate resilient.

The writer holds a Master’s degree in Environmental Conservation from New York University
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