OUR world is urbanising fast. Fifty-four per cent of the global population is currently living in cities. By 2050, almost 70pc or close to seven billion people will be living in an urban environment: either in new towns or in the sprawl of existing cities.

Urban growth puts pressure on the land, on natural resources, and on human infrastructure, a situation likely to worsen if not planned for. Already more than 70pc of global CO2 emissions come from cities.

In the Global South, a combination of demographic compulsions and rural-to-urban migration triggered by economic hope, climate despair and extreme weather events is contributing to urban sprawl. By the end of this decade, there may be as many as 44 megacities, with 10m inhabitants or more, most of them in developing countries. Such a rapid swell by mid-century will have a significant environmental footprint.

Unlike the Global North, where urbanisation takes place in a systematic manner that generally respects environmental considerations, in developing countries irregular urban sprawl is creeping into agricultural lands, forests and wetlands. This is a recipe for catastrophe. When unfettered urban development spills over into the very ecosystems that sustain life, it leaves cities, particularly their most vulnerable residents, susceptible to large-scale clima­­te disasters like floods, mudslides, avalan­ches, and dangerously high temperatures.

Pakistan has the highest urbanisation rate in South Asia.

Conversion of fertile lands around cities and in the mofussil into housing estates is another dimension of unplanned urbanisation and improper land-use management. It also puts food security at risk. Illegal construction along riverbanks and seasonal streams that obstructs or diverts the water flow from its natural course has led to flash flooding.

South Asia — home to more than a quarter of the global population — is faced with alarming urban challenges. Rising temperatures, which also put city dwellers at greater risk, are partly attributable to receding green cover, which provides shade and lower ambient temperatures, and to excessive concretisation around cities, which contributes to intense heating known as the ‘urban heat island’ effect. The World Meteorological Organisation reported in June that Asia is warming twice as fast as the rest of the world.

The long-term impact of climate change on water and agriculture productivity is pushing rural populations to shift to cities. When displaced by disasters, rural communities quickly relocate to nearby cities where they are forced to reside in shanty conditions. Such urban spread harms the environment and threatens public health through untreated municipal and industrial waste, and water and air pollution.

Pakistan has the highest rate of urbanisation in South Asia. Inadequate civic support and lack of industrial infrastructure diminish economic opportunities in rural areas, thus becoming a major driver of the rural-to-urban shift. Currently about 50pc of the population in Pakistan’s major cities is reported to live in slums and squatter settlements. Investing in rural development can prevent villages from becoming disorderly pockets of pollution, waste and destitution, often devoid of basic facilities.

With an increase in population from 150m in 2000 to 250m plus today, Pakistan faces a huge housing deficit. Securing a safe, healthy environment and investing in affordable, climate-resilient urbanisation will not be easy in financially challenging times. But neglecting these issues will have even graver consequences. Any delay in prioritising climate-resilient housing solutions will impair the productive capacity of Pakistani cities. The 2025 Climate Risk Index report by Germanwatch has placed Pakis­tan first on the Climate Risk Index as the country’s economy suffered a GDP loss of 4pc between 1993 and 2022.

The sheer scale of forthcoming urbanisation in Pakistan demands a holistic approach, which takes all factors — land-use management, nature loss, climate risks, healthcare, human rights etc — into account. Such an approach will help make capital, climate financing and capacity-building more meaningful.

The Living Indus initiative, a flagship project of the UN Decade on Ecosystem Restoration, aims to restore 25m hectares of degraded land through nature-based solutions for protecting ecosystems from the impact of climate change and urbanisation. It can make a real difference, if completed in time and implemented effectively in coordination with local bodies.

By equipping urban councils and local authorities with the right tools, we can build cities that not only increase the standard of living for those who call them home, but decrease the risk of widespread biodiversity loss, help adaptation to climate change and stem the flow of pollution.

The writer is director of intergovernmental affairs, United Nations Environment Programme.

Published in Dawn, July 15th, 2025