Karachi has been in the news recently for the heat waves and the resulting deaths. This isn’t the first time this has happened. For example, in 2015, the heatwaves left over 1200 people dead. It is an annual affair and again, we fail to learn lessons and start with mitigation strategies. We adapt to these situations temporarily, but it is evident from the constant occurrence that drastic mitigation measures also need to be taken into account. Unfortunately, the government is busy further increasing urban areas which would exacerbate the heat waves and increase land surface temperatures. Climate change coupled with our negligence is going to take us down a dark path and as this year, the hottest temperature ever recorded in April on Earth was in Pakistan; this should be a wake-up call for us.
Karachi is a highly urbanized city with an estimated population of 20 million with a 70% increase in the population from 1990 to 2015. It is also one of the most densely populated city and according to Forbes, it is the fastest growing megacities of the world with a 27% increase in the built-up/urban area from 1990 to 2015. There has also been a significant increase in annual maximum temperatures and annual average temperature in Karachi, where average maximum temperature increased by 4.6°C from 1947 to 2005.
The main reason for the heat waves in Karachi can be attributed to the urban heat island phenomenon. Urban heat island effect is caused by reduced green spaces and increased sources of anthropogenic heat sources, for example, the air conditioning systems and industrial heat production. According to research, if the night-time temperature is close to an elevated body temperature of 37°C, it adds to the significant stress on the body, enough to cause death.
You can have two responses to the urban heat island impacts; adaptation and mitigation. Adaptation strategies include; using fans, cooking outsides rather than insides, wearing light clothes and sleeping outside. Another option is air conditioning but it has significant drawbacks. Firstly, it is extremely expensive (to purchase and operate) and the poor cannot get access to such a resource. Second, it is technically going to make the urban heat island impact worse.
There are two major mitigation strategies suggested by Solecki et al. (2005) in their research paper ‘Mitigation of the Heat Island Effect in New Jersey’. Those include increasing vegetation cover and introducing high albedo surfaces. High albedo surface refers to surfaces that reflect more of the incident light. Surfaces that are smoother or lighter in color e.g. houses painted white, reflect off more light thereby reducing the surface temperature of the object. In this article, we will keep our focus on increasing vegetation cover.
There is scientific evidence to support that planting trees and increasing vegetation cover reduces the surface temperatures. There are other benefits of increasing vegetation cover also, like reduced air pollution and associated public health effects. Unfortunately, Pakistan as a whole isn’t doing a lot to increase the forested area cover. Even though the country agreed under the Millennial Development Goals (MDG) in 2005 to increase the forest cover from 4% to 7%, as of 2015 there has barely been a 1% increase.
Satellite images are also being shared on the social media comparing vegetation cover in Karachi to other cities like New York City and Washington DC. I don’t believe it is fair to compare the places mentioned as they have different climate and weather conditions, water supply sources, population, and even literacy rate (which could result in how informed people would be of different issues). However, this doesn’t mean we don’t have the potential to increase vegetation in Karachi. The satellite image is still eye opening to the little green spaces we have in the megacity of Pakistan.
Before considering planting any shrub or tree, it is important to take into consideration a couple of factors. Firstly, the plant should be native to the region; do not introduce non-native species as it has huge repercussions on the ecosystem in the long run. Secondly, the plant should be drought-resistant which means it should be able to tolerate long dry spells so the demand for watering the plants is reduced. Thirdly, it should be fast growing; we don’t have time to plant slow-growing trees and shrubs. Although it doesn’t mean we don’t plant slow-growing trees and shrubs at all; it should be the second option. Plants with long life would be an added bonus. While planting it is also important to keep in mind the appropriate growing and planting seasons, otherwise, your efforts would be futile.
The best place to add vegetation can be your rooftops if one does not have a lawn. Rooftop gardens are gaining popularity; it can be as simple as grabbing a few pots and placing them on the rooftop. A simple search on the internet can give you a lot of ideas and options for creating your own rooftop gardens. These gardens can help in keeping your houses cool, as the soil and the plants have the ability to trap heat and reduce surface temperature. It would also look aesthetically pleasing. Plants indoors can also help as natural air conditioners and air purifiers. It should be made a priority to visit your local nurseries and get information regarding which plants to plant and how to take care of them.
The issue of heat waves is further exacerbated by the increased population and power outages. It also becomes harder to implement adaptive, preventive, and mitigation measures. Increasing population increases the demand for resources such as water and the power outages make it harder to keep the homes and workplaces cool.
So far we have failed to solve both of these issues. The controlling population growth would still take considerably longer time than resolving the power shortage to some extent. Pakistan is reported to have approximately 300 days of sunlight annually (in most cities) with long daylight sunshine hours during summer, that can be used to generate solar power. The government should subsidize the solar panels and encourage the people to use and employ this amazing technology. Non-profit and other organizations need to introduce soft interest-free loans for the people who are underprivileged so they are better able to access this technology.
Government and non-government organizations need to actively play their role, however, in the end, this comes down to the common people at some point. We as Pakistanis need to involve ourselves in the local political scenes and encourage our leaders to take these initiatives. We don’t realize the power we have as a people. We need to raise awareness of the potential that we have and need to utilize it as soon as possible.