Mumbai: Changing the temperature

Cities are important in climate change governance as they are concentrated sites of land use change and human activity and consequently are associated (both directly and indirectly) with 75-90% of all greenhouse gas emissions (Rice 2014). Most studies of climate change focus on mitigation, however, it has come to a global consensus that climate change is inevitable, therefore, the focus should turn towards adaptation (Betsille & Bulkey 2007).

One of the effects of urbanisation in a city is the urban heat island (UHI) effect. Human activities in cities and towns cause the climate in that area to rise, which in turn increases use of air conditioning and therefore fossil fuel consumption whilst providing that energy. UHI is especially important in India, where a summer heatwave resulted in 2330 deaths in 2015 (Imam & Banerjee 2016).

An adaptation to UHI is green roofing, which can be seen in Mumbai. Green roofing is when the roof of a building (and sometimes its walls) is covered with vegetation planted over a waterproof membrane. Benefits of green roofs include minimising stormwater management costs, filtering airborne pollutants and the aesthetic pleasure of vegetation. Green roofs reduce temperatures in two ways. Firstly, by cooling the air through the process of evapotranspiration. Secondly, green surfaces absorb less heat due to a lower albedo and cooler surfaces mean the surrounding air is also cooler. Green roofs also have the potential to act as a carbon sink, although studies do show that there is greater benefit in ground level green landscapes.

Example of Green Roof Technology

In Mumbai, green roofs will be particularly beneficial for many reasons. To begin with, the risk of flooding from monsoon season will be significantly lower. With Mumbai’s growing population, its energy demand increases also, therefore implementing green roofs on buildings means that fossil fuel consumption will be reduced. Cooling via green roofs is more significant in hotter areas – consequently, green roofs could reduce the temperature in Mumbai by up to 3 degrees Celcius. However, as discussed in last week’s post, Mumbai’s sustainable development plan is highly flawed and as it is not yet available to the public, it is hard to see if green roofing has made it onto the agenda.

The effectiveness of green roofs to counteract climate change on a large scale has yet to be investigated. As it has been shown, it is more effective to have green spaces at ground level, which is perhaps what Mumbai should be focusing on, as it currently falls way below the UN recommended green space per person. The question of the effectiveness of local governance on climate change also arises, as certain matters (such as national regulations) are out of their control (Rice 2014). But all hope is not lost, as India made ambitious pledges during COP23 in Bonn 2017, which should mean that its constituencies will follow suit.

3 Billion Plastic Bags

That’s the number of plastic bags 5.5 million Singaporeans use a year, and it averages to about 545 plastic bags used per person every year. This insanely high amount of plastics consumed has led to the leading supermarkets in Singapore coming together to discuss the possibility of charging shoppers for each plastic bag.

Looking at the success that the UK, Hong Kong and other countries/cities has experienced with the plastic bag charges, many proponents in Singapore are looking forward to this change, exclaiming that it is “about time” for such taxes to be introduced. Yet, debate has ensued in whether it wise to mindlessly import successful strategies from abroad into Singapore without considering the numerous contextual differences:

The climate in Singapore is a big factor. The hot and humid weather in Singapore means that hygiene standards have to be held higher, as diseases grow and spread much faster. The use of plastic bags in supermarkets serve to ensure that the food products people buy are not easily contaminated. The disposability of these plastic bags also mean that once the bags are dirtied, it can be quickly gotten rid of.

Further, it is an almost-Singaporean culture to reuse the plastic bags from supermarkets to line bins with, and household trash have to be tied up before disposal for similar sanitary reasons. I’ve noticed in my few months of staying in London that people here purchase special garbage bags to line their bins, suggesting that despite the use of plastic shopping bags have reduced, the total use of plastic bags may not necessarily have decreased. Another consequence of these extra charges is the increase in total expenditure per household (since now even bagging trash would cost money, estimated by an NGO to be SGD37 per year*), which could prove burdensome to the lower-income households.

What seems like a very simple solution to reducing the use of plastic bags actually turns out to be a multi-faceted issue. Perhaps alternative and multi-pronged solutions should be considered, for example:

• classification of products at supermarkets such that most easily contaminated will have to be plastic-bagged
• supermarkets change the plastic bags they give out to bio-degradeable plastics
• encourage recycling more, such that the total amount of trash produced is decreased and therefore, a decrease in demand for plastic bags to bag trash in
• a major supermarket is currently carrying out a rewards system whereby shoppers can collect points for every 1 less plastic bag they use each time they shop. Once enough points are accumulated, they get to enjoy a small discount in their next purchase. (The benefit of this is that Singaporeans LOVE rewards systems.)

* to put this amount into context: SGD37 is approximately GBP20, which might not seem like much. But to a lower-income Singaporean household, it could mean a month’s worth of pocket-money for a primary school student. You could also buy 12 plates of chicken rice (and one plate is a very substantial meal).