Are you uncomfortably warm this summer? The lack of green spaces in Manila has a lot to do with it

City-dwellers know too well how uncomfortably hot summer can be — and has become.

It is easy to point to global warming as the reason for the rise in temperature, and it is correct, but a recent I-Witness documentary tells us the extreme heat is a result of something more specific. 

"Urban Island Heat Effect" is the elevated temperature that most urban areas experience.

Heat is able to escape from land — from soil — but in cities, where there is more cement, asphalt, and concrete than soil, heat is absorbed and trapped in the surface.

According to World Atlas, “these materials have different surface radiative properties, which means they emit energy as thermal radiation or heat.”

This makes cities a lot warmer than rural areas, and in Manila, which has less than five percent of green space, the Urban Island Heat Effect is only too real.

Green parks and forests are considered the ‘lungs of the city.’ They help fight pollution, and thanks to its natural shade and a process called evaporative cooling, they help lessen the heat. They also absorb rain water.

In Metro Manila, we have the Arroceros Forest Park, considered the last lung of the city. It is the only forest park in Manila. It has 1,567 trees, according to the Manila Doctors and University of the Philippines Los Banos College of Forestry and Natural Resources.

Arroceros’ importance becomes even more pronounced in during summer, when the Urban Island Heat Effect” is in full throttle, and during rainy season, when flooding becomes rampant.

"'Yong halaman, hindi lang nagsisilbing lilim kung hindi sa pamamagitan ng kanyang  natural na proseso naa-absorb din niya 'yong sobra-sobrang init sa paligid," said Jeffrey Mancera, a botanist and associate professor and University of the Philippines Manila.

He said plant leaves have holes, called stomata, that absorb water. Plants use them for growth, and through them, plants are able to release some of its water molecules to the atmosphere, making its surroundings a whole lot cooler. That's the process called evaporative cooling.

I-Witness tried putting thermometer inside Arroceros and another just outside Arroceros where buildings abound, and it proved that trees indeed help reduce heat.

The temperature within the Arroceros premises clocked in at 34.5 degrees Celsius, while the temperature outside is 36.6 degrees Celsius.

Given the dangerous levels of heat this summer has brought, perhaps it’s time to rethink having more tress — more parks and more green spaces — in the city. — LA, GMA News