(First of two parts)

No matter one’s age, disposition, wealth, or upbringing, no phenomena brings us, Filipinos, together than the assault of record-high temperatures like the one we’ve been experiencing in the past weeks.

If only you had a peso for every time you heard, “It's so unbearably hot!” in various affectations, right? And who would have thought we would reach a point when schools have to suspend classes not because of heavy flooding or typhoons, but as a preventive measure against heat exhaustion?

Denis Villeneuve’s blockbuster film Dune doesn’t feel so alien when you can feel the desert heat here, in real life. These remind us of how the effects of climate change can disrupt daily life and the functioning of society.

But did you know climate is just one of nine indicators of the Earth’s health?

These indicators are called planetary boundaries and, scientifically speaking, these represent the limits of conditions on Earth that are necessary for human life to thrive for generations to come.

Going over these boundaries can mean irreversible environmental changes with serious consequences for humankind. A quick look at the latest model highlights that we may have already crossed six of the nine boundaries.

Earth’s nine planetary boundaries

The planetary boundaries framework was first conceived by international researchers led by Johan Rockström of the Stockholm Resilience Centre in 2009, and later updated in 2023. These boundaries are environmental systems being impacted by human activity, with baseline values representing the “safe operating space” for humans as we know it.

The underlying idea of the model is derived from how the Earth is becoming increasingly removed from the conditions of the current geologic epoch because of human activity. This “human effect” is what the planetary boundaries framework hopes to measure, and with these discernable indicators, we can move forward with meaningful individual and collective action to reverse or mitigate the consequences.

It is worth talking about each of the boundaries, and while each deserves a separate discussion of their own, a quick primer will help provide us a holistic view of the model.

The boundaries have no particular order, but each —like human life itself — is interconnected with the others. Crossing one threshold is like a stack of dominoes that invariably affects the rest of the boundaries.

The first and arguably most well-known boundary is climate change, which is measured by the amount of CO2 in the atmosphere that causes global warming.

Another boundary is novel entities or the unnatural pollutants introduced into the environment, such as microplastics.

These two alone greatly impact the next boundary, biosphere integrity, which is best seen in the increasing number of plant and animal species becoming endangered or lost on a constant basis. This boundary is an easy example of the domino effect I cited in the previous paragraph — a breach in others cascades to and impacts the rest.

Next is land system change, which takes into account the loss of forest cover around the world. Recent studies suggest that only 60 percent of global forest cover remains and is continuously decreasing. This relates to biogeochemical flows, which primarily measures the global flow of gasses produced by human actions such as in agriculture. As building blocks of life, changes to nutrient flows from land to water sources can change and disrupt ecosystems.

Freshwater change, meanwhile, is a boundary that deals with the availability of freshwater, and the increased human consumption of freshwater since the industrial revolution has impacted this metric greatly.

A 2023 study concluded that the above six boundaries have already been breached while the following three remain in the safe zone: atmospheric aerosol loading, which measures the effects of particulate pollution in the atmosphere and how they affect global weather systems; ocean acidification, which looks at the amount of carbon absorbed by the Earth’s oceans; and stratospheric ozone depletion, which serves as our guidepost for successfully reversing the negative impact of human action on the environment.

A little throwback for you: remember the massive hole in the ozone layer that set off alarm bells worldwide back in the 80s? This gave birth to the 1987 Montreal Protocol that banned ozone depleting substances, particularly, chlorofluorocarbons that have been largely blamed for the hole. Continued awareness and global action have helped to shrink the hole and promote the ozone’s continued recovery. This is, by far, one of the most inspiring examples of how cooperation can achieve the seemingly impossible, which explains how atmospheric aerosol loading is in the safe zone.

(Continued next Monday, 6 May 2024)

Ginggay Hontiveros-Malvar is the Chief Reputation and Sustainability Officer of the Aboitiz Group and president of Aboitiz Foundation. With over three decades of senior management experience, she has led projects focusing on stakeholder engagement and sustainability, reshaping the Group's agenda. A passionate artist and avid traveler, Ginggay finds inspiration in drawing, painting and exploring diverse cultures, and balances her dynamic career with personal joy and companionship. For any feedback and recommendations, please reach out directly to Ginggay at ana.margarita.hontiveros@aboitiz.com.