‘BSG for SDG’ Sustainable Newsletter | Issue 18 | July 2024

The fathomless depths of the oceans are home to great wonders. From entire mountain ranges to deep canyons, the oceans keep much buried at their core. A fun fact: The world’s most active volcanoes are underwater and are all located in an area in the Pacific Ocean, called the “Ring of Fire” (UNESCO,2022). Another fun fact: Mount Everest would fit in the Pacific Ocean’s Mariana Trench with over a mile to spare (UNESCO, 2022)! But here’s the catch: though the oceans seem vast, they’re certainly not limitless.

While we admire the magnificence of the world beneath the waves, we are also confronted with a harsh reality. Amidst these majestic underwater landscapes lies a deep malady — patches of plastic and trash — reminders of humanity’s impact on even the most remote corners of our planet. Research says that by 2050, there will be more plastic than fish in the sea. But this is not the only threat to the health of our oceans.

The oceans’ vastness flows far beyond their physical boundaries. For a considerable period, they have been acting as a heat sink, absorbing more than 90% of the excess warmth generated by greenhouse gas emissions. Consequently, the ocean waters have been steadily increasing in temperature and undergoing thermal expansion. However, this phenomenon only accounts for a portion of the tale behind rising sea levels. The complementary factor paints a picture of glacial ice melting, contributing further to the rise in sea levels. It has been reported that Antarctica is losing about 150 billion tons of ice a year, while Greenland is losing about 280 billion tons a year (World Economic Forum, 2022). Over 410 million people are predicted to be at risk from rising sea levels by 2100 (World Economic Forum, 2022).

The blatant neglect towards oceans alters our world in ways more than one. Ocean warming is one of the most lethal weapons for damaging coral reefs. An excessive rise in water temperature bleaches and dries out the coral reefs. This implies that what is home to more than 7000 species of fishes, invertebrates, plants, sea turtles, birds and marine mammals, could be gone forever, along with all its inhabitants. National Oceanic and Atmospheric Administration scientists have now discovered that coral reefs possess the potential to help create medicines that can combat drug-resistant bacteria effectively. Moreover, coral reefs reduce the strength of the waves hitting the coast and are an important source of income for millions of people.

When animals eat pieces of plastic, they reduce the intake of nutrients from real food. This can affect small plankton all the way up to big fish and shellfish. Small plastic bits also soak up harmful chemicals, which build up in the animals that eat them. This buildup of plastic and toxins in the food chain can also put human health at risk. Studies have revealed that microplastics can inflict harm on human cells, impair reproductive functions, and interfere with the endocrine system.

Thermal expansion of ocean waters, caused by rising temperatures, accounts for roughly 50% of the increase in global sea levels observed during the last 25 years. Normally, glacier melting in summer is offset by snowfall in winter. However, higher temperatures from global warming now cause excessive glacier melt and reduced snowfall. The world, when left undisturbed, could harmonise meltwater runoff with evaporation. Accelerated global warming has disrupted this balance, signalling the urgent need for climate action.

Reversing climate change may seem like a daunting and impossible task. However, much is still under our control. Being conscious about what we take from the world and give back to it becomes a good starting point. Personal action, or ‘sustainable human behaviour’, therefore, is of paramount importance.

Shifting Landscapes: The Columbia Glacier, Alaska, USA, between 2009 and 2015. Credit: James Balog and the Extreme Ice Survey.