A new analysis of ocean health indicators suggests that marine ecosystems globally are facing a more dire situation than previously understood, with several regions already past critical thresholds.

The study, published in Global Change Biology, reveals that ocean acidification, driven by the absorption of excess atmospheric carbon dioxide, surpassed a crucial “planetary boundary” five years ago.

“A lot of people think itS not so bad,” said Nina Bednaršek, a senior researcher at Oregon State University and one of the study’s authors. “But what we’re showing is that all of the changes that were projected, and even more so, are already happening-in all corners of the world, from the most pristine to the little corner you care about. We have not changed just one bay, we have changed the whole ocean on a global level.”

The research, which included contributions from scientists at the UK’s Plymouth Marine Laboratory and the National Oceanic and Atmospheric Administration (NOAA), indicates that by 2020, the world’s oceans were nearing a dangerous level of acidity, with some areas already exceeding it.

Scientists have established that ocean acidification reaches a critical point when the availability of calcium carbonate-essential for the growth of marine organisms’ shells-falls below 20 percent of pre-industrial levels. The latest findings indicate this figure is now around 17 percent.

“ocean acidification isn’t just an environmental crisis, it’s a ticking time bomb for marine ecosystems and coastal economies,” said Steve Widdicombe, director of science at the Plymouth lab, in a press release. “as our seas increase in acidity, we’re witnessing the loss of critical habitats that countless marine species depend on and this, in turn, has major societal and economic implications.”

Experts have identified nine planetary boundaries, the transgression of which could jeopardize human well-being. Climate change, fueled by greenhouse gas emissions, has already exceeded its safe operating limit.Ocean acidification, another consequence of fossil fuel combustion, is now following a similar trajectory.

Impact on Marine Life and Economies

The increasing acidity of the ocean poses a significant threat to marine life,particularly shellfish and coral reefs. As the ocean absorbs more carbon dioxide, it becomes more corrosive to the calcium carbonate shells and skeletons of these organisms, hindering their growth and survival.

“Ocean acidification isn’t just an environmental crisis, it’s a ticking time bomb for marine ecosystems and coastal economies.”

This decline in marine life can have cascading effects throughout the food web, impacting fish populations and the livelihoods of communities that depend on them. Coastal economies that rely on fishing, tourism, and aquaculture are particularly vulnerable to the effects of ocean acidification.

What is Ocean Acidification?

Ocean acidification is the ongoing decrease in the pH of the Earth’s oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. The ocean absorbs about 30% of the CO2 released into the atmosphere by human activities, such as burning fossil fuels, deforestation, and industrial processes (NOAA).When CO2 dissolves in seawater, it forms carbonic acid, which lowers the ocean’s pH, making it more acidic (EPA).