Oceans Are Becoming Humanity’s Sewer, Leonardo Boff Warns at UFSC

Theologian and philosopher Leonardo Boff told an audience at the Federal University of Santa Catarina (UFSC) that the oceans are turning into a “human sewer,” urging coordinated global action to curb pollution and climate risks.

Boff spoke after a lecture at the Planeta DOC event, which hosted discussions and documentary screenings focused on environmental issues.

Boff said the scale of marine waste is unacceptable, citing vast accumulations of floating debris.

He argued for a worldwide campaign to restore ocean health, noting that marine ecosystems contribute significantly to oxygen production and climate regulation.

Without rapid changes in behavior and policy, he warned, communities and coastal cities could face escalating harm.

Pointing to scientific projections, Boff referenced scenarios in which sea levels rise by about one to one-and-a-half meters as global temperatures increase and polar ice melts.

Oceans Are Becoming Humanity’s Sewer, Leonardo Boff Warns at UFSC

He highlighted the exposure of low-lying urban areas, using Rio de Janeiro’s flat coastal plain as an example of potential inundation if rising seas advance inland.

Boff called for tackling root causes, including high waste generation and pollution, which he linked to broader drivers of climate change.

He argued that public debate often focuses on symptoms rather than the underlying systems that enable environmental degradation.

Paulo Horta, a tenured professor at UFSC and a PodDoc in marine ecology, supported the call for short-term action.

He stated that the next 15 years will be crucial to limit global warming and avoid severe ecological disruptions, a negative tipping point for coral reefs, accelerating the sixth mass extinction.

Horta emphasized that mitigation depends on decisions by governments and companies, as well as individual choices.

Horta also warned of more frequent and intense coastal flooding and erosion if greenhouse gas emissions remain high.

Noting past periods in which sea levels rose by more than 10 meters in 350 years, he cautioned that accelerating ice loss at the poles could herald faster increases.

Both speakers urged policies that reduce pollution, strengthen coastal resilience, and prioritize long-term ocean stewardship.