Ocean

Rising sea levels around the world is one of the most visible consequences of human-caused climate change. As global temperatures rise, oceans absorb more heat and expand, while melting glaciers and ice sheets add even more water to the seas.

Rising seas are threatening coastal towns and cities all over the world. According to an analysis by researchers at Tulane University, Yale, and other institutions, coastal Louisiana faces sea level rise of 10 to 23 feet as this century moves forward. It is one of the lowest lying regions in the world, and New Orleans is particularly exposed. It sits in a bowl-shaped basin, mostly below sea level, in the middle of a rapidly shrinking delta.

Climate change is raising sea levels. Sea level rise has been tracked for quite a while and its risks to people who live in coastal areas have been the focus of a great deal of attention. But sea level rise is not a simple matter in that defining the baseline sea level is difficult to do.

Projections are that a strong El Niño is on the way. An El Niño is a natural release valve for ocean heat. It starts with shifts of swirling ocean currents and winds over the Pacific. The result is that huge stores of tropical ocean heat surges from the Western Pacific in the area between Australia and Indonesia northward to Japan. The ocean heat then spills into the atmosphere in pulses that change weather patterns, reroute high-elevation winds, raise global temperatures, bleach coral reefs, and disrupt fisheries and ocean ecosystems.

The Best of Our Knowledge explores topics on learning, education, and research.On this episode, we’ll learn how an unusual fossil offered scientists a new glimpse into the evolutionary history of some of Earth’s earliest animals.And we’ll learn how pirate gold helped dispel a centuries-old rumor among seafaring European traders.

The Best of Our Knowledge explores topics on learning, education, and research.On this episode, we’ll learn how an unusual fossil offered scientists a new glimpse into the evolutionary history of some of Earth’s earliest animals.And we’ll learn how pirate gold helped dispel a centuries-old rumor among seafaring European traders.

The oceans are home to a quarter million species that have been catalogued and undoubtedly a far greater number undocumented, hosting over 80% of global biodiversity. Oceans are the planet’s primary life-support system, producing at least half of its oxygen.

Toxic algal blooms have been a growing problem in recent years associated with warming waters and nutrient-rich agricultural runoff in lakes, rivers, and oceans. These outbreaks can damage ecosystems, degrade water quality, and release toxins that threaten both wildlife and people. But a recent discovery suggests that nature may have found a way to fight back.

Significant blooms of the brown seaweed Sargassum in the tropical Atlantic have been taking place since 2011, impacting tourism in the Caribbean. A more general observation is that between 2003 and 2022, macroalgal mats and microalgal scum have expanded around the globe. A recent study looked at the rise of macroalgae blooms across the globe over the past two decades.

The world’s oceans just keep getting hotter. International analysis published in the journal Advances in Atmospheric Sciences finds that the oceans stored more heat in 2025 than in any year since modern measurements began.