Climate and environment updates: October was 2nd warmest month on record, NOAA says

A global coral bleaching event that began in Feb. 2023 is now the largest bleaching event on record, according to the National Oceanic and Atmospheric Administration (NOAA). The agency says nearly 77% of the world's coral reef areas have experienced bleaching-level heat stress.

NOAA says the previous record, which occurred between 2014 and 2017, impacted 65.7% of the world's reef area.

"We've eclipsed the previous record by 11.3% and did so in about half the amount of time," said NOAA in a statement to ABC News. "This percentage is still increasing in size."

The world's oceans experienced record-breaking temperatures in 2024, and when the water is too warm, coral can expel the algae inside it, causing it to turn completely white. While bleaching doesn't necessarily kill the coral, it can increase the likelihood of permanent damage or death.

This latest mass bleaching event marks the 4th global bleaching event since 1998 and the second since 2010. NOAA says each event has been more extensive than the last, with the current one setting a global record.

Since Feb. 2023, 74 countries and territories have been impacted by the mass coral bleaching event, affecting the Atlantic, Pacific, and Indian Oceans, according to NOAA.

Coral reefs are among the planet's most diverse and valuable ecosystems. While they only cover 1% of our oceans, they provide a home to at least 25% of our marine life and significantly impact the global economy. Reefs attract millions of tourists and visitors, supporting local businesses and jobs.

-ABC News Climate Unit's Matthew Glasser and Dan Manzo

In 2022, world leaders agreed to a landmark deal to protect the planet's biodiversity at the UN Conference of Parties convention (COP15) in Montreal. Dubbed "30 by 30," the historic agreement called for protecting 30% of the globe's land and waters by 2030. As a result, many of the participating nations strengthened and expanded protected areas for plants and animals.

But, according to new research conducted by the National History Museum in London, biodiversity in these protected areas is declining faster than in non-protected areas. Using their own "Biodiversity Intactness Index," which estimates how much of an area's biological diversity is left in an area in response to human interventions, the Museum found that life in protected areas declined by around 2% compared to 1.8% globally.

The difference was even more significant in areas with the most critical ecosystems. Protected areas saw a loss of 2.12% compared to 1.91% overall.

The study's authors don't know for sure why there is this discrepancy but say it could be because many protected areas only focus on protecting a specific species. They also say many of the protected areas were already in trouble, and that's why they were protected.

The team says we need to not only protect individual species but the land and ecosystem where they live. They are also calling for better monitoring of these critical areas.

The study comes while world leaders meet in Columbia for the UN's COP16 Biodiversity Conference—a global effort to protect the planet's biological diversity.

-ABC News Climate Unit's Matthew Glasser