Climate and environment updates: UN issues vital warning on avoiding climate disaster

The number of billion-dollar weather and climate disasters in the United States keeps growing. The National Oceanic and Atmospheric Administration (NOAA) has added Hurricanes Debby, Helene and Milton to their official 2024 Billion-Dollar Weather and Climate Disaster list. The agency also added a tornado outbreak.

This brings the year-to-date total for billion-dollar disasters to 24 unique events. That's the second-highest total for the same period, only eclipsed by 2023, when there were 27 billion-dollar disasters in the same time frame.

The final damage costs for Hurricane Helene and Milton are still being determined, but NOAA says they will both surpass the billion-dollar threshold..

According to NOAA, tropical cyclones (or hurricanes) cause more damage than any other kind of weather disaster, with over $1.3 trillion in damages since 1980.

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

The United Nations is calling out the world's largest polluting nations for failing to take decisive action in their efforts to reduce greenhouse gas (GHG) emissions significantly. And they're warning that it will require nothing short of "a quantum leap in ambition" if we are to avoid the worst-case global warming scenarios.

According to the United Nations Environment Programme's Emissions Gap Report 2024, aptly titled, "No more hot air … please!" the world has made little progress in reversing the use of fossil fuels and faces twice as much warming as agreed to during the Paris Climate Agreement. The report finds that unless we significantly reduce our global emissions and do so quickly, the planet is headed toward a 3.1° C (5.6° F) increase in warming above pre-industrial levels by 2100.

The annual report looks at countries' emission reduction promises and where we are in meeting those goals. The report said that despite the urgent need to reduce GHG emissions, global emissions actually set a new record in 2023, increasing by 1.3%.

However, the report made a point to emphasize that the majority of global emissions are coming from G20 countries, specifically China, the United States and India. Only the U.S. showed a slight reduction in emissions in 2023, down 1.4%. China and India saw an increase of 5.2% and 6.1% respectively. Both countries produce many of the products purchased and used by American consumers, and some experts say their emissions are our emissions.

In 2015, during a summit in Paris, the majority of the world's governments agreed to work toward limiting global warming to 1.5° C (2.7° F). This new report said it would require a 42% cut in yearly GHG emissions by 2030 if we want to try to avoid surpassing that milestone.

World leaders will meet in Azerbaijan next month for the UN climate summit COP29 to work on meeting the goals first agreed to in Paris.

-ABC News Climate Unit's Matthew Glasser

The Northeast and Mid-Atlantic regions are experiencing an unprecedented dry spell, raising concerns of fire danger.

Central Park in New York City is also facing an unusually dry October. The world-renowned landmark has seen zero rainfall this month. Since record-keeping began in 1869, there has never been a month in Central Park that didn't have some rainfall. With no rain in the forecast through the end of the month, this could be a first.

Similarly, Philadelphia is on the brink of shattering its record for the longest period without rain, reaching 25 days as of Oct. 24. If the city doesn't receive any precipitation by the end of Monday, Oct. 28, it will surpass an historic 29-day dry streak, the current record. Records go back to 1871.

As a result of these near-record dry conditions, fire danger levels have surged. Elevated warnings stretch from Massachusetts to Virginia, with humidity levels plummeting to around 30% and gusty winds of nearly 30 mph. New Jersey is particularly vulnerable, with most of the state under a Red Flag Warning, indicating a high threat of wildfires. The combination of low moisture and wind creates an environment ripe for the spread of any fire, making it crucial for residents to remain vigilant.

-ABC News meteorologists Max Golembo and Kenton Gewecke and ABC News Climate Unit's Matthew Glasser

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