Climate and environment updates: 7 key measures of Earth's health in danger, report warns

Although floods and hurricanes often dominate headlines, extreme heat is the deadliest weather-related hazard in the United States, according to the National Weather Service. And among all the extreme weather events, the science linking climate change to extreme heat is among the strongest and supported by the highest level of confidence.

Now, a new report by Climate Central, Red Cross Red Crescent Climate Centre and World Weather Attribution found that human-amplified climate change is responsible for exposing half the world's population to an additional month of extreme heat.

Researchers examined the role of climate change in extreme heat events over a 12-month period, from May 1, 2024, to May 1, 2025. During that time, 4 billion people experienced at least 30 additional days of extreme heat due to climate change, according to the report, which has not been peer-reviewed. The study defined extreme heat as temperatures warmer than 90% of historical observations at a given location, compared to the average climate between 1991 and 2020.

The analysis also found that climate change at least doubled the number of extreme heat days in 195 countries and territories worldwide compared to a planet without global warming.

Last year was the planet's warmest year on record and the first calendar year in which Earth's global average surface temperature measured 1.5 degrees Celsius (2.7 degrees Fahrenheit) above the 1850-1900 pre-industrial average, a key warming threshold established in the 2015 Paris Climate Agreement.

Released in advance of Heat Action Day, a global day of awareness and action on extreme heat, the authors of the report say their findings should serve as a warning about the dangers of extreme heat.

"These frequent, intense spells of hot temperatures are associated with a huge range of impacts, including heat illness, deaths, pressure on health systems, crop losses, lowered productivity, and transport disruptions," World Weather Attribution researcher Mariam Zachariah wrote in a statement.

While early June does not mark peak heat in all regions, the organization emphasizes that designating a single, coordinated day delivers a strong global message. It aims to help individuals and communities everywhere prepare for the growing risks posed by extreme heat.

-ABC News meteorologist Dan Peck

Tropical forests, such as the Amazon rainforest, are often referred to as the "lungs of the Earth" because they absorb carbon dioxide and influence rainfall patterns, making them crucial for our survival and efforts to combat the climate crisis. However, a staggering number of acres were lost in 2024, with much of the loss attributed to wildfires.

Nearly 17 million acres of tropical forest were destroyed last year, according to the University of Maryland's 2024 tree cover loss data displayed by the World Resources Institute's Global Forest Watch. That's equivalent to 18 soccer fields every minute and nearly twice as much as was lost in 2023.

The new data found that fires accounted for about half that loss, marking the first time on record fires were the dominant driver of tropical forest destruction. That's a significant change over previous years when fires were responsible for just 20% of forest loss.

Brazil, Bolivia, the Democratic Republic of the Congo and the Republic of Congo were among the countries most impacted.

Fires eliminated 7 million acres of Brazilian tropical forest, making up 42% of the total loss. In Brazil, the flames, intensified by drought, propelled 66% of the forestry loss. Bolivia lost 3.7 million acres of tropical primary forest loss, a 200% increase. The Democratic Republic of the Congo lost 1.5 million acres and the Republic of Congo lost 150,000 acres, according to the research.

In other areas of Latin America, unprecedented fires accounted for at least 60% of forestry destruction in Belize, Guatemala, Mexico and Guyana.

Despite these devastating losses, some countries have managed to preserve their forests, such as Indonesia, which experienced a 11% decrease in forest loss compared to the previous year, and Malaysia, which saw a 13% decrease year over year.

According to the research, the fires also released 4.1 gigatons of greenhouse gas emissions back into the atmosphere, resulting from the destruction of trees that naturally absorb carbon dioxide.

"Forest fires and land clearing are driving up emissions, while the climate is already changing faster than forests can adapt. This crisis is pushing countless species to the brink and forcing Indigenous Peoples and local communities from their ancestral lands. But this isn't irreversible -- if governments, businesses, and individuals act now, we can stop the assault on forests and their custodians," World Resources Institute Director of Forests and Nature Conversation Rod Taylor said.

-WABC's Jordyn Pykon

In 2024, the planet achieved an unwanted milestone when it broke the mark for the warmest year on record. Unfortunately, that record isn't likely to last long. According to a new forecast from the World Meteorological Organization (WMO), global temperatures are likely to remain at or near record highs over the next five years.

The organization's annual update to its decadal climate report shows an 80% chance that at least one year between 2025 and 2029 will set a new annual global temperature record. It also warns that the planet is increasingly at risk of officially surpassing the 1.5 degree Celsius warming threshold established in the 2015 Paris Climate Agreement.

Last year was also the first calendar year in which the planet's global average surface temperature measured 1.5 degrees Celsius (2.7 degrees Fahrenheit) above the 1850-1900 pre-industrial average. WMO estimates an 86% chance that at least one of the next five years will exceed this threshold.

The WMO also projects that the five-year warming average for the entire period of 2025 to 2029 is likely to exceed the 1.5 degrees Celsius threshold. While this is a troubling trend, surpassing the threshold over a single year or even five years is not considered a failure to meet the Paris Agreement, as climate averages are analyzed over multiple decades. However, the latest findings show that a sustained breach of that climate threshold is becoming increasingly likely.

The report's authors emphasize that every additional fraction of a degree of warming is significant. Present-day warming is already driving more harmful heat waves, extreme rainfall events and rising sea levels, impacts that are expected to intensify as the planet continues to warm.

"We have just experienced the ten warmest years on record. Unfortunately, this WMO report provides no sign of respite over the coming years, and this means that there will be a growing negative impact on our economies, our daily lives, our ecosystems and our planet," said WMO Deputy Secretary-General Ko Barrett.

The Arctic region is warming significantly faster than the global average, making it a key area of concern, according to the report. Over the next five extended winters, from November to March, the average temperature anomaly in the Arctic is expected to be more than three and a half times greater than the global average recorded from 1991 to 2020.

Recent La Niña conditions across the equatorial eastern Pacific Ocean make it very unlikely that 2025 will break last year's global temperature record. However, as the WMO report notes, these pauses typically don't last long. Unchecked greenhouse gas emissions from human activity will continue to drive long-term warming, threatening global temperature records for many years to come.

-ABC News meteorologist Dan Peck

Drought and extreme heat frequently coincide, drying out vegetation, which can lead to agricultural losses and increase the risk of wildfires. While previous studies have shown extreme heat can worsen drought conditions, much less is known about how drought might influence a heat event.

However, new research funded by NOAA's National Integrated Drought Information System has found drought doesn't just accompany heat, it can actually extend the duration of heat waves when the two overlap.

Researchers used air temperature, soil moisture and soil temperature data from dozens of weather stations across the country to examine the influence of drought on heat wave intensity, duration and human exposure to extreme heat. They found that the presence of drought conditions increased the average duration of heat waves by 12 to 48 hours at two-thirds of the stations analyzed in the recently published study in the Journal of Applied Meteorology and Climatology.

While heat waves are more likely to coincide with drought in the western U.S., the study found that even in the eastern part of the country, heat waves occurring during drought conditions led to higher daily maximum temperatures. One likely driver of this connection is soil moisture. The researchers observed that dry soils not only suppress local evapotranspiration but can also retain more heat. That stored heat is then released into the atmosphere, contributing to elevated air temperatures.

According to the researchers, when a heat wave and drought overlap, people face a heightened risk of heat exposure due to both higher temperatures and longer periods of heat. The study's authors suggest improved monitoring of soil moisture and temperature could lead to more accurate assessments of the wide-ranging impacts of extreme heat, including threats to public health and agriculture, as well as elevated wildfire risk.

Much of the Plains and Southwest are beginning meteorological summer, which starts June 1, under widespread drought conditions. According to the latest update from the U.S. Drought Monitor, nearly 90% of Nebraska is experiencing a drought, while more than 60% of Arizona is facing an extreme drought (level 3 of 4). These regions are likely to see near- or below-average precipitation in June, according to NOAA's Climate Prediction Center.

-ABC News meteorologist Dan Peck