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

Forests play a crucial role in stabilizing the planet’s carbon balance, the equilibrium between carbon emissions and carbon absorption. They are also essential in limiting the worst impacts of human amplified climate change.

As essential carbon sinks, forests usually absorb more carbon dioxide than they emit. They also remove excess carbon dioxide from the atmosphere, providing a net reduction of the heat-trapping greenhouse gas. However, new research suggests that their vital role is now under threat due to increasing global wildfire activity.

In a typical year, forests and other vegetation absorb about 30% of the carbon dioxide released from burning fossil fuels, according to the World Resources Institute (WRI). However, new data from WRI’s Global Forest Watch (GFW) and Land & Carbon Lab shows that in 2023 and 2024, extreme wildfires significantly reduced the ability of forests to absorb carbon dioxide, taking in only a quarter of their average annual carbon intake.

Globally, forests still remain a net carbon sink, but their influence is dwindling and this recent decline reflects a troubling longer-term trend. While some forest regions, including parts of the eastern U.S., continue to act as strong carbon sinks, others are shifting from net sinks to net sources of CO2.

For example, Canada’s boreal forests became a net carbon source in 2023 due to an extreme wildfire season, which accounted for 79% of global forest fire emissions, according to the analysis. That same year marked the lowest “forest carbon sink” in over two decades when factoring in both wildfire-related losses and ongoing deforestation.

According to the National Oceanic and Atmospheric Administration (NOAA), these effects extend beyond Canada, impacting the Arctic tundra. Rapidly warming conditions and increasing wildfire activity are now transforming the vast region, from a critical carbon sink that existed for thousands of years into a growing source of carbon dioxide emissions.

While reducing fossil fuel emissions is the most effective way to curb the impacts of human-induced global warming, protecting and sustainably managing forests is essential to preserving this vital carbon budget resource for future generations.

The Appalachian region in the eastern U.S. offers a promising example of how conservation efforts and natural regeneration can reverse the impacts of past land use. By the mid-20th century, much of the region’s forests had been cleared for agriculture and logging. However, many of these lands were later abandoned and allowed to regrow naturally. Today, according to WRI, these recovering forests now account for a quarter of the country’s net forest carbon sink despite only making up about 14% of U.S. forested area.

- ABC News meteorologist Dan Peck

A critical weather model used by the National Oceanic and Atmospheric Administration is getting an AI-powered partner. The National Weather Service, part of NOAA, is beginning testing of an artificial intelligence version of the model to determine if it can more accurately forecast the weather and do so faster than traditional tools.

"This represents a significant leap forward in the application of artificial intelligence to environmental modeling," wrote project manager Isidora Jankov. "By leveraging new, high-resolution observations that help us better understand fine-scale physical processes, physical models can be improved, thereby improving the data on which AI-driven models are trained," she added.

NOAA recently announced it had turned over HRRR-Cast, a data-driven AI weather model, to the NWS for testing and evaluation.

The new model is NOAA's first experimental AI weather forecast system, and the agency said it's trained on three years of data from its widely used High-Resolution Rapid Refresh model, a short-term forecast model that has served as the agency's flagship for a decade.

The HRRR model and other traditional weather models combine real-time weather observations with complex atmospheric and physics-based equations to simulate weather conditions for a future period. Meteorologists and forecasters use these models to help predict events such as severe thunderstorms, heavy precipitation and other impactful weather phenomena on a global, regional and local level.

Unlike traditional weather models, which require a substantial amount of time and computing power to run, NOAA says HRRR-Cast can produce forecasts in a fraction of the time, on a single laptop, by learning to recognize specific weather patterns from historical data.

The developers found that the HRRR-Cast performed comparably to its traditional counterpart and even excelled in producing more realistic depictions of thunderstorm structure.

The developers also found that the AI model was 100 to 1,000 times more computationally efficient than the traditional model, meaning it can be run and deployed without relying on an energy and compute-intensive supercomputer.

Curtis Alexander, acting director of NOAA's Global Systems Laboratory, noted the AI model serves as a powerful proof of concept and the NWS will likely expand its capabilities by forecasting additional weather variables.

Both the AI version and the traditional version of the HRRR model will run together tangentially.

-ABC News meteorologist Kyle David Reiman

Last month was the third-warmest June on record globally, according to new data analyzed by the Copernicus Climate Change Service (C3S). The previous three Junes now rank one, two and three for the warmest in history.

June was just the third month in the past two years that did not surpass the 1.5 degree Celsius warming threshold established in the 2015 Paris Climate Agreement. Instead, it registered 1.3 degrees above the pre-industrial reference period (1850-1900).

The planet’s average surface air temperature was 16.46 degrees Celsius, or 61.63 degrees Fahrenheit, according to Copernicus.

Scientists anticipated a short-term drop in global temperatures due to the recent La Niña event in the equatorial eastern Pacific Ocean. This climate pattern typically brings a temporary dip in global average temperatures. However, climate scientists caution that this pause is unlikely to last, as human-caused greenhouse gas emissions continue to fuel the long-term warming trend.

Global daily sea surface temperatures across much of the world’s oceans remained above average in June. Between the latitudes of 60 degrees south and 60 degrees north, which include most of the continents and oceans, the average global sea surface temperature was 69.3 degrees Fahrenheit, the third-highest value on record for the month.

In the polar regions, sea surface temperatures also frequently registered above average, negatively impacting sea ice. Antarctic sea ice coverage was 9% below average in June, ranking as the third-lowest value on record for the month. In the Arctic, it was 6% below average, marking the second-lowest June extent on record, Copernicus said.

-ABC News meteorologist Dan Peck

Rising temperatures, amplified by climate change, are contributing to an increase in cases of sleep apnea, a condition in which breathing repeatedly stops during sleep, according to a new study published in the journal Nature Communications.

"If temperature keeps rising the way they project it to, the burden and prevalence of sleep apnea may double, increasing by 20-100%, depending on greenhouse gas emission reduction," Bastien Lechat, the study's author and a senior research fellow at Flinders University in Australia, told ABC News.

Obstructive sleep apnea, or OSA, affects about 1 billion people globally, and 80% of people who have it are unaware and untreated. OSA has been linked to an increased risk of heart disease, stroke, dementia, diabetes and depression. People with OSA also have two times greater risk of getting in a car accident, according to Lechat.

The study followed over 115,000 people from numerous countries for up to two years, measuring their sleep quality with below-the-mattress sleep monitors and then cross-referencing this information with weather data to evaluate the relationship between temperature and OSA.

When comparing 80-degree Fahrenheit days to days in the 40s, there was a 40 to 45% increase in the frequency or severity of sleep apnea. The risk was even higher for males and individuals who normally sleep longer or have higher body weight.

Extreme heat can exacerbate OSA by making it even harder to sleep, the study noted. Higher temperatures can disrupt the body's ability to cool down during the night, which interferes with the natural sleep cycle. This can lead to more frequent awakenings, shallower sleep and worsened airway instability, resulting in more apnea events.

Using existing health-economic models, the researchers estimated over 788,000 healthy years of life were lost or disabled in 2023 due to temperature-related increases in OSA, equivalent to a loss of approximately $68 billion, according to the models.

"When you look at the rate of years of life lost per 100,000 people, this is similar to a disorder like Parkinson's disease, or bipolar disorder, or similar to low physical activity as a risk factor, so it's a significant burden," Lechat told ABC News.

Lechat said that increased access to air conditioning and better diagnosis and treatment of OSA could offset some of the increases caused by climate change. However, he emphasized that limiting global warming through policy changes is the most effective and cost-efficient option.

"Limiting global warming is probably cost effective, when you look at the numbers -- the loss of well-being and the economic costs of increasing temperature," he added.

-Dr. Ilan Kokotek, a board-certified family physician and member of ABC News' Medical Unit