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

Plastic pollution remains one of the planet’s most critical environmental threats, accounting for the majority of marine litter found across our oceans and coastlines, according to the UN Environment Programme. The UN says the thin, single-use bags can harm and kill aquatic life when the animals get entangled or ingest the plastic. And the nonprofit The Ocean Cleanup reports that plastic can also release toxic chemicals into the ocean.

In response, plastic bag bans and fees have emerged as popular policy tools to combat this issue, aimed at reducing plastic waste and preventing litter from reaching waterways. Now, a new study published in the journal Science shows that these policies have been broadly effective, adding to a growing body of evidence that supports the effectiveness of such regulations.

Researchers examined nationwide data from more than 45,000 shoreline cleanups to assess the effectiveness of plastic bag bans and taxes. They looked at the hundreds of state and local bag policies enacted across the United States between 2017 and 2023 and compared the regions with and without such measures.

The researchers found that plastic bag policies resulted in a 25% to 47% decrease in plastic bags as a share of total items collected compared to areas without policies.

Despite the positive findings, the study’s authors caution that global waste generation is expected to continue rising through the end of the century. Without significant, large-scale policy changes, the leakage of plastic debris into the world’s oceans will likely remain a significant environmental challenge for decades to come.

In August, the United Nations Environment Programme will resume negotiations on a global plastics treaty following a breakdown in talks last December in Busan, South Korea, where countries failed to reach consensus on the scope of a final agreement.

Although there is growing evidence that plastic bag policies are effective, critics have argued the regulations fall short, or even backfire, by increasing the production and use of other types of plastic. Earlier this year, President Trump signed an executive order banning the federal use of paper straws, reigniting the debate on plastic bans.

-ABC News meteorologist Dan Peck

When wildfires fill the air with heat and smoke, the danger isn't just outside. A new study in PLOS Climate finds that when people move indoors en masse, it creates ideal conditions for viruses like flu, RSV and COVID-19 to spread more easily.

Severe weather events, including wildfires, are becoming more frequent as the planet warms. To stay safe during these emergencies, people often seek safety inside -- but that response comes with its own risks, according to the study. Close quarters, poor ventilation and extended time in shared spaces make it easier for viruses to pass from person to person.

During wildfires, smoke can travel far beyond the fire zone, affecting air quality across entire regions. In 2020, counties in Oregon and Washington recorded sustained Air Quality Index levels above 150, the threshold for unhealthy air. The researchers found that in response to the poor air quality, indoor activity in those areas increased between 10.8% and 14.3%, respectively. Urban areas, such as Portland, saw an 11% jump in indoor activity, while Seattle's increase reached 16%.

Even for viruses that spread less easily, and in communities with relatively high immunity, more time spent indoors led to noticeable spikes in viral transmission.

"Places with greater density have worse problems," Giulia Pullano, a Georgetown University researcher and one of the study's authors, explained to ABC News.

While the physical dangers of climate change -- such as extreme heat, wildfire smoke, or poor air quality -- often draw the most attention, Pullano said the indirect effects, like how people behave in response to those threats, also shape public health in meaningful ways.

The PLOS Climate researchers used mobile device data to track indoor versus outdoor activity, comparing wildfire-affected counties with similar counties that had no air quality alerts. They then used computer data to model how this behavior change could affect the spread of respiratory viruses, using different scenarios based on virus characteristics and population immunity.

The study also highlighted one practical way to mitigate the increased disease risk associated with spending more time indoors. Modeling predicted that if 10% of people wore masks indoors during wildfire events, virus spread could be curtailed substantially. If half the population wore masks indoors, infection curve peaks could be flattened.

As climate-amplified disasters become more common, Pullan told ABC News that, "Understanding disruptions of behavior during natural disasters will be critical to protecting public health."

-Board-certified family physician and ABC News medical unit's Dr. Ilan Kokotek

Droughts often unfold quietly, lacking the dramatic visuals of hurricanes or flash floods. Yet their impacts can be equally devastating, and increasingly so, as human-amplified climate change fuels more frequent and intense droughts worldwide.

According to a new report by the Organisation for Economic Co-operation and Development (OECD), the global land area affected by drought has doubled in the last 120 years, with 40% of the planet experiencing more frequent and intense droughts in recent decades.

The OECD’s Global Drought Outlook provides a comprehensive worldwide assessment of drought risks, impacts and policy responses, examining how countries can strengthen drought management to adapt to a changing climate. The report highlights that the growing effects of drought are fueled by multiple compounding factors, including deforestation, urban development, unsustainable farming and human-amplified climate change.

The new analysis reveals a sharp rise in the economic costs of drought, which, on average, have at least doubled since 2000. The report estimates that by 2035, a drought event could cost a national economy at least 35% more than it does today. Globally, agriculture is the most affected sector, with crop yields declining by as much as 22% during the driest years.

In California, for example, the 2021 drought alone resulted in $1.1 billion in agricultural losses, underscoring the vulnerability of even advanced economies. The human toll of drought is equally concerning. While droughts account for only 6% of natural disasters, they are responsible for 34% of all disaster-related deaths, according to the report.

Worsening drought impacts can also influence other weather events, such as heat waves. A recent study published in the Journal of Applied Meteorology and Climatology showed that drought doesn’t just accompany heat; it can also extend the duration of heat waves when the two overlap.

Effectively addressing the escalating drought threat, according to the OECD, requires a coordinated global response and decisive, proactive action from stakeholders. For example, building more efficient irrigation systems could significantly reduce global water use and expanding the number of drought-tolerant crops can help mitigate drought impacts and strengthen long-term climate change resilience.

-ABC News meteorologist Dan Peck

Google has developed a new AI weather model that can help forecast tropical cyclones and is partnering with the National Hurricane Center to make their models available to forecasters for testing.

Google's Weather Lab website allows users to interact with its AI weather models and compare live and historical tropical cyclone tracks to traditional weather forecasting models.

"When read together, these predictions can help weather agencies and emergency service experts better anticipate a cyclone's path and intensity," Google wrote in a recent press release. "This could help experts and decision-makers better prepare for different scenarios, share news of risks involved and support decisions to manage a cyclone's impact," they added.

The new AI model is trained using key historical data from nearly 5,000 observed cyclones over the past 45 years, along with a comprehensive global weather re-analysis dataset comprising millions of weather observations.

Unlike traditional weather models, which rely on atmospheric and physics-based simulations that require significant time and computing power to complete, AI weather models can produce forecasts within seconds. The new AI model is also capable of generating 50 possible scenarios for a tropical cyclone's formation, track, intensity, size and shape up to 15 days in advance.

Google found that their new AI tropical cyclone model performed at a comparable level in most cases to traditional models and outperformed them in a few tests.

In addition to their partnership with the National Hurricane Center, Google's Weather Lab team is working with the Cooperative Institute for Research in the Atmosphere at Colorado State to evaluate the new model's performance. According to Google, CIRA scientists found the new AI model had "comparable or greater skill than the best operational models for tracking and intensity."

-ABC News meteorologist Kyle David