Methane emissions soar to new highs
Despite their damaging effect on the Earth’s climate, global methane emissions are soaring, with human activities now responsible for two-thirds of them, a new study finds.
Published Sept. 10 in Environmental Research Letters, the research found methane emissions are at their highest in at least 800,000 years, reaching a level that is 2.6 times higher than they were in the pre-industrial era.
Annual methane emissions have risen by 20% over the past two decades, driven primarily by coal mining, oil and gas use and production, cattle and sheep ranching, and decomposing waste in landfills, the study found. Nearly 65% of global methane emissions, which heat the atmosphere and fuel global warming, came directly from human activities in 2020.
The largest regional increases in human-generated methane emissions occurred in China and Southeast Asia, while decreases occurred in Europe. Other regions with increases included the U.S., Brazil, Central America and the Middle East.
At current rates of emissions, global warming will increase by 5 degrees Fahrenheit by the end of the century, study researchers predicted. Under the 2015 Paris climate agreement, nations around the world pledged to limit long-term global warming to below 2 degrees Celsius — 3.6 degrees Fahrenheit — above pre-industrial levels.
While the impacts of climate change would become increasingly severe at 2 degrees Celsius, they are already being felt across the globe through extreme temperatures, heavy rains, flooding and other threats to health.
Data from the study were also published Sept. 10 in an accompanying paper in Earth System Science Data. Both papers are the work of the Global Carbon Project, a Stanford University initiative that tracks global greenhouse gas emissions.
‘Forever chemical’ linked with colorectal cancer
A recent study has added colorectal cancer to the list of risks associated with a “forever chemical” that’s often detected in drinking water supplies.
Researchers found that mice exposed to perfluorooctanesulfonic acid, also known as PFOS, in their drinking water experienced changes in their intestinal cells that are linked to colorectal cancer.
The same changes are found in tumors of human patients with the disease, according to the study, which was published in Chemosphere.
PFOS has previously been linked to breast, liver and kidney cancers, as well as high cholesterol, lower birth weight and immune system problems. The new study is the first to establish a link to colorectal cancer, researchers said.
Researchers also tested whether dietary enhancements could offset PFOS-induced intestinal changes, as previous research indicated that was a possibility. The new study, however, found that supplements containing inulin and pectin — soluble fibers naturally found in fruits and vegetables — failed to counteract the effects.
PFOS are one of thousands of types of chemicals known as per- and polyfluoroalkyl substances, or PFAS. They are often referred to as “forever chemicals” because of their inability to break down in the human body or the environment.
PFOS were used for decades in non-stick cookware, carpets and upholstered furniture to make them resistant to stains, grease, dirt and water. They were phased out of use from U.S. consumer products, but are still used in firefighting foam and at industrial sites.
About 45% of drinking water sources are estimated to be contaminated by at least one type of PFAS, with PFOS among the most commonly detected. In April, the Environmental Protection Agency released a final rule that set maximum levels of five types of PFAS in U.S. drinking water, including PFOS.
Severe injuries on the job lead to thousands of amputations, hospitalizations
More than 88,200 U.S. workers have experienced severe injuries on the job since 2015, resulting in almost 72,000 hospitalizations, a new reporting tool from the Occupational Safety and Health Administration shows.
Released Sept. 4, the agency’s new online dashboard shares nine years of data on severe injuries from across the U.S. that were reported to OSHA. Under federal regulations that took effect in 2015, employers must notify OSHA of a work-related hospitalization, amputation or loss of an eye within 24 hours of an incident.
Top causes of severe injuries from 2015 to 2023 included falling, getting caught in running equipment or machinery, and being compressed or pinched by shifting objects, the dashboard shows. Floors were the top sources for injuries, but equipment such as forklifts, order pickers and platform truck-powered devices were also commonly involved.
The injuries resulted in more than 28,000 fractures, 23,000 amputations and nearly 4,300 cuts and lacerations. Fingers were the most commonly injured parts of the body.
Dashboard users can search and download data by state, year, industry, state, company name and injury classification codes. OSHA encouraged workers and employers to use the tool to help prevent injuries in their workplaces.
Chemical compound used in fragrances implicated in early puberty
Exposure to certain endocrine-disrupting chemicals may be a trigger for early puberty in girls, a new study in Endocrinology reports.
Researchers screened 10,000 chemical compounds found in pharmaceuticals, environmental chemicals and dietary supplements, finding several had the ability to stimulate hormone receptors in the brain that are linked to puberty. Of those, the most concerning was musk ambrette, a fragrance sometimes used in detergents, perfumes, air fresheners and personal care products.
While the U.S. Food and Drug Administration removed musk ambrette from its “generally recognized as safe” list, it is still used in some products and has been detected in wastewater. The compound is banned from use in cosmetics in the European Union and Canada because of its potential neurotoxicity.
Early puberty in children has been a growing concern, with environmental exposures a suspected contributor. A study published in May confirmed the average age at which girls in the U.S. experience their first period has fallen since 1950. Early puberty is associated with increased risks for obesity, diabetes, breast cancer and other health concerns.
While the new study findings do not establish a direct link to musk ambrette and early puberty, they are conclusive enough to warrant further study, according to the researchers, who were affiliated with the National Center for Advancing Translational Sciences, National Institute of Environmental Health Sciences and Northwestern University.
Other recent public health news of note includes:
• U.S. lakes are monitored less for water quality if they are located in communities of color, according to a new study in Frontiers in Ecology and the Environment. Lakes in communities of color were seven times less likely to have long-term monitoring data than lakes in white communities.
• Older women are physiologically more vulnerable to high heat and humidity than older men, says new research in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. The findings are especially concerning as heat waves increase with climate change, researchers said, as heat already kills more women than men.
• New science in the Proceedings of the National Academy of Sciences finds cities around the world receive more rainfall than surrounding rural areas. Urban development influences rainfall, which could worse flash flooding in densely built areas as the climate changes further.
• Nearly half of all tuberculosis cases and deaths among U.S.-born patients will be linked to racial and ethnic inequities if current trends continue, predicts a study in JAMA Network Open.
• People exposed to high levels of fine-particle pollution during infancy have lower economic earnings as adults than those without such exposure, finds research in the Proceedings of the National Academy of Sciences.
The Watch is written by Michele Late, who has more than two decades of experience as a public health journalist.