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Harmful algal blooms and climate change

September 5, 2025 By EarthWise Leave a Comment

An algal bloom is a rapid increase in the density of algae in an aquatic system. Harmful algal blooms occur when bodies of water get overloaded with nitrogen and phosphorus runoff from agriculture and other human activities. These excess nutrients can facilitate the out-of-control growth of cyanobacteria, also known as blue-green algae.

Some species of blue-green algae produce a toxin called microcystin. These toxins pose a serious health hazard to people, animals, and the environment. Microcystin affects liver function and can cause death in animals, as well as humans in rare instances. A notable incident occurred in the summer of 2014, when cyanobacteria contamination in Lake Erie left 500,000 residents in Ohio and Michigan without water for 72 hours and sickened more than 100 people.

According to a study led by researchers from Carnegie Science, as climate change warms the earth, higher-latitude regions will be at a greater risk for microcystin produced by algal blooms. The study found water temperatures of 68 to 77 degrees Fahrenheit as being at the greatest risk for developing dangerous levels of microcystin.

In the study, which was published in the journal Nature Water, the research team also demonstrated that the areas most susceptible to high toxin concentrations will continue to move northward. And in some areas, researchers say the relative risk of exceeding water quality guidelines will increase by up to 50% in the coming decades.

The research team hopes its findings raise more awareness about water sustainability, and the need to focus on the quality of the water as much as the quantity of water.

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Geographic redistribution of microcystin hotspots in response to climate warming

Photo, posted October 27, 2010, courtesy of Nara Souza / Florida Fish and Wildlife Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Airplanes and climate change

May 26, 2025 By EarthWise Leave a Comment

The aviation industry is a powerful force in the global economy. In fact, according to some estimates, the industry transports the equivalent of nearly half the world’s population every year. But the world’s airports were largely designed for an older era – a cooler one.

As air warms, it becomes less dense, which makes it harder for airplanes to generate lift, which is the force that enables them to fly.

According to a new study by scientists from the University of Reading in the U.K., rising temperatures due to climate change may force aircraft at some airports to reduce passenger numbers in the coming decades.

The research team examined how warmer air affects aircraft performance during takeoff at 30 sites across Europe. The study, which was recently published in the journal Aerospace, focused on the Airbus A320, which is a common aircraft used for short and medium-distance flights across Europe.

By the 2060s, the research team found that some airports with shorter runways may need to reduce their maximum take-off weight by the equivalent of approximately 10 passengers per flight during summer months.

Of the sites included in the study, Chios in Greece, Pantelleria and Rome Ciampino in Italy, and San Sebastian in Spain will be the four most affected popular tourist destinations.

Climate change is also making air travel increasingly turbulent, and the aviation industry itself remains a growing contributor to global greenhouse gas emissions.

Taking meaningful action to curb greenhouse gas emissions, including those from the aviation industry, is one of the most crucial ways to mitigate global climate change.

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Holiday flights could carry fewer passengers as world warms

Photo, posted September 29, 2017, courtesy of Hugh Llewelyn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Benefits of electric school buses

July 1, 2024 By EarthWise Leave a Comment

There are about half a million school buses in use in the U.S. A large number of them are older, highly polluting diesel buses. There are well-established health and climate benefits of switching from diesel vehicles to electric vehicles but making the switch is expensive. Diesel buses generally cost between $65,000 to $120,000, depending on the type and configuration. Electric buses cost about $250,000 each.

The substantial cost makes it a difficult decision for local, state, and federal officials, particularly since the actual magnitude of the benefits is not well known.

A new study by researchers at Harvard’s T.H. Chan School of Public Health has quantified these benefits. According to the study, replacing each bus may yield up to $247,600 in climate and health benefits. These benefits derive from fewer greenhouse gas emissions and from reduced rates of adult mortality and childhood asthma.

The study compared the amounts of carbon dioxide emitted from diesel bus tailpipes to the emissions associated with generating electricity for the buses and producing their batteries. It also compared how these respective emissions contribute to fine particulate air pollution, which is linked to adult mortality and the onset of childhood asthma. The study concluded that particularly in dense urban settings, the savings incurred from electrifying older school buses easily outweigh the costs of replacing them.

An important question not tackled in the study is how electric school buses impact children’s exposure to in-cabin air pollution while riding the bus. This issue could further inform policy decisions.

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Electric school buses may yield significant health and climate benefits, cost savings

Photo, posted May 9, 2008, courtesy of Christine H. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Otters to the rescue

February 23, 2024 By EarthWise Leave a Comment

California sea otters were hunted almost to extinction in the 19th century. Only a small number survived along California’s central coast. But over time, the otters recovered and increasingly recolonized their former habitats.

Sea otters are playing an important role in safeguarding California’s kelp forests and marshlands against the harmful effects of climate change.

Over much of the 20th century, increasing ocean heat had devastated underwater kelp forests by driving a population explosion of sea urchins that devour kelp. But sea otters eat urchins and as the sea otter population has grown, kelp has flourished. According to a new study published in PLOS Climate, the underwater kelp canopy along the central coast increased by 56% since 2016. Kelp forests have become more extensive and resilient to climate change wherever sea otters have reoccupied the California coastline.

At the same time, sea otters started recolonizing their former habitat in a central California estuary several decades ago and erosion has slowed by as much as 90%. The main reason is that otters love to eat the marsh crabs that were devouring the plants in this coastal ecosystem. The marsh plants establish dense root systems that can withstand waves and flooding. It would cost millions of dollars for humans to rebuild creekbanks and restore these coastal marshes. Instead, sea otters have been stabilizing them for free in exchange for a crab feast.

Sea otters are playful creatures that people enjoy watching. It turns out that they are also very valuable ecosystem engineers that are helping to mitigate the effects of the warming climate.

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How Sea Otters Are Protecting the California Coast Against Climate Change

Photo, posted May 17, 2021, courtesy of Michael L. Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Zinc Batteries | Earth Wise

May 17, 2023 By EarthWise Leave a Comment

The rapid growth of wind and solar power continues to drive a global quest for new battery technologies that can be used to store the energy generated by these sources when the sun isn’t shining, and the wind isn’t blowing.

For the most part, current battery energy storage systems use lithium-ion batteries – the same sort of batteries found in cellphones and electric vehicles. There are many other battery chemistries, but they mostly have shortcomings in performance, economy, or longevity.

Batteries store electricity in the form of chemical energy and chemical reactions convert that energy into electrical energy. Every battery has two electrodes: the anode, from which electrons flow into external circuits, and the cathode, which receives electrons from the external circuit. The electrolyte is the chemical medium through which the electrons flow.

One technology that has great potential is zinc-based batteries. Zinc itself is a metal that is safe and abundant. Batteries based on it are energy dense. However, zinc batteries have faced the challenge of having a short cycle life. The batteries end up plating zinc on their anodes and battery performance degrades.

A team of researchers at Oregon State University and three other universities have recently developed a new electrolyte for zinc batteries that raises the efficiency of the zinc metal anode to nearly 100% – actually slightly better than lithium-ion batteries.

Zinc batteries have a number of potential advantages over lithium-ion. The new hybrid electrolyte developed by the researchers is non-flammable, cost-effective, and has low environmental impact. Lithium-ion batteries rely on the supplies of relatively rare metals that are often difficult and environmentally harmful to obtain.

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Researchers develop electrolyte enabling high efficiency of safe, sustainable zinc batteries

Photo, posted May 13, 2017, courtesy of Jeanne Menjoulet via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollution In The Middle Of Nowhere

July 10, 2017 By EarthWise

The Pitcairn Islands are a group of four volcanic islands in the South Pacific, mostly known from the famed mutiny on the British ship Bounty. Pitcairn Island itself is where many of the mutineers settled and where some of their descendants live today. That small island, with a population of 57, is the only one of the group that is inhabited.