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Slow-moving landslides

October 17, 2024 By EarthWise Leave a Comment

Landslides are mass movements of rock, earth, or debris down a slope. They can be initiated by rainfall, snowmelt, changes in water level, erosion by streams, earthquakes, volcanic activity, or by various human activities. Most landslides we hear about are sudden events that can cause all sorts of calamities. But not all landslides are rapid occurrences. There are also slow-moving landslides.

A new study by the University of Potsdam in Germany has found that as urban centers in mountainous regions grow, more people are building homes on steeper slopes prone to slow-moving landslides. Slow-moving landslides can move as little as one millimeter a year and up to as much as three meters per year. Locations with slow-moving landslides can seem safe to settle on; in some cases, the movement itself can be inconspicuous or even completely undetected.

Slow slides can gradually produce damage in houses and other infrastructure and there can also be sudden acceleration from heavy rain or other influences.

The study compiled a new database of nearly 8,000 slow-moving landslides with areas of at least 25 acres located in regions classified as “mountain risk.” Of the landslides documented, 563 are inhabited by hundreds of thousands of people. The densest settlements on slow-moving landslides are in northwestern South America and southeastern Africa.

In all regions of the study, urban center expansion was associated with an increase in exposure to slow-moving landslides. As cities expand in mountainous areas, people are moving into unsafe areas, but poorer populations may have few other options.

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Slow-moving landslides a growing, but ignored, threat to mountain communities

Photo, posted March 4, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The global chocolate supply is threatened

May 16, 2024 By EarthWise Leave a Comment

The world is facing the biggest deficit of cocoa in decades. Most cocoa beans are grown in West Africa, where climate change-induced drought has ravaged crops. Harvests are forecasted to fall short for the third consecutive year.

The harvest shortfall has triggered a steep rise in cocoa prices. In fact, cocoa prices have more than doubled in the first four months of this year, and have more than tripled in the past 12 months.

But drought isn’t the only threat: A rapidly spreading virus is also threatening the future of chocolate.

Approximately half of the world’s chocolate originates from cacao trees in Ghana and the Ivory Coast. The Cacao Swollen Shoot Virus Disease is spread by small insects called mealybugs, which eat the leaves, buds, and flowers of cacao trees. The virus is attacking cacao trees in Ghana, resulting in harvest losses of 15-50%.

Pesticides don’t work well against mealybugs. Farmers can vaccinate trees to inoculate them from the virus. But the vaccines are expensive, and the vaccinated trees produce a smaller harvest of cacao.

According to a new paper recently published in the journal PLOS ONE, an international team of researchers has developed a new strategy to combat these pests: using mathematical data to determine how far apart vaccinated trees need to be planted in order to stop mealybugs from hopping from tree to tree. The researchers developed two models that allow farmers to create a defensive ring of vaccinated trees around unvaccinated trees

The research team hopes its models will help farmers protect their crops and achieve better harvests in the future.

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Cacao sustainability: The case of cacao swollen-shoot virus co-infection

Will rising cocoa prices trigger a chocolate crisis?

Photo, posted April 1, 2019, courtesy of Konrad Lembcke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Confusion about monarch butterflies

February 9, 2024 By EarthWise Leave a Comment

For years, we have heard that the iconic monarch butterfly is in great peril. Monarchs east of the Rocky Mountains undertake a 4-generation, 3,000-mile migration in late summer to their winter home in central Mexico. Since the 1990s, the overwintering monarch colonies began a steep decline causing scientists to fear for the sustainability of the species. Trying to help, ordinary citizens have been planting milkweed – the food for the caterpillars – and have been rearing eggs and caterpillars on their porches and releasing adult butterflies.

A number of recent studies have rocked the world of monarch science. A growing group of scientists now believe that monarchs are not in fact imperiled and that the home rearing and commercial breeding of monarchs is actually a major threat to the butterfly.

According to a comprehensive 2022 study, there has been no sharp decline in Eastern monarch populations across their summer breeding range. The long-term declines in winter colony sizes are real but do not appear to be affecting the collective breeding population of Eastern monarchs.

An undisputed major threat to monarchs is a parasite known as OE, which weakens butterflies and also makes it unlikely for them to complete migrations. It turns out that overcrowding of butterflies resulting from the efforts of backyard and commercial breeders is increasing the spread of the disease. The butterflies are in need of social distancing.

Monarch scientists are split into two camps. One group calls for the protection of the butterfly under the Endangered Species Act. The other says that what monarchs most need is for us to leave them alone. It is a confusing situation.

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Rethinking Monarchs: Does the Beloved Butterfly Need Our Help?

Photo, posted October 1, 2021, courtesy of Renee Grayson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Offshore Wind | Earth Wise

November 16, 2022 By EarthWise Leave a Comment

California has tremendous potential offshore wind resources. The state set a preliminary target of 15 GW of offshore wind by 2045 earlier this year and may increase that number to 25 GW. But installing offshore wind on the West Coast is much more challenging than it is on the East Coast. The reason is that the ocean floor drops off rapidly on the Pacific Coast and it is simply not practical to attach wind turbines to the sea bottom. Instead, floating turbine technology will be required. That is more complicated and more expensive.

Despite the challenges, offshore wind in California is moving forward. The federal Bureau of Ocean Energy Management announced that the auction for rights to develop waters off central and northern California will be held on December 6. This will be the first wind auction ever along the U.S. Pacific Coast.

The auction will include three lease areas in the Morro Bay Wind Energy Area and two proposed areas in the Humboldt Wind Energy Area. Combined, the two areas cover over 370,000 acres and could potentially host over 4.5 GW of wind generating capacity. The projects developed in these areas are likely to become the first floating offshore wind projects in operation in the U.S.

Apart from the challenges of building floating wind installations, there will be the issue of the electric grid in the proposed regions being able to support the added generation from the wind farms. Substantial grid upgrades will be needed to accommodate all the power coming from the offshore facilities. In addition, California offshore wind projects will need to jump-start new supply chains in the U.S.

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Date is set for California offshore wind lease auction

Photo, posted March 24, 2016, courtesy of Andy Dingley / TEIA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cities And Monarch Butterflies

August 13, 2019 By EarthWise Leave a Comment

Monarchs are some of the most well-known butterflies in the U.S. It is well-known that populations of the iconic orange-and-black butterflies have been in a steep decline for the last 20 years. In fact, the Monarch population has declined by 80% over that period.

Milkweed, the only plant that Monarchs can lay their eggs on, continues to disappear across the United States and with it, the butterflies can disappear too.

Two new studies published in the journal Frontiers of Ecology and Evolution show that one of the most important things that can be done to save the Monarchs is to plant milkweed in cities.

We tend to think of cities as being the enemy of nature. But metropolitan areas actually matter for wildlife conservation and that is especially true for pollinators like butterflies that can actually survive with very small patches of habitat.

The new study estimates the amount of habitat in cities that is available to Monarchs and other pollinators and how much more can potentially be added. It looked at cities from the Monarch’s point of view by identifying the best places and most effective ways to engage land owners to transform low-quality green space – such as lawns – into high-quality homes for butterflies and other wildlife.

Just because urban dwellers can plant milkweed doesn’t always mean that they will. There has to be a public perception that milkweed and other native flowers are acceptable and beautiful elements in home landscaping. It will require some shifting of societal norms of what is desirable in neighborhood gardens in order for cities to be able to do their part in protecting butterflies and other species struggling in the modern world.

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Cities are Key to Saving Monarch Butterflies

Photo, posted August 31, 2012, courtesy of Chris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.