patterns

More Dam Failures Likely | Earth Wise

June 24, 2020 By EarthWise Leave a Comment

Two dams in Central Michigan were breached by rain-swollen floodwaters in May and forced the evacuation of tens of thousands of residents and prompted officials to warn of life-threatening danger from a flooded chemical complex and a toxic waste cleanup site. Engineers say that most dams in the U.S. were designed many decades ago – in some cases, a century ago – and are not suited to a warming world with ever stronger storms.

The dams in Michigan gave way for the same reason behind most dam failures: they were overwhelmed by water, in this case by five inches of rain falling over two days after earlier storms had saturated the ground and swollen rivers.

It can’t be proven whether this specific set of events was triggered by climate change, but global warming is definitely causing some regions to become wetter and is increasing the frequency of extreme storms. And these trends are expected to continue as the world continues to warm.

All of this puts more of the 91,500 dams in the U.S. at greater risk of failing. The American Society of Civil Engineers, in its latest report card on infrastructure issued in 2017, gave the nation’s dams a “D” grade.

Historically, dams have been designed based on past weather history to predict the magnitude of the maximum potential flood that a dam would have to withstand. There was no expectation that future weather patterns might be very different. Infrastructure designers will clearly need to change their practices.

For existing dams, operational changes might be called for, such as reducing water levels in anticipation of more extreme storms. Upgrades might include changing spillway designs to accommodate larger water volumes over a longer time period.

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‘Expect More’: Climate Change Raises Risk of Dam Failures

Photo courtesy of Eye in the Sky/Youtube.

Earth Wise is a production of WAMC Northeast Public Radio.

Bird Migration And Climate Change | Earth Wise

January 22, 2020 By EarthWise Leave a Comment

A new study of bird migration shows the migration patterns are shifting as a result of climate change. Researchers at Colorado State University, the University of Massachusetts, and the Cornell Lab of Ornithology, looked at the impacts of climate change on a continental scale.

The team looked at the nocturnal migratory behaviors of hundreds of species representing billions of birds using radar and other data. They found that spring migrants are likely to pass certain stops earlier now than they would have 20 years ago. Temperature and migration timing are closely aligned and the greatest changes in migration timing are occurring in regions warming most rapidly. During the fall, shifts in migration were less apparent.

Migratory birds play an important role in ecosystems. They consume insects, disperse seeds, and perform various other significant functions. Birds serve as critical metrics of the health of ecosystems.

Bird migration is a global phenomenon that can provide unique visibility into changes in the climate. The ability to look at it on a global scale has only recently become practical as a result of big data technology and cloud computing. The team was able to crunch the numbers for the study in 48 hours, a task that previously would have taken over a year of continuous computing.

The findings have implications for understanding future patterns of bird migration because birds depend on food and other resources as they travel. As the climate changes, the timing of blooming vegetation or the emergence of insects may end up out of sync with the passage of migratory birds. This could have negative consequences for the health of migratory birds.

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Bird migration timing skewed by climate, new research finds

Photo, posted November 5, 2019, courtesy of Jerry Kirkhart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And El Niño

December 2, 2019 By EarthWise Leave a Comment

The term El Niño refers to a large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperature across the central and east-central equatorial Pacific Ocean. Amazingly, the phenomenon was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean.

According to a new study published in the Proceedings of the National Academy of Sciences, climate change is increasing the frequency of extreme El Niño events, leading to intensifying droughts, worsening floods, and shifting hurricane patterns.

The study, led by scientists in China and the US, looked at data from 33 El Niños dating back to 1901. Since the 1970s, El Niños have been forming farther to the west in the Pacific Ocean, where temperatures are warmer. Strong El Niños can cause severe drought in dry climates such as Australia and India, intense flooding in wetter climates such as the US Pacific Northwest and Peru, and more hurricanes to form in the Pacific and fewer in the Atlantic.

Before 1978, 12 out of 14 El Niños formed east of the International Dateline. Since 1978, all 11 have formed in the central or western Pacific Ocean a shift of hundreds of miles. There have been three so-called super El Niños since the shift – in 1982, 1997, and 2015. These have set new average temperature records and triggered catastrophic natural disasters.

With rising global temperatures, El Niños are likely to continue to intensify, with major impacts on human societies around the world.

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Climate Change is Making El Niños More Intense, Study Finds

Photo, posted January 20, 2016, courtesy of Los Angeles District via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

100% Renewables Does Not Necessarily Mean Carbon-Free

July 16, 2019 By EarthWise Leave a Comment

Hundreds of companies around the world have committed to use 100% renewable energy in order to fight climate change. But a new study from Stanford University points out that 100% renewable energy does not necessarily mean 100% carbon-free energy.

The problem is that the carbon content of electricity can vary a lot over the course of a day in many locations. Using yearly averages can overstate the carbon reductions associated with a particular power source, in some cases by significant amounts.

Suppose a California company purchases or generates enough solar power to match 100% or more of their electricity use over the course of the year. In reality, it may generate far more electricity than it uses during the afternoon and sell the excess. Then, at nighttime, it purchases power from the grid, which would be far more carbon-intensive if it involves the burning of fossil fuels.

But in Britain, for example, the situation is very different. With a high reliance on wind power, grid carbon intensity is actually lower at night. So very different consumption patterns over the course of a day would be less carbon-intensive.

If sufficient energy storage capacity can be implemented into the grid as well as suitable long-range transmission, these time-based fluctuations in the electricity supply could be ironed out. Until such time, electricity consumers need to evaluate the environmental benefits of their renewable strategies on an hourly basis rather than using averages. And the best strategies are entirely dependent upon the characteristics of the specific grid they interact with. The need for this kind of analysis will only grow as renewable generation expands. Transparent, precise and meaningful carbon accounting is necessary.

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100% renewables doesn’t equal zero-carbon energy, and the difference is growing

Photo, posted January 29, 2013, courtesy of U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Insurance

May 17, 2019 By EarthWise Leave a Comment

While there are still some people who remain dubious about the reality of climate change, insurance companies are not among them. And, in fact, insurers are warning that climate change could make coverage for ordinary people unaffordable.

Munich Reinsurance, the world’s largest reinsurance firm, blamed global warming for $24 billion in losses from California’s recent wildfires. Such costs could soon be widely felt as premium rises are already under discussion with insurance companies having clients in vulnerable parts of the state.

With the risk from wildfires, flooding, storms and hail increasing, the only sustainable option for the insurance industry is to adjust risk prices accordingly. Ultimately, this may become a social issue. Affordability of insurance is critical because if rates go up too much, many people on low and average incomes in some regions may no longer be able to buy insurance.

The great majority of California’s 20 worst forest fires since the 1930’s has occurred since the year 2000 driven by abnormally high summer temperatures and persistent drought. The reinsurance giant analyzed decades of data with climate models and concluded that the fires are likely driven by climate change.

It isn’t just wildfires. Insurance premiums are also being adjusted in regions facing an increased threat from severe convective storms whose energy and severity are driven by global warming. These include parts of Germany, Austria, France, southwest Italy, and the U.S. Midwest.

Linking extreme weather events to climate change is a bit like attributing the performance of a steroid-using athlete to drug use. The connections are clearer in patterns than in individual disasters. But the pattern these days is pretty clear.

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Climate Change Could Make Insurance Unaffordable for Most People

Photo, posted June 12, 2013, courtesy of Jeff Head via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shipping And Invasive Species

May 7, 2019 By EarthWise Leave a Comment

The increasing numbers of invasive species around the world are a major driver of biodiversity change and cause billions of dollars in economic damages annually. Climate change is a major factor in the spread of invasive species, but a new study by McGill University suggests that global shipping growth will far outweigh climate change in the spread of non-indigenous pests to new environments in the coming decades.

One of the most significant ways in which the disparate regions of the world are interconnected is via transportation networks. The global shipping network is the primary means by which materials and goods are moved worldwide, accounting for over 80% of world trade. And for this reason, the global shipping network is responsible for much of the introduction of non-indigenous species across the planet.

Living organisms are often transported through ballast water, which is taken up to stabilize cargo vessels. Other species are transported by biofouling, whereby they attach to the hulls of ships. Taken together, these two pathways account for anywhere between 60 and 90% of marine bioinvasions. (Terrestrial invaders are generally moved as a byproduct of shipping, for example by infesting wood packaging material).

The McGill study looked at trends in global shipping and how socioeconomic factors are driving change. For example, China’s share of global container throughput has gone from 1.4% in 1990 to 20.1% in 2013. So, the distribution and patterns of shipping have been changing dramatically and with it the spread of non-indigenous species.

Awareness of this issue is increasing. For example, there have been policy initiatives such as the International Ballast Water Management Convention that is an effort to control bio-invasions through measures such as ballast exchange. We need to take measures to limit the unintentional spread of species.

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Global forecasts of shipping traffic and biological invasions to 2050

Photo, posted December 3, 2009, courtesy of Roger W via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Dietary Diversity And Health

September 26, 2018 By EarthWise Leave a Comment

For decades, we have heard from public health sources that we should eat a variety of foods. Dietary diversity is touted as important for health. However, there has never really been a consensus about what so-called dietary diversity actually is, how it is measured, or how it necessarily is healthy.

Greenhouse Emissions And Food Choices

August 6, 2018 By EarthWise Leave a Comment

Changes in diet have often been proposed as a way to reduce overall greenhouse gas emissions. However, there has not been much research about the affordability and feasibility of such changes.

Traffic Jams In The Jet Stream

July 13, 2018 By EarthWise Leave a Comment

Many extreme weather events are associated with unusual behavior by the jet stream. Jet streams are the global air currents that circle the earth. The meandering and speed changes in the jet stream affect weather and also play a big role in how long it takes aircraft to make their way across the country. The behavior that leads to extreme weather events is known as “blocking” in which the meandering jet stream stops weather systems from moving eastward.

Extreme Weather Increasing

May 11, 2018 By EarthWise Leave a Comment

It sure seems like extreme weather is increasingly common: floods, droughts, extreme rainfall, powerful snowstorms, hurricanes and so on. But we tend to focus on recent events and often give them undue emphasis. So, it is reasonable to ask whether extreme weather really is more common these days.

Mapping Emerging Infectious Diseases

July 12, 2016 By WAMC WEB

Ebola. Hantavirus. Lyme disease. What do they have in common? Like most emerging infectious diseases, they originated in mammals. So many debilitating pathogens make the jump from wildlife and livestock to humans, yet at the global scale little is known about where people are most at risk of outbreaks.