stagnant

Tearing down small dams to restore rivers

March 11, 2025 By EarthWise Leave a Comment

There are more than 31,000 dams in the northeastern United States. More than 4,000 of them are in the Hudson River watershed. Most of these dams are quite small and were built in the 19^th century to form ponds and to power grist, textile, paper, saw, and other kinds of mills as the region developed its industrial infrastructure. The nonprofit organization American Rivers estimates that 85% of U.S. dams are unnecessary at best and pose risks to public safety at worst.

Dam removals have been occurring for over 100 years, but the vast majority have taken place since the mid-2010s and have increased dramatically since the 2021 Bipartisan Infrastructure Law, which provided funding for such projects.

So far, 806 Northeastern dams have come down and hundreds more are in the pipeline.

Dam removals improve aquatic fish passage, water quality, watershed resilience, and habitat for all the organisms in river ecosystem food chains, ranging from insects to fish to otters to eagles. Small dams have degraded habitat and altered downstream hydrology and sediment flows. They have created warm, stagnant, low-oxygen pools that trigger algal blooms and favor invasive species.

But removing even small dams is not an easy matter. Projects range in cost from $100,000 to $3 million and qualifying for funding – whether federal or state – requires projects to meet a variety of requirements including community support. Not all dams can be removed, but many more should.

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How Tearing Down Small Dams Is Helping Restore Northeast Rivers

Photo, posted September 20, 2010, courtesy of Doug Kerr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Hot July | Earth Wise

August 24, 2022 By EarthWise Leave a Comment

At the beginning of July, the National Oceanic and Atmospheric Administration’s monthly climate outlook predicted temperatures well above average across much of the United States. The prediction was quite correct. Beyond that, world-wide, there were multiple heat waves, especially in Europe and Asia, where there were thousands of heat-related deaths. On July 19th, the United Kingdom had its hottest day ever reported with a temperature over 104 degrees.

In the U.S., a series of atmospheric high-pressure systems resulted in stagnant heat domes, which resulted in more than 150 million people living under heat warnings and advisories. Nearly every part of the continental U.S. saw above-average temperatures. There were record-breaking triple-digit highs in several states, sometimes persisting for days.

The south-central part of the country developed a ridge of high pressure that established a heat dome that acted like a lid, trapping hot air over that area. The extreme heat persisted throughout the month, at times expanding to the Southwest, Upper Midwest, and Southeast.

In the second half of the month, the Great Plains experienced temperatures as high as 115 degrees. Utah and Oklahoma both broke long-standing records for the most consecutive days on which temperatures exceeded 100 degrees. Utah saw 16 straight days over 100.

In the Pacific Northwest temperatures reached 110 degrees in Dallasport, Washington, and 114 in Medford, Oregon. In the Northeast, Newark, New Jersey saw a record-breaking five straight days over 100 degrees.

In Albany, New York, where the average daily high temperature is 82 degrees in July, there were 10 days in the 90s, with highs of 97 on three occasions.

July was a hot month indeed.

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A July of Extremes

Photo, posted July 10, 2022, courtesy of Dominic Alves via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Side Effects Of Geoengineering | Earth Wise

July 20, 2020 By EarthWise Leave a Comment

As the world struggles to reduce the greenhouse gas emissions that are warming the global climate, some researchers are exploring proposals to deliberately engineer climate changes to counteract the warming trend. One of the most widely discussed approaches is to shade the Earth from a portion of the sun’s heat by injecting the stratosphere with reflective aerosol particles. Proponents of this idea point out that volcanoes do essentially the same thing, although generally for only a limited amount of time. Particularly large eruptions, such as the Krakatowa eruption of 1883, wreaked havoc with weather around the world for an entire year.

Schemes to launch reflective aerosols – using planes, balloons, and even blimps – appear to be quite feasible from the standpoint of physically accomplishing them. But this says nothing about the political, ethical, and societal issues involved. The point is that such an approach could indeed lower global temperatures and thereby potentially offset the warming effects of greenhouse gases.

A study by scientists at MIT looked at what other effects such a solar geoengineering project might have on the climate. Their modeling concluded that it would significantly change storm tracks in the middle and high latitudes. These tracks give rise to cyclones, hurricanes, and many more ordinary weather phenomena.

According to the study, the northern hemisphere would have weakened storm tracks, leading to less powerful winter storms, but also stagnant conditions in summer and less wind to clear away air pollution. In the southern hemisphere, there would be more powerful storm tracks.

Aside from turning the world’s weather patterns inside out, solar geoengineering would do nothing to address the serious issue of ocean acidification caused by increasing carbon dioxide levels.

As many have pointed out, playing the geoengineering game would have many unintended consequences.

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Study: Reflecting sunlight to cool the planet will cause other global changes

Photo courtesy of MIT.

Earth Wise is a production of WAMC Northeast Public Radio.

A Record Drop In Coal Consumption

August 2, 2017 By EarthWise

Global consumption of coal dropped by 1.7% last year. This is a major change considering that it had increased by an average of 1.9% per year from 2005 to 2015. China, which accounts for about half of the coal burned in the world, used 1.6% less in 2016, as compared to an increase of 3.7% per year over the previous 11 years.