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Rivers are drying up

November 4, 2024 By EarthWise Leave a Comment

According to a new U.N. report, the world’s rivers had their driest year in at least three decades. Record heat and droughts in many places contributed to low levels of water in many of the world’s rivers.

The world faces problems of either too much or too little water. The warming climate has fueled both powerful storms with heavy rainfall and intense droughts around the globe.

Last year was the hottest year on record, and it’s a record that is unlikely to last long. The Mississippi River and Amazon River basins were at all-time lows. Major rivers with headwaters in the Himalayas – the Ganges, Brahmaputra, and Mekong Rivers – were all unusually dry.

According to the World Meteorological Organizations State of Global Water Resources Report, nearly half of the nearly 1,000 rivers tracked around the world had below-normal levels of water. Only 17% had above-average levels. Over the past 32 years, on average only a quarter of the rivers monitored had below-normal water levels and last-year’s 45% was the largest ever.

Last year’s severe heat shrank glaciers that are a crucial source of meltwater that feeds rivers. Glaciers lost more ice last year than they have in at least 50 years.

More than half of the world’s population lives within a couple of miles of a body of fresh water. The places with the highest population densities around the world are almost all near large rivers. Rivers provide freshwater for irrigation, consumption, and transportation and are an important source of energy. Historically, they have played an important role in the development of human society. The shrinking of rivers is a big deal.

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World’s Rivers Are Driest They Have Been in Decades

Photo, posted August 22, 2023, courtesy of Radek Kucharski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Thawing permafrost: Is it a ticking timebomb?

July 8, 2024 By EarthWise Leave a Comment

Permafrost covers about a quarter of the landmass in the Northern Hemisphere. It stores vast quantities of organic carbon in the form of dead plant matter. As long as it stays frozen, it is no threat to the climate. But as it thaws, microorganisms start breaking down that plant matter and large amounts of carbon are released into the atmosphere in the form of carbon dioxide and methane.

This process has often been described as a ticking timebomb for the climate. The theory is that once global warming reaches a certain level, the process will become self-amplifying setting off a catastrophic amount of warming. If that level was reached, it would be a tipping point in the changing climate.

An international research team from the Alfred Wegener Institute in Germany has extensively researched this hypothesis. Their conclusion is that within the permafrost, there are multiple geological, hydrological, and physical processes that are self-amplifying and, in some cases, irreversible. However, these processes act only locally or regionally. There is no evidence that some particular threshold in global warming could affect all permafrost and accelerate its thawing on a global level.

This research does not mean that Arctic permafrost is nothing to worry about. In fact, there are ways in which it is more worrisome. Because the permafrost is very heterogenous – meaning it is very different in different places – there will be numerous small, local tipping points that will be exceeded at different times and at different levels of warming. All of this will proceed in step with global warming, contributing to the overall worsening situation. There is no warming level below which permafrost thawing is not a problem.

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Thawing permafrost: Not a climate tipping element, but nevertheless far-reaching impacts

Photo, posted January 24, 2014, courtesy of Brandt Meixell / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon dioxide and wildfires

May 14, 2024 By EarthWise Leave a Comment

Climate change is a key factor in the increasing risk and extent of wildfires. Wildfires require the alignment of several factors, including humidity, temperature, and the lack of moisture in fuels, such as trees, shrubs, and grasses. All of these factors have strong ties to climate variability and climate change.

While the global surge in wildfires is often attributed to hotter and drier conditions, a new study by researchers from the University of California – Riverside has found that increasing levels of a greenhouse gas may be an even bigger factor.

According to the study, which was recently published in the journal Communications Earth & Environment, carbon dioxide is driving an increase in the severity and frequency of wildfires by fueling the growth of plants that become kindling.

Centuries of burning fossil fuels to produce heat, electricity and to power engines has added alarming amounts of carbon dioxide to the atmosphere. In fact, atmospheric CO2 levels are measuring more than 420 parts per million, which is a level not seen on earth for 14-16 million years.

Plants require carbon dioxide, along with sunlight and water, for photosynthesis. But rising levels of CO2 in the atmosphere are driving an increase in plant photosynthesis – an effect known as the carbon fertilization effect. This effect can make plants grow bigger and faster.

Warming and drying are important fire factors. These are the conditions that make the extra plant mass more flammable. But the study found that the increase in fires during hotter seasons is driven by the CO2-fueled growth of plants.

The researchers hope their findings will urge policymakers to focus on reducing carbon dioxide levels in the atmosphere.

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CO2 worsens wildfires by helping plants grow

Current carbon dioxide levels last seen 14 million years ago

Photo, posted January 17, 2024, courtesy of Jennifer Myslivy, BLM Fire/NIFC via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting coastal areas with tidal range electricity generation

February 13, 2024 By EarthWise Leave a Comment

Tidal range electricity generation uses the water level difference between high and low tides to operate generator turbines. The method requires the construction of barrages and sluices to capture water during high tides and then release it during generation at low tide. Tidal range generation is predictable renewable energy driven by the gravitational pull of the moon and sun.

It is only a practical scheme in those places that have large tidal ranges. The largest tidal range in the world is in the Bay of Fundy in Canada. The second largest is the Severn Estuary, in the UK. Tidal ranges are large in many places around Britain’s coasts. But they are also vulnerable to flooding and surges from rising seas.

A new study by Lancaster University in the UK has found that the environmental and economic benefits are huge because tidal range barrages can protect coastal areas from flooding and sea level rise. With two-way generation and pumping, the full range of existing tides can be maintained to protect and support low-lying intertidal areas such as saltmarshes and mudflats. High tides can be limited to existing levels simply by closing sluices and running turbines and low tide levels can be maintained by pumping. The study determined that with modern technology and operating procedures, these so-called estuarine barrages may be the only practical way to protect vital coastal habitats.

Earlier work by the researchers found that tidal range projects under commercial consideration in the UK can produce about 5% of the country’s electricity use and additional projects are feasible for 4 or 5 times as much generation.

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How tidal range electricity generation can protect coastal areas from flooding

Photo, posted August 17, 2014, courtesy of Andrea via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A New Low For Lake Powell | Earth Wise

November 2, 2021 By EarthWise Leave a Comment

Lake Powell is the second largest reservoir by capacity in the United States. It straddles the border of southeastern Utah and northeastern Arizona and was created by the Glen Canyon Dam, completed in 1963. The reservoir serves as a bank account of water that is drawn upon in times of drought and has made it possible to weather extended droughts by sustaining the needs of cities, industries, and agriculture in western states. Hydroelectric power by the dam’s eight generators provides electricity to seven states.

As a result of the protracted drought in the west, the water levels in Lake Powell have reached the lowest point since 1969. As of September 20, the lake held only 30% of its capacity and federal managers started releasing water from upstream reservoirs to help keep Lake Powell from dropping below the so-called minimum power threshold which is the water elevation that must be maintained to keep the dam’s hydropower turbines working properly.

With the entire Lower Colorado River water system below 40% of capacity, Bureau of Reclamation recently announced that water allocations in the U.S. Southwest would be cut over the next year. The Colorado River basin is managed to provide water to millions of people including those in San Diego, Las Vegas, Phoenix, and Los Angeles.

Successive dry winter seasons over the past two years along with a failed 2020 summer southwestern monsoon, have led to the lowest precipitation levels on record in the Southwest going at least as far back as 1895. With warm temperatures, reduced snowpack, and increased evaporation of soil moisture, most of the American West suffers from persistent and widespread drought.

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Lake Powell Reaches New Low

Photo, posted June 28, 2021, courtesy of the USFWS – Mountain Prairie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conserving The Colorado River | Earth Wise

August 13, 2020 By EarthWise Leave a Comment

Last year, we talked about the troubles facing the Colorado River. Nearly two decades of drought conditions have reduced the water levels of the two largest reservoirs of Colorado River water and have threatened the water supply of millions of people in the region. Clear scientific evidence shows that climate change is constricting the iconic river and will do further damage as temperatures rise.

Faced with these facts, water resource managers have been implementing conservation policies in the region and the results so far are very encouraging.

The use of Colorado River water in the three states of the river’s lower basin – Arizona, California, and Nevada – fell to a 33-year low in 2019. The three states consumed just over 6.5 million acre-feet for the year, which is about 1 million acre-feet less than the three states are entitled to use under the legal agreement that allocates Colorado River water.

The last time water consumption from the river was that low was in 1986, which is the year that Arizona opened a large canal that extracts river water for its entitlement.

A key indicator of river health is the depth of Lake Mead, the largest reservoir of Colorado River water. It has been steadily dropping in recent years, but last year, with the reduced consumption, the water level actually increased by 12 feet.

According to water managers, the steady drop in water consumption in recent years is a sign that conservation efforts are working and that there are strategies that can deal with chronic shortages on the river in the future. It represents an important demonstration that it is possible to use less water in a region that irrigates 5 million acres of farmland and has 40 million people in 2 countries and 29 tribal nations.

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Remarkable Drop in Colorado River Water Use a Sign of Climate Adaptation

Photo, posted July 7, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.