tracking

Tracking emissions by satellite

June 20, 2025 By EarthWise Leave a Comment

Carbon dioxide and nitrogen oxides are two of the most problematic human-generated air pollutants that negatively impact air quality, the climate, and human health. Satellites are an important tool for monitoring emissions of these pollutants, but they have limitations. For the most part, satellites have limited spatial resolution, meaning that they can’t reliably narrow down the source of emissions sufficiently to pin down a specific location such as a power plant.

Until now, there have been no instruments that can detect both carbon dioxide and nitrogen oxide simultaneously with high spatial resolution. Often just nitrogen oxide measurements are made, and carbon dioxide levels estimated based on the fact that both are emitted together with typical ratios.

A German research team from the Max Planck Institute and the Heidelberg Institute have developed a technology for the EnMAP environmental satellite to detect both gases with an unprecedented spatial resolution of 30 meters. Data from the satellite makes it possible to track multiple sources of emission plumes over several tens of kilometers.

The EnMAP system was originally designed for remote sensing of land surfaces. The new research demonstrates that reliable measurements of trace gases are possible even with an instrument not specifically designed for atmospheric observations. When using it, it’s possible to determine the distribution of carbon dioxide and nitrogen oxide in emission plumes from individual power plants. The ability to measure both gases individually means that conclusions can be drawn about the technology, efficiency, and operating mode of the systems being measured.

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German satellite measures CO2 and NO2simultaneously from power plant emissions for the first time

Photo, posted September 19, 2020, courtesy of Sandor Somkuti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking atmospheric mercury

May 13, 2025 By EarthWise Leave a Comment

Atmospheric mercury is a toxic pollutant released into the air from natural sources—such as volcanoes and wildfires—and from human activities like coal burning and gold mining. Once in the atmosphere, mercury can travel long distances before settling onto land or into water, transforming into toxic forms that threaten ecosystems and human health.

But tracking atmospheric mercury is a costly and challenging endeavor, requiring specialized equipment and trained personnel. Active monitors, which pump air to collect mercury, are expensive and need electricity, while passive samplers, using activated charcoal for remote areas, cost up to $100 each.

Researchers from Cornell University have found a cheap method for tracking toxic atmospheric mercury near gold mining sites throughout the Global South: wild fig trees. In the study, which was conducted in the Peruvian Amazon and recently published in the journal Frontiers in Environmental Science, the research team found that the rings in wild fig trees can serve as natural archives of atmospheric mercury, capturing and preserving historical pollution levels over time.

The technique itself is not actually new. Previous studies have used tree rings to track mercury pollution from coal combustion, particularly in Canada. But the research team wanted to test this method in regions of the Global South, where mercury emissions from gold mining are widespread.

According to the research team, wild fig trees might soon serve as an important biomonitoring tool, helping scientists better understand how mercury disperses across landscapes and through time.

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Tree rings track atmospheric mercury cheaply

Photo, posted November 13, 2012, courtesy of Steve Kessler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Why was 2023 so hot?

February 2, 2024 By EarthWise Leave a Comment

Five separate weather-tracking organizations have proclaimed 2023 as the hottest year on record. They all agreed that 2023 beat the previous record-holder – 2016 – by a wide margin. Organizations that use a pre-industrial baseline of 1850-1900 found that 2023 was 1.45 to 1.48 degrees Celsius above the baseline. But what caused 2023 – especially the second half of it – to be so hot?

Scientists believe that there were multiple factors that contributed to the record-breaking heat.

First and foremost is the long-term rise in greenhouse gases. Over 100 years of burning fossil fuels along with major changes in land use (particularly deforestation) have led to a significant rise in the heat-trapping blanket of the gases in the atmosphere.

On top of this long-term trend, the return of the El Niño condition in the Pacific in May helped temperatures rise further.

At the same time, the tropical Pacific was not the only ocean that was hotter than normal. The global sea surface temperature set new records in 2023 and there were multiple marine heat waves. Heat trapped by the atmosphere is absorbed by the oceans, raising their temperatures.

Another factor is the quantity of aerosols in the atmosphere. Many of these aerosols actually cool the atmosphere by reflecting the sun’s light back into space. Society’s efforts to reduce air pollution and improve air quality have led to decreasing levels of aerosols.

2024 started with some seriously cold weather in some places but predictions are that this year will be roughly as warm as 2023 and possibly warmer given that the dynamics driving last year’s weather are all still in place.

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Five Factors to Explain the Record Heat in 2023

Photo, posted February 22, 2016, courtesy of Jasmin Toubi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking down PFAS toxins

December 5, 2023 By EarthWise Leave a Comment

PFAS – per- and polyfluoralkyl substances – are a group of organic compounds that have been extensively used to provide water-, oil-, and dirt-resistance to a wide range of products ranging from non-stick pans, clothing, and packaging to paint, car polish, and fire-suppressant foam. Exposure to specific PFAS compounds is associated with multiple adverse health effects, including altered immune and thyroid function, liver disease, kidney disease, poor reproductive and developmental outcomes, and cancer. PFAS compounds do not break down in the environment and therefore, over time, become concentrated in plants, animals, and people.

Government agencies such as the EPA in this country and the EU have set strict limits for allowable levels of PFAS in drinking water. Testing water for the trace amounts of PFAS that constitute the limits is time-consuming and expensive and requires complex equipment and experienced personnel.

Researchers at MIT have now introduced a technique for making a portable, inexpensive test that can easily and selectively detect PFAS in water samples. The test makes use of a special polymer containing fluorinated dye molecules that cause the polymer to fluoresce red. If PFAS are present in the sample, they enter the polymer and displace the dye molecules and switches off the red fluorescence.

The new technique is suitable for on-site detection in highly contaminated regions. Detecting smaller concentrations can be achieved with sufficient precision after pre-concentrating the samples using the process of solid-phase extraction.

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Tracking down Environmental Toxins

Photo, posted October 16, 2021, courtesy of Nenad Stojkovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Hottest Summer | Earth Wise

October 13, 2023 By EarthWise Leave a Comment

It was a very rainy and relatively cool summer in much of New England as well as in New York’s Capital Region, where Earth Wise originates. Despite that fact, according to NASA scientists, the summer of 2023 was the Earth’s hottest since global record keeping began in 1880.

The months of June, July, and August taken together were .41 degrees Fahrenheit warmer than any other summer on record as well as being 2.1 degrees warmer than the average summer between 1951 and 1980.

The record summer heat was marked by heatwaves in South America, Japan, Europe, and the US. The heat exacerbated wildfires in Canada that dumped smoke across much of the northern tier of our country and also led to severe rainfall in Europe. All sorts of temperature records were set in places across the globe.

According to NASA, exceptionally high sea surface temperatures, fueled in part by the reemergence of El Niño in the Pacific, were a major factor in the summer’s record warmth.

The record-breaking heat of this summer continues a long-term trend of warming. Scientists around the world have been tracking the warming that is driven primarily by human-caused greenhouse gas emissions. The combination of this background warming and the marine heatwaves set the stage for new temperature records. The El Niño was enough to tip the scales.

In the current environment, heat waves will last longer, be hotter, and be more punishing. The atmosphere can hold more water producing hot and humid conditions that are harder for the human body to endure.

Scientists are expecting the biggest impacts of El Niño in the early parts of next year. We can expect to see extreme weather of many kinds over the next year.

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NASA Announces Summer 2023 Hottest on Record

Photo, posted June 8, 2023, courtesy of Anthony Quintano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Large Lakes In Decline | Earth Wise

June 27, 2023 By EarthWise Leave a Comment

Globally, freshwater lakes and reservoirs hold 87% of the planet’s liquid freshwater, making them a valuable resource for both people and wildlife. Despite their value, the long-term trends and changes to water levels of lakes have been largely unknown – until now.

According to a new assessment recently published in the journal Science, more than half of the largest lakes around the world are losing water. Using satellite observations and climate data, the research team created a technique to measure changes in water levels in nearly 2,000 of the world’s biggest lakes and reservoirs, representing 95% of the total lake water storage on Earth.

The results are staggering. According to the findings, 53% of Earth’s largest lakes and reservoirs now store significantly less water than they did in 1992. The total amount of water lost is estimated to be 144.5 cubic miles, which is equivalent to the volume of 17 Lake Meads (the largest reservoir in the U.S.).

Unsurprisingly, climate warming and human consumption were the main drivers of water loss from lakes, whereas sedimentation — the buildup of debris — was the biggest driver of water loss in reservoirs. Roughly one-quarter of the world’s population – two billion people – live in the basin of a drying lake, indicating the urgent need for sustainable water resources management.

But the news is not entirely bleak. According to the research team, the new method of tracking lake water storage trends can give water managers and communities insight into how to better protect this critical resource.

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Satellites reveal widespread decline in global lake water storage

Photo, posted February 10, 2010, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seaweed On The Way | Earth Wise

April 28, 2023 By EarthWise Leave a Comment

A type of seaweed called sargassum has long formed large blooms in the Atlantic Ocean. It gets its name from the Sargasso Sea in the western Atlantic. Since 2011, scientists have been tracking massive accumulations of the stuff each year that starts out off the coast of Africa and works its way across the Atlantic to end up in the Gulf of Mexico.

The amount of sargassum present each year can shift depending on factors like changes in nutrients, rainfall, and wind conditions. But since the 1980s, nitrogen content in the Atlantic has gone up by 45%. This is likely due to human activities such as agriculture and fossil fuel production dumping materials into the rivers that feed into the ocean.

According to recent observations, the mass of seaweed now heading for Florida and other coastlines throughout the Gulf of Mexico may be the largest on record. The giant blob of sargassum spans more than 5,000 miles in extent. It is moving west and will pass through the Caribbean and up into the Gulf during the summer. The seaweed is expected to become prevalent on beaches in Florida around July.

The seaweed provides food and protection for fishes, mammals, marine birds, crabs, sea turtles, and more. But unfortunately, when sargassum hits the beaches, it piles up in mounds that can be difficult to walk through and eventually emits a gas that smells like rotten eggs.

Tourist destinations in the Caribbean region have their work cut out for them to remove seaweed that can pile up several feet deep. For example, in Barbados, locals were using 1,600 dump trucks a day to clean their beaches. Caribbean and Florida resorts spend millions of dollars each year to remove sargassum seaweed.

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A 5,000-mile-wide blob of seaweed is headed for Florida, threatening tourism across the Caribbean

Photo, posted February 24, 2020, courtesy of Bernard Dupont via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking Global Forest Changes | Earth Wise

January 30, 2023 By EarthWise Leave a Comment

India is one of the most biodiverse countries in the world. An estimated 47,000 plant species and 89,000 animal species can be found in India, with more than 10% of each thought to be on the list of threatened species.

India is also one of the 10 most forest-rich countries in the world. Trees cover approximately 25% of the nation. But this is still a significant decline from years past. In fact, between the 1890s and 1990s, a combination of rapid development and resource overexploitation caused India to lose nearly 80% of its native forest area. Today, as India’s forests continue to disappear, researchers are trying to help preserve what forest remains.

Using satellite-monitoring data, researchers from The Ohio State University have developed a deep learning algorithm that could provide real-time land use and land cover maps for parts of India.

The land use monitoring system was trained using satellite data from Norway’s International Climate and Forests Initiative. By combining this data with a global land cover map produced by Tsinghua University in China, the researcher team’s deep learning model was able to acquire a more detailed type of base map of the area. Using their model, the researchers were able to process 10 monthly maps. Their research was recently presented at the annual meeting of the American Geophysical Union.

Using these maps, the researchers were able to detect seasonal shifts across india. These include changes to barren land, how crop land was affected by monsoons, and the distribution of forests in mountainous regions.

Understanding the impact of these seasonal changes will help scientists better predict the effects of climate change on forests.

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Using deep learning to monitor India’s disappearing forest cover

Photo, posted January 20, 2013, courtesy of Frontier Official via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mauna Loa Eruption And Climate Tracking | Earth Wise

January 9, 2023 By EarthWise Leave a Comment

Mauna Loa, the largest active volcano in the world, erupted for the first time in nearly 40 years in late November. A 124-foot aluminum tower at the top of the volcano has been the site of carbon dioxide measurements for over 60 years but the eruption cut off power to the site, stopping the monitoring.

Carbon dioxide measurements on Mauna Loa began in 1958. The project was started by geochemist Charles Keeling and eventually taken over by his son Ralph Keeling upon his father’s death in 2005. It is the longest continuous record of the rising levels of carbon dioxide in the world.

Mauna Loa is an ideal location for carbon dioxide monitoring because it is a remote location away from both carbon dioxide sources like dense population centers and roads, and carbon sinks like areas of heavy vegetation.

There are hundreds of carbon dioxide monitoring stations around the world, including more than 70 operated by the National Oceanic and Atmospheric Administration, so the interruption will not stop global recordkeeping. But Mauna Loa holds significant symbolism as the first and most frequently sited source of carbon dioxide data.

There have been other interruptions in the measurements. Federal budget cuts in 1964 paused them for about 3 months. A 1984 eruption also cut off power to the facility and shut it down for about a month.

When the facility first started operating, the average carbon dioxide concentration was measured at 313 parts per million. Most recently, levels have peaked at around 421 parts per million, the greatest concentration in at least 4 million years.

Power will be restored to the Mauna Loa facility and its measurements will resume.

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Mauna Loa Eruption Threatens a Famous Climate Record

Photo, posted November 29, 2022, courtesy of L. Gallant / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tracking Small-Scale Fishers | Earth Wise

October 4, 2022 By EarthWise Leave a Comment

About half of all global seafood is caught by artisanal fishers. These are individuals who operate on a small scale – often on a subsistence level – and typically fish only a short distance from shore. Over 85% of the estimated 2.5 million motorized fishing vessels in the world are less than 12 meters in length. Compared with large-scale commercial fishing operations, these enterprises are very small. However, they are essential to the food security and livelihoods of their communities. Because of their sheer numbers, artisanal fishers are an important sector to monitor, manage, and advocate for. They may be small-scale, but their importance and impact are huge.

Large ships make use of vessel tracking systems, which were originally conceived to prevent maritime collisions. Over time, VTS technology has become useful for other purposes including monitoring fishing activity in sensitive marine areas and looking out for forced labor on the high seas.

Among small fishing vessels, only an estimated 0.4% are equipped with VTS technology. So, a massive number of vessels accounting for a big part of the global catch cannot be monitored.

Researchers at UC Santa Barbara surveyed hundreds of artisanal fishers in Indonesia and Mexico to see if they were willing to pay to participate in a VTS program, or participate for free, or be paid to participate. Having the equipment would provide multiple benefits to the fishers including increased safety and better fisheries management. Two-thirds of the survey participants said they were willing to pay for the technology. The study is the first effort to explore the potential for encouraging wide adoption of VTS technology among artisanal fishers.

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Tracking Small-Scale Fishers

Photo, posted November 30, 2014, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking Ocean Plastics | Earth Wise

July 30, 2021 By EarthWise Leave a Comment

Plastic pollution in the oceans is a major problem. An estimated 8 million tons of plastic trash enters the ocean every year. Most of it is broken up by sun and waves into microplastics, which are tiny bits that ride currents for hundreds or thousands of miles. All of this debris is harmful to marine ecosystems, and it is both challenging to track and very difficult to clean up.

University of Michigan researchers have developed a new technique for spotting and tracking ocean microplastics across the globe. The approach relies on the Cyclone Global Navigation Satellite System, or CYGNSS, which is a constellation of eight microsatellites launched in 2016 to monitor weather near large storm systems. It turns out that the radar systems on CYGNSS that measure surface roughness to calculate the wind speed near the eyes of hurricanes can also be used to detect the presence of microplastics.

With the satellite measurements, the researchers have found that global microplastic concentrations tend to vary by season, peaking during the summer months. For example, June and July are the peak months for the Great Pacific Garbage Patch. The data also showed spikes in microplastic concentration at the mouth of China’s Yangtze River, long suspected to be a chief source of plastic pollution. The researchers produced visualizations that show microplastic concentrations around the world.

The information provided by the new technique could help organizations that clean up microplastics to deploy ships and other resources more efficiently. Data of single-point release of plastics, such as from rivers, may also be useful to UNESCO, which has sponsored a task force to find new ways to track the release of microplastics into the world’s waters.

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Ocean microplastics: First global view shows seasonal changes and sources

Photo, posted April 3, 2018, courtesy of Rey Perezoso via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sea Turtles And The Sargasso Sea | Earth Wise

June 15, 2021 By EarthWise Leave a Comment

The lifecycle of sea turtles includes a longstanding mystery, often called the “lost years”. Turtles hatching from nests along Florida’s Atlantic coast head into the ocean and are generally not seen again for several years before they return in their adolescence. Very little is known about where they spend this time in the open ocean.

Researchers at the University of Central Florida have learned that green turtles as well as loggerhead turtles – both iconic species in conservation efforts – may be spending their youth in the legendary Sargasso Sea. The Sargasso Sea is located off the east coast of the U.S. in the North Atlantic Ocean. It has frequently been featured in popular culture, such as in the novel Twenty Thousand Leagues Under the Sea, as a place where ships could be trapped in thick mats of floating, brown Sargassum seaweed for which the sea is named.

The researchers tracked the baby turtles by attaching advanced, solar-powered tracking devices, about an inch long, to their shells. They used a special adhesive that held the devices to the turtle shells but would allow the devices to fall off after a few months causing no harm to the turtles or inhibiting shell growth or behavior.

It was previously thought that baby turtles would passively drift in sea currents and simply ride those currents until their later juvenile years. The new research shows that the turtles actively orient to go into the Sargasso Sea.

Studies of where turtles go as they develop are fundamental to sound sea turtle conservation. If we don’t know where turtles are and what parts of the ocean are important to them, we are doing conservation blindfolded.

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Legendary Sargasso Sea May be Sea Turtles’ Destination during Mysterious ‘Lost Years’

Photo, posted October 23, 2016, courtesy of Kris-Mikael Krister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tracking Endangered Species From Space | Earth Wise

March 4, 2021 By EarthWise Leave a Comment

Scientists at the University of Bath and the University of Oxford in the UK have developed a technique for remotely surveying elephants and other wildlife using satellite images and deep learning. The technique has the same accuracy as human counts done on the ground or from low-flying airplanes.

The new computer algorithm can analyze high-resolution satellite images and detect African elephants in both grasslands and forests. Previous techniques for monitoring wildlife from space were limited to homogenous habitats, such as the case of tracking whales in the open ocean.

On-the-ground or airplane surveys to monitor animal numbers are expensive and time-consuming. Satellites can collect nearly 2,000 square miles of imagery in a few minutes thereby eliminating the risk of double counting and reducing a process that previously took weeks to just a few days. The use of satellites also eliminates the logistical problems of monitoring species populations that cross international borders.

Accurate monitoring is important for efforts to save endangered species. There are only 40,000 – 50,000 African elephants left in the wild. It is essential to know where the animals are and how many there are in various locations. The new method is able to count elephants in mixed ecosystems, such as savannah and forests, where tree cover would previously have made satellite tracking difficult.

With satellite imagery resolution increasing every few years, it should be possible to see ever-smaller things in greater detail. The new algorithm works well for elephants; it may eventually become practical to track animals as small as an albatross from space.

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A New Way to Track Endangered Wildlife Populations from Space

Photo, posted March 15, 2008, courtesy of Michelle Gadd/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Genetic Variation And Survivability | Earth Wise

January 21, 2021 By EarthWise Leave a Comment

A massive but unintended experiment in animal conservation has revealed an unexpected result. Thousands of desert tortoises moved to a translocation site in Nevada had a greater chance of surviving if they had lots of genetic variation.

From 1997 to 2014, over 9,000 Mojave desert tortoises were moved to a 39-square-mile translocation site in the Ivanpah Valley. The tortoises were either abandoned pets or were displaced by developments in suburban Las Vegas and by solar farms in the desert.

The U.S. Fish and Wildlife service took blood samples to screen for diseases and marked each animal before releasing them into the site, enabling them to be tracked in later surveys.

When the researchers compared tortoises that lived or died over the same time period after being relocated to the site, they found that survivors averaged 23% greater heterozygosity than those that perished. Heterozygosity is a measure of genetic variation. Like most organisms, tortoises have two copies of their entire genome, with one from each parent. The more those copies differ from each other, the higher the organism’s heterozygosity.

Researchers are not really sure why greater genetic variation is linked to survival rates. Potentially, individuals with higher heterozygosity have more genomic flexibility. It is the case that tortoises with more genetic variation have a better chance of having at least one copy of a gene that works really well in stressful or new environments.

Human activity and the changing climate are increasing the need to relocate plants and animals. Often the chances for success in doing this are not good, so anything we can learn about things that increase the chances for survival can be very important.

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UCLA study of threatened desert tortoises offers new conservation strategy

Photo, posted August 23, 2016, courtesy of the Bureau of Land Management California via Flickr. Photo by Dana Wilson, BLM.

Earth Wise is a production of WAMC Northeast Public Radio.

Tracking Locust Swarms | Earth Wise

June 12, 2020 By EarthWise Leave a Comment

Plagues of locusts have been reported since the times of the Egyptian pharaohs. In recent history, there have been desert locust plagues during multiple decades of the 20th century. Since January, a very large population of locusts gathered in Kenya and has destroyed over 2,000 square miles of pasture and crop land. Swarms have since reached portions of Ethiopia, Somalia, Uganda, and South Sudan. Apart from East Africa, there are locust swarms in Yemen and other Middle East countries and in Pakistan as well. The current situation continues to represent an unprecedented threat to food security and livelihoods in East Africa. Locust swarms can range in size from less than half a square mile to hundreds of square miles, each containing 20 to 40 million locusts.

The National Oceanic and Atmospheric Administration uses a powerful air quality model to track the movement and deposition of pollution from wildfires, volcanoes and industrial accidents. Called the HYSPLIT dispersion model, it has now been refined for the purpose of tracking swarms of locusts.

Because desert locusts are passive fliers that drift with the wind, the model’s high-quality data on wind speed and direction can lead to accurate predictions of where the locusts will go and when.

NOAA is working with the United Nations Food and Agriculture Organization – the FAO. The new web application based on HYSPLIT is being used by the FAO to issue forecasts and warnings to affected countries about forthcoming waves of locust swarms. Such forecasts enable local officials to conduct aerial spraying to reduce the impact of desert locusts which can destroy grains, grasses and other greens that are life-sustaining foods for entire regions.

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