satellite data

New Orleans is sinking

August 14, 2025 By EarthWise Leave a Comment

As climate change accelerates, rising sea levels are putting coastal communities at greater risk of flooding and storm surge. Driven by melting glaciers and warming oceans, global sea levels are rising at an increasing rate. For low-lying cities like New Orleans, even small increases can have serious consequences. And that risk is compounded by another factor: the land itself is sinking.

Much of New Orleans already sits at or below sea level, and parts of the city and its surrounding wetlands are gradually sinking. While most of the city remains stable, a new study by researchers from Tulane University suggests that sections of the region’s $15 billion post-Katrina flood protection system may require ongoing upgrades to keep pace with long-term subsidence.

The study, recently published in the journal Science Advances, used satellite data to track changes in ground elevation across Greater New Orleans between 2002-2020. The researchers found that some areas – including neighborhoods, wetlands, and even concrete floodwalls – are sinking by more than an inch each year. In some spots, the land is dropping by nearly two inches annually.

Alarmingly, some of the concrete floodwalls and levees built to protect the city after Hurricane Katrina are themselves sinking. In a few cases, they are losing elevation faster than sea levels are rising, reducing their capacity to block storm surges.

The study highlights how satellite monitoring can play a critical role in guiding infrastructure maintenance and urban planning – not just in New Orleans – but in vulnerable coastal cities around the world.

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Vertical land motion in Greater New Orleans: Insights into underlying drivers and impact to flood protection infrastructure

Photo, posted September 22, 2010, courtesy of U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Threats to the Amazon Rainforest

August 1, 2024 By EarthWise Leave a Comment

Brazil has made great progress in reducing deforestation in its Amazon Rainforest. In 2023, the rate of deforestation in Brazil dropped by 50% over the previous year. This was the result of the efforts by conservation-minded President Luiz da Silva, who replaced Jair Bolsonaro, a big proponent of deforestation. Da Silva’s government has cracked down on land clearing by farmers and ranchers.

In the first quarter of this year, deforestation decreased by 40% over the previous year’s quarter. Deforestation levels are the lowest they’ve been in six years, although the amount of forest cleared in the period was still nearly 200 square miles.

Unfortunately, the Amazon Rainforest is facing another growing threat: climate change. Because of pervasive drought and increasing temperatures, the number of wildfires in the region have hit a 20-year high.

According to satellite data from the national space agency, from January through June, Brazil recorded 13,489 wildfires in the Amazon. That is 61% more fires than during the same period last year. And the wildfire season has yet to reach its peak, which usually is in August or September.

Many of these fires begin in pastures or recently cleared rainforest, but then spread into the surrounding rainforest areas. Many are huge fires. Hundreds of square miles of rainforest have been consumed by fire, comparable in size to the areas deforested by farmers and ranchers.

Going forward, worsening wildfires could reverse the gains being made by the government’s deforestation policies. This could not only threaten forest protection, but also weaken public support for the government’s commitment to protecting the region.

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Brazil Is Seeing a Record Number of Wildfires This Year

Photo, posted January 26, 2018, courtesy of Chris Parker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Trees Are Dying | Earth Wise

August 19, 2022 By EarthWise Leave a Comment

California relies on extensive forests to help reduce the amount of carbon dioxide entering the atmosphere. But extensive drought and increasingly frequent wildfires have been reducing the state’s tree population for the past three decades.

A comprehensive study by a team of scientists from the University of California Irvine used satellite data to study vegetation changes between 1985 and 2021. Across the entire state, tree cover area has declined 6.7% over that time period. The results varied from region to region across the state.

Southern California exhibited the sharpest decline, where 14% of the tree population in local mountain ranges vanished, potentially permanently. In the Sierra Nevada mountains, tree populations were relatively stable until about 2010. After that, a severe drought followed by historically large wildfires resulted in a 8.8% die-off of trees. The northern parts of the state, with higher rainfall and cooler temperatures, fared better, being able to more easily recover from wildfires.

The study goes beyond measuring the tree population of the state and its effects on carbon storage. The data is also important for understanding how changes in forest cover affects water resources and fire behavior in the state.

The decline of trees in California is affecting the carbon storage abilities of the state. The satellite survey showed that as the tree populations have dropped, the state’s coverage of shrubs and grasses has risen, possibly indicating that permanent ecosystem shifts are occurring. The forces contributing to the decline of trees in California are not going away any time soon. As a result, the threat to California’s ability to mitigate the effects of climate change continues to grow.

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UCI study: California’s trees are dying, and might not be coming back

Photo, posted March 24, 2016, courtesy of David Fulmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Levels Of Deforestation In The Amazon | Earth Wise

March 25, 2022 By EarthWise Leave a Comment

The Amazon rainforest is the largest rainforest in the world, covering more than 2.5 million square miles. It’s home to 10% of all known species in the world. The Amazon rainforest’s biodiversity is so rich that scientists are still discovering new plant and animal species today.

The Amazon rainforest absorbs huge amounts of carbon dioxide from Earth’s atmosphere, making it a key part of mitigating climate change. The vast rainforest acts as what’s known as a carbon sink. Simply put, a carbon sink is anything that absorbs more carbon from the atmosphere than it releases. But as trees in the Amazon disappear, so does the ability of the rainforest to absorb carbon dioxide.

Deforestation of the Amazon rainforest remains a major problem. According to satellite data from the Brazilian government, the number of trees cut down in the Brazilian Amazon in January far exceeded deforestation figures for the same month last year. Approximately 166 square miles of land was deforested in January alone, which is five times greater than what was lost in January, 2021.

Cattle ranching – both for beef and for leather – remains the leading cause of deforestation in the Amazon rainforest. Trees in the Amazon are also cut down for their wood, as well as to clear the land in order to grow food crops, such as soy, sugar, and oil palm.

Many companies have pledged to achieve “net zero” deforestation in their supply chains over the years, but most have not lived up to the commitment.

Deforestation is not only a major driver of climate change, but it’s also the leading cause of species extinction. Preserving the Amazon rainforest is vital.

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Web Links

Amazon deforestation: Record high destruction of trees in January

Greenpeace calls on fast food giants to take a stand against Bolsonaro’s Amazon destruction

Hundreds of Companies Promised to Help Save Forests. Did They?

Photo, posted July 14, 2018, courtesy of Alexander Gerst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Overwintering Fires | Earth Wise

July 6, 2021 By EarthWise Leave a Comment

Fires that go on for long periods of time, surviving the snow and rain of winter to reemerge in the spring, are becoming more common in high northern latitudes as the climate warms. Such fires are called holdover fires, hibernating fires, overwintering fires, or even zombie fires. Whatever people choose to call them, this type of wildfire is occurring more often.

These smoldering fires start out as flaming fires but then enter an energy-saver mode. They start above ground but then smolder in the soil or under tree roots through the winter. They barely survive based on the oxygen and fuel resources that they have but can transition back into flaming fires once conditions are more favorable.

Dutch researchers used ground-based data with fire detection data from NASA’s Moderate Resolution Imaging Spectroradiometer instruments on the Terra and Aqua satellites to study fires in the boreal forests of Alaska and Canada’s Northwest Territories. They found a way to identify overwintering fires based on their unique characteristics.

Their data indicates that overwintering fires tend to be linked to high summer temperatures and large fire seasons. Between 2002 and 2018, overwintering fires generally accounted for a small amount of the total burned area in the region but in individual years with hot and severe fire seasons, the number can escalate. In 2008 in Alaska, for example, overwintering fires accounted for nearly 40% of the burned area.

Early detection of these overwintering fires could help with fire management and reduce the amount of carbon – which is stored in large amounts in the region’s organic soils – that gets released to the atmosphere during fires.

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Overwintering Fires on the Rise

Photo, posted September 14, 2017, courtesy of Andrew R. Mitchell/USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Deep Learning And Dirty Air | Earth Wise

May 6, 2021 By EarthWise Leave a Comment

Poor air quality is a major global problem. According to the World Health Organization, exposure to air pollution is linked to the premature deaths of an estimated seven million people every year. In fact, 9 out of 10 people breathe air that contains more pollutants than what the WHO considers safe. Air pollution is the fourth largest threat to human health, trailing only high blood pressure, dietary risks, and smoking.

But predicting pollution levels at a given place and time remains challenging. According to a new study recently published in the journal Science of the Total Environment, scientists are turning to deep learning to improve air quality estimates.

According to researchers, satellite observations and ground observations both measure air pollution, but both have major limitations. For example, satellites may collect data at the same time and at the same location each day, but they miss how emissions may vary throughout the day. Ground-based observations from weather stations do continuously collect data, but they only do so in a limited number of locations.

As a result, scientists have turned to deep learning – a type of machine learning – to analyze the relationship between satellite and ground-based observations of nitrogen dioxide around Los Angeles. Nitrogen dioxide is associated with emissions from traffic and power plants. The researchers were able to rely on the learned relationship to take daily satellite observations and create hourly estimates of atmospheric nitrogen dioxide levels in approximately three mile grids.

According to the research team, this study could be repeated for other greenhouse gases, and applied to different cities and regions – or even whole continents.

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Scientists turn to deep learning to improve air quality forecasts

Air Pollution

Photo, posted November 4, 2019, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shrinking Ice In The Bering Sea | Earth Wise

October 19, 2020 By EarthWise Leave a Comment

The Bering Sea forms the divide between the two largest landmasses on Earth: Eurasia and the Americas. Recent analysis of vegetation from a Bering Sea island has determined that the extent of sea ice in the region is the lowest it has been for over 5,000 years.

St. Matthew Island, a small island in the middle of the Bering Sea, has essentially been recording what is happening in the ocean and atmosphere around it, in the form of the composition of peat layers on the island. By analyzing the chemical composition of peat core samples, scientists can estimate how sea ice in the region has changed over the course of time.

Changes in the relative amounts of two oxygen isotopes in the sediment and plant debris trapped in the peat on the island reflect the nature of precipitation during the period when the peat layers formed. That ratio is correlated with the amount of sea ice in the region. Satellite data acquired over the past 40 years confirms this correlation.

Analysis of the data shows that the current ice levels are unprecedented in the last 5,500 years. These long-term findings affirm that reductions in Bering Sea ice are due to more than recent higher temperatures associated with global warming. Atmospheric and ocean currents, which have also been altered by climate change, play a large role in the presence of sea ice.

Summertime sea ice in the Arctic was expected to reach its second-lowest extent in September in 40 years of observation. Sea ice typically builds up again each winter, but the changes in ice extents actually lag behind changes in greenhouse gas level by decades. Future ice loss is already built into the system.

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Bering Sea ice extent is at most reduced state in last 5,500 years

Photo, posted December 2, 2012, courtesy of Bering Land Bridge National Preserve via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Big Problem For The Giant Panda

November 10, 2017 By EarthWise Leave a Comment

The giant panda, a national icon of China, has been the focus of an intensive, high-profile conservation campaign since the 1970s. In an update to the IUCN’s Red List of Threatened Species last year, the giant panda had its designation changed from “endangered” to “vulnerable” following a nationwide census that revealed its population was improving. But it appears as though this conservation success may be short-lived.