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Our everyday hero in the sky: Environmental monitoring satellites

Environmental monitoring is of the utmost importance to our safety – and our survival – as human beings. And none of what we are capable of seeing and understanding today would be possible without Earth Observation (EO) satellites.

EO satellites allow us to monitor and collect reliable data for weather forecasting, our oceans and our land. This includes data for tracking tropical cyclones, storms, sea surface temperatures and sea level height, wind speeds and direction, cloud cover, oil spills, vegetation cover and even soil moisture. What’s more, EO satellites do this every day, all day, for any place around the world, no matter how remote the environment or how small the event is.

And of course, environmental monitoring satellites also allow us to collect invaluable information on climate change and natural disasters (and natural disasters made worse by climate change).

Here are some examples in which our ability to “watch over” Earth using satellites has helped us live (and learn) in the face of climate change and natural disaster.

Keeping up with El Niño 

El Niño is part of the ENSO climate cycle of warm and cold temperatures across the Pacific Ocean that often has the strongest influence on Australia’s climate variability from year to year. In places like California and Peru, El Niño is associated with torrential storms, floods and mudslides; while in Indonesia and Australia, El Niño means drought, a later monsoon season and an increased risk of bushfires.

With climate change having increasingly dangerous and deadly effects on our environment, understanding the potential range of the next El Niño’s impacts is vital.

Through environmental monitoring using satellites such as the U.S. NOAA’s Jason-3, the possible effects of El Niño are easier to foresee. This means that farmers can be informed about possible droughts adapt their yearly crops thereafter. Warnings about higher temperatures can be given to rural communities earlier on, meaning they can prepare in case they need to buy cooling systems or create evacuation plans.

El Nino

Warm streams of water moving between Africa and Australia. Credit: NASA

The Great Barrier Reef

Something that lies very close to every Australian’s heart is the Great Barrier Reef (GBR), the largest coral reef system in the world. As with other coral reefs around the world, it withstands coral bleaching events every year; but researchers are now working their hardest to try to save it from the worsening impacts of global warming, as the increasing oceanic temperatures can lead to coral bleaching.

Coral bleaching is also closely correlated with El Niño and La Niña, which is why every year it is of the utmost importance to know the extent of these global weather patterns in a time of inexorable rises in global temperatures.

And the El Niño that preceded 2016-2017 set off a series of global coral bleaching events. ESA satellite Sentinel-2 captured the devastation of the GBR during this time, which was one of the areas hardest hit by this series of coral bleaching. By the end of 2017, over half of the Great Barrier Reef had died from coral bleaching, including several reefs that had never been bleached before in the northernmost part of the GBR.

At first, scientists working at ESA’s Sen2Coral project weren’t sure what they were seeing. Observation of bleaching is usually done by airborne surveys or diving, meaning that many reefs are not effectively monitored.

Without the Sentinel-2 satellite, we would not have known about this mass coral bleaching event as quickly as we did. Between the second and third bleaching events scientists were able to draw national and international attention to the plight of the coral reefs, and are now keeping a closer eye and stirring up more efforts to ensure the survival of the Great Barrier Reef.

This map from Australia’s ARC Center of Excellence for Coral Reef Studies shows the extent of the coral bleaching in certain parts of the Great Barrier Reef, especially in the northern parts. Airborne surveys were swiftly undertaken following and thanks to the satellite imagery that initially alerted scientists.

Check out the interactive map here.

Icelandic volcanic chaos


The plume from Eyjafjallajökull visible over the Atlantic Ocean. Credit: NASA (MODIS)

The volcano known as Eyjafjallajökull (yes, it’s supposed to be hard to pronounce) in Iceland has erupted a total of times: first in around 920, then 1612, two between 1821-1823 and most recently 2010.

In 2010 the eruption began in January with the onset of small earthquakes. But it wasn’t a one-time cluster of earthquakes: by mid-March, the earthquake activity was so frequent and intense that fountains of lava began exiting Fimmvörduháls Pass near the Eyjafjallajökull glacier. The lava melted and vaporized the glacier ice above. Then, mud, ice and meltwater quickly swelled local rivers and streams that in turn flooded farmland and damaged infrastructure.

Steam from the volcanic crater, combined with wind-blown ash, made it too difficult for the Icelandic Met Office to monitor the eruption from land. Expanding gases from the rapid vaporization of ice started a series of moderate phreatomagmatic explosions (a result from the contact of water and magma) that sent a plume of steam and ash almost 11km into the atmosphere.

Winds carried this plume into northern Europe and chaos followed. Fearing the damage to commercial aircraft as well as potential loss of life that could result from flying through the ash cloud, many European countries closed their national airspace and grounded flights for several days.

NASA’s MODIS device on its Aqua satellite was one of the satellites that helped keep track of the ash clouds from above, monitoring its movements as well as wind patterns, and helping European officials determine which airports and cities had to close down.


The data sets that are collected by environmental monitoring satellites are used not only by scientists but also emergency responders, educators and researchers to understand more about natural as well as human-caused climate changes. Through these data sets, they can also examine the ecological impacts of natural disasters such as floods, investigate and measure the effectiveness of environmental policies in certain areas or countries and help preserve our planet for future generations. By using the data we have at hand today, we can try and create a better tomorrow.

Written by Karin Ericsson

Edited by Megan Toomey and Samuel Lindsay

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