Remote sensing can be incredibly helpful for obtaining data in areas where ground investigations are difficult or impossible, as can be the case in times of conflict, war, or suffering. It can be essential for rapidly collecting information about destruction levels, famine, and other humanitarian questions.
Synthetic Aperture Radar (SAR) measures the elevation of surfaces, giving researchers the ability to analyze changes over time. Most commonly, a satellite will pass over the area, sending radar waves down to Earth’s surface. When they hit something and are reflected back, we can gather information about the returned wave, telling us the elevation of the surface or structure at that specific point. By compiling many points and multiple scans, we can get a digital image of the area without even touching the ground.
To identify damaged infrastructure, researchers look at coherence in the data. As they scan the same areas multiple times over, they can compare the signals to each other. If the signals are very similar, that would correlate to a high coherence. If the coherence is stable, that indicates no change in the environment. But if the coherence decreases, that would indicate a change like damage between the two scans.
In places where missile strikes or ground attacks have occurred, SAR can prove an essential tool for gathering information. In the case of Palestine, ground data from people in the besieged Gaza Strip has been hard to obtain. This makes remote sensing technologies like SAR uniquely capable of mapping damaged infrastructure.
One study used SAR coherence over the first two months of Israel’s invasion to produce a map of likely damaged locations in Gaza. They determined that about 61% of all health facilities, 68% of all educational facilities, and 42% of all water infrastructure had sustained some level of damage as of November 2023, in addition to comparing damage in different areas to assess evacuation corridors. There, they found similar patterns of damage to infrastructure as they did in the rest of Gaza. Similar infrastructure classification was done in Ukraine as well with the goal of “capturing the evolution of destruction during the war and providing insights into the dynamics of urban warfare.” Based on the coherence comparisons they were able to flag the more damaged cities, documenting the areas of destruction.
Satellite-based SAR isn’t the only form of remote sensing used in hazardous situations. Imaging with uncrewed aerial systems (UAS) can also safely collect valuable information. In Ukraine, due to the invasion of the Russian military, huge amounts of the area are mined as of February 2023 and it is difficult to track and keep up with the pace of expansion. Using UAS has been essential for safely finding and neutralizing mines, and UAS are recognized as a real tool for mitigating threats by the UN Mine Action Service.
A 2024 paper details how, using high resolution cameras, UAS can be used to find partially buried mines using atypical visual elements. These can be “tire tracks, dry grass on a green surface, unusual traces of movement on the grass, sudden breaks in colour, texture, content, shape and size,” according to the study. When a mine is not visible above the surface, an infrared detector attached to the UAS can be used to scan under the surface. Mines have different thermal mass than the ground surrounding it, so IR systems can detect buried mines and even identify the different types. Imaging might also be able to compare current environments to previous images, identify changes, and essentially map a minefield in 3D.
Remote sensing is often used to study the environmental impacts of human activities, and conflict can affect the environment, as well. One study looked into this in Syria, which has been entangled in a civil war since 2011. Warfare can damage or even ruin landscapes through bombings, repeated foot and vehicle traffic, and displacement of people. Having a large concentration of people move to one area can put a lot of pressure on the environment as settling commences, like how 6 million people in Syria were displaced in March of 2011 when conflict began.
By looking at open source urban planning data combined with remote sensing, they could analyze how the area was changing around the new settlements. This study concluded that in the main area people fled to, 19.3% of the forest cover was lost in the nine years after—indicating that armed conflict was a direct cause of deforestation in Syria—while there had been a steady increase in forested areas prior to 2011, producing 30 million tree seedlings annually. This isn’t even including wildfires and burning caused by explosive events.
Confirming this kind of data on the ground is difficult, and remote sensing data is not as precise as closer assessments. However, the rapid and broad availability of remote sensing data can be extremely useful in ongoing crises. Additionally, researchers can compare their work to official reports, and can also attempt to get in contact with journalists in the areas that can do their own validation of the data from the ground.
These geophysical tools enable researchers to gather information from areas with dangerous conditions, and can help put a spotlight on human suffering, giving many groups of people a voice. They can use the data gathered to explain to others the severe impacts of conflicts on civilians and help uphold human rights standards, allowing people to advocate for conflict-affected regions. The use of satellite imagery and remote sensing to observe and monitor areas has become a significant humanitarian branch of science that will likely continue to expand, bringing light to human struggles.