SDG 13. Climate action

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The climate is changing, and space technology is essential to help us understand and adapt to it

Benoit Meyssignac, Climatologist
CNES, Toulouse, France

My research focuses on the evolution of global water and energy cycles to understand climate change. Space technology enables scientists to monitor the rise in sea levels to understand its causes, and to provide risk assessments to help coastal communities adapt.

Interview

Benoît Meyssignac.
Photo: CNES/Emmanuel GRIMAULT

I’m a climatologist at the French space agency (CNES). As a student I studied physics and mathematics and then, after a PhD in oceanography, I joined CNES when I was about 25 years old. At CNES my first mission was astrodynamics, computing orbits for satellites. And then I switched to the analysis of satellite data for the understanding of climate change.

My work at CNES consists of analysing satellite data to monitor and understand climate change. I am particularly interested in the changes in the Earth’s water and energy cycles in response to climate change, and I analyse the changes in these cycles with satellite altimetry techniques and space geodesic techniques.

The Pine Island Glacier recently spawned an iceberg over 300 sq km that very quickly shattered into pieces. Thanks to the combination of both optical and radar images from the Copernicus Sentinel satellite missions, growing cracks were spotted in the Pine Island Glacier, and scientists have been keeping a close eye on how quick the cracks were growing. The Pine Island Glacier, along with its neighbour Thwaites glacier, connect the centre of the West Antarctic Ice Sheet with the ocean, and together discharge significant quantities of ice into the ocean.
Image: contains modified Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO

One important aspect of changes to the Earth’s water and energy cycles is the rise in sea level; this threatens millions of people, so our research has a special focus. The rise in sea levels is alarming. Right now sea levels are rising much faster than before, about five to 10 times faster than what the earth has experienced over the past 5-6000 years. This is because of anthropogenic greenhouse gas emissions. Because of these emissions, the infrared radiation of the Earth gets trapped and causes global warming. Most of the heat generated in global warming enters the ocean. As heat enters the ocean, the sea water expands making sea levels rise. Part of this heat has also entered the cryosphere melting the glaciers, but also melting ice sheets. This is also making sea levels rise.

Space techniques are absolutely essential in understanding the current rise in sea levels and we use space technologies to directly monitor this, but also to monitor coastlines for rises in sea level.

We use satellite altimetry radar developed by CNES and NASA to observe the current rapid rise, and we use space geodesics to observe the causes of rising sea levels, such as ice melting from the glaciers and ice sheets. Space technologies also enable us to evaluate the impact of rising sea levels. High resolution technology in particular enables us to estimate changes to local sea levels along the coast, and to assess the risk for coastal communities. We use interferometry radar with satellites, like SWOT that will be launched next year, to estimate local sea level changes at very local places like towns or even villages. On the continent, we can use high resolution imagery to evaluate the response of the coastline to changing sea levels, and also to evaluate floods during extreme events.

The Somme Bay, one of the most important European ornithological sites, is particularly vulnerable to climate change. Satellites monitor the dynamics of coastal environments and help decide the best course of action to take to mitigate rising sea levels.
Image: European Union, Copernicus Sentinel-2 imagery

This exhibition, Space for our Planet, is an opportunity to send a message to anybody listening. It is a message from scientists in the satellite community working on climate change.

When we work with satellite data, we realise that climate change is on-going. All our simulations in models show that climate change will last for hundreds of years or even more. We need to act as soon as possible, the sooner the better if we want to reduce the impact for the generations to come.

Gallery

The San Quintín Glacier has been in rapid retreat for the past 30 years contributing to rising sea levels. Satellite data are fundamental to improving our understanding of the rising sea levels caused by climate change.
Extra-high tides are a known phenomenon in the Marshall Islands. As climate change raises sea levels, low-lying coral islands, such as the Kwajalein Atoll, risk being submerge by 2035.
Sea ice along the eastern coast of Greenland. Sentinel-3 image acquired on 25 September 2020. Sea ice is of capital importance in climate dynamics as it reflects most of the solar radiation that it receives, thus affecting the average albedo of the earth, and also because it interposes a solid layer between the ocean and the atmosphere which reduces the free transfer of heat and moisture between the two. The Copernicus Sentinel-3 mission allows to develop innovative applications for sea ice monitoring, thanks to the onboard instruments that are able to retrieve accurate information about sea ice extent, temperature and thickness.
The Gangotri Glacier is one of the largest glaciers in the Himalayas and one of the main sources of water for the Ganges River. Satellite data show that the Gangotri Glacier has retreated by 3 km in two centuries, and this retreat is continuing at a rate of about 10 metres a year.
At around 120 km wide, Thwaites is the largest glacier on Earth and one of the most fragile glaciers in Antarctica.
JASON 3 Satellite.
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The Pine Island Glacier recently spawned an iceberg over 300 sq km that very quickly shattered into pieces. Thanks to the combination of both optical and radar images from the Copernicus Sentinel satellite missions, growing cracks were spotted in the Pine Island Glacier, and scientists have been keeping a close eye on how quick the cracks were growing. The Pine Island Glacier, along with its neighbour Thwaites glacier, connect the centre of the West Antarctic Ice Sheet with the ocean, and together discharge significant quantities of ice into the ocean.
The Pine Island Glacier recently spawned an iceberg over 300 sq km that very quickly shattered into pieces. Thanks to the combination of both optical and radar images from the Copernicus Sentinel satellite missions, growing cracks were spotted in the Pine Island Glacier, and scientists have been keeping a close eye on how quick the cracks were growing. The Pine Island Glacier, along with its neighbour Thwaites glacier, connect the centre of the West Antarctic Ice Sheet with the ocean, and together discharge significant quantities of ice into the ocean. Image: contains modified Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO
Kiribati, a remote Pacific nation, with atolls and coral islands rising no higher than 2 m above sea level. This characteristic makes them extremely vulnerable to rising sea levels.
Kiribati, a remote Pacific nation, with atolls and coral islands rising no higher than 2 m above sea level. This characteristic makes them extremely vulnerable to rising sea levels. Image: ESA/EU
The San Quintín Glacier has been in rapid retreat for the past 30 years contributing to rising sea levels. Satellite data are fundamental to improving our understanding of the rising sea levels caused by climate change.
The San Quintín Glacier has been in rapid retreat for the past 30 years contributing to rising sea levels. Satellite data are fundamental to improving our understanding of the rising sea levels caused by climate change. Image: European Union, Copernicus Sentinel-2 imagery
The Somme Bay, one of the most important European ornithological sites, is particularly vulnerable to climate change. Satellites monitor the dynamics of coastal environments and help decide the best course of action to take to mitigate rising sea levels.
The Somme Bay, one of the most important European ornithological sites, is particularly vulnerable to climate change. Satellites monitor the dynamics of coastal environments and help decide the best course of action to take to mitigate rising sea levels. Image: European Union, Copernicus Sentinel-2 imagery
Extra-high tides are a known phenomenon in the Marshall Islands. As climate change raises sea levels, low-lying coral islands, such as the Kwajalein Atoll, risk being submerge by 2035.
Extra-high tides are a known phenomenon in the Marshall Islands. As climate change raises sea levels, low-lying coral islands, such as the Kwajalein Atoll, risk being submerge by 2035. Image: European Union, Copernicus Sentinel-2 imagery
Sea ice along the eastern coast of Greenland. Sentinel-3 image acquired on 25 September 2020. Sea ice is of capital importance in climate dynamics as it reflects most of the solar radiation that it receives, thus affecting the average albedo of the earth, and also because it interposes a solid layer between the ocean and the atmosphere which reduces the free transfer of heat and moisture between the two. The Copernicus Sentinel-3 mission allows to develop innovative applications for sea ice monitoring, thanks to the onboard instruments that are able to retrieve accurate information about sea ice extent, temperature and thickness.
Sea ice along the eastern coast of Greenland. Sentinel-3 image acquired on 25 September 2020. Sea ice is of capital importance in climate dynamics as it reflects most of the solar radiation that it receives, thus affecting the average albedo of the earth, and also because it interposes a solid layer between the ocean and the atmosphere which reduces the free transfer of heat and moisture between the two. The Copernicus Sentinel-3 mission allows to develop innovative applications for sea ice monitoring, thanks to the onboard instruments that are able to retrieve accurate information about sea ice extent, temperature and thickness. Image: European Union, Copernicus Sentinel-2 imagery
The Gangotri Glacier is one of the largest glaciers in the Himalayas and one of the main sources of water for the Ganges River. Satellite data show that the Gangotri Glacier has retreated by 3 km in two centuries, and this retreat is continuing at a rate of about 10 metres a year.
The Gangotri Glacier is one of the largest glaciers in the Himalayas and one of the main sources of water for the Ganges River. Satellite data show that the Gangotri Glacier has retreated by 3 km in two centuries, and this retreat is continuing at a rate of about 10 metres a year. Image: ESA/EU
At around 120 km wide, Thwaites is the largest glacier on Earth and one of the most fragile glaciers in Antarctica.
At around 120 km wide, Thwaites is the largest glacier on Earth and one of the most fragile glaciers in Antarctica. Image: ESA/EU
JASON 3 Satellite.
JASON 3 Satellite. Photo: NASA
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