Both to continue studying it and to take concrete action, launches are multiplying and giving rise to increased cooperation between space agencies and private companies.

Among the most successful areas of collaboration: tracking greenhouse gas emissions.

One of these most powerful gases, methane, is regularly measured in the atmosphere by a large satellite of the European Earth observation programme, Copernicus.

The craft can scan the entire globe, but its resolution of the order of several kilometers makes it difficult to identify the cause of the emissions.

That is where companies come in.

Canada's GHGSat currently has nine satellites in orbit, the size of a microwave. Their mission: to fly over the sites of the oil and gas industries, looking for methane leaks.

Evolving at lower altitudes, they can "zoom" at each site.

Copernicus officials regularly inform GHGSat of places "where there are increased concentrations, which we should go and see," Stephane Germain, founder of the company, told AFP.

GHGSat then sells its information to oil operators – such as Total, Chevron, ExxonMobil, or Shell.

The latter realize "that they need to better understand their carbon footprint", because "their own customers" demand it, explains Stephane Germain. But identifying the location of a leak among "millions of parts" can be complex.

However, if the leak comes from an extinguished flare (used to burn excess gas), it can be re-ignited.

GHGSat says it has already avoided 10 million tonnes of CO2 equivalent – that's the emissions of 2.2 million cars over a year.

Other companies are planning to enter this methane niche, such as the French Absolut Sensing. Another, Kayrros, has no satellites of its own, but analyzes Copernicus data to track down the biggest leaks.

Complementary

The mountains of data generated by public agencies, combined with the more targeted firepower of the private sector, are thus complementary.

"The general view shows you that there is a problem, and the small one focuses on it at a higher resolution (...) It works very well together," said Josef Aschbacher, who led the Copernicus programme for years before becoming head of the European Space Agency (ESA).

But government agency constellations, made up of large, very expensive satellites, remain the backbone of the Earth observation system.

Copernicus will soon enter a new phase, with missions such as CO2M, to measure CO2 released specifically by human activities.

The French-American SWOT satellite on the launch pad of SpaceX's Falcon rocket, on December 15, 2022 at Vandenberg Air Force Base, California © Patrick T. Fallon / AFP/Archives

NASA has about thirty Earth observation missions.

In the last six months alone, the US space agency has launched SWOT to study the movement of water on Earth, TEMPO to track the spread of air pollutants over the United States, and TROPICS, to monitor the evolution of hurricanes hour by hour.

"It can be said that without satellites, we would not understand the problem of climate change, or clearly not as much as today," says Josef Aschbacher. And technological advances make it possible to measure things today that were "unimaginable ten or five years ago," he said.

Partnerships

In addition to these scientific missions, there are meteorological satellites from the National Oceanic and Atmospheric Agency (NOAA) on the American side and EUMETSAT on the European side.

These are also crucial in the face of climate change, says Mitch Goldberg, chief scientist at NOAA.

On the one hand, it is their data, collected over decades, that make it possible to measure changes and feed climate models for the future.

NOAA satellite image of Hurricane Ian approaching Florida, September 28, 2022 © Jose ROMERO / NOAA/RAMMB/AFP/Archives

On the other hand, they play a major role in adapting to global warming.

To reduce the impact of natural disasters, which are expected to multiply, "we need better weather forecasts", allowing for example to order early evacuations, says Mitch Goldberg.

Again, the agency has launched partnerships with the private sector. For example, it uses the constellation of the company GeoOptics to collect information on the humidity or temperature of the atmosphere.

"There will be more and more companies with capabilities," Goldberg said. "We ask them: What do you have available that might be relevant to NOAA?"

According to a report by Inmarsat and Globant, if current satellite technologies were universally adopted – for example to optimise the routes of cargo and aircraft – they would reduce greenhouse gas emissions by 9%, compared to 2.5% today.

© 2023 AFP