Jean-Yves Le Gall
Jean-Yves Le Gall, president of the French space agency, CNES. Credit: CNES/C. Charrier

Profile | Jean-Yves Le Gall
President, French space agency, CNES

Climate Change in a Changed Climate

The expected arrival of more than 100 heads of state in Paris for a conference on climate change Nov. 30-Dec. 11 offers the French government a unique opportunity to showcase the indispensable role of satellites in climate monitoring. It intends to make the most of it.

The COP21 United Nations Conference on Climate Change is being maintained despite the terrorist attacks in Paris on Nov. 13 and the state of emergency declared on all French territory.

As of Nov. 18 it remained unclear how many government leaders would attend. But French President Francois Hollande has made COP21 a priority and confirmed Nov. 16 his government’s intention to proceed with the meeting despite a tense security situation.

As president of the French space agency, CNES, Jean-Yves Le Gall’s role at COP21 will be to advise France and other delegations of what current and planned climate-monitoring satellites can do.


Le Gall cautioned that a binding commitment to reduce emissions of carbon dioxide and methane, both considered major actors in global warming, is not likely to emerge from the conference. But Le Gall, who has probably had more bilateral discussions with national space agencies worldwide than any other space agency chief, said even smaller nations have begun to understand satellites’ role in climate monitoring.

Half of the 50 Global Climate Observing System Essential Climate Variables used to calculate global change are measurable exclusively or principally through satellite data. One of the most pertinent — a rise in global sea levels — has been documented by the uninterrupted series of French-U.S. ocean altimetry missions starting in 1992 with the Topex-Poseidon satellite and continuing with the Jason series of spacecraft.

The Jason data have provided evidence of an average 3-millimeter-per-year rise in ocean levels. The latest in the series, Jason-3, is scheduled for launch in January.

Le Gall spoke with SpaceNews staff writer Peter B. de Selding.

Do we need an agreement that obliges nations to comply with greenhouse gas emissions commitments, with satellite measurements used to measure any infractions?

As soon as you evoke a legal regime of this nature people get nervous. What we need at the moment is for everyone to recognize the priority in collecting observations, and then to keep to their voluntary commitments. People sometimes refer to satellites as treaty verification devices, saying satellites can be a kind of climate police. I prefer to see them as measuring tools. We’ll measure and then ask people to stick to their commitments without obliging people to do things. It’s in everyone’s interest.

But does there not need to be an international agency — the World Meteorological Organization, for example — to validate measurements that are taken so that no nation can say it’s politically motivated?

That is among the subjects under discussion. But WMO is oriented toward the meteorology. What strikes me today is that many of the satellite sensors we’re talking about are built and operated as part of scientific studies of the atmosphere and the climate — and not as part of operational systems. We have not yet moved to real operational observations.

So to answer the question: Let’s say the idea is circulating. It’s too early to say that people have accepted this as the way forward.

That means the data can be dismissed as unreliable?

If I have a satellite that allows me to tell my neighbor that he’s a bad polluter, his immediate reaction will be to say he doesn’t trust my satellite’s data. That’s why we need satellites whose data are shared, and whose results are accepted by everyone.

Our CFOSat with China is one example of an advance here. The satellite, studying wind and wave movements, is a joint project. Its data will be shared equally between France and China. There will not be different appreciations between the two science teams because the data will be coming from a jointly owned instrument. It changes a bit the way we act with the Chinese. But it’s just a start.

The Chinese-French CFOSat. Credit: CNES artist’s concept
The Chinese-French CFOSat. Credit: CNES artist’s concept

How do you assess the level of international cooperation in environment-monitoring satellites in terms of minimizing sensor duplication?

There is still a way to go on this. We have shown the way with PEPS [an Internet cloud-based program for the exploitation of European Sentinel satellite data] with free access to data. But most likely the next step is to organize all of this internationally.

COP21 will put the problem on the table. Starting next year we will start to work on how to organize it.

How can this improved coordination be pursued?

We have to admit there are lots of Earth observation programs developed in many nations, not all of them coordinated. We are starting to do this at the European level. For me, one objective is to work through the International Astronautical Federation. I have been elected IAF president and this is one of the subjects I will be pressing once I begin serving in that position in a year’s time.

One of the advantages of the IAF is that you have just about all the heads of agencies of the planet at the [International Astronautical Congress] meeting. This is a very promising place to promote coordination and this is what we talked about, among space agencies, at the recent IAF conference in Jerusalem. Coordination of all the efforts being made around the world to study greenhouse gases should be possible. That would be a good step.

What about between Europe and the United States: Is there coordination in instrument development?

At the science level, yes, but I think we need to go further. With China, for example, we have an agreement on coordinating. There are sensors being launched in every direction now in many nations, and there is a need for new ones. But while having multiple satellites that observe the climate is a good thing, they need to be better coordinated.

And despite all this — lack of coordination, and the need to mitigate greenhouse gas emissions — there is no need for a new international agency to monitor emissions via satellite?

I don’t think so. The era we live in is one in which administrative layers are being reduced, not added. We need to work with existing institutions.

But one of the successes you can put to the credit of COP21 even before it started is that this kind of subject is being put on the table. You wouldn’t have posed this question a couple of years ago. Let’s start with common objectives, which will lead to better coordination of investment.

What are some of the more important climate-monitoring projects CNES is now working on?

With Germany we are working on the Merlin methane-monitoring satellite, and we are also, on our own, developing Microcarb for CO2 emissions. So this is a subject that really is a coming priority. Several European nations have expressed interest in joining Microcarb. Both will be launched in 2019 or 2020.

What I see is that around the world there are projects for those wanting to get involved in observing greenhouse gas emissions, and monitoring regions where these gases are absorbed.

There are three areas of concentration here: rising temperatures, rising sea levels and greenhouse gas levels — the latter being the cause of the two others.

French-German Merlin methane-monitoring satellite. Credit: Airbus artist’s concept
French-German Merlin methane-monitoring satellite. Credit: Airbus artist’s concept

The French-German Merlin program seems to have moved slowly since its announcement by both nations’ heads of state. What is its status?

It’s true that it took some time for the contract to be signed. But now it is advancing well. DLR is working on the lidar instrument, the laser, and CNES is working on the platform. That is a priority for both agencies, with a strong political backing.

Is there a sense that a specific satellite-related resolution will come out of the conference?

I don’t know what will come out of COP21. But the fact that it is being held is already a sign. I was with French President Francois Hollande in China two weeks ago, and the agreement with the China on climate monitoring seemed to me to be a good signal for COP21.

Under the agreement every five years we will take stock of the situation. Beyond that, there is a rising consciousness of climate change. And people are beginning to realize how important space is.

What is the status of the Surface Water and Ocean Topography, SWOT, mission with the United States?

SWOT will do for inland waterways and fresh water what Jason is doing for the oceans. I recently spoke with our U.S. colleagues about its status. It is a big project, but I am confident that both France and the United States are keeping to their commitments on it.

And India?

With India, we have the Megha-Tropiques and SARAL-AltiKa missions, and we are thinking about a project carrying an infrared sensor.

We see many emerging nations that arrive on the space scene first with a telecommunications satellite. Then they create a space agency and want an Earth observation satellite, which is tied to the climate. We have seen this trend accelerate in the past couple of years.

The U.S.-French Jason satellite series is being succeeded by a U.S.-European program. Is it on solid footing?

Yes, it is. It has been 23 years that Topex-Poseidon and the Jason satellites have been permanently measuring sea surface levels. Now everyone agrees that the sea level has been rising by 3 millimeters per year on average. This is an example of why you need satellites in a series. After Jason 2 is coming Jason 3 in a couple of months, and then Jason Continuity of Service — Jason CS — which is Euro-American.

Peter B. de Selding was the Paris bureau chief for SpaceNews.