From 1 to 11 October 2021, BRGM took part in the 30th edition of the Fête de la science. Here is a look back at this event, including the participation of our scientists in the daily Science en direct programme hosted by L'Esprit Sorcier.
4 November 2021

2021 Festival of Science: meet our ambassador!

The Festival of Science is 30 years old and this year's theme is the emotion of discovery. For the occasion, our ambassador, Caroline Prognon, head of the Knowledge, Imaging and Modelling of the Subsoil unit, shares one of the most exciting moments of her professional life.



hosts the Science Festival October 9th and 10th, 2021

Meet Our Ambassador

Hello, I'm Caroline Prognon, I've been a BRGM geologist for 15 years. My area of expertise is near-surface formations. I look at what's under our feet at depths of 0 to 100 m, what's known as the Earth's skin.

Geologists… Do they just look at rocks all day?

I wish, but no, I don't look at rocks all day. When I'm out in the field on specific projects, then yes. I bring samples back to my office to analyse and observe them, then part of my work is also on the computer to build maps or geological models to be used for risk management, water management, and any number of other applications.

Are you proud to be the Science Festival's ambassador?

Yes, I'm proud to be the voice of science, all the sciences for that matter. At BRGM, we do geology and so much more. We do mathematics, physics, chemistry. Combining all these fields is exciting and that's the message I want to communicate as ambassador.

Is it easy to make science understandable?

Not all the time, it can be very difficult especially when you're highly specialised in a field. You're used to going into detail and explaining using a technical vocabulary. It's rather difficult but also very fulfilling. It helps you get a different perspective on things. Sometimes when kids ask questions, it forces you to really think about what you do and how you talk about it. They ask if there are lakes of lava beneath our feet. That's how they understand it, and you have to explain the reality in simple terms.

How is BRGM involved in the Science Festival?

BRGM is involved across France, Overseas Territories and regions included. Then every four years, we host the festival at our site in Orléans.

How do you experience the wonder of discovery?

There are two separate things there, discovery and wonder. Discovering new things is common in this line of work. Discovering all the time, sometimes small things. I feel a little bit like a detective on a treasure hunt looking for clues and specific minerals in rocks as well as fossils that may change my approach entirely. There are lots of emotions involved. There's doubt, joy, worry at times. Sometimes things don't turn out at all like I foresaw them. But that's fine, back to the drawing board. Those emotions are important. I think of one experience I had. I originally started doing geology because I was interested in volcanology. When I was little, I loved volcanos and read everything about them. My dream was to see an active volcano. I finally did three years ago on assignment. I went to Réunion and at night I saw a volcanic eruption, lava, etc. That was just incredible! It was an unbelievable sight to me and very moving. I felt so joyful and also surprised because it was greater than I imagined.


Science live 2021 - Are you interested in switching to different energies?

For the 30th edition of the Fête de la science, the ‘Science live’ event offered a daily appointment, from 1 to 10 October 2021.

In the 1 october programme ‘Are you interested in switching to different energies?’, Mariane Peter-Borie, geologist at BRGM, head of the DEEPEGS project, geothermal energy and storage unit, talks about the potential of geothermal energy, particularly deep geothermal energy, for the energy transition. In particular, she talks about the deep drilling project she coordinated in extreme conditions in Iceland, where the temperature reaches 600°C at a depth of 4,600 metres, and its interest (drilling in a super-hot reservoir represents an opportunity to produce at least ten times more energy than an exploitation borehole present today in a volcanic context).

© L’Esprit Sorcier

SCIENCE LIVE! We begin with this energy from the depths, called geothermal energy. Just to clarify: geothermal energy is a science, but it is also a technology. Yes, geothermal energy is a science that studies temperature increases deeper into the earth. It is also the range of technologies that allow this heat to be extracted and exploited for the purposes of heat and electrical energy. An important question: where does this heat come from? I must confess I always learn things in TV shows. So first, where does it come from? I'm tempted to say from the power in the ground! It must be bubbling, there must be life. Let's look at a cross section. I thought it came from the core of the Earth too. How hot is it? The Earth's core is over 5,000°C. It comes from when the Earth was formed. The residual heat within the planet is huge: 5,000°C, several thousand kilometers beneath our feet. But that's not the main cause of the heat. The explanation lies in the Earth's crust. Let's see a cross section. We can see, in the Earth's crust, the few dozen kilometers beneath our feet, rocks which naturally contain radioactive elements.

- Naturally.

- Very much so. Uranium, thorium, potassium... The radioactive decay they generate is exothermic, i.e. it gives off heat. Meaning that beneath our feet is something hot. How thick is the Earth's crust on average? 30km thick? It varies, but the average is around 30km. But do the temperatures change in volcanic regions, or in... What type of region do geologists call it? Intracratonic. On cratons. You need to think of it in terms of tectonic plates. OK, so let's take the example of volcanoes: the temperature, the gradient. The geothermal gradient is the increase in temperature relative to depth. In volcanic areas, the magma rises. Temperatures can rise by up to 100°C per 100m.

- So we go down 100m...

- And it's 100°C hotter. OK. I didn't think the variations were that extreme, relative to each layer of the Earth's crust. Yes, it can vary a lot. For example, in places with geysers, the surface temperature is 100°C.

- There's a smell...

- Of rotten eggs. Yes! It's sulfur. The waters are loaded with minerals and have that smell... The water isn't dirty, it just has an odor. Because down below it has flowed through rocks loaded with those minerals. Returning to regions like metropolitan France, what will this gradient be over 100m? The figure will be around 3°C per 100m, meaning temperature rises by 3°C relative to the average temperature

- 12°C in France

- when we go down 100m. Looking at a map of France, we see a lot of variations. In the Paris region, for example. Looking at the map, we see regions in France... The areas in blue are where water circulates naturally and can be exploited for geothermal energy. The areas in light blue, like the Paris basin or the Aquitaine, have a normal geothermal gradient of around 3°C. We are also fortunate in France in having the whole Rhine rift, the Limagne rift, the whole of Alsace, which were at one stage an ancient ocean blocked by Africa, leading to the formation of a mountain chain. But the thermal anomaly remained. The gradient in places like Soultz-sous-Forêts in Alsace can be as high as 10°C per 100m.

- So... I'm sorry.

- No, go ahead. We understand where it comes from, and the variations globally and within France. We have a model here to explain geothermal energy. How does it work?

- How to exploit geothermal energy...

- It lights up, too! I'll show you here... The different layers of rock in the ground allow water to circulate. Some of the water circulates close to the surface, which we siphon off to drink. We venture down much deeper, around 1.5 to 2km below. From here, we pump the hot water, which is about 80°C in these places, and bring it to the surface. Thanks to a heat exchanger, we can recover the thermal energy in this water to send it to a heat network to heat up housing, buildings, in some cases, industrial heaters, etc. Once we have extracted the heat from the water... Let's be clear, this isn't the water going around your radiator pipes. There's a heat exchanger... Here, we circulate a fluid designed to transport heat. It's more efficient than the water on the surface. So it isn't the same water. Here we're on a closed circuit. We recover the heat in our exchanger, which sends it to another network. Once cooled, the water is sent back a few hundred meters, or even a kilometer further down in the same layer to preserve our resource. They are kept apart to keep away the cold water, which then gradually reheats. Exactly. The heat comes from below to heat up the cooled-down water. We don't want it cooling the source from which we are drawing water for its heat. After 30, 40 or 50 years, won't the water table cool down a little? Local cooling has been studied. To avoid it happening, we produce models and studies to prevent a "cold bubble" from developing around our re-injection well and cooling the producing well. An example in the Paris region is known as the Dogger: a water table at a depth of between 1,600m and 2,000m. And the temperature? Between 60°C and 80°C, depending on location. So in this case, it allows neighborhoods and buildings to be heated. Exactly. But it cannot be used to generate electricity? With current technology, 80°C isn't enough to produce electricity. But if we take a short trip to Guadeloupe... You've been there? You know Bouillante? You mentioned smells. In Bouillante, they are rather striking! The Soufrière heats up the underground. We can see images of Guadeloupe. It has a geothermal power plant. How hot is the water? Water is brought up from a depth of around 1.5km at a temperature of 350°C

- 250 to 350°C depending on location

- meaning it is hot enough to generate electricity. It can produce steam to turn the turbines. Exactly. If we go to Iceland... Iceland is beautiful. Wonderful! Let's see some lovely images! In Iceland, 90% of homes are heated by geothermal energy. 50% of electricity there is geothermal. You've dug down to some very high temperatures. Yes, we had a project with Icelanders that ended 2-3 years ago. The idea was both a geothermal project and scientific research, drilling to find the highest temperatures possible. Usually in Iceland, you can find temperatures of around 200 to 300, maybe 350°C. Here, we wanted to find higher temperatures to produce more energy with a single borehole. So we targeted the mid-oceanic ridge, the spot where the tectonic plates deviate. We found temperatures of up to 600°C, 4.6km down. It's a technological challenge, and a fabulous scientific adventure too. It's really extraordinary. We can sense how excited about it you are. You spent several months there. Yes, working with the teams there. When you're actually involved, it's really... It's beautiful in eastern France too. We'll be talking again about Soultz, where there is a power plant producing geothermal energy. This is another geological phenomenon. Geothermal energy is everywhere beneath our feet. In some places, it's easy to exploit, as in Iceland. In other places, the technology is routinely used, as in the Paris basin. Other places have real potential. The thermal anomaly in the Rhine rift has the potential to give us heat to make electricity. On the other hand, the rocks are not permeable, meaning they don't let water through easily. Water circulates through faults and fractures. Exploiting the resource and collecting the hot water requires the right technology that will allow us to improve this natural system and collect the hot water. So there are a few issues. The geology is slightly different, the faults must be expanded so the water can circulate. I brought a small sample. This piece of rock is granite. It is the rock that occurs naturally in Soultz. You can see it in the picture too. What Fred is showing us is a natural fracture through which water can flow. But the openings are actually very small: around one micron wide, so the water struggles to get through. The technological solutions we are currently developing involve opening these fractures. We have several technologies to do this, but as soon as we do, it will cause movement. That movement will generate a wave. That wave is called an earthquake. Mostly it won't be felt on the surface. This is 4 or 5km down, searching for temperatures of between 160 and 200°C. Most of the time, these movements are not felt on the surface. People were worried, though. It registered something like 3 or 3.5 on the seismic scale.

- Yes, we had earthquakes...

- It isn't negligible. It did happen, unfortunately. It's very worrying for people. Even if there is no real risk to human life, we need to be aware of it. A magnitude-3 earthquake is the lowest you can feel. It might shake things up, but houses aren't going to crumble. It could happen if we lose control in an unfamiliar situation. These are complex environments, 4 or 5km beneath our feet. There are plenty of unknowns, so we may have earthquakes. Some operations close to Strasbourg triggered earthquakes that people felt. In those cases, the work was halted and scientists said: "We need to check this out before continuing." The local authorities halted the operation, and a panel of experts was set up to assess what happened and ensure it doesn't happen again because it's unacceptable. But geothermal energy is the future. Absolutely!

Science live 2021 - Natural resources: solutions for the future!

For the 30th edition of the Fête de la science, the ‘Science live’ event offered a daily appointment, from 1 to 10 October 2021.

In the 3 october programme ‘Natural resources: solutions for the future!’, Stéphane Loigerot, Head of the Risk Information and Services department, explains how digital solutions can provide services for geoscience, using the example of the MétéEauNappes application and the Géorisques website. The aim of MétéEauNappes is to forecast the state of water tables in the same way as the weather. The objective of this platform is to enable water resource users and decision-makers to better anticipate actions regarding the management of the resource, to better understand the phenomena and to avoid serious crises, such as having to stop irrigation or restricting access to drinking water.

© L’Esprit Sorcier


Stéphane, you're not a hydrogeologist, you're a digital engineer and part of the team that created MétéEAU Nappes, an online platform for researching and seeing in real time the state of aquifers and forecasting their water levels.

That's exactly right. As you said, we have a website with a map of France containing what we call models: areas where we have simulated the behaviour of aquifers. Thanks to this, we can visualize aquifers in real time. As we'll see later, there are also predictive curves of where the water level will be in a week, a month, or even a few months.

Can you remind everyone what an aquifer is?

The groundwater table or an aquifer is a rock layer that can store water. It's a given circumference. As my colleague Delphine explained earlier, we've been working a long time to understand where aquifers start and end. They are hard to pinpoint but we are able to map out their areas.

Very well, OK, so we know they're essential resources, but the tool you're developing is intended for whom? Professionals? To know what's in he groundwater tables?

Yes, it's intended for professionals, people who need water. That can be farmers, manufacturers, and politicians in a given region when there's conflict over water use. Generally, an official will decide how to divvy up water resources. We prioritize making drinking water available, but we often need legal recourse when there's conflict over use of groundwater.

I imagine it can help farmers.

First and foremost. Because farmers are among the primary users of groundwater, for irrigation purposes. Some crops need a lot of water. It's important to know the state of the aquifers because irrigation relies heavily on groundwater.

How is it possible to see groundwater levels at depths beneath us where nothing is visible?

We use a piezometer. It burrows into the earth. Let's see the video. Usually it's a bore hole. It tends to look like this. A mini well or a hole down to a given depth.

This here's a probe?

Yes, he's sending down a transducer that will beep when it touches water and give a reading of the aquifer level. You see the transducer unravelling. We measure the aquifers of France and have 1,400 different sites where we measure.

What we just saw, - there's 1,400 of those?

Yes. Someone can send down a transducer for a live measurement, but we also have tools to measure every hour.

People aren't measuring all the time, it's automatic. You're saying you don't consult the device, it sends you information.

The instrument takes a measurement every hour. It then sends its 24 different readings every night, so almost real time. We then look at the previous 24 hours.

So it can provide information at any time.

Right, in real time across France, we know how much water we have.

How interesting. So if I go onto the site, I'll be able to see an aquifer in Brittany, wherever. I can click on it and see the readings.

Not on the MétéEAU Nappes site. That lets you forecast in different areas. But there is the ADES databank, where you see all the piezometers in France and their data in real time.

So the purpose of MétéEAU Nappes is to forecast for the future and foresee aquifer behaviour. How far into the future?

Several months.

OK. The real-time readings aren't enough.

That's right. We have what we call aquifer models. We are able to digitally simulate aquifer behaviour. We need to feed it data to simulate the behaviour. There's piezometer data, like we just saw, and we add to that rainfall, and water flow rates. With these three types of data, we try to understand and forecast behaviour.

We just saw a graph.

I didn't see it.

It came and went. Here it is again.

This is a typical piezometer reading. We see the national code of the meter up top. The downward curve is the low-water mark, water being taken out. This is the transition from spring to summer. And the dotted lines are forecasted levels, meaning different scenarios. We forecast for wet years and dry years.

How do you forecast? Based on the past?

Yes, we look at past piezometer data, weather data and river data, and then we simulate.

So you might say, "We had this situation..."


How far do you go back?

Our piezometers go back... several decades.


So you say, "Look, this situation is similar to..." 1976 or whenever. That allows us to say, "It might behave in this way."

That's important.

Very important. It also enables us say... As I said earlier, there are different types of users who need to know if there's groundwater available. It means they can say, "We're at a critical point." Let's say it's April. "Around mid-June, things will get drastic. "Let's start reducing our water use." You can adjust practices.

Will you keep developing this tool?

Absolutely. I don't know if the map was shown. The points represent the models. It's a representative piezometer. It's like a weather map, but only with a few points forecasted.

And you want to keep building it. Even weather maps now are getting more complex.

We would like to use models that can predict a whole series of things, with more graphics, across France.

So the philosophy behind all this is, "Let's monitor our aquifers and not abuse them."

Exactly. It's very important, as I was saying, for different regions. We're also seeing climate change take effect. We want to see how it affects our water tables, using those predictive graphs several months out is key. We know we'll see more crises in the upcoming years, so being able to forecast is crucial. MétéEAU Nappes is our first tool for doing so. Demand will increase over time. We'll improve predictions. There's a lot of anxiety in society about if we'll have water reserves in the future. We must use them rationally.

Science live 2021 - Exploring the past and understanding the present!

For the 30th edition of the Fête de la science, the ‘Science live’ event offered a daily appointment, from 1 to 10 October 2021.

In the 10 october programme ‘Exploring the past and understanding the present!’, Caroline Prognon, head of the Knowledge, Imaging and Modelling of the Subsoil unit, and BRGM's ambassador for the 2021 Festival of Science, explains why geology helps us understand the past. The surface formations, between the soil and the unaltered geological layers of the subsurface, support human activity. The Quaternary surface formations contain the oldest traces of humankind and are an invaluable archive of its evolution and our past. This is where archaeologists dig. These areas, at the interface between the atmosphere and continental surfaces, are also valuable archives for reconstructing past climates, rainfall, major atmospheric circulation patterns, and the response of environments and populations to these climates. But for a long time geologists were not very interested in these formations. The situation changed and the detailed mapping of surface formations throughout France is underway.

© L’Esprit Sorcier

SCIENCE LIVE! Hello, Caroline Prognon. Hello. You are a surface-formation geologist at BRGM. Together we are going to investigate sediments in the ground and reconstitute the climates and landscapes of the past. First of all, I'd like to talk about the surface formations beneath our feet that we are unaware of. Can you explain them to us? Yes, surface formations are what we might call sediments: sand or limestone, for example, which have been deposited by running water, glaciers, wind or sea. So this is river sand, for example, the silt we see developing, say, in Beauce. It's also anything connected to the rock alterations we see everywhere: formations such as weathered granite. These are surface formations. OK. Can they be found all over France? Yes, surface formations can be found over a large part of the country. Most of these formations are less than three million years old, which is recent in the context of the Earth's evolution and age. Relative to the age of the Earth. Three million years sounds like a lot! Three million years ago corresponds to the Quaternary, is that right? Absolutely. OK. So these geological formations are on the surface as the name suggests. So they are affected by human activity, but also by variations in climate. So a wide variety of clues can be collected in the field. Do you go out into the field? Yes, absolutely. As a geologist, and with other colleagues, archaeologists, for example, we work in the field. So we go there and investigate what's going on, looking for clues within the formations, within the sands, within the rocks, so we can trace past climates. Let's focus on formations located near a river, the Seine in this case. We'll look at a first parameter which is the sediment itself. What exactly does this sediment tell us? So many things. We can look at particle size. It allows us to better understand the surrounding repository. Are we in a calm environment? Are we in an environment where deposits are rather turbulent? For instance, an area close to the sea. Or are we in what is now a river, with coarser, sandier formations? So we can examine granularity. It's an important parameter. We can also find particular figures which give geologists clues about... What do you mean by figures? What are they? For example, traces in the rock. We can find tiny lines, small fish bones, the kind of things that allow us to say: "Here, we are close to an estuary." "It was tidal." Clues like that. OK, so we'll come back to other types. You take samples in the field, then date them. But how do you date samples? There are different ways of dating samples. We've all heard of carbon-14 dating, but there are other methods. For example, we target certain minerals. Here, it's quartz. We analyze it in the laboratory to date the sediments. OK. Back to the Seine... How old are the sediments found there? So, around the Seine, the age of sediments ranges from a million years up to the present day. OK. So in terms of other clues for our investigation... You mentioned the size of sediment particles, but also trapped within the sediment can be found objects and things. What are these objects? It's true, we may find fossils, for example. I can show you some. This is the kind of fossil we may find in our sediments. Using these markers, we can ascertain the age of the rock. There are other types of markers, such as traces of human occupation. We may find tools, which will also allow us to date the formation. This tool, for example, is rather ancient, more than two million years old. I have another one here. This beautiful biface, found in sediment, is 400,000 years old. All right, and the first... They are at different levels. That first one... what exactly is it? It's known as a chopping tool. I meant the first example you showed us... that's the one. The fossil? Yes, here it is. It's basically snail-shaped. OK, so is it unusual or is it common to find clues

- fossils, flints, etc? We quite often find them. You have to search a bit, but yes, they can be easily found, depending on the environment, the location. But yes, we find them. We spend time sifting through, it can be complex. What I showed you was pretty big but they're often much smaller. Mammal teeth, for example, things like that. OK. So you need a sharp eye to spot them. More surprisingly you sometimes find pollen. What form is the pollen found in? It's actually microscopic, often found in levels rich in organic matter. We do some analysis, looking for pollen, examining it under a microscope. It enables us to determine the climate. We find pollen from trees present during warm periods, and other pollen from plant life present in cold periods. So that tells us about the environment and the climate at that time. So the bundle of clues you gather gives you a vision of the climate and landscape at the time. Exactly. In the case of the Seine, if we summarize, what do the clues tell us about the climate and landscape one million years ago? The climate has changed a lot around the Seine. We had alternating hot periods and cold periods, periods called climatic cycles. That changed the landscape a lot, varying the plant life, and the environment. Likewise human occupation varied according to the period. During the coldest periods, man retreated. During the warmest, they settled close to the Seine. OK. Today, surface formations all over France have been mapped. The problem is that there are gaps in the maps. Why don't we have a complete vision of the territory? It's true that we don't have a complete view because we haven't been studying the formations for very long. Some formations weren't necessarily studied by geologists at first. When we began making geological maps, the focus was on mining, mineral potential, etc. The surface formations weren't really studied. Today they are especially important, as we said at the start. These are the formations that human settlements have developed on, so with the stakes particularly high, social issues, risk factors... For instance? Related to land-use planning. Materials too. OK, so the challenge now is to complete this mapping. At BRGM, you make predictive maps? How does that work? Absolutely. Obviously we now go out into the field, but we use different methods to analyze the morphology of our landscape for example. Using geological clues, we try to make what are called predictive maps, trying to project what is present beneath our feet. OK. So from the clues found in the current landscape, you can fill in the gaps on the map? Is that it?

- Yes, exactly.

- Good. One last word: you are in an amazing place. I can see a lot of flint there. Where are you exactly? I'm at BRGM, the French Geological Survey, in Orléans. Like any good geologist, I have lots of samples of every type behind me. Every time I study some terrain, I collect samples. Collecting them is kind of my specialty. So there you have it, I have a lot. It's a geologist's lair! Good, well, you have a lot of work ahead. Thank you for the clarification.

Science live 2021 - Anthropocene: a small footprint for a human, a big one for humankind

For the 30th edition of the Fête de la science, the ‘Science live’ event offered a daily appointment, from 1 to 10 October 2021.

In the 11 october programme ‘Anthropocene: a small footprint for a human, a big one for humankind’ François Gemenne, researcher in political science at the University of Liège, author of the Atlas of the Anthropocene, explains live from BRGM in Orléans what is meant by the Anthropocene and spells out the major impacts of the current ecological crisis and insists on the way it is globally and drastically remodelling the Earth system.

© L’Esprit Sorcier


Hello, François Gemenne.


Hi. You're a researcher in political science at the University of Liège and a professor at Sciences-Po. You're also a member of the IPCC and the author of Atlas of the Anthropocene.

That's correct.

It's great to have you with us today, for the Science Festival's open days.

A talk on the Anthropocene just wrapped up at the BRGM.

It gave you a chance to reflect on the topic. I'll make clear that you don't work at BRGM.

No, I don't work at BRGM, I'm a guest today.


You'll perhaps notice these big vats behind me, they're for depollution.

Exactly, we'll get to that in just a moment with another speaker today who does work at BRGM. But we're going to talk about the Anthropocene. I'd like to start with a question. Can you give us your definition of the Anthropocene?

Yes. Simply put, it's the age of humans. In other words, it's the moment when human activity began to substantially alter the planet's surface. We used to think we were negligible, short-lived, but we're realizing that we've changed Earth in major ways that extend far beyond our lifetimes. The Anthropocene is a new geological age, the age in which we realize how drastically we've changed the Earth.

What are the important signs of the Anthropocene?

Climate change, of course, is one of the biggest signs. A lot of people still think if we stop emit greenhouse gases, we'll just fall back into the climate of the past. In reality, we've set in motion a transformation that's irreversible. We can try to limit the effects, but we can't go backwards. There will be no return to normal. Another sign is the extinction of biodiversity. A number of biologists are saying we're seeing a 6th mass extinction of species. There's other pollution as well. We tried to understand all this as nine limits of our planet that were basically nine pollution indicators, nine indicators of human impact on the planet. And we're seeing that these nine indicators are nine signs of the Anthropocene. This is an age of acceleration.

Do you think humankind is truly aware of both its vulnerability and its impact?

Not fully yet. Something has occurred in the past few years in Western countries. We have become aware, I'd say, of the enormity of the changes we're making to the planet. I also think that unfortunately natural disasters, like those seen this summer, contribute to making us aware of our vulnerability. But the problem is, this awareness is not widespread across the entire human population, and there are still large swathes of people who are directly impacted by the consequences of climate change, but who lack information about what's going on. There's also a divide in our societies. Many young people are taking action for the climate. In Europe today, kids marched for the climate, in Belgium certainly. But some young people feel uninformed or unconcerned. So I can't say that humankind in its entirety is aware. Certainly a lot of people are, but we've a long way to go.

All right. We've mentioned factors of climate change and biodiversity loss. Are we seeing an acceleration of these phenomena? The great indicator of the Anthropocene is this acceleration, so fast it's almost sudden. The challenge we face today is how to slow down, how to hit the brakes. It as if we've powered a machine that's in overdrive, going faster and faster. Here's a simple example. The concentration of greenhouse gases in the atmosphere, which is causing climate change, is measured in parts per million. Throughout the Holocene, which is the geological age that preceded the Anthropocene and lasted 12,000 years, the rate of concentration remained fairly stable, around 280 parts per million. With the Industrial Revolution, the level began to skyrocket. In 1980, when I was born, it was at 337 parts per million. Today, in 2021, we're reaching 420 parts per million. We're on a curve like this, which ticked up very quickly when the Anthropocene began. That's just one example. I could give others concerning pollution or biodiversity. What really marks this era is this acceleration. Our leaders must figure out how to slow down.

You just mentioned leaders. The finger often gets pointed at private individuals, but we also expect a lot from government. How do we go about tackling this issue?

The first thing to do is not distinguish between society's choices and individual acts. Looking at climate change, we know that individual actions represent some 25% of the effort necessary, if we all lived like Greta Thunberg. If you add to that investments we can each make, maybe solar panels on your home, heat pumps, etc., we reach 45% of the effort. That's a very optimistic scenario. Everyone would have to change their lifestyle in a radical way. More realistically, we feel individual contribution to the effort needed is about a fifth or a quarter, 20 to 25%. Meaning that the rest must come from collective action taken by governments and private companies complying with public policy. One thing that's very effective for combating climate change is politics. That means young people taking to the streets to influence the direction we take as a society. I want to say that today we run the risk of creating great disillusionment if individual efforts are not followed by collective action. People will feel discouraged and hopeless if they see that what they've implemented in their everyday lives to reduce their footprint isn't also being reflected in policy decisions made by government and industry. So governments and industry have a huge role to play. Without large-scale change, we won't succeed.

OK. Who is directly impacted by the signs of the Anthropocene, such as global warming?

Everywhere in the world, it's the most vulnerable people who are affected first and the hardest. By vulnerable I mean the poor as well as those with less education, less internet access, less access to power grids, and fewer options for mobility. It's also the elderly and the sick. These are the populations that will be hit the hardest. On the global scale, those in the poorest countries with less internet access will be hit hardest. Likewise on the national scale, the most vulnerable will be hit the hardest. Take the flooding in New York last week. The majority of those who lost their lives were in their apartments, but these apartments were in the basements of buildings and thus the quickest to flood. Such apartments are the cheapest and the only option for low-income earners.

Climate change will also bring about mass movements of migrants.

We're already seeing that today.

What are some of the consequences of the migration caused by climate change?

The impacts of climate change are one of the main causes of migration and displacement across the globe. Looking at last year's statistics, some 30 million people were displaced by natural disasters caused by climate change, that means flooding, droughts, hurricanes and fires. Thirty million people, that's 10 times... Sorry, that's three times more than the number of people displaced by war or conflicts occurring in 2020. We see today how major these displacements are. Add to the numbers of people displaced by disasters, the vast numbers of people displaced by slower degradation to their surroundings, such as rising sea levels, or soil degradation. That means that today, very large migrations are being caused by climate change. Often times, displacements don't extend beyond the borders of the country. In other words, people just try to flee the environmental damage. They won't necessarily flee their country, but simply try to escape disaster. That means all the effort of taking in and managing migrants is done by governments in countries that among the poorest on the planet.

How can we adjust to these changes which you say are irreversible?

I just want people to be aware of our vulnerability. That's the obvious first step for adjusting. For a long time, we thought we were invincible, meaning we were not at all prepared. Regrettably, we've seen the damage this caused in Belgium and Germany, which have experienced flooding. Number one: become aware of our vulnerability. After that, there is a whole set of infrastructure changes we have to meet. This can be updating homes, being more stringent about where we allow people to build. We also need to bring back green space, in cities as well as around them, so that the subsoil can absorb excess precipitation. Another challenge will be to prepare people. We will have to improve evacuation plans. The evacuation of populations is a topic that has been neglected. And adjusting isn't just a concern for the Global South. Industrialized countries need to be prepared too. This will take different forms. In industrialized countries, infrastructure solutions will be necessary. In the Global South, it will be adapting lifestyles. But everyone will be impacted because what used to be occasional is becoming the new normal.

Before we let you go, quickly, a word of optimism. What can you say to give us hope?

If we want to have hope for the future, paradoxically, we have to abandon the hope that we can return to the past climate and come to terms with the fact that the changes in motion are irreversible. That's what the Anthropocene is. We're in a new geological age. What we have to do now is figure out which cards will help us live in this new era. There are plenty. In terms of technology, adjustments, attitude change and resilience. I think what will help us to live in this new era, the Anthropocene, is coordinating efforts beyond geographic borders and generational divides. Belonging to a certain generation or having a certain nationality should come second to being alive, and what we need to be alive along with all other living things is to make Earth viable. Once we integrate that into our identity, meaning we become aware that we have a role to play in keeping Earth habitable, then we will have the cards to live in this new era, the Anthropocene. That's my message of hope to conclude.


Science live 2021 - Soil pollution

For the 30th edition of the Fête de la science, the ‘Science live’ event offered a daily appointment, from 1 to 10 October 2021.

In the 11 october programme ‘Anthropocene: a small footprint for a human, a big one for humankind’, Francis Garrido, Deputy Director of the Water, Environment, Processes and Analyses Directorate talks about a consequence of human activity, soil pollution, which is not well known to the general public. He details the various solutions developed by BRGM to diagnose and alleviate the various types of pollution. In particular, he discusses the role of the PRIME platform, an innovative facility dedicated to the analysis of environmental pollution and the means to remedy it.

© L’Esprit Sorcier



- Hello, Francis Garrido. - Hello. You're a geomicrobiology researcher and Deputy Director of BRGM's Water, Environment, Processes and Analyses Directorate. Together, we're going to focus on what is beneath our feet and which we too often tend to forget or overlook. I am of course talking about soils. I'd like to start by asking you what is the quality of the soil in France right now? When we talk about soil quality in France, we must bear in mind that in the soil beneath our feet, there are naturally occurring elements linked to the rock that makes up the basis of soil formation. So some soils contain elements such as metals or metalloids, which have specific properties, naturally generated in the environment. This is what we call the geochemical background of our soils. But of course, the human activity that has taken place in recent decades, be it agricultural or industrial, has produced an accumulation of molecules and contaminants in soils which may be of agricultural origin... linked to the products used. So we have significantly altered, as a result of intensive agriculture, our soil resources. And as for polluted sites, there are over 320,000 former industrial sites in France, 9,700 of which are monitored and managed by the public authorities because they are regarded as polluted or potentially polluted. So, in short, the situation has clearly evolved, with soil quality in France affected by human activity. 320,000 sites all over France seems like a huge number. These are old sites, from our past, our industrial past. Sites of past activity in France. It's obviously a lot but it is also the reality. The list is regularly updated so the numbers can vary. The figures I quoted were 320,000 and 9,700. In two years' time they may be different, as we identify more sites when making an inventory of our past. You mentioned pollutants linked to human activity, particularly products used in agriculture. Could you give us more concrete examples of pollution linked to human activity, whether agricultural or industrial? Sure. As regards agriculture, the public has a good awareness about this from media coverage. The addition of nitrogen fertilizers, for example, necessary for plant growth. This is one of the enriching agents used in the soil, which allow farmers to grow more, to increase agricultural production. Other agents are treatments, such as phytosanitary products. So that's agriculture. Then in the field of industry, less well known to the public because it is more site-specific, sites are contaminated as a result of industrial or economic activity. The biggest pollutants on a national scale in France are hydrocarbons, followed by the metals generated by industrial activity. Any examples of hydrocarbons that are familiar to us? Hydrocarbons are found, for example, as a result of petrol station leaks. Remember that service stations have underground storage tanks from which chemicals sometimes escape. Another example, which aren't exactly hydrocarbons, are chlorinated solvents produced by the chemical industry for use in the construction industry. These chemicals have strange names, such as dichloromethane and dichloroethane. They're strange names, sorry! Eliminating these pollutants from our soils is a real challenge. Are some pollutants easier to eliminate than others? Yes. I need to be careful how I answer because some chemicals... When discussing remediation treatments, or elimination of pollutants, we must distinguish between inorganic pollutants: i.e. metalloid metals whose behaviour depends on their degree of oxidation-reduction. Their mobility varies according to their state. Then there are other far more complex pollutants. These are often organic pollutants, like the ones we mentioned: chlorinated solvents and hydrocarbons. They have complex molecular chains. They are mixtures of carbon, hydrogen, nitrogen, chlorine. Sometimes they are very complex and very stable. These pollutants can form what is known as persistent organic pollution. Their great stability in the environment is problematic. So at BRGM, to study the future and behaviour of these pollutants, you use something called the PRIME Platform. Could you tell us in concrete terms what it is used for? Yes, part of the PRIME platform is behind me. It's only a small part because it represents a surface area, including experimental equipment, of more than 1,000 m2. In it we have devices which allow us to gradually move from the laboratory to on-site reality. It's fundamental for a scientist when faced with a complex problem, to be able to finely characterize the mechanisms, first on a small scale, under controlled conditions, then on a more complex level. So the PRIME platform allows us to operate on anything from a metric scale to a plurimetric scale, as you see on screen. This our largest reactor on our PRIME Platform. The platform is unique in Europe as it allows us to do tests under controlled conditions with volumes of up to 150 m3, i.e. close to real life, and thus study migration both vertically and laterally. Earlier we talked about local pollution on industrial sites or in fields. But this pollution has an impact nationwide. It can spread and have consequences on our water resources. Is that correct? Yes, that is indeed the challenge in terms of groundwater resources. Because the pollution of soil can lead to direct exposure to humans, given that we live on it. Moreover, in France three-quarters of our tap water comes from groundwater resources, i.e. water that we do not see. It is, however, essential in our daily life. All the pollution that accumulates in the soil may at some point migrate into the groundwater and suddenly impact a territory, a zone, a body of water, covering a large area. It heavily impacts a given territory, way beyond the site on which the contaminants have accumulated. Very quickly before concluding, I would like to give a message of hope and talk about decontamination solutions, particularly the solutions built around the richness of biodiversity found in the ground. What are these decontamination techniques? One original aspect of our work is our harnessing - although it isn't the only approach we have developed - of the life present beneath our feet, in the ground, down to a great depth. Very few people are aware that there are microorganisms present in the subsoil which can play an important role in breaking down molecules and transforming pollutants into a form that is both easier to remove and less harmful to humans and the environment. So we can, in some cases, select certain microorganisms in the environment for use in decontamination. We have been able to do this on a number of sites. It means we can now stimulate the bacterial biomass naturally present in these soils and thus harness nature to clean up the site in a natural way without too much intervention on our part. So there are solutions. We'll take away that message. Thank you very much, Francis Garrido.