Seven sad forests
A Hard Rain’s A-Gonna Fall
Oh, what did you see, my blue-eyed son?
Oh, what did you see, my darling young one?
I saw a newborn baby with wild wolves all around it
I saw a highway of diamonds with nobody on it
I saw a black branch with blood that kept drippin’
I saw a room full of men with their hammers a-bleedin’
I saw a white ladder all covered with water
I saw ten thousand talkers whose tongues were all broken
I saw guns and sharp swords in the hands of young children
And it’s a hard, and it’s a hard, it’s a hard, it’s a hard
And it’s a hard rain’s a-gonna fall
(From: A Hard Rain’s A-Gonna Fall, by Bob Dylan)
Who will save the wonders of the Amazon, and with them the climate? Part 3
The world needs the Amazon for its biodiversity and its carbon," said the scientist and "godfather of biodiversity" Thomas E. Lovejoy (1941-2021), who spent decades studying the Amazon rainforest.
Biodiversity and carbon are not the only reasons we need the Amazon. But whether we look at water, air, forests, economic development and urbanization in the Amazon, and the consequences of changes there for the rest of the world, somewhere in the story of the Amazon's life cycle we always end up with these two: biodiversity and carbon, and their intimate relationship.
Since 2015, in the Uatumã Nature Reserve, one hundred and fifty kilometers northeast of the Brazilian Amazon city of Manaus, a three-hundred-and-twenty-five-meter steel research tower has risen like a needle out of the tropical rainforest. It is the tallest climatological tower in the world, taller than the Eiffel Tower. Next to it are two other towers, each eighty meters high.
The Amazon Tall Tower Observatory, or ATTO for short, is an "atmospheric laboratory" built to understand how the Amazon rainforest affects climate change, and vice versa, how climate change affects the health of the Amazon rainforest. ATTO's altitude allows scientists to make atmospheric measurements over such a large area that they can accurately predict the impact of various factors - including human activity - on the climate.
In Manaus, the ATTO data are sent to the National Institute for Amazonian Research (INPA), and in Germany they are analyzed by the Max Planck Institute for Biogeochemistry in Jena and the Max Planck Institute for Chemistry in Mainz.
By Land, Sea, and Air
In the fall of 2021, when ATTO will have been in operation for a few years, I'll talk to Santiago Botia, an ATTO researcher at the Max Planck Institute for Biogeochemistry in Jena, Germany.
Like his colleague Carlos Sierra, Santiago Botia was born in Colombia. He studied environmental engineering and then followed a program in oceanography in the United States. This took him to the Pacific Ocean on a sailing ship, where he collected samples and conducted research. Wanting to advance in science, specifically climate change and the carbon cycle, Santiago Botia moved to Wageningen in the Netherlands in 2015. There he received his Master's degree in 2017.
In Wageningen, Santiago Botia started working in the Carbon Cycle and Atmospheric Composition research group, led by Prof. Dr. Wouter Peters, which studies the rising levels of carbon dioxide in the atmosphere. The group's agenda includes the carbon cycle of the Amazon rainforest and the Arctic, as well as urban areas in Europe.
In Wageningen, Santiago Botia first conducted research on the Amazon, specifically on the impact of fires on the Amazon's carbon budget. This eventually led him to the Max Planck Institute for Biochemistry in Jena, where he is a Ph.D. student involved in ATTO. He is part of the Airborne Trace Gas Measurements and Mesoscale Modeling research group. Mesoscale refers to weather phenomena that are relatively "small," spanning a few kilometers to hundreds of kilometers and affecting areas on a regional and local scale. It is the scale at which thunderstorms or tornadoes develop and manifest.
I want to talk to Santiago Botia mainly about the until recently unexplained nocturnal methane readings at the top of the three-hundred-and-twenty-five-meter ATTO tower in the Amazon rainforest northeast of Manaus. But first: Why is it so important that the atmosphere at the ATTO site is virtually free of anthropogenic influence? Or as the ATTO coordinator at the Max Planck Institute, Prof. Dr. Susan Trumbore, told me earlier: "Where ATTO is, the atmosphere is the cleanest on the planet, at least over land. It is the most pristine atmosphere that we think the atmosphere was before industrialization."
In a 2018 interview with Jošt Lavrič, then a researcher at Jena and leader of the Tall Tower Atmospheric Gas Measurements (TAG) research group, he noted that the environment at ATTO is largely untouched, at least for part of the year. Jošt Lavrič: "There's always some kind of anthropogenic influence, so you can't say it's 100 percent unpolluted. But there are days and periods of the year when it is almost free of pollution, and then it is interesting to see how the forest itself influences various processes related to, for example, aerosols, which are related to the water cycle, and the intensity and frequency of rainfall. If you understand these processes, you can explain how they work and better predict what will happen if something changes."
Three years later, I also put the question of the location of ATTO to Santiago Botia.
Santiago Botia: "Ground-based research stations are mainly located in northern latitudes. So in most data-driven analyses where we try to limit or estimate the carbon footprint of a particular place, there is always a bias or lack of data in the tropics, in Africa, Indonesia and Southeast Asia, but also in the Amazon. Although I would say that the Amazon is probably better equipped compared to Africa and other places. To give you an idea: Europe has a greenhouse gas network called ICOS, the Integrated Carbon Observation System. They have more than fifty stations covering an area smaller than the Amazon. I work in the Amazon with five stations covering an area larger than Europe. You can imagine how difficult it is to get good quality data there. One of the things ATTO was built to do is to provide continuous long-term data to better understand what is happening in the Amazon in terms of CO₂, methane, aerosols, and many other things.
"ATTO is in the northern part of this constellation of sites. The Tall Tower Observatory is there to provide data on the eastern part of the Amazon. But we still do not have a good picture of, for example, the Peruvian, Colombian and Ecuadorian Amazon near the Andes because of the wind. All the signals generally move from east to west, and all the sites are mainly in the Brazilian Amazon. So ATTO fills a gap for a lot of data, but there are still gaps further west. It would be nice to address that at some point.
"We are trying to add information to the discussion with ATTO to better understand the dynamics in the region, especially in the eastern Amazon. The ATTO report provides a great opportunity to study variability on a daily scale from year to year. This is possible because at ATTO we have an hourly data point in the daily CO₂ cycle, which is mainly determined by photosynthesis during the day - the vegetation absorbs carbon and as a result the CO₂ level drops. At night, microbial activity and vegetation respiration dominate, and concentrations rise. These daily cycles are fairly constant, and everything has a very consistent rhythm, at least if you look at each day individually. If you look at a longer time span, such as a monthly report, you can see that the CO₂ concentration is increasing both inside and outside the continent. This is mainly due to global warming caused by the accumulation of CO₂ in the atmosphere."
Dead Landscape
When I visited the Max Planck Institute in Jena in 2018 - ATTO had been in use for a few years - forest scientist Carlos Sierra and others noted that they had observed amounts of methane that were difficult to explain. As the aforementioned Jošt Lavrič, then head of the Tall Tower Atmospheric Gas Measurements (TAG) research group specializing in greenhouse gases, explained:
"We measured methane and saw interesting events of increased concentrations, with sharp peaks in the middle of the night, when they shouldn't have been there, and we didn't know exactly where the increase was coming from. Interestingly, this coincided with events related to aerosols. A certain type of aerosol. Someone told me that these types of aerosol events had been seen before, but they did not know that methane also appeared at the same time. Our questions now are: What is it? Where does it come from? How does it work? It seems to be partly related to hydrology. Once we understand that, we will know under what conditions and at what frequency more methane comes out of an ecosystem. That can then help us understand what might happen if, for example, the entire Amazon - theoretically speaking - becomes 20 percent drier; that this event might lead to an increase or decrease in the emission of a certain type of greenhouse gas by a certain amount. This is very valuable information that can be incorporated into global models."
They did not know exactly where the methane was coming from. Now they do.
Santiago Botia wrote a paper about it: Understanding Nighttime Methane Signals at the Amazon Tall Tower Observatory (ATTO).
Santiago Botia: "This was my first paper. It is mainly wetlands that produce methane, and wetlands in the Amazon cover about 14 percent of the surface. So it's a big area. At ATTO, we measure methane concentrations in the atmosphere. With that information, we try to understand the ecosystem processes and make connections about what are the main drivers of methane variability in the region that I see. We have five measurement points on the tower, and at the top we saw a high concentration of methane. This is remarkable because the methane sources are on the ground. And it happened mostly at night. When we looked at the data, there was a clear seasonal pattern during the dry season, especially in the month of August.
"We then looked further and tried to see if it was caused by fires. We did some analysis, and it did not seem to be caused by fires. There are fires during the dry season, and they also emit methane, but ATTO is a little far from the fire hotspots. That led us to conclude that the cause was not fires. We looked at methane emissions from the Amazon River. But that is too far away at night. One possible explanation we are now looking at is the Uatamá River, which flows south and southeast of ATTO, if you look in a straight line from the tower. Northwest of this river is a hydroelectric plant, Balbina. It produces methane. It goes into the atmosphere. But it also leaks into the river. This increases the concentration of methane downstream in the river. If you compare the concentration in the river with other rivers, it is higher. So that is one indication. Another is the change in the flood pattern of the river. The Balbina dam changed the seasons of the flooding of the river, which caused a lot of trees to die in the flooded forest along the Uatamá River.
"So there is a massive change in the ecological and hydrological conditions caused and influenced by the forest. We now suspect that there is a greater amount of carbon in the river that can be broken down and produce methane. We also found that the increase in methane at ATTO coincides with the direction from which the wind blows, and occurs more frequently when it comes from the river areas. Given the seasonal pattern, it is very likely that the methane is coming from the Uatamá River. We still have to do a full analysis by going there and taking measurements. That will happen. But because of Covid, we have not been able to go back to Brazil. But there is a lot of evidence that this is the source of the methane. All the rainwater, all the biomass produced in the area, and also the input of animals in the forest, contribute to a constant increase of carbon in the reservoir, and this carbon, which goes to the deeper parts, is decomposed without oxygen and produces methane."
Balbina. This wretched dam, destroying everything, keeps popping up.
"Dam the Rivers, Damn the People: Development and Resistance in Amazonian Brazil" was the title of a book written by Barbara J. Cummings in 1990 to draw attention to the construction of huge hydroelectric dams in the Amazon region and the resulting destruction of people and nature. "Dam the Rivers, Damn the People" focuses on two of the most affected areas, the Xingu River in the state of Pará and the Balbina River in the state of Amazonas. Dam the Rivers, Damn the People was the first book that confronted me with the ecological devastation that the construction of a dam can cause in the Amazon region. And its impact on local socio-cultural life. Six years later, I saw with my own eyes the dead landscape of Balbina, a shocking experience.
October 1996. I am on my way from Manaus, a city of millions that grew out of the rainforest, to the Brazilian state of Roraima. The road to Boa Vista, the capital of Roraima, runs through the Waimiri-Atroari reserve, and there are problems between the local population and a mining company operating in the area. The day before, cars were stoned. To the left and right of the road is water, lifeless. Tree stumps protrude, black and rotten, like stakes driven through the earth's crust from the inside. The desolate landscape, where not a bird can be seen, owes its lifelessness to the Balbina Dam, built 146 kilometers from Manaus on the Uatamá River.
Built between 1985 and 1989, the Balbina Dam flooded nearly 3,000 square kilometers of forest. Millions of trees were drowned, rotting in the water and becoming a source of greenhouse gases, CO₂ and methane. The project caused an immense, deliberately organized ecological disaster and robbed indigenous peoples, especially the Waimiri-Atroari, of their land on a massive scale.
Many years after my first encounter with the Balbina Dam, well into the 21st century, the area still looks as desolate as it did then, as evidenced by images by Alberto César Araújo, a photographer from Manaus and co-founder of the news agency Amazônia Real. They bring to mind the old apocalyptic prediction of Bob Dylan's 1962 "A Hard Rain's A-Gonna Fall”: "I saw a black branch with blood that kept dripping." From the same song comes the line: "I've stepped in the middle of seven sad forests." As if the singer foresaw what would become of the rainforests near the dams built in the Amazon by successive Brazilian governments, driven by a hunger for power and, as we now know, bribes.
"I've stepped in the middle of seven sad forests"
Nighttime methane emissions
Back to Santiago Botia in Jena, and through him to the Amazon, where the Balbina Dam remains a source of climate-changing greenhouse gases decades after its construction. The question remains why the gas in question, methane, is measured at night, on top of a tower three hundred and twenty-five meters high, far above the ground and the canopy of the Amazon rainforest. But a possible answer has been found.
Santiago Botia: "Why at night? The first thousand, two thousand meters of the atmosphere is called the boundary layer. In this part of the atmosphere there is a daily cycle that is influenced by the transport of heat, water vapor and carbon dioxide, among other things, from the Earth's surface. The thickness of the boundary layer varies. Temperature and humidity, as well as CO₂ and methane concentrations, are within a similar boundary layer during the day. At night, the height of the boundary layer drops to a few hundred meters because there is less radiation and less vertical mixing. So the volume of the atmosphere is smaller at night. In a sense, the volume is compressed. One of the effects of that is a higher concentration of molecules, which is normal, but the amount of methane that we measured was sometimes so high that there must be another source, because it cannot be explained just by the compression of the boundary layer. This means that the methane released from the river at night stays in the boundary layer and is transported to the tower by the strong flow in this layer of the atmosphere. We measure these high methane peaks that last for a few hours and then drop off. The transport situation in the boundary layer is a very complex mixture at night."
As we're about to say goodbye, he has one last thing to say about the Balbina Dam.
Santiago Botia: "A lot of research has been done on the ecological impact of Balbina. There are also articles about how the species composition changes in the flooded forest. If you look at the number of floods, it is not that many, but it shows how fragile these ecosystems are, where a very small change can have an enormous impact."
To be continued...
Note to Dutch readers: An extended version of this article can be found here
Now listening: Patti Smith performs a moving rendition of Bob Dylan’s A Hard Rain’s A-Gonna Fall at the Nobel Prize Award Ceremony at Stockholm Concert Hall.
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