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Public Radio's Environmental News Magazine (follow us on Google News)

Carbon in the Congo

Air Date: Week of

Fields bordering the forest near the territory of Yangambi in the Democratic Republic of Congo. (Photo: Axel Fassio, Flickr, CIFOR, CC BY-NC-ND 2.0)

A team of scientists recently found a massive peatland holding more than 30 billion metric tons of carbon in the Congo Basin. It is crucial the carbon remain sequestered there to avoid exacerbating the climate crisis. Senior reporter for Mongabay John Cannon, wrote a four-part series looking into the Congo peatlands and joined host Bobby Bascomb. 


CURWOOD: It’s Living on Earth, I’m Steve Curwood.

BASCOMB: And I’m Bobby Bascomb

The Congo Basin is home to one of the largest rainforests in the world, second only to the Amazon, and rich with biodiversity. A team of British and Congolese scientists recently found that this heart of Africa is also home to an enormous carbon-rich peatland roughly the size of England. There’s three times as much carbon in the soil of this planet as in the atmosphere, and left alone for millions of years nature can eventually convert dead vegetation into peat and then coal. But if the process is interrupted carbon is released into the atmosphere where it can warm the climate. So, it’s crucial that the Congo Basin peatlands remain sequestered there to avoid exacerbating the climate crisis. For more I’m joined now by John Cannon, who wrote a four-part series looking into the Congo peatlands as a senior reporter for Mongabay. Welcome back to Living on Earth John!

CANNON: Thanks, Bobby, great to be with you.

BASCOMB: Beyond being a biodiversity hotspot, these peatlands contain a tremendous amount of carbon from the slowly decaying plant material that's there. Can you tell us about that, please? And about the amount of carbon that's likely trapped up in these soils?

CANNON: Sure. Yeah, that's I mean, that was really the thing that changed the conversation. When the publication came out in 2017 mapping these peatlands, one of the key statistics was that it contains more than 30 billion metric tons of carbon, which is the equivalent of, say, three years of the emissions that we as the world economy put out every year, or maybe 20 years of the economic output of the United States, for example. So just an enormous amount of carbon has been sequestered, basically, in this partially decayed soil that's sitting below this part of the forest. And what that means really, for the climate is its carbon that's kept out of the atmosphere. So it's not warming the climate at this point. The trouble might be in the future, if something happens to these peatlands, whether it's caused by us as humans, or happens, you know, as a result of changes to the global climate overall, that could be released back into the atmosphere and kind of accelerate climate change. So that's really drawn a lot of attention from all sorts of different scientists, as well as policymakers around the world who want to see, make sure that this carbon stays where it is, and that it doesn't contribute further to climate change.

BASCOMB: So normally, in a rainforest, you would have leaves and plant matter fall to the ground decay and then that carbon gets released up into the atmosphere. But in a peatland like this, it falls to the ground and sort of gets trapped in all of the water there in the soil and doesn't decay at the same rate, it's just sort of retained in the soil.

CANNON: That's exactly right. It's really a fascinating process. Because you have this surplus of water, it's this this swampy wetland area, it slows down that decay that usually happens caused by insects and bacteria and fungi in those those sorts of things. So the carbon that would ordinarily be released very quickly in the rainforest, often, this happens almost immediately, but over time with this water logging that either comes from the rivers that kind of spill over their banks and flood maybe seasonally or because there's a lot of rainfall in the rain forests, that can lead to these creation of these wetlands. So that slows down that decay process and that's where that carbon builds up over thousands of years.

BASCOMB: Yeah, you write in your article, it's on the order of 10,000 years. These soils are about 10,000 years old, that's how long it's taken for this process to get where we are today.

CANNON: Yeah, and I think at least 10,000 years, that was the early estimate. And I think, you know, as the scientists are looking at the area, and you know, this is active, ongoing research was is really fascinating. They're finding different parts of it are different ages, so some of them might be up to 17,000 years old. And in other parts of the world, tropical peat on the order of 40 to 50,000 years old. So this is, you know, it's a long, long process. A long, long time over which this carbon has accumulated.

BASCOMB: Wow, that's amazing to think of these soils as being as much as 50,000 years old, but to drain them out and completely change the hydrology. I mean, you could do that pretty darn quickly, you know, within a matter of months or certainly a year or so.

CANNON: Sure. And that's, that's something that the scientist I spoke with, emphasized again and again. We humans unfortunately have become very good over the last couple 100 years, especially at draining these peatlands. As one scientist put it to me you can do it with a sort of windmill, that was the sort of technology that was available a couple 100 years ago. And it's the same sort of thing that has happened in the British Isles, or in places like the Netherlands where they've drained these peatlands and they've, you know, built up farmland and that sort of thing in these areas but they didn't know it at the time that they were losing that carbon. And obviously, if that happened in this area you'd run that risk as well as losing the habitat for biodiversity and that sort of thing.

BASCOMB: Well, what does this enormous stockpile of carbon in the Congo mean for the world's carbon budget? I mean, it's so new that we're really learning about this. Is this something that scientists are really accounting for even?

CANNON: It's a really good question. I think at this point as I understand it, a lot of the Intergovernmental Panel on Climate Change the IPCC models right now, don't account for this in an active way, and it's not deliberate. It's just the sort of it is so new and they're trying to figure out how you account for this stockpile that's sitting there, and it's not accumulating at say the rate of a forest because you know as the forest grows, the trees start siphoning carbon from the atmosphere and they do that relatively quickly compared to the peatlands. The peatlands are only pulling a little bit of carbon each year but the value really is in over that time. So a lot of scientists are trying to model what it means to have this carbon there and what it means if that carbon is released.

BASCOMB: Now, of course, the Congo is home to the world's second largest rainforest, second only to the Amazon and that's been known for a really long time, but this peatland was only discovered as you say relatively recently by Western researchers within the last decade or so. How is that possible that we're only just now learning about this?

CANNON: Yeah, I think, you know, that was one thing that attracted me to this series, I think in the first place, because it is rare, I think, these days to have a discovery, a quote, unquote, scientific discovery, because the communities obviously living in this area have known about this, you know, the resources that are there for a long time. I think the biggest aspect really is just how remote it is. I mean, it is very difficult to get to, there's not a lot of infrastructure, the communities that live in this area, you know, get around by boat, they're oftentimes subsistence farmers. So they're, you know, relatively cut off from the market, say in Brazzaville, or Kinshasa and in the Republic of Congo, or the Democratic Republic of Congo. So I think, really boils down to that remoteness. And as we've learned more about our climate and the value that these forests bring, I think researchers have become more interested in finding places like this and trying to establish what value they do provide so that we know what we need to protect going forward.

BASCOMB: Right. I mean, unlike, you know, the Amazon or Indonesian rainforest, we haven't seen a whole lot of development in the Congo Basin. As you described it's very difficult to work there and political instability and crime has, you know, largely discouraged investment in the past. But what are you seeing on the horizon in terms of possible development, and, you know, keeping these peatlands intact as they are now?

CANNON: Yeah, I don't want to, you know, I don't want to be too alarmist because, again, they are pretty intact at this moment. But I would say something like 80% of the peatlands are covered by concessions that may be in the future, doled out for oil and gas exploration, or timber extraction, or the creation of agricultural plantations. So those are really the three big threats I would say on the horizon and it's difficult to say how quickly those would happen. You know, I've spoken with the environment ministers in the Republic of Congo and the Democratic Republic of Congo and they're very interested in protecting this area. They see the value that it provides not only to the communities and the wildlife that live there but to the global community in terms of keeping that carbon out of the atmosphere. But they also say, we need to develop as countries as all countries do. And the you know, these are relatively poor countries. So they, you know, they're looking for ways to improve their economic situation. It could be seen, you know, you could look at this area and say, if there is oil below it, that could be a temptation to extract that, sell it and bring money into a country's economy. So the leaders in the country say, you know, we would like to protect this area, but we need help from the global community, we need resources to help provide employment and development for our citizens, so that protecting this area doesn't come at the cost to us, so that we are able to develop in a similar way to other countries around the world.

BASCOMB: And from what I understand, even if the Congo Basin doesn't necessarily see large scale development, you know, you don't have palm oil plantations, or oil dikes in the peatlands, but just the infrastructure to explore could be really damaging here. Can you tell us about that?

CANNON: Yeah, it was a really interesting story, actually, from the, you know, sort of head of this Congo peat research, Simon Lewis, he's a professor in the UK. And he mentioned the fact that I think it was early on when he was sort of exploring this area and thinking about the research. But he found this road basically through the peatlands, and it had been built, I think, several decades prior. But on one side, there was green forest and on the other side is this dried dead forests, basically. And what had happened, he thinks is that building this road had changed the movement of water back and forth. And once that water was cut off from a particular area, that forest ended up dying on that side. So it's not as simple as looking at the wholesale destruction. Even our little incursions to bring a road in, say, for a truck to dig an oil well or something like that might have detrimental effects to parts, or even huge parts of the peatlands.

The Yangambi Research Station is located along the banks of the Congo River. The Congo peatlands lock in 30 billion tonnes of carbon making the region one of the most carbon-dense tropical ecosystems on Earth. (Photo: Ahtziri Gonzalez, Flickr, CIFOR, CC BY-NC-ND 2.0)

BASCOMB: And, you know, often, as we see in Brazil, you know, there's this sort of fishbone pattern, when you build one road, then people will come in and say, "oh, there's a road here, let me build a smaller side road and a smaller side road off of that". And before you know it, you have this network of roads, and cascading problems associated with them.

CANNON: Yeah. And that's, you know, that's something that tropical ecologist like Bill Lawrence have looked at for decades now. It allows us humans access to areas that we weren't able to get to before. And this sort of comes back to why this area is such a amazing repository of wildlife, because it's so remote because it doesn't have these roads built into it, yet. These animals are able to thrive there in a way that they might not otherwise. And as soon as you start to build access into these areas, and unfortunately destroy large parts of forest very quickly.

BASCOMB: And what concern is there if any that climate change could maybe push these peatlands towards releasing some of the carbon that's locked up there.

CANNON: That's another aspect of the research that's both fascinating and a little worrying I think at some point. What could happen with it these particular peatlands is that as the climate warms, it could change their fundamental nature. So the peatlands rely on a certain amount, a certain input of water to keep that decomposition at a relatively low level, again, that can come from the rain or can come from rivers, in many parts of the peatlands it actually comes from the the rainfall. However, in this part of the Congo Basin, there's relatively small amount of rainfall that occurs over the course of the year compared to say, the peatlands in the Amazon or Indonesia, which have, you know, some places maybe twice as much rainfall. It's still a lot of rain compared to, you know, a drier forest. But the issue is- how much climate change would it take to change the length of that rainy season? That really seems to be the key variable at this point. It's not so much the amount necessarily, but over how long a period it actually falls. And so if the scientists are a little bit concerned that if that period shortens, it may tip the scales one way or the other, to say start drying out the peatlands, allowing more of this decomposition to happen and then releasing more of that carbon into the atmosphere. It's early days, I think, for a lot of that research that's something they emphasize a lot, but that is an active line of research right now, is to understand what does our currently warming climate mean going forward.

BASCOMB: John Cannon is a reporter for Mongabay. John, thank you so much for taking this time with me today.

CANNON: Thanks so much for having me.



Read Mongabay's series on the Congo peatlands starting with Part 1

Check out John Cannon’s Twitter

Read the study Age, Extent and Carbon Storage of the Central Congo Basin Peatland Complex from the journal Nature

Mongabay "The past, present and future of the Congo peatlands: 10 takeaways from our series"


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