The ‘big story is carbon’, but more research needed on forgotten greenhouse gases found in peat, says expert

BOGOR, Indonesia (22 November, 2012)_In this conversation with Forests News, Kristell Hergoualc’h, a scientist at the Center for International Forestry Research (CIFOR), explains the technical aspects of her research in measuring and monitoring greenhouse gas emissions (GHG) from tropical forests, in particular from carbon rich peat swamp forests found in Indonesia.

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BOGOR, Indonesia (22 November, 2012)_In this conversation with Forests News, Kristell Hergoualc’h, a scientist at the Center for International Forestry Research (CIFOR), explains the technical aspects of her research in measuring and monitoring greenhouse gas emissions (GHG) from tropical forests, in particular from carbon rich peat swamp forests found in Indonesia.

She discusses the often forgotten GHG gases in the climate change debate, such as methane and nitrous oxide that are emitted from peat forests, and the effect of converting these forests to other uses such as oil palm plantations.

In the context of forests and climate change, what are MRV and RELs?

Kristell: In the framework of reduction of greenhouse gas emission from deforestation and degradation (REDD+), MRV or measurement, reporting and verification, is the system of monitoring, reporting and verifying the effectiveness in greenhouse gas emissions reduction. Then Reference Emissions Levels (RELS) define a benchmark scenario of greenhouse gas emissions that would happen in the absence of a REDD+ project or scheme.

Now, emission levels are calculated as a combination of what we call ‘activity data’ and ‘emission factors’. So the activity data describes the types of land-use changes and is expressed as a surface unit. This information is generally derived from satellite imagery. The emission factors provide and estimate greenhouse gas for a given activity.

So for instance, if we know that an area is threatened with deforestation. We can assign to this area an emission factor and calculate the greenhouse gas emissions. Then if this area isn’t deforested we can calculate the avoided greenhouse gas emissions.

The emissions that would happen in the absence of any mitigation scheme, reference [levels] are a business-as-usual scenario.

Q: What research is CIFOR doing in this area?

CIFOR is doing research on MRV and on emissions levels, both on activity data and emissions factors. In Indonesia most of our research focuses on peatlands. There are three reasons for this:

First, tropical peatlands are among the largest carbon pools on earth, so when these ecosystems are converted, huge amounts of carbon are released into the atmosphere.

Second, Indonesia is one of the tropical countries that hold the largest areas of peatlands, and is also a country where 80 percent of national greenhouse gas emissions are from land-use change. Fifty of the 80 percent come from fires and land-use change in tropical peat swamp forests.

Finally, there are significant gaps in the knowledge and methods for quantifying carbon losses from land-use change in these ecosystems.

When peat swamp forests are converted, we estimate that 60-80 percent of emissions come from the peat. Therefore, we have oriented our research in providing details and accurate data from these emissions from the peat.

For this we use a general method, which is proposed by the IPCC (Intergovernmental Panel on Climate Change) and is called the “gain-loss approach” or input-output approach. So this method consists of measuring all the fluxes coming into the peat and all the fluxes coming out of the peat and in calculating the balance.

To simplify it, we could compare this peat carbon stock to a bank account and calculate how much money is saved or lost during the year by making the balance of the transfers in and out of the account.

Now lets go back to the peat. So the main carbon inputs from the peat are from leaves, branches and dying roots. Carbon is released from the peat through peat decomposition, fires, methane emissions, and soluble and physical removal.

In this specific CIFOR project, the three PhD students are focusing their research on the changing levels of greenhouse gas emissions across one of the main land-use change types found here in Indonesia, which is peat swamp forest conversion to oil palm plantations.

So Sebastian Perch is quantifying carbon inputs through root mortality. Louis-Pierre Comeau is assessing how much carbon is entering through natural debris and lost through peat decomposition. Jodi Harthill is measuring the fluxes of methane and nitrous oxide and the losses through soluble and physical removal.

What is it about peat that makes it store so much carbon?

In their natural state these ecosystems are waterlogged so you have a very low decomposition of organic matter. This organic matter accumulates and that is how the peat builds over millennia. Once you drain peat, for example, to convert the land for other uses, you reverse the situation and the carbon that has accumulated in the soil is emitted as carbon dioxide or methane.

How is this research important to fighting climate change?

Indonesia is one of the greatest emitters of greenhouse gases in the world. A large majority of these emissions are from peat. So climate-change mitigation schemes in Indonesia should therefore focus on protecting peat swamp forests. However, the implementation of such schemes depends on the supply of reliable greenhouse gas estimates.

And for REDD+?

Especially for a scheme such as REDD+ that aims to protect forests, it is very important. At the moment our estimates of emission levels and our potential estimates of avoided greenhouse gas emissions are not appropriate. So it is urgent and very important to provide better estimates of the levels of these gases. At CIFOR, four scientists are involved in writing a new chapter of the IPCC national greenhouse gas inventories. This chapter is specific to wetlands.

Have peat forest ecosystems been included in IPCC (Intergovernmental Panel on Climate Change) guidelines before?

Within the different chapters, there are specific sections for peat soils. But actually these ecosystems are so specific that they require a chapter to themselves. There are other carbon rich soils such as mangrove soils, for example.

What are some examples of your findings so far?

We were able to provide emissions factors for peat swamp forests converted to both oil palm plantations and acacia plantations. And now with research being carried out in Berbak National Park in Sumatera, and in Tanjung Puting National Park in Kalimantan, we will be able to refine these estimates regarding the conversion to oil palm plantations in these areas.

We have also recently released an emission factor – the emission of nitrous oxide following nitrogen application in oil palm plantations on peat.

What effect do other greenhouse gases found in forests, besides carbon, have on climate change?

Usually when we monitor greenhouse gas from an ecosystem, we monitor the carbon dioxide, methane and nitrous oxide. Methane and nitrous oxide are very important because of their global warming potential. Their capacity to heat the atmosphere is respectively 25 and 300 times more powerful than carbon dioxide. On the other hand, their concentrations in the atmosphere are much lower. However, where land is converted for agricultural and palm oil, nitrogen fertilizers are often used to speed up growth, so these can increase amounts of nitrous oxide in the atmosphere. So we need to find ways so that these do not become too high. There are ways to reduce them: By reducing fertilisation without reducing the productivity of the system.

How significant is the application of nitrogen to crops such as oil palm and their impact on levels of nitrous oxide emissions?

We are investigating this situation in peat land cleared for palm oil plantation.  When the land has recently been cleared and opened, the nitrogen in the soil is no longer available to the plant. Nitrogen fertilizers are then applied to increase fertilization, allowing the plant to grow quickly. During the first three or four years of growth, we may see significant emissions of nitrous oxide. After that, the amount of nitrogen fertilisers used can be reduced as there is more available in the soil for the plant. However, although at a slower rate, there will still be fertilisation and the release of nitrous oxide emissions.

How does this compare to carbon emissions in peat?

In terms of peatlands, especially after land-use change, the big story is about carbon dioxide. The state of the carbon found in waterlogged peat land is completely different from the carbon found in drained peat land and this process speeds up the decomposition of carbon dioxide.

What inspires you to work on this aspect of climate science?

It’s challenging to work in these virgin ecosystems that are usually located in remote areas, which are accessed through the rivers and through swamps. We also have to face the local biodiversity such as tigers and snakes, orangutans and monkeys. But it is also challenging because there is a lot to learn about and discover and we are really looking forward to verifying our research hypothesis.

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