Land is Finite.

Nobuko SAIGUSA,Director,Center for Global Environmental Research
National Institute for Environmental Studies,Japan(NIES)
Lead author of Chapter 6 of IPCC Special Report on Climate Change and Land (SRCCL)
Interview date: 17 September 2019
Interview venue: NIES
Interviewer: Mikiko KAINUMA,Senior Research Advisor,IGES

Kainuma: First of all, would you tell us what you particularly wanted to convey with the SRCCL?

Saigusa: First and foremost, I wanted to convey that land is finite. Increasing the amount of land that can serve as a carbon sink — large-scale plantations and crop production for biomass fuels — in the name of climate action has the potential to compete with food supply, water security, and ecosystem conservation. It is necessary to remember that land is finite and take appropriate actions with this fact in mind.
Secondly, it is essential to take ambitious actions to significantly reduce anthropogenic greenhouse gas emissions across various sectors of society. This can curb the negative impacts of climate change on terrestrial ecosystems and food systems.
Thirdly, to meet the long-term objectives of the Paris Agreement, in addition to the rapid reduction of anthropogenic greenhouse gases, it is absolutely necessary to stop deforestation, plant new vegetation, and utilise biomass energy and negative emissions. On top of this, in order to prevent adverse effects on food security, it is essential to overcome the formidable challenge of simultaneously improving agricultural productivity by preventing land degradation, and making our food systems low-carbon by, among other approaches, examining our eating habits.
I wrote about this point in the October issue of NIES’s CGER News (“Land is finite: what climate actions are in harmony with food, water, and ecosystems?”)


Kainuma: Sustainable land management is necessary, but can you please share with us some specific options?

Saigusa: In the Summary for Policymakers (SPM), one figure (Figure SPM3) summarises the main countermeasure options with respect to land management. For each of the countermeasure options, the efficacy and extent of trade-offs are evaluated in terms of five areas: mitigation, adaptation, desertification, land degradation, and food security. The blue shaded regions indicate the positive effects of policies, while the red shaded regions indicate negative effects. Figure 1 below (Figure IPCC SRCCL SPM Figure SPM 3A) shows response options for land.

Figure 1: Response options without or with limited competition for land (IPCC SRCCL SPM Figure SPM 3A)


Many response options based on land management have positive effects for areas such as food security. For example, there are hopes that introducing agroforestry will have positive impacts in many respects, such as increases in agricultural productivity.


Kainuma: Among response options, which involve the greatest competition for land?

Saigusa: If implemented very widely, the four options (forestation, reforestation, BECCS, and the introduction of biochar in soil) have the possibility of increasing the competition for land that is necessary for food production. BECCS, in particular, is said to be a necessary response for climate stabilisation, but some have pointed out that it has a high probability of adversely affecting food security. In research examining the relationship between bioenergy and food security, it is estimated that the large-scale introduction of bioenergy creates the risk of exacerbating world hunger for up to 150 million people.


Kainuma: How much land, approximately, is necessary for biomass energy?

Saigusa: If we consider the pathway to limit warming to 1.5℃ via a shared socio-economic scenario (SSP) as shown in the IPCC Special Report of Global Warming of 1.5℃ (SR1.5), it is estimated that additional land will be required. The estimated results can be found in Figure 2.


Kainuma: So, to interpret this figure, IGES has arranged the emission pathways of the SR1.5 (top) and the SRCCL’s necessary land use changes, respectively, to limit global warming to 1.5℃ (bottom). This may make it slightly easier to understand.

Figure 2: The breakdown of contributions to global net CO2 emissions for four pathways


Saigusa: The figure shows the necessary land-use changes for three scenarios: a sustainability-focused society that adopts social and technological innovations at a high rate (SSP1), a moderately transitioning society (SSP2), and a society that continues to rely on fossil fuels (SSP5). It shows how land for agriculture, pasture, biofuel cultivation, forestry, and natural land, change.
Figure 2A’s pathway (SSP1) is sustainability-focused. By moving forward with sustainable land management and making the agricultural system (including agricultural productivity and consumption patterns) more sustainable, even if the per capita food consumption increases in the future, it will be possible to reduce the cropland and pasture area necessary to produce food and use the remaining land for reforestation, forestation, and biofuel resource cultivation. This will enable mitigation measures to take place. On the other hand, for the other pathways, i.e., Figure 2B’s middle of the road pathway (SSP2) or Figure 2C’s resource intensive pathway (SSP5), greenhouse gas continues to be emitted at high levels, so these pathways require that mitigation measures via biofuel production and BECCS be scaled up very quickly before 2050. As a result, it is predicted that competition for land will decrease cropland, pastures, and natural land, increasing the risk of adversely affecting food security and ecosystems.


Kainuma: For SSP5, it is necessary to have an additional 7.6Mkm2 of land for biofuel cultivation by 2100. Even for SSP1, 4.3Mkm2 of land for biofuel cultivation is necessary. Considering that the world’s surface area is 148Mkm2, and India’s total area is 3.28Mkm2, reserving 7.6Mkm2 of land for biomass fuels sounds difficult. What are your thoughts?

Saigusa: It is, indeed, difficult. Moreover, in the SSP5 scenario, land used for biofuel cultivation must increase very rapidly from 2030 to 2050. This is a pace of about 0.2Mkm2 per year. This is equivalent to the area of Hokkaido, the Tohoku region, the Kanto region, Nagano Prefecture, and Niigata Prefecture combined. While there is a possibility of converting grasslands to biofuel cultivation land, this is quite a large area.


Kainuma: And cultivated land is decreasing. Some scenarios project that the global population will exceed 10 billion people by 2100, but can we secure enough food for everyone?

Saigusa: This report states that improving the food systems via initiatives such as those that decrease food loss and food waste is one effective measure to address climate change. For example, 25-30% of food produced between 2010 and 2016 has been wasted, and this amount is estimated to be equivalent to 8-10% of anthropogenic greenhouse gas emissions. Moreover, the report also states that, by changing to diets that consume more plant-based food (cereals, beans, etc.), whose production requires less land, water, and energy than animal-based food, there is a potential to decrease emissions by 0.7~8 Gt CO2e per year by 2050.


Kainuma: I guess that proceeding with countermeasures related to land is difficult. What were considered the barriers?

Saigusa: Certainly, it is extremely difficult to change land use. In many cases, social, economic and cultural barriers have hindered the implementation of specific policies. For example, issues regarding unstable land rights due to social inequality and political instability, as well as the lack of opportunity to disseminate the products of innovation and raise public awareness have been making policy adoption and market changes difficult.
However, natural disasters such as typhoons, floods, and heat waves have become more frequent and intense, and climate mitigation measures are vital. To avoid relying on BECCS as much as possible, we must urgently drive global warming countermeasures forward.


Kainuma: We may need to start wrapping up, but please share with us anything you forgot to mention or want to re-emphasise.

Saigusa: With this report, there is a tendency to focus on sensational aspects such as “food prices will increase,” or “we should limit beef consumption”. However, we must first do everything we can to limit global warming to 1.5℃ and, on top of this, quickly plan about how land — a finite resource — will be used. Additionally, this report does not sufficiently consider the costs associated with individual climate change countermeasure, but in thinking about the competition with land for food production in the future, careful consideration of the costs is essential. I think that, when food prices soar in the future, another important challenge is how this will affect the problem of global poverty.
By the way, the report’s official title is the “Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems.” Since this official title is long, it has been shortened to “Special Report on Climate Change and Land” in English and “Tochi Kankei Tokubetsu Houkokusho” (translated as: Special Report Related to Land) in Japanese. Perhaps it is because the word “tochi” (“land”) holds the connotation of “personal estate,” but we may struggle to understand what the report is about if we just read the Japanese shortened title. On the other hand, the English word “land” can be thought of in contrast to the sea, and can also be thought of as “earth.” I think it is necessary to appeal to readers, in an easily understandable manner, the original significance of this report: how climate change affects terrestrial ecosystems and agricultural land; how, by managing land sustainably, we may prevent land degradation; and how we must balance food security and climate action simultaneously.
I have thought in the past that this message can be communicated proactively from Japan as well. For example, Japan’s national territory is two-thirds forest land and has the highest proportion of forest land among all developed countries. The summers are warm and humid, allowing trees to grow well. I think that, starting from highly effective use of woody biomass, there must be great room to promote policies that capitalise on the specific characteristics of regions. Even with respect to improvements in the food system, while significantly reducing food loss and food waste, re-evaluating the Japanese culture of local production for local consumption may be one synergistic approach to combat climate change.


Kainuma: Thank you very much for taking the time to do this interview. I clearly understand that land management—which forms the basis of daily life—is extremely difficult. I hope that you can continue to disseminate information on the necessity of global warming countermeasures and how this ought to be done in an easy-to-understand way.


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