--What made you decide to study the relationship between climate change and hunger?
Mr. Fujimori:
Around 2013, when I was at the National Institute for Environmental Studies, the first thing that came to my mind about the relationship between food security and climate change was that climate change would make it impossible to produce crops.Around that time, models emerged that required large amounts of bioenergy in some cases to reduce greenhouse gas emissions.At that time, the main sources of bioenergy were sugar cane (mainly Brazil) and corn (mainly the United States).In addition, it has been argued that if we grow a lot of plants that are not edible and have only energy uses, energy production will increase.The Paris Agreement adopted in 2015 set a long-term climate goal of keeping temperatures below + 2 ° C, but to achieve this, CO emitted from the use of bioenergy.2At that time, it was known in the IPCC's Fifth Report published in 2014 that it was necessary to take out and bury it in the ground, that is, to make it a negative emission.However, previous model studies have assumed that these measures against global warming do not affect food production.However, if bioenergy is profitable, it will be economically rationalized, and if that happens, the food market will surely be affected, and I thought that the most serious problem would be hunger.However, no one had mentioned that at that time, and I started to realize that this could be a big problem.
――Taikan Oki, a professor at the University of Tokyo, said that sudden changes could cause wrinkles to the vulnerable.
Mr. Fujimori:
Yes, sudden changes are, of course, a big factor.However, another important thing is policy design.It is quite possible that there will be negative impacts if we pursue only the most efficient ways to reach our climate goals, without caring for the poor.Therefore, it is important to consider the poor and proceed with things so as not to adversely affect them.Last year weNature Climate Change He insisted that meticulous attention should be paid to policy design, as weird ways of combating climate change can have a negative impact.I asked the world in the form of a warning.
――In this kind of modeling, it is pointed out that this is really the case.That is why I think it is a big point that similar results were obtained by verifying 6 different simulations and multiple parameters this time.
Mr. Fujimori:
That's right.In fact, from 2013 to 14, we have already confirmed by model simulation that simple measures against global warming have unintended adverse effects.Convinced that there is something, in 2015, one of the top journals in this field, a paper using only our model,Global Environmental Change Posted in.However, the reaction was not good, and in the end it was published in a journal with a slightly lower hurdle.3..With this background, I suggested that all of my peers around the world should do it this time, first last year.Nature Climate Change Issue a warning withThis paperI suggested that there is such a solution to the warning.It was good that multiple research institutes around the world worked on it, got robust results, and came to similar conclusions.We have stepped up one by one, and I am deeply moved by the feeling that we have finally come to this point.
――What are your thoughts on policies to prevent hunger?
Mr. Fujimori:
Hunger isn't just about giving out money or getting food aid.Therefore, I wrote the dissertation with the feeling that it could be solved virtually at such a cost.It is presented in a symbolic form rather than concrete.It costs a lot of money to deal with climate change, such as changing the energy system, but I wanted to say that the amount presented in the paper is one-hundredth or tiny.
Some people who are skeptical about global warming countermeasures should not do it because there is no basis and strange warming countermeasures will have a bad effect, and it is better not to change the current system suddenly. There is a person who says.But if you think about it and deal with it properly, you can do something without spending so much money.In fact, even at the time of peer review, it was pointed out that poverty and hunger cannot be slammed by such a global simulation.There is always a counterargument that this is not a reality, as each site has its own problems and things can be completely different depending on governance issues and national circumstances.We know it a hundred and think that individual measures are needed to really solve this problem.However, the issue of how much, where, and what such individual measures are needed is left to the experts in the field, and how much can happen globally and is it a serious problem? Perhaps that is not the case, I wanted to get a macro picture of the whole thing, so I presented it in the form of a cost estimate.
To truly save poverty, we need a decent education system and social infrastructure, and it is important to build invisible trust.Simply transferring technology does not work, and food aid often does not reach where it is needed, as in North Korea.
Mr. Hasegawa:
The first thing I wanted to say in my paper was that I know that climate change mitigation will increase hunger, but that's an excuse to stop not doing it.The goal is to show that a small additional cost can be used to reduce hunger.
Figure 1 Regarding global CO2 emissions, carbon tax on reduction of global warming effect gas, and hunger risk population associated with global warming countermeasures, if global warming countermeasures are not taken (Baseline), if the emission targets of the Paris Agreement are achieved and maintained (NDC) ), 2 models (AIM, IMAGE, MESSAGE-GLOBIOM, REMIND-MAgPIE, POLES, WITCH) for 2 scenarios when the temperature rise is suppressed to 1.5 ° C (1.5 ° C) and also to 4 ° C (6 ° C). ) Results of the simulation (a to c). d is the cost of controlling the hunger-risk population as a percentage of GDP if it stabilizes at + 2050 ° C in 1.5.
--Now, the Sustainable Development Goals (SDGs) are involved.
Mr. Hasegawa:
ち ょ う どNature Sustainability The following papers accepted by4Mentions the eradication of hunger in SDGs2.In fact, if we only consider eradication of hunger, agriculture will have a negative impact on the environment and climate.If you try to increase food, agricultural activities themselves will increase and contribute to global warming.Most of the methane, which accounts for 16% of total greenhouse gas emissions, comes from agriculture, primarily from rumination and paddy fields in cattle.How to eradicate hunger while balancing food production and greenhouse gas emissions.How can we eradicate hunger without causing any negative effects?The paper proposes that if food loss is reduced and food is distributed in a balanced manner, it is possible to supply the food necessary for eradicating hunger without significantly increasing food production. ..Until now, we had to think only about climate change, but from now on, we have to think about SDGs as well.Recent studies have focused on finding the best sustainable path by considering factors such as climate change and hunger, food affairs, or water.I think one of them is this paper.
Mr. Fujimori:
The SDGs have had a huge impact on our research.We are basically climate changers, but our perspective has expanded.Climate change is also associated with SDGs2 starvation, SDGs3 health, SDGs6 water problems, SDGs7 energy, SDGs8 economy, and ecosystem SDGs14.In fact, over the last five years, one of the trends in the research field has been to deepen understanding by simulating what is happening with interrelationships, synergies, and trade-offs.
Mr. Hasegawa:
Nowadays, one index is not enough, and it is required to look at multiple indicators.
――Simulation has become complicated, hasn't it?
Mr. Hasegawa:
Not only the model but also the scenario has become complicated. The number of variations has increased, such as when A was taken and not taken, and when B was taken and not taken.
Mr. Fujimori:
We use an integrated evaluation model, and as the name suggests, we evaluate by including various factors.Therefore, I think the SDGs are a good issue for expanding new fields, although they have some difficulties.
――The SDGs aim to eliminate various problems, so I think it's very difficult.
Mr. Hasegawa:
Certainly hunger seems difficult.In addition to the national system and countermeasures, conflict is also a major factor.In fact, hunger has been declining all the time, but has been rising since 2016.The FAO report stated that the cause was a dispute.
Mr. Fujimori:
RecentNature Was also out5However, there are many papers saying that conflict may be greatly affected by climate change.Syria is said to have that effect.In areas where the natural environment is harsh, if there is stress from the environment just before the conflict, a little pressure will put you in a state of conflict.
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