Kiyoshi Takahashi

National Institute for Environmental Studies · Social Systems Division

Climate mitigation is reported to benefit biodiversity globally. However, the impacts of mitigation measures based on large-scale land-use modifications can be concentrated in the regions where they are introduced, resulting in regional mismatches between mitigation efforts and biodiversity benefits. Here, we evaluated the impacts of large-scale de...

Various climate projection and impact assessment information has recently been created and published. However, such information has yet to reach individual decision-makers, and it is difficult to say that it is effectively utilized for decision-making on climate change adaptation. To address this issue, experts from various fields were gathered to...

Based on an extensive model intercomparison, we assessed trends in biodiversity and ecosystem services from historical reconstructions and future scenarios of land-use and climate change. During the 20th century, biodiversity declined globally by 2 to 11%, as estimated by a range of indicators. Provisioning ecosystem services increased several fold...

Red meat consumption is associated with an elevated risk of mortality from non-communicable diseases (NCDs). In contrast, forage fish, as highly nutritious, environmentally friendly, affordable, and the most abundant fish species in the ocean, are receiving increasing interest from a global food system perspective. However, little research has exam...

Afforestation is a major carbon dioxide removal technology but can negatively affect food and land systems. Here, we used an integrated assessment model to quantitatively demonstrate how the selection of forest type to use in afforestation could increase global carbon sequestration without compromising global food and land sustainability. Our findi...

Fire emits hazardous air pollutants, the most dominant of which is fine particulate matter of diameter ≤2.5 μm (PM2.5). PM2.5 is a great concern due to its adverse effects on public health. Previous studies have examined the health burden from fire-related PM2.5 for the historical period; however, future global mortality associated with fire-PM2.5,...

Recent criticisms have suggested that future emissions are unlikely to lead to the warmest climate scenario available (SSP5-8.5), which has resulted in the second highest scenario (SSP3-7.0) receiving increased attention. The distinctiveness of SSP3-7.0 has not been well recognized, but it is relevant for the proper interpretation of studies that u...

The impact of climate change on power demand in Japan and its related CO2 emissions is a matter of concern for the Japanese authorities and power companies as it may have consequences on the power grid, but is also of global importance as Japan is a significant contributor to global greenhouse gas emissions. In this study, we trained random forest...

Wildfires affect human health by emitting hazardous air pollutants. The contribution of climate change to global fire-induced health impacts has not been quantified so far. Here, we used three fire-vegetation models in combination with a chemical transport model and health risk assessment framework to attribute global human mortality from fire fine...

What will be the aggregated cost of climate change in achieving the Paris Agreement, including mitigation, adaptation, and residual impacts? Several studies estimated the aggregated cost but did not always consider the critical issues. Some do not address non-market values such as biodiversity and human health, and most do not address differentiati...

Many countries have set ambitious long-term emissions reduction targets for reaching the goal in alignment with the Paris Agreement. However, large-scale emission reduction efforts may influence poverty by various economic channels. Here, we show the extent to which climate change mitigation, excluding climate change impacts, has the potential to i...

Afforestation is considered as a major carbon dioxide removal (CDR) technology, but if implemented inappropriately in large scale, can negatively affect food and land systems. Here we quantitatively showed how a forest-type selection in afforestation would enlarge the global carbon sequestration and affect global food and land systems and sustainab...

Fires and their associated carbon and air pollutant emissions have a broad range of environmental and societal impacts, including negative effects on human health, damage to terrestrial ecosystems, and indirect effects that promote climate change. Previous studies investigated future carbon emissions from the perspective of response to climate chan...

Researchers agree that there is substantial evidence of an increasing trend in both the frequency and duration of extreme temperature events. Increasing extreme temperature events will place more pressure on public health and emergency medical resources, and societies will need to find effective and reliable solutions to adapt to hotter summers. Th...

Climate change can cause economic losses and increase poverty. However, climate change mitigation measures can also cause economic losses and increase poverty. Previous studies have not assessed the impact of climate change and climate change mitigation on poverty simultaneously. This study aimed to quantitatively assess the impact of climate chang...

The impact of climate change on power demand in Japan is a matter of concern for the Japanese authorities and power companies as it may have consequences on the power grid. We trained random forest models against daily power data in ten Japanese regions and for different types of power generation to project changes in future power production and it...

Since many new generation earth system models (ESMs) have been suggested to overestimate future global warming, the latest report of the Intergovernmental Panel on Climate Change used the constrained range of global warming instead of that in the raw ensemble. However, it is not clear how the constraints of climate change projections potentially re...

Climate scenario data set are indispensable for assessing future climate impacts. In this study, we developed statistically downscaled climate scenarios in Japan using modified bias correction method based on five general circulation models selected from the Coupled Model Intercomparison Project (CMIP) Phase 6 to facilitate impact assessments and a...

Representation of spatial dependence on temporal variations in climate scenarios is quite important when performing impact assessments in various sectors, including water resource management, agriculture, and energy. Although the complex terrain of Japan is closely related to the formation of regional climates, the spatial aspects of climate scenar...

Estimates of future climate change impacts using numerical impact models are commonly based on a limited selection of projections of climate and other key drivers. However, the availability of large ensembles of such projections offers an opportunity to estimate impact responses probabilistically. This study demonstrates an approach that combines m...

Climate change is one of the greatest long-term challenges faced by humanity. In the projection of climate change impacts, scenarios based on assumptions regarding future conditions are commonly used. Shared socio-economic pathways (SSPs) are widely employed as socio-economic scenarios for global-scale predictions. The SSPs provide future projectio...

Existing climate change mitigation scenarios for attaining the 1.5°C goal generally phase out hydrocarbon use through decarbonization of the energy system to eliminate fossil fuel usage. However, they require rapid changes in energy-demand technologies and human behaviors or extensive reliance on bioenergy for carbon dioxide removal (CDR). Carbon c...

Assessing the impacts of future climate change on electricity demand is critical to managing electricity systems efficiently and identifying reliable adaptation measures to mitigate the adverse effects of climate change. This study assessed the impacts of future climate change on electricity demand while considering simultaneous interactions among...

This is supplementary material (Appendix A－Appendix I) for the following article. Regional and temporal variations in the impacts of future climate change on Japanese electricity demand: Simultaneous interactions among multiple factors considered, May 2022, Energy Conversion and Management X

Biomass energy is projected to be a critical resource for defossilization of the energy system. While urban area extension and land conservation would constrain potential biomass supply, there is little understanding of their impacts. This paper presents global and regional bioenergy supply potential estimates by newly implementing urban area expan...

Assessing the impacts of climate change in multiple fields, such as energy, land and water resources, and human health and welfare is important to find effective strategies to adapt to a changing climate and to reduce greenhouse gases. Many phenomena influenced by climate change have diurnal fluctuations and are affected by simultaneous interaction...

Earlier studies have noted potential adverse impacts of land-related emissions mitigation strategies on food security, particularly due to food price increases—but without distinguishing these strategies’ individual effects under different conditions. Using six global agroeconomic models, we show the extent to which three factors—non-CO2 emissions...

Conserving biodiversity is one of the great concerns for developing sustainable society. This study attempts to identify in what regions and what measures are effective to conserve the biodiversity by integrating economic, land-use and biodiversity models in a single modeling framework. More specifically, we implemented scenarios to change the diet...

Over the past twenty years, vast amounts of quantitative and qualitative information have been created on climate change and its impact on society. However, various issues still remain until such information can be widely utilized by national and local governments and enterprises. Here, the authors, who have long been involved in research on climat...

Climate change is expected to increase the frequency, intensity and spatial extent of extreme climate events, and thus is a key concern for food production. However, food insecurity is usually analysed under a mean climate change state. Here we combine crop modelling and climate scenarios to estimate the effects of extreme climate events on future...

The average household size in China has declined over the past few decades and will continue to drop, which leads to a loss of scale economies. Its implications for electricity demand and sustainability could be especially profound because of the high ecological/environmental intensity of electricity in China and the expected boom in demand. Using...

One of the major barriers to climate communication is that climate change is often presented to the public in such a way that impacts seem distant in time. To improve how climate change resonates with people, we propose a simple indicator: how many extreme events (hot days and heavy precipitation days) are grandchildren projected to experience that...

Process-based models are powerful tools for simulating the economic impacts of climate change, but they are computationally expensive. In order to project climate-change impacts under various scenarios, produce probabilistic ensembles, conduct online coupled simulations, or explore pathways by numerical optimization, the computational and implement...

Globally, many parts of fire emissions are driven by deforestation. However, few studies have attempted to evaluate deforestation and vegetation degradation fires (DDF) and predict how they will change in the future. In this study, we expanded a fire model used in the Community Land Model to reflect the diverse causes of DDF. This enabled us to dif...

Assessing climate change impacts on local communities is an urgent task for national and subnational governments. The impact assessment requires socioeconomic scenarios, including a long-term outlook for demographic and economic indices. In Japan, the National Institute for Environmental Studies developed the Japan Shared Socioeconomic Pathways (JP...

Mapping the elderly population exposure to heat hazard in urban areas is important to inform adaptation strategies for increasingly-deadly urban heat under climate change. However, fine-scale mapping is lacking, because global climate change projections have not previously been integrated with urban heat island effects especially with urban three-d...

Climate change impact assessment studies often use future projections of only a few global climate models (GCMs) due to limited research resources. Here we develop a novel method to select a small subset of GCMs that widely capture the uncertainty range of large ensemble. By applying this method, we select a subset of five GCM projections from the...

Actions tackling with climate change can cause co-benefits and trade-offs with Sustainable Development Goals (SDGs) concerned with air pollution, water scarcity, food security, land use, and sustainable energy. Such interactions can be greatly influenced by socioeconomic conditions. The impacts of socioeconomic conditions on multiple SDGs have not...

Agriculture, Forestry and Other Land-use (AFOLU) are thought to play a vital role in long-term GHG emissions reduction, especially for their importance in non-CO2 emissions, bioenergy supply and carbon sequestration realized by afforestation. Several studies have noted potential adverse impacts of land-related emissions mitigation on food security,...

In order to project climate-change impacts under a wide-range of scenarios or conduct on-line coupled simulations, the computational and implementation cost of economic impact calculations should be reduced. To do so, in this study, we developed various emulators that mimic simulation outputs, namely economic models coupled with bio/physical proces...

Future changes in the climate system could have significant impacts on the natural environment and human activities, which in turn affect changes in the climate system. In the interaction between natural and human systems under climate change conditions, land use is one of the elements that play an essential role. On the one hand, future climate ch...

Synergies and trade-offs exist between climate mitigation actions and target indicators of the Sustainable Development Goals (SDGs). Some studies have assessed such relationships, but the degree of such interaction remains poorly understood. Here, we show the SDG implications associated with CO 2 emissions reductions. We developed ‘marginal SDG-emi...

Bioenergy could play an important role for Japan's long-term mitigation strategy and energy supply but understanding of Japan's domestic bioenergy supply capacity is limited. Here, we estimated Japan's technical and economically feasible bioenergy potential throughout this century. We used an integrated assessment framework covering various feedsto...

To halt climate change this century, we must reduce carbon dioxide (CO2) emissions from human activities to net zero. Any emission sources, such as in the energy or land-use sectors, must be balanced by natural or technological carbon sinks that facilitate CO2 removal (CDR) from the atmosphere. Projections of demand for large-scale CDR are based on...

Coastal areas provide important services and functions for social and economic activities. Damage due to sea level rise (SLR) is one of the serious problems anticipated and caused by climate change. In this study, we assess the global economic impact of inundation due to SLR by using a computable general equilibrium (CGE) model that incorporates de...

Shared socio-economic pathways (SSPs) are alternative global development scenarios focused on the mitigation of and adaptation to climate change. However, global SSPs would need revised versions for regional or local assessment, which is the so-called extended version, because global narratives may lack region-specific important drivers, national p...

Under the session “Quantifcation of the population”, the following sentence Population curves of Japan SSP1 and Japan SSP2 are close, because the diference between high fertility and medium setting is not remarkable by NIPSSR.

Despite the scientific consensus on the extinction crisis and its anthropogenic origin, the quantification of historical trends and of future scenarios of biodiversity and ecosystem services has been limited, due to the lack of inter-model comparisons and harmonized scenarios. Here, we present a multi-model analysis to assess the impacts of land-us...

Bias corrected climate scenarios over Japan were developed using two distinct methods, namely, the cumulative distribution function-based downscaling method (CDFDM) and Gaussian-type Scaling approach (GSA). We compared spatial distribution, monthly variation, and future trends. The seasonal distribution of bias-corrected data using CDFDM closely fo...

The annual globally averaged atmospheric carbon dioxide concentration is expected to reach 550 ppm around 2050 unless measures are taken to mitigate its increase. Field experiments suggest that the nutrient contents of food crops are decreased substantially under elevated carbon dioxide conditions, which will lead to additional nutritional conseque...

The ensemble average projections of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) ensemble show future increases in shortwave radiation at the surface (SW) in Japan. We reveal that the Arctic Oscillation-like atmospheric circulation trends cause cloud cover decreases around Japan, leading to increases in the SW. In many cases, impact a...

More than half of the world’s population currently live in urban areas and are particularly at risk from the combined effects of the urban heat island phenomenon and heat increases due to climate change. Here, by using remotely sensed surface temperature data and social-ecological indicators, focusing on the hot dry season, and applying the risk fr...

In Asia, where rice is a major crop, there is high concern about the detrimental effects of climate change on rice productivity. Evaluating these effects, considering the country-specific cultivars’ responses to climate, is needed to effectively implement the national adaptation plans to maintain food security under climate change. However, to date...

In this study, we clarified the health damage caused by climate change mitigation throughout undernourishment using multiple global agriculture economic models. As a result, the ambitious climate policy, if it is not properly implemented, would negatively affect human health. In the scenario equivalent to the 2 °C target agreed in the Paris Agreeme...