CGER Reports


Development of an integrated land surface model incorporating ecosystems, human water management, crop growth, and land-use change:


It is known that about 80% of human carbon dioxide emissions are due to the burning of fossil fuels and the rest due to land-use change such as deforestation. Agricultural land is expanding, especially in developing countries, by logging forests to produce crops in response to population growth. Deforestation and agricultural land expansion result in carbon dioxide emissions as well as loss of biodiversity. On the other hand, as an important measure to stabilize the climate, it is considered necessary to increase the production of biofuel crops instead of fossil fuels. In order to increase the production of biofuel crops, a large amount of land is required for growing bioenergy crops. Climate change is causing dryness in some areas, and large amounts of water are needed to grow crops for food and biofuels.

In order to discuss whether we can secure the land and water resources necessary for food and bioenergy production under the changing climate, and how climate change will affect human society and ecosystems, it is important to consider the interaction of various processes by using a numerical model that deals with the global environment and human activities at the same time. For this purpose, we developed a global land surface model considering human water management such as irrigation and dam operations, crop growth processes, and land use for food and bioenergy crops, called MIROC-INTEG-LAND (MIROC INTEGrated LAND surface model, Figure).

Analyzing the behavior of the Earth system and human activity over the next few centuries is a very important issue for understanding the future of the global environment and how to change our society. For this reason, it is important to conduct studies using a model that considers the interaction between the Earth and human systems. The use of a supercomputer is indispensable for performing long-term calculations using a complicated numerical model such as MIROC-INTEG-LAND. In addition, since complicated numerical models have various uncertainties, it is very important to carry out a large number of experiments using a supercomputer in order to investigate the uncertainty parameters in the model. This report describes the details of MIROC-INTEG-LAND based on published papers.

Figure: Diagram for MIROC-INTEG-LAND. The components of the integrated model (sub-models) are shown as colored boxes. Inputs into the model are shown as boxes of climate and socio-economic scenarios. Solid arrows between the boxes indicate the exchange of variables between the sub-models. Dashed arrows indicate the input variables of the sub-models.