Interview - The Earth Simulator and Its Contributions to Global Warming Projection Research

In what fields is projection research being used?

In the area of environmental policy measures, there are mitigation measures (CO2 reduction) as causal therapies to eliminate causes, and there are adaptation measures as symptomatic therapies. An adaptation measure in populated coastal areas, for example, where the sea level is rising due to global warming, is to provide basic formulations for policy decisions such as the relocation of a community. Today, we live in an age that has begun to experience the effects of global warming, and concerns about the future are growing, so the projection results of the Earth Simulator are being utilized in such adaptation research. Looking at the global situation today, it is now important to use both adaptation and mitigation measures in conjunction.

For example, our cooperation has been requested for adaptation research in World Bank projects, one involving the coastal regions in the Caribbean and the other the alpine ecosystem in Colombia, South America. Because adaptation research requires regionally detailed projection, an Earth Simulator-based projection with super-high resolution is an ideal tool for such projects. In addition, while a projection with lower resolution, such as 300x300 sq km, is sufficient for reproducing planetary scale atmospheric circulation, it cannot reproduce the detailed climate changes around the "folding screen" formations of the Andes and other detailed topographies. However, the super-high resolution of the Earth Simulator-based atmospheric model can resolve these complex topographies. The Meteorological Research Institute of Japan, which developed the super-high resolution atmospheric model, has therefore been cooperating in these projects and setting them on sound footing. Recently, the World Bank issued a project report with a picture of the Earth Simulator on the cover page.

We are also working with the Japan International Cooperation Agency (JICA) to promote international bilateral cooperation. For example, in the Andes region of Argentina, the cultivation of wine grapes depends on irrigation canals fed from melted snow. If the snowfall decreases, it will deal a blow to the winery industry and people's lives in the region. This is the sort of area where adaptation research can be valuably applied. Our role is to supply the World Bank projects with computed data and to cooperate with Argentinean engineers in analyzing Earth Simulator outcomes.

What can we expect from research and technology in the future?

An initiative under the name of the "Innovative Program of Climate Change Projection for the 21st Century" was launched by the MEXT in April 2007. This initiative addresses not only projection research but also impact studies of climate change on natural disasters. With research groups that have contributed to the achievements of the IPCC Fourth Assessment Report participating, the initiative is now actively advancing further development of their models.
In their former studies, the projection target was 100 years in the future, which was not sufficient for actual policy decision-making. So, it was felt important to also focus attention on the near-term future of 25 years. Predicting extreme events such as floods and heat waves in a 25-year interval would provide a more realistic tool in adaptation studies for formulating disaster prevention policy.
At the same time, in another research area, we are extending the projection horizon to 300 years by developing an advanced earth system model that incorporates the influence of the carbon cycle on plants, organisms, and the ecosystem for long-term environmental projection.

The Earth Simulator is drawing attention in the field of earth science as one of the fastest computers in the world. Research organizations from 11 countries-including the United Kingdom, France, and Singapore-are now conducting global joint research and other activities by using the Earth Simulator.

Going forward, we will continue to harness the ever-increasing power of computing technology to further refine models in projection research and adaptation research.