ARCTIC CLIMATE RESEARCH IN THE FRONIER RESEARCH PROGRAM FOR GLOBAL CHANGE
M. Ikeda
1 Frontier Research Program for Global Change/International Arctic Research Center 2 Graduate School of Environmental Earth Science, Hokkaido University
We have just begun to realize that accumulated effects from anthropogenic activities may reach the level that is sufficiently high so as to change global climate. Impacts from human activities, particularly emissions of greenhouse gases, are believed to be no less than negligible. Indeed, climate changes, in this case a warming arising from increasing greenhouse gases, are predicted to be greater in both polar regions. In comparison with the Antarctic, the Arctic region is characterized with the vast extent of oceans and sea ice. The Arctic is thus believed to play a major role as a sink in the terrestrial heat engine. Nonetheless, details of climate changes in the Arctic region and their relation to global climate changes are far from well understood. Numerous issues are in order: how to separate natural variabilities from anthropogenic effects? What are the key processes in climate changes? How are they inter-related? What are the key feedback mechanisms? How to parameterize those key processes and represent feedback mechanisms in climate models? What are the criteria for a "reasonable" climate model? How important is Arctic climate in global climate? Size and complexity of the problem with which we are facing clearly require a long-range strategy for the Arctic climate research.
A. Missions and Objectives
Missions of the International Arctic Research Center (LARC)
* Reveal roles of the Arctic region in global change.
* Predict impact of the global change on the Arctic region.
* Understand the mechanisms of climate variability particular to the Arctic.
* Contribute and support international Arctic research as one of the central institutions.
* Train the next generation of Arctic scientists.
B. Importance of Arctic research in global change
It is highly recognized that we, as human beings, need a tool to predict future changes in global climate and impacts caused by global change. The impacts are believed to be largest in the high latitude regions, and hence, we obviously need to concentrate our investigations on the impacts of global change on the Arctic. Taking advantage of the largest impacts, we may be able to detect global change by looking at the Arctic. Beyond the regional impacts, it is likely that the Arctic climate plays an important role for the global change: i.e., there may be feedback between the global change and the Arctic climate. It is emphasized that this possible feedback should be understood well and kept in our mind as one of the key issues.
M. Ikeda, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan 060
mikeda@ees.hokudai.ac.jp
Is it possible to make a reliable prediction of global change and Arctic change? Is it possible to separate natural variability and anthropogenic effects? The prediction is a challenging task that faces the climate research community. In the high latitude regions, the natural variability seems the largest, the seasonal variability is obviously larger, and the past data suggests that the variability up to a century time scale is more pronounced. The glacier-interglacier variability appeared most significantly near the Arctic. Can we make this analogy to the future global change, for example, global warming which is predicted in most climate models? The prediction becomes difficult for the Arctic, which has large variability at various time scales with strong nonlinearity in its mechanisms.
In order to achieve a deep understanding of the feedback mechanism and a reliable prediction of the regional impact, it is necessary to understand physical, chemical and biological behaviors occurring in the coupled land-atmosphere-ocean system. The cryosphere is a characteristic feature in the high latitudes: i.e., sea ice which covers the sea surface acts as a reflector of short-wave radiation and an insulator between the atmosphere and the ocean. Sea ice is also a reservoir of fresh water, which can be advected out of the Arctic Basin depending on a wind pattern. Aerosol is carried by atmospheric circulation and affects surface albedo, which in turn modifies the wind pattern and cloud cover. Ice algae absorbs a significant amount of atmospheric CO2 and hence plays an important role in the global carbon cycle. Changes in glacier and tundra influence surface albedo, hydrology and greenhouse gas emission. Ozone depletion is highly coupled with dynamic variability in the atmosphere. Therefore, there is great value for the IARC to tackle this sophisticated Arctic system with great diversity. The diverse research disciplines are described in section C.
We should contribute to international Arctic studies and also enrich the IARC studies through collaboration with the other institutions. The scientific advances and collaboration may be accelerated focusing on connecting different disciplines; e.g., cloud-sea ice interactions, land-atmosphere interactions, physical-chemical-biological coupling in the ocean and the atmosphere, etc. As well, promotion and training of new researchers are included as the main goals of IARC.
* Coordination with the other programs
We are keenly aware that there are many programs focusing on the Arctic, and incidently, they are highly useful for understanding the Arctic climate system and predicting its change. Research activities carried out at the IARC will be
