COE Program at Hokkaido University
PREDICTON AND AVOIDANCE OF AN ABRUPT CHANGE IN THE BIO-GEOSPHERE SYSTEM
Graduate School of Environmental Earth Science and Institute of Low Temperature
Science have started the 21st century Center of Excellence (COE) program in the
fall of 2002.
Our program title "Prediction and avoidance of an abrupt change
in the bio-geosphere system" is meant to be a 100-year-scale abrupt
change as con-sequence of an inability of environ-ment's self-recovery,
which could be caused by the interactions between the geosphere and the
biosphere.
"Global warming by CO2", "ozone depletion", "forest
destruction by ex-ploitation" and "pollutants" are not influencing
the environment inde-pendently. A possible feedback loop is that "Low
absorption of CO2 caused by forest destruction" promotes "global
warming", and then, "global warming" in turn enhances "forest
destruction". They interact each other. Therefore, we need to understand
these phenomena as a coupled system and to predict a future change. We
are trying to understand and predict the phenomena by clarifying on the
basis of bio-geoscience and intercomparison between the high latitude region
and the low-to-mid latitude region.
Our final objective is to avoid the abrupt change by not controlling
nature but helping it from the cycle between natural ecosystem and material
circulation.Our roles in the education are guiding Asian younger generation
to environmental-oriented personnel and proceeding an international collaboration
for the prediction of the environmental change. We have hired 8 postdoctors
who play a central role in our project. We have also assigned 20 students
as research assistants in the school and are educating them through the
project. We hold a symposium in this autumn with the 10th anniversary celemony
of our graduate school.
In the high latitude region, CO2 is absorbed into the ocean by enhanced marine productivity, but in the low latitude region, it is emitted to the atmosphere. The productivity in the North Pacific Ocean is seriously influenced by declining of the global ocean conveyor belt and also vertical mixing following the proceeding global warming. If it continues to a critical level, the marine ecosystem might change its nature, and the high latitude region would start emitting CO2. As a final stage, these phenomena might accelerate global warming. We investigate the key process of the ecosystem and the carbon-nitrogen circulation by observations. We also build a numerical model of ocean physical, bio-geochemical processes and verify it against the observations.
On the other hand, permafrost deterioration and biodiversity reduction which is caused by ozone depletion may retard forest growth in the geosphere. An increase in ultra-violet rays B by a decrease in ozone causes the decomposition of soil and emission of gas such as methane, which then promotes global warming. To predict the CO2 absorption to forest, we develop the bio-geo-atmosphere model which takes in the effect of global warming and ozone depletion. The model will be verified against various data sets collected in Siberia and the tropical areas.
As indicated above, interactions between biosphere and geosphere are
the key to the global change. Fixation ofcarbon in the ocean is suggested
as one of the effective methods to avoid the abrupt change. However, we
will closely assess such a method, and publicize the assessments of any
suggestion to avoid the abrupt change. For an overall purpose, we are proposing
the protection and improvement of the global environment.
Group of "Global Warming"
We need to clarify the effects of global warming, because we cannot avoid
the warming anymore. We investigate the interactions between the biogeochemical
cycle and the climate system. On the other hand, some methods to restrain
global warming are suggested, for example, isolation or fixation of CO2.
Our concern is that an effective solution would have a critical influence
on the nature. We are trying to predict the risks of both global warming
and restraint methods and to find the realistic solution.
Group of "Ozone Depletion"
Some data suggest that an increase in chlorine and/or bromine compounds has almost stopped in the stratospheric layer. Nonetheless, we still need to pay attention to the issues of Ozone Depletion, because the ozone hole over the South Pole is reaching the maximum
extent this time, and the ozone is decreasing even in the stratospheric
layer of low-to-mid latitude area. It is also important to predict the
effects of UV radiation on ecosystems. We aretherefore progressing our
studies especially on the effects of UV radia-tion on the food chain and
the material circulation in oceanic ecosystem. The other issue is a positive
feedback between ozone depletion and global warming through dynamical-chemical
processes in the stratosphere.
Group of "Biofunctional System"
Reduction of organic population and extinction of species have been progressing because of forest destruction and division, disturbance by the naturalized organisms, and overhunt of useful organisms. Global warming and ozone depletion also accelerate a decrease in the ecosystem diversity. At first, we analyze the mechanisms:
(1)photosynthesis in boreal forest of coniferous trees in winter, and
(2)coexistence of coniferous trees and deciduous trees in the same forests.
Then, based on that analysis, we solve the issues of regeneration and preservation
of boreal forest. We investigate the diversity from genes to seeds in the
high latitude area, and then compare the results with the data which are
collected in the low latitude area. An ecosystem-climate model is under
development for qualitative and further quantitative estimates of feedback
between the ecosystem and climate system.Group of "Assessment and
Remadiation of pollutants"
In recent years, the existence of pollutants, which can give serious effects on the reproductive and immuno- processes in the living body even if the concentration is very low, is found out. In order to protect the human race and the ecosystem from the attack of the new type of the pollutants, it is necessary to build up and operate a research system consisting of the sequential processes of "screening - assessment - monitoring - remediation". That is, the unknown harmful chemicals and factors for environments are searched by a new screening method based on apoptosis and differentiation of cell, neuro- and immuno-system, and the assessment of these chemicals and factors is performed by a new assessment method. The development of the new screening and assessment methods can be expected to lead to the discovery of new pollutants which have been overlooked. Some remediation methods to reduce the effects of the pollutants on the environments are developed on the basis of the decomposition by electrochemical or catalytic reaction, bio-remediation and by preparation of new materials having a selective adsorbing ability for harmful chemicals.
