The Influence of the Greenhouse Effect and Ozone Depletion on Agricultural Production

抄録

Tropospheric temperature rises due to the greenhouse effect could be beneficial at high latitudes where the present climate is cold. However the greenhouse effect reduces stratospheric temperature, which could affect the stratospheric ozone depletion. There are two types of ozone depletion. In the first one originally proposed by Molina and Rowland all participating substances are in the gas phase (homogeneous chemistry), but in the second one corresponding to the ozone hole participating substances are in the gas and solid or liquid phases (heterogeneous chemistry). Stratospheric cooling suppresses the first one but enhances the second. The latest calculation shows that the latter effect is larger than the former and the greenhouse effect worsens stratospheric ozone depletion. The combined influence of the greenhouse effect and stratospheric ozone depletion on rice production in Northern Japan, which is known to be climate-sensitive, is investigated. At present, the benefits of the greenhouse effect are much greater than the detriments of ozone depletion, though in the future the detriments might prevail, because the heterogeneous processes are also initiated by strato-spheric sulphate aerosols, which have recently been increasing at an alarming rate. Therefore the argument that the greenhouse effect could be beneficial at high latitudes should be viewed with caution.