||Nobuyuki Takashima, International environmental agreements between asymmetric countries: a repeated game analysis, Japan and the World Economy, 10.1016/j.japwor.2018.08.001, 48, 38-44, 2018.12, This paper introduces a new approach to performing a relaxed analysis using a repeated game to achieve an international environmental agreement (IEA) with the full participation of countries when an asymmetric relationship exists with respect to emissions related benefits and environmental damage. Our model reveals that a stable IEA depends on the magnitude of the relationship between the benefit cost ratios of the two types of countries, not on their compositions. That is, the number of punishing countries for a weakly renegotiation proof equilibrium depends on the benefit cost ratios of the two types of countries. Our results show that a global cooperation on abatement among the two types of countries can be achieved by addressing deviation through flexibly selecting punishing countries based on benefit cost ratios..
||Nobuyuki, Takashima, The Impact of Accidental Deviation by Natural Disaster-Prone Countries on Renegotiation-Proof Climate Change Agreements, Environmental Modeling and Assessment, 10.1007/s10666-016-9542-2, 22, 4, 345-361, 2017.08, This study provides a new framework for international
environmental agreements (IEAs), which include punishment
exceptions for accidental deviation, using repeated
games. We consider that deviation from an agreement can
occur accidentally because of phenomena such as natural disasters,
even if the agreement is sustained as a weakly
renegotiation-proof equilibrium. If an IEA signatory deviates
accidentally, it fails to achieve its emission abatement target.
In the repeated game, a cooperative relationship among signatories
is sustained by a strategy that prescribes rules of cooperation
and punishment for deviation. We present a new
strategy, called Regional Cooperative, which integrates accidental
deviations into an IEA. Our model reveals that
punishing countries tend to revoke the punishment of deviators
and return to cooperation if an accidental deviator increases
its abatement volume. That is, the abatement efforts
of the accidental deviator can lead to renegotiation. The
Regional Cooperative strategy motivates the accidental deviator
to try to engage in abatement and the punishing countries
to restart cooperation by renegotiation. We conclude that social
welfare loss by punishment is prevented through renegotiation
in cases of accidental deviation..
||Nobuyuki, Takashima, International environmental agreements with ancillary benefits: Repeated games analysis, Economic Modelling, 10.1016/j.econmod.2016.10.011, 61, 312-320, 2017.02, Both ancillary and primary benefits, generated by climate change mitigation, are indispensable key factors to
implement the full participation in international environmental agreement (IEA). This paper presents a new
IEA model with ancillary benefits, using a repeated game with the linear and quadratic emission abatement cost
functions of each country. This study also investigates the effect of ancillary benefits on the condition for full
participation in IEA. Ancillary benefits function as a complementary device of punishment scheme for IEA. Our
main results show that ancillary benefits can facilitate full participation in IEA, thus suggesting that they should
be considered in climate change negotiations..