報告書番号

Y93015

タイトル（和文）

グローバルＣＯ２抑制方策の検討－公平性と効率性の実現に向けて－

タイトル（英文）

ANALYSIS OF GLOBAL ECONOMIC INSTRUMENTS FOR CO2 EMISSION REDUCTION -EQUITY AND EFFICIENCY-

概要 （図表や脚注は「報告書全文」に掲載しております）

排出権取引費用を無視した場合、排出権市場の持つ効果は「全地域に対する均一税率の炭素税」と「所得移転」の効果に分離出来る（コースの定理）。このとき、排出権市場においては効率性と公平性の問題が分離する。このことを利用して、グローバルＣＯ２排出権市場についての試算を行い、以下の結果を得た：・排出権価格（＝排出削減の限界費用）は、２０００年において、世界全体の排出削減率が１５、２９、４３％のとき、それぞれ５４、１３２、２５１〔＄（９１）ｔ〕となる。排出権売買を行わない場合に比べて先進国の限界費用は著しく低く抑えられる。さらにこのとき、限界費用は全世界で等しくなり、最大の効率が達成される。・排出権初期割当方式について、人口比例、ＧＮＰ比例、排出量実績比例の３通りを検討した。人口比例割当の場合、先進国のＧＮＰの１－３％が、排出権売買によって途上国へ所得流出する。これは途上国にとっては、排出削減に伴

概要 （英文）

THE GLOBAL MARKET FOR CO2 EMISSION PERMITS HAS THE POTENTIAL TO ACHEIVE EFFICIENT GLOBAL CO2 CONTROL WHILE MAINTAINING A FAIR SHARE OF THE ECONOMIC BURDEN AMONG WORLD REGIONS BY INITIAL ALLOCATION AND SUBSEQUENT TRADES. WE SIMULATED THE PERMIT MARKET ASSUMING THE TRANSACTION COST ASSOCIATED WITH THE PERMIT TRADE IN NEGLIGIBLE.IN THIS SCHEME:(1) THE PERMIT PRICE IS DETERMINED SOLELY BY THE GLOBALTOTAL EMISSION TARGET: AND (2) INCOME TRANSFER ASSOCIATED WITH THE PERMIT TRADE IS DETERMINED SOLELY BY THE DISTRIBUTION OF THE INITIAL ALLOCATION. THUS, THE PROBLEM OF EQUITY IS SEPARATE FROM THE PROBLEM OF EFICIENCY. THIS CASE ILLUSTRATES AN APPLICATION OF COASE S THEOREM. NOT ONLY DOES THE THEOREM GIVE US A TECHNIQUE TO SIMULATE THE PERMIT TRADE, BUT IT ALSO SUGGESTS THAT WE CAN HAVE A SYSTEM EQUIVALENT TO THE PERMIT MARKET BY A COMBINATION OF REGIONAL CO2 CONTROL, JOINT IMPLEMENTATION, AND SUITABLE INCOME TRANSFER REFLECTING EQUITY. THE EQUIVALENT SYSTEM MAY BE EASIER TO IMPLEMENT THAN THE PERMIT MARKET WHILE MAINTAINING THE DESIRABLE CHARACTERISTICS OF THE PERMIT MARKET. THE EDOMONDS-REILLY MODEL WAS USED FOR THE SIMULAITON IN THE YEAR 2000. THREE INITIAL ALLOCATIONS WERE ANALYZED: ALLOCATIONS PROPORTIONAL TO POPULATION, GNP, AND CO2 EMISSION IN THE CASE WITHOUT CO2 CONTROL. WE OBTAINED THE FOLLOWING RESULTS: (1)THE PERMIT PRICE IN THE YEAR 2000 IS $54/T-C FOR A GLOBAL EMISSION REDUCTION RATE OF 15%, $132/T-C FOR 29%, AND $251/T-C FOR 43% (1991 VALUES). THE MARGINAL COSTS IN DEVELOPED REGIONS ARE DRASTICALLY REDUCED FROM THE CASE WHERE EACH REGION INDEPENDENTLY ACHIEVES ITS TARGET; (2)IN THE CASE OF POPULATION-BASED ALLOCATION, 1% TO 3%

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