Seite - 188 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

188 F.SimlingerandB.Mayer but of its reliance on fossil fuels as an economicmotor, i.e. frommany activities. Secondly, damages from climate change results not from the conduct of a single state but from the concomitant conduct ofmultiple states,with the resulting harm notconfinedtoasinglestatebutaffectingvirtuallyallstates.Thirdlyandrelatedly,the harmresultsnot fromanyparticular activity, but fromanaccumulationofactivities overdecades. For thesereasons, inthe1990s, theInternationalLawCommissionexcludedphe- nomena such as creepingpollution andpollutionderiving fromordinary economic activities from itswork on theArticles on the Prevention of TransboundaryHarm fromHazardousActivities (Rao2000:9). The International LawCommission con- sidered these situations toocomplex, andpossibly toopolitically sensitive, tomake statementsabouttheir legalnature.AlthoughtheArticlesarenotbindingassuchand donot reflectexistingcustomary international lawin their entirety, this is indicative of thedifficultyofapplying theno-harmprinciple tonewsituations. The multiplicity of states contributing to climate change and impacted by its consequencesat leastcomplicates theapplicationoftheno-harmrule.Scholarshave questioned the applicability of the no-harmprinciple to circumstanceswhere harm is caused not directly by a single source, but by multiple diffuse sources over a long period of time, which accumulate and result in harm (Zahar 2014; Okawa 2010:307;Scovazzi2001:61).Mostcasesbeforetheinternationalcourtsandtribunals are decided over situations where a single activity caused harm to another state. Environmentalharmaccruingbecauseoftheconductofmultiplestateswasdiscussed inthepleadingsbeforetheICJinonecase.IntheirsubmissionsontheLegalityof the ThreatorUseofNuclearWeapons, somestates raisedconcernswith thepossibility that the repeateduseofnuclearweaponsover a relatively short spanof timewould createa“nuclearwinter”—acataclysmicupheavaloftheclimatesystemwhichcould wipe outmost of life on our planet (Mexico 1995, para 65; Egypt 1995, para 32; Ecuador, paraD).Whenmentioning that the damages caused by nuclearweapons couldnot“becontained ineitherspaceor time”andhad“thepotential todestroyall civilizationandtheentireecosystemof theplanet,” (Legalityof theThreatorUseof NuclearWeapons, para. 35) the International Court of Justicemade no distinction betweenmediateddamagesanddamagescausedbycumulativecausationbutimplied that the no-harmprinciple applied equally to both (see alsoDissentingOpinion of JudgeWeeramantry:456–458;Mayer2015:8). If there is indeedanobligationforstatesnot tocause transboundaryenvironmen- tal harms through greenhouse gas emissions, itsmodalities remain ill-defined (see alsoMayer 2016b, 2018a). In particular, the scope of the no-harmprinciple is ill- determined. Ingeneral, theduty toprevent significant harmexistswhenever a state hasor shouldhavebeenable to foresee the riskof harm.Unfortunately, there is no interpretationofthesemodalitiesof theno-harmprinciplebytheInternationalCourt of Justiceor sufficientclarification through theworkof the InternationalLawCom- mission.However, it appears possible to assume that a statemust havehad at least somescientifichintsoftheimpactsofgreenhousegasemissions.Thus, thehistorical failureofastate topreventactivitiesgeneratingexcessivegreenhousegasemissions does not constitute a breach of the no-harm rule until at least some scientific evi-