Seite - 189 - in Loss and Damage from Climate Change - Concepts, Methods and Policy Options

7 LegalResponses toClimateChange… 189 dencesuggestedthat theymayhaveaseriousimpactontheclimatesystem.It isalso unclear towhatextentastatemusthavebeenabletoforeseethespecificdamagethat mightoccur.Very fewcases involving indeterminatedamagehavebeendecidedby international courts and tribunals. In theNaulilaa case, anArbitral Panel held that Germanyshouldhaveanticipated that itsattackonsomePortuguesecolonieswould likely expose Portugal to further turmoil in an unstable colonial context, although Germanycouldnothaveforeseen thenatureandextentof the turmoil thatunfolded. On thisbasis, thePanel condemnedGermany to thepaymentofan“equitableaddi- tional compensation”establishedexaequoetbono (Responsabilitéde l’Allemagne à raison des dommages causés dans les colonies portugaises du sud de l’Afrique: 1032-3). Another areaof uncertainty existswith regards to the stringencyof theduedili- gence obligation of states under the no-harmprinciple. The International Court of Justiceheldthatinordertofulfilitsobligationtoexerciseduediligenceinpreventing significanttransboundaryenvironmentalharm,astatemustcarryoutanenvironmen- tal impact assessmentwhen there is a risk of such harmand, if the risk of signifi- cant transboundaryharmisconfirmed,notifyandconsultwithanystatespotentially affected (see e.g.CertainActivities andConstruction of aRoad, paras. 104, 168). Wherea statehasacted induediligence toprevent significant transboundaryharm, itcannotbemaderesponsibleforharmthatoccursnonetheless, inwhichcaseastate has to prevent further damages.This, however, does not result in a right for a state toveto anactivity conducted in another state.Notably, in relation to environmental matters, the ICJ has often put emphasis on procedure, including the obligation to conduct anenvironmental impact assessment, rather thansubstantiveobligations to refrain fromacertainconduct.However, it is reasonable toassumethata statemust ultimately refrain fromcertainactivities if that is theonlywaytoprevent significant harm.Nevertheless, thequestionoftheactualcontentoftheno-harmrule,especially in thecontextofclimatechangewhereproceduralprocessessuchasconsultingwith allpotentiallyaffectedstates isoftenunhelpful,will remaindifficult tobeanswered. Statescertainlyarenotunderanobligationtostopallgreenhousegasemissionsat once (seee.g.Voigt2015:162).Thescopeof theirduediligenceobligationdepends on their capacity.Theobligationof all states under theno-harmprinciple is oneof employing all their best efforts to limit and reduce greenhouse gas emissions from activitieswithin their jurisdiction inorder toprevent andminimise injuriouseffects onotherstates. Inanyevent, thequestionwhetherastatehasfulfilled itsobligations of duediligencemust be assessed in the light of the specific circumstances and the normsof customary international lawemerging from the general practice of states accepted as law (see e.g.CertainActivities carriedout byNicaragua in theBorder Area,SeparateOpinionofJudgeDonoghue,para.10).Especially,theextenttowhich effortsofeconomicgrowthshapetheunderstandingofduediligenceremainsunclear andshouldbe further researchedwithin theconceptof sustainabledevelopment. Thus, there remainmanydifficulties in defining themodalities of applicationof theno-harmprinciple in relation toclimatechange.Someauthors suchasVerheyen (2005:146)conclude that thevaguenessof thecustomaryno-harmruleprovides for spacefor interpretation.Certainly,onlyanauthoritative interpretationbyaninterna-