Ryan Ba­choo

The re­cent ad­vi­so­ry opin­ion by the In­ter­na­tion­al Court of Jus­tice (ICJ) on states’ le­gal oblig­a­tions to ad­dress cli­mate change is shap­ing con­ver­sa­tions at COP30, ac­cord­ing to Al­liance of Small Is­land States (AO­SIS) ne­go­tia­tor Car­lon Men­doza.

Men­doza, who serves as Cli­mate Pol­i­cy Ad­vi­sor with Cli­mate An­a­lyt­ics Caribbean, said the ICJ opin­ion has be­gun in­flu­enc­ing how some coun­tries ap­proach ne­go­ti­a­tions un­der the Paris Agree­ment and the UN Frame­work Con­ven­tion on Cli­mate Change. “What we’ve seen so far is that some par­ties have start­ed cit­ing or us­ing lan­guage from the ICJ opin­ion,” he said.

The ICJ’s ad­vi­so­ry opin­ion, is­sued in Ju­ly 2025, reaf­firmed that lim­it­ing glob­al tem­per­a­ture rise to 1.5 de­grees Cel­sius is not on­ly a moral im­per­a­tive but now a le­gal bench­mark un­der in­ter­na­tion­al law.

“It set and reaf­firmed 1.5 de­grees Cel­sius as the le­gal lim­it for the tem­per­a­ture goal as stat­ed in the Paris Agree­ment,” Men­doza ex­plained.

“The Paris Agree­ment ref­er­ences 2 de­grees Cel­sius, but the ICJ con­firmed 1.5 as the ab­solute red line.”

He not­ed that the Court al­so clar­i­fied states’ oblig­a­tions of con­duct and re­sult, mean­ing coun­tries’ cli­mate pledges, or Na­tion­al­ly De­ter­mined Con­tri­bu­tions (ND­Cs), must be­come more am­bi­tious over time. That, he said, has strength­ened AO­SIS’s case for an of­fi­cial as­sess­ment of the glob­al emis­sions gap. “We’ve seen par­ties, par­tic­u­lar­ly AO­SIS, go­ing to the pres­i­den­cy, com­ing to this con­fer­ence, and lay­ing out an agen­da item call­ing for an as­sess­ment of that NDC syn­the­sis gap—the gap be­tween where we are and where we need to be,” Men­doza said.

Asked whether ma­jor emit­ters such as the Unit­ed States, Chi­na, or In­dia had shift­ed their ne­go­ti­at­ing po­si­tions in light of the rul­ing, Men­doza said it was “still ear­ly days.” How­ev­er, he added, “We haven’t seen any change or ref­er­ence or budg­ing in terms of how they treat or view the ICJ opin­ion.”

While the ICJ opin­ion has in­spired new mo­men­tum, Men­doza said dis­cus­sions about coun­tries pur­su­ing le­gal ac­tion against oth­ers, such as the Dutch is­land of Bonaire, are not cur­rent­ly part of the COP30 ne­go­ti­a­tions. “The ICJ opin­ion gives us the roadmap as to how states could be held ac­count­able,” he said.

Still, he be­lieves the rul­ing’s in­flu­ence will grow. “We al­ready see the mo­men­tum that it’s build­ing,” Men­doza said. “We can on­ly hope that it’ll be greater mo­men­tum as le­gal minds delve deep­er in­to the rul­ing and how it could be ap­plic­a­ble in all con­texts.”