The Al­liance of Small Is­land States (AO­SIS) is warn­ing gov­ern­ments not to treat the pos­si­bil­i­ty of glob­al tem­per­a­tures ex­ceed­ing 1.5°C as a rea­son to aban­don the cli­mate tar­get, fol­low­ing the re­lease of a new Unit­ed Na­tions En­vi­ron­ment Pro­gramme re­port on lim­it­ing tem­per­a­ture over­shoot.

In a state­ment is­sued in New York on Wednes­day, AO­SIS said 1.5°C is not an ar­bi­trary tar­get that coun­tries can aban­don, but a tem­per­a­ture lim­it they com­mit­ted to pur­sue un­der the Paris Agree­ment.

The al­liance said the goal is ground­ed in the need to pro­tect peo­ple and the plan­et from the most dan­ger­ous im­pacts of cli­mate change and point­ed to the In­ter­na­tion­al Court of Jus­tice's recog­ni­tion of coun­tries' le­gal oblig­a­tions to pro­tect the cli­mate sys­tem.

For decades, small is­land de­vel­op­ing states (SIDS) have warned of the con­se­quences of unchecked glob­al warm­ing. AO­SIS said the lat­est sci­ence is now re­in­forc­ing those con­cerns.

It said every frac­tion of warm­ing above 1.5°C in­creas­es the risk of ir­re­versible and po­ten­tial­ly cat­a­stroph­ic im­pacts, in­clud­ing sea-lev­el rise, loss of hab­it­abil­i­ty in low-ly­ing is­lands, in­sta­bil­i­ty of glac­i­ers and ice sheets, for­est dieback and coral reef degra­da­tion.

The al­liance al­so warned of in­creas­ing threats to food and wa­ter se­cu­ri­ty.

For SIDS, AO­SIS said, these are not dis­tant pro­jec­tions but risks al­ready un­fold­ing.

How­ev­er, the al­liance stressed that the tra­jec­to­ry of glob­al warm­ing has not yet been fixed and the UN­EP re­port should be viewed as a warn­ing rather than a rea­son to sur­ren­der the 1.5°C tar­get.

AO­SIS said the Glob­al Stock­take has iden­ti­fied path­ways for clos­ing the emis­sions gap, while sci­en­tif­ic ev­i­dence in­di­cates that the mag­ni­tude and du­ra­tion of any tem­per­a­ture over­shoot can still be lim­it­ed.

It called on gov­ern­ments to fo­cus not on­ly on whether tem­per­a­tures tem­porar­i­ly ex­ceed 1.5°C, but on min­imis­ing any over­shoot and re­turn­ing glob­al tem­per­a­tures be­low the thresh­old as quick­ly as pos­si­ble.

The al­liance is al­so call­ing for the next In­ter­gov­ern­men­tal Pan­el on Cli­mate Change (IPCC) as­sess­ment to be com­plet­ed in time to in­form the next Glob­al Stock­take, say­ing gov­ern­ments need the best avail­able sci­ence to guide de­ci­sions af­fect­ing glob­al warm­ing for decades.

AO­SIS urged coun­tries to ho­n­our their com­mit­ments un­der the Paris Agree­ment and Unit­ed Na­tions Frame­work Con­ven­tion on Cli­mate Change by ac­cel­er­at­ing the tran­si­tion away from fos­sil fu­els and rapid­ly cut­ting emis­sions.

It al­so called for in­creased sup­port for adap­ta­tion, re­silience and loss and dam­age in vul­ner­a­ble coun­tries.

The al­liance said tech­no­log­i­cal progress must be ac­com­pa­nied by rapid glob­al de­car­bon­i­sa­tion.

“1.5°C must re­main the North Star,” AO­SIS said, warn­ing that po­ten­tial tem­per­a­ture over­shoot must not be­come an ex­cuse for fur­ther in­ac­tion.