Heat is on to stop the ris­ing threat of global warm­ing

Irish Independent - - Broadband Fiasco News - Frank McGovern Frank McGovern is chief cli­mate sci­en­tist with the En­vi­ron­men­tal Pro­tec­tion Agency

IT IS three years since world gov­ern­ments signed off on the Paris Agree­ment, with its goal to hold global tem­per­a­ture in­crease to well be­low 2C and to pur­sue ef­forts to limit it to 1.5C. They did so in the knowl­edge this re­quired strong and rapid ac­tions to re­duce green­house gas emis­sions. To clar­ify how strong and rapid re­duc­tions needed to be, they also asked the UN In­ter­gov­ern­men­tal Panel on Cli­mate Change (IPCC) to pro­vide a re­port on warm­ing of 1.5C.

In re­sponse, it has pub­lished a re­port which is per­haps the most star­tling in its clar­ity, and chal­leng­ing in its mes­sages, that it has pro­vided in the 30 years since its for­ma­tion in 1988.

The IPCC spe­cial re­port on global warm­ing of 1.5C was pub­lished in Oc­to­ber. It sets out the sci­en­tific frame­work for ac­tions to de­liver on the Paris Agree­ment.

It ex­plores is­sues at the heart of global cli­mate pol­icy; that is the tem­per­a­ture goal which is con­sid­ered es­sen­tial to avoid­ing large-scale, ir­re­versible cli­mate change im­pacts and their con­se­quences.

The aim to limit the in­crease to 2C has in­formed EU cli­mate pol­icy since the 1990s, when it was adopted ahead of the ne­go­ti­a­tions on the Ky­oto Pro­to­col. It pro­vides the ba­sis for the EU-wide emis­sions re­duc­tion tar­gets to 2020 and 2030.

The goal to limit the global tem­per­a­ture in­crease to 1.5C is more re­cent. It arises from in­creas­ing aware­ness of the im­pact cli­mate change is al­ready hav­ing, and will have, on vul­ner­a­ble com­mu­ni­ties and re­gions.

The ex­is­tence of some small is­land states and low-ly­ing coastal ar­eas is threat­ened by sea-level rise so it has been strongly pro­moted by small is­land states and lesser-de­vel­oped coun­tries.

As an is­land na­tion with coastal com­mu­ni­ties at risk from ris­ing sea lev­els and coastal ero­sion, this has a par­tic­u­lar res­o­nance for Ire­land.

The IPCC out­lines the ben­e­fits of such a goal as well as the chal­lenges of meet­ing it. The mes­sages are clear; hu­man ac­tiv­i­ties have al­ready caused warm­ing of 1C. The im­pacts of this are ev­i­dent in sealevel rise and changes in ex­tremes such as heat waves and in­tense rain­fall events.

Each global in­cre­ment in­creases the risks and scale of im­pacts.

There are greater rea­sons for con­cern and costs in man­ag­ing these ei­ther through adap­ta­tion or re­me­di­at­ing ac­tion.

Key thresh­olds for the on­set of large, ir­re­versible ef­fects due to loss of ma­jor ice-shelfs and per­mafrost ar­eas are con­sid­ered by the IPCC to ex­ist around 1.5-2C.

As such, the re­port iden­ti­fies con­sid­er­able ben­e­fits for ev­ery­body in lim­it­ing the global tem­per­a­ture in­crease to 1.5C.

How­ever, an es­ti­ma­tion of the costs of the avoided im­pacts, which are lo­cal in na­ture and dis­trib­uted glob­ally, are dif­fi­cult to de­ter­mine. These in­clude avoid­ing the chal­lenges of dis­placed pop­u­la­tions.

The good news is that warm­ing of 1.5C can still be avoided. But the rate, and par­tic­u­larly the scale of col­lec­tive ac­tion re­quired to do so, are un­prece­dented.

The global tem­per­a­ture in­crease will largely be de­ter­mined by fu­ture emis­sions of car­bon diox­ide. These uniquely ac­cu­mu­late in the at­mos­phere and in the oceans, where they con­trib­ute to in­creased acid­i­fi­ca­tion.

The IPCC has es­ti­mated how much more car­bon diox­ide can be pumped into the at­mos­phere if warm­ing is to be lim­ited to ei­ther 1.5C or 2C. Glob­ally, we must reach net-zero car­bon diox­ide emis­sions around 2050 if we are to stay be­low 1.5C, and around 2075 to stay be­low 2C.

En­sur­ing the global tem­per­a­ture is sta­bilised around 1.5C is ex­cep­tion­ally chal­leng­ing. The re­port ex­plores over­shoot sce­nar­ios in which the global tem­per­a­ture ex­ceeds 1.5C and is later re­duced through re­movals of car­bon diox­ide from the at­mos­phere – neg­a­tive emis­sions.

These sce­nar­ios in­creas­ingly rely on changes to land use to pro­vide neg­a­tive emis­sions, in­clud­ing con­ver­sion of agri­cul­tural land to forestry and en­ergy crops.

Emis­sions of other warm­ing agents in­clud­ing meth­ane, ni­trous ox­ides and par­tic­u­late black car­bon (soot from burn­ing) should also be re­duced.

How­ever, food pro­duc­tion re­quire­ments mean there are lim­its for these op­tions.

The mes­sages are stark and high­light the con­se­quences of our his­toric and on­go­ing reliance on fos­sil en­ergy. The ques­tion is how rapidly this reliance can be re­versed. This week, world gov­ern­ments meet in Poland where the IPCC re­port will be high on the agenda.

Ahead of this meet­ing, the World Me­te­o­ro­log­i­cal Or­gan­i­sa­tion has an­nounced at­mo­spheric green­house gas lev­els have reached a new record, with no sign of a rev­er­sal in the in­creas­ing trend.

More pos­i­tively, the EU Com­mis­sion has just pub­lished its re­vised 2050 roadmap tak­ing ac­count of the Paris Agree­ment.

It en­vi­sions a cli­mate-neu­tral Europe by 2050 based on trans­for­ma­tion of key ar­eas in­clud­ing in en­ergy, trans­port and com­mu­ni­ca­tions, ad­vanc­ing the cir­cu­lar econ­omy and us­ing car­bon sinks and car­bon cap­ture and stor­age to pro­vide neg­a­tive emis­sions.

The costs of do­ing this are likely to be im­mense but the costs of not do­ing so may be im­mea­sur­able.

The costs are likely to be im­mense – but costs of do­ing noth­ing may be im­mea­sur­able

Burn­ing is­sue: Plans are in place to make the EU cli­mate neu­tral by 2050

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