Zero Point Five

The Half Point We Should Fight For

The McGill Daily - - Sci + Tech - Jus­tine Ro­nis-le Moal The Mcgill Daily

What is half a de­gree? In the grand scheme of things, it may not sound like much. In this case, it could have a dra­matic im­pact. On Oc­to­ber 8, the United Na­tions’ In­ter­na­tional Panel on Cli­mate Change ( UNIPCC) re­leased a re­port ex­plor­ing the im­pacts of a 0.5° C ( 0.9° F) dif­fer­ence in global tem­per­a­ture. More specif­i­cally, they looked at the dif­fer­ence be­tween a 2° C ( 3.6° F) rise in global tem­per­a­tures com­pared to a 1.5° C ( 2.7° F) in­crease. The dif­fer­ences are colos­sal.

At an in­crease of 1.5° C, the UNIPCC ex­pects a mere 1% of co­ral to sur­vive. At an in­crease of 2° C, this per­cent­age is mul­ti­plied by ten. What’s more, this fig­ure does not even cap­ture the im­pact on broader marine ecosys­tems, in which corals play a vi­tal role. 25% of all marine species are sup­ported by co­ral. The con­se­quences of corals go­ing ex­tinct would be dev­as­tat­ing.

Un­sur­pris­ingly, the Arc­tic will also be gravely af­fected by tem­per­a­tures ris­ing, mak­ing ice­free sum­mers in the Arc­tic a much more preva­lent oc­cur­rence. The ex­act fre­quency will be de­ter­mined by our abil­ity to limit the tem­per­a­ture in­crease. Reach­ing a 2° C in­crease would cause this phe­nom­e­non to hap­pen every 10 years, as op­posed to every 100 years, if we keep it un­der 1.5° C.

The de­struc­tion of this ecosys­tem is dra­matic in and of it­self. Many en­dan­gered species would be fur­ther threat­ened. More­over, the Arc­tic is dis­tinct from other ecosys­tems on the planet. It plays a vi­tal role in global cli­mate reg­u­la­tion via the cool­ing ef­fect it cre­ates in both sea and air cur­rents. Its de­struc­tion would cause cli­mate dereg­u­la­tion, in­ten­si­fy­ing and in­creas­ing the fre­quency of floods, droughts, and heat waves more so than ever. With the vol­ume of Arc­tic sea ice de­creased by 70% com­pared to 40 years ago, we have al­ready caused far- reach­ing dam­age.

The di­rect im­pact of melt­ing Arc­tic ice­bergs on hu­mans is a rise in sea lev­els. This would have dev­as­tat­ing im­pacts on our coastal cities; Shang­hai, for ex­am­ple, would be flooded and en­tirely sub­merged with a 3° C tem­per­a­ture in­crease. The half a de­gree dif­fer­ence would im­pact dou­ble the amount of peo­ple sim­ply from wa­ter stress alone. Fur­ther­more, an es­ti­mated 420 mil­lion peo­ple more would be ex­posed to ex­treme heat waves in the case of a 2° C in­crease com­pared to the 1.5° C.

Jo­han Rock­ström, co- au­thor of the “Hot­house Earth” re­port pub­lished in Au­gust 2018, ex­plains that “[ The UNIPCC] re­port is re­ally im­por­tant. It has a sci­en­tific ro­bust­ness that shows 1.5° C is not just a po­lit­i­cal con­ces­sion. There is a grow­ing recog­ni­tion that 2° C is dan­ger­ous.”

The “Hot­house Earth” re­port ex­plores the im­pact of a 2° C in­crease. One of the pos­si­ble out­comes put forth is the es­tab­lish­ment of a ‘ hot­house Earth’ cli­mate. Here, global tem­per­a­tures sta­bi­lize at 4° C or 5° C above pre- in­dus­trial lev­els and sea lev­els are 10 me­tres to 60 me­tres higher than they are to­day. The au­thors ar­gue that this will hap­pen through “feed­backs” – Earth sys­tem pro­cesses that may be trig­gered by global warm­ing. A 2° C in­crease might al­ready be too much, as it may prompt these pro­cesses, tak­ing global warm­ing be­yond hu­man con­trol and past the point of no re­turn. “Places on Earth will be­come un­in­hab­it­able if ‘ hot­house Earth’ be­comes a re­al­ity,” says Rock­ström.

The UNIPCC and “Hot­house Earth” re­ports both stress the ur­gency of tak­ing ac­tion. We have al­ready reached a 1° C in­crease com­pared to pre- in­dus­trial tem­per­a­tures, and with the cur­rent lev­els of com­mit­ment, we are headed to­wards a 3° C rise in tem­per­a­tures by 2100. Any es­ca­la­tion past the 2° C in­crease ex­plored in these re­ports be­comes in­creas­ingly dan­ger­ous.

To pre­vent any fur­ther in­crease, both re­ports un­der­score the im­por­tance of cut­ting our car­bon diox­ide and green­house gas emis­sions as fast as pos­si­ble. Will St­ef­fen, the lead au­thor of the “Hot­house Earth” re­port, stresses the im­por­tance of do­ing so; he ex­plains that feed­backs will come into ef­fect and cause tem­per­a­tures to rise even with­out any ad­di­tional emis­sions.

We need to re­duce our green­house gas emis­sions much faster than ini­tially be­lieved– we have less than 12 years to make an im­pact. This means im­pos­ing much stricter and much lower lim­its than the ones pro­vided at the Paris Agree­ment, rat­i­fied in 2016. It may also in­clude ex­plor­ing faster ways of re­mov­ing car­bon diox­ide from the at­mos­phere. This can in­clude the pro­tec­tion and ex­pan­sion of forests and veg­e­ta­tion, as well as the de­vel­op­ment of car­bon cap­ture and stor­age tech­niques.

It can be done, but gov­ern­ments need to push forth poli­cies and take a hard stance on the mat­ter. As Jim Skea, a co- chair of the work­ing group on mit­i­ga­tion for the UNIPCC re­port, said, “We show it can be done within the laws of physics and chem­istry. Then the fi­nal tick box is po­lit­i­cal will. We can­not an­swer that. Only our au­di­ence can– and that is the gov­ern­ments that re­ceive it.”

Hans Joachim Schellnhu­ber, an­other co- au­thor of the “Hot­house Earth” re­port, crit­i­cized po­lit­i­cal lead­ers’ state­ments con­cern­ing what is achiev­able, blam­ing their lack of mo­ti­va­tion on their in­ter­est in short- term goals, for which they can take credit.

In Am­s­ter­dam, while the ap­peals court did not agree with this ex­pla­na­tion, it did sup­port the ar­gu­ment that more could, and should, be done in the way of lim­it­ing green­house gas emis­sions. On 0cto­ber 9, the court up­held a pre­vi­ous rul­ing de­mand­ing the Dutch gov­ern­ment to cut green­house gas emis­sions by 25% be­fore 2020. The main ar­gu­ment for ap­peal was the fact that a court was de­cid­ing on gov­ern­ment pol­icy. This claim was dis­missed on the ba­sis that courts have to hold the gov­ern­ment ac­count­able to both lo­cal and in­ter­na­tional laws and reg­u­la­tions.

The Dutch court rul­ing is a great ex­am­ple of what needs to be done. If politi­cians are go­ing to be com­pla­cent, it is up to other ar­eas of so­ci­ety to step up and show their sup­port for en­vi­ron­men­tal is­sues. De­bra Roberts, a co-chair of the work­ing group in the UNIPCC re­port, re­ferred to the re­port as “the largest clar­ion bell from the science com­mu­nity,” and hopes that “it mo­bi­lizes peo­ple and dents the mood of com­pla­cency.”

This just might be the case within the Mcgill com­mu­nity. This Mon­day Oc­to­ber 22, Di­vest Mcgill or­ga­nized a rally for di­vest­ment, de­mand­ing the univer­sity to stop sup­port­ing the fos­sil fuel in­dus­try. Schellnhu­ber com­mented, “I think that in the fu­ture peo­ple will look back on 2018 as the year when cli­mate re­al­ity hit. This is the mo­ment when peo­ple start to re­al­ize that global warm­ing is not a prob­lem for fu­ture gen­er­a­tions, but for us now.”

There is still some hope left within the sci­en­tific com­mu­nity, linked to the re­cent and re­cur­ring heat­waves. With ab­nor­mally hot tem­per­a­tures ex­pected to last un­til at least 2022, cit­i­zens across the globe will ex­pe­ri­ence the im­pact of global warm­ing for them­selves. A sil­ver lin­ing lies in the hope that this first-hand ex­pe­ri­ence will spark a de­sire for change and push peo­ple to ac­tion. With a bit of luck, it won’t be too late.

“1.5°C is not just a po­lit­i­cal con­ces­sion. There is a grow­ing recog­ni­tion that 2°C is dan­ger­ous.” -Jo­han Rock­ström, co-au­thor, “Hot­house Earth” Re­port

If politi­cians are go­ing to be com­pla­cent, it is up to other ar­eas of so­ci­ety to step up and show their sup­port for en­vi­ron­men­tal is­sues.

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