Geo­engi­neer­ing to cool down Earth

THE OTHER, FAR MORE CON­TRO­VER­SIAL AP­PROACH, WOULD DEFLECT ENOUGH SUN­LIGHT BACK INTO SPACE TO COOL PLANET BY A DE­GREE OR TWO

Gulf News - - TODAY -

ven if you are ter­ri­fied of heights, jump­ing out of a plane with a makeshift para­chute may be­gin to look like a good idea once you know the air­craft is run­ning out of fuel.

That, ar­guably, is akin to the mind­set of cli­mate sci­en­tists and pol­i­cy­mak­ers brain­storm­ing in Berlin this week on how to com­pen­sate for hu­man­ity’s col­lec­tive fail­ure to curb the green­house gases — caused mainly by burn­ing fos­sil fu­els — that drive global warm­ing.

In 2015, 195 na­tions mirac­u­lously, if be­lat­edly, vowed to cap the rise of the Earth’s av­er­age sur­face tem­per­a­ture at “well be­low” two de­grees Cel­sius, and to make a good-faith ef­fort to hold the line at a 1.5 de­grees Cel­sius.

But the Paris Agree­ment did not man­date how or when to hit those tar­gets.

With a sin­gle de­gree Cel­sius of warm­ing so far, a crescendo of im­pacts — in­clud­ing trop­i­cal storms en­gorged by ris­ing seas, along with deadly heat­waves, fires and droughts — sug­gest that time is not on our side and that the range of op­tions is nar­row­ing.

“It has be­come very clear that get­ting to 2 de­grees Cel­sius, and es­pe­cially 1.5 de­grees Cel­sius, is very de­pen­dent on our abil­ity to re­move large amounts of CO2 from the at­mos­phere,” Naomi Vaughan, a cli­mate sci­en­tist at the Univer­sity of East Anglia, told the open­ing ple­nary of the Cli­mate En­gi­neer­ing Con­fer­ence 2017.

In­deed, 90 per cent of pro­jec­tions in the UN cli­mate sci­ence panel’s most re­cent re­port that would keep the planet un­der the 2 de­grees Cel­sius thresh­old de­pend heav­ily on such “neg­a­tive emis­sions”. (The oth­ers as­sume green­house gas emis­sions peaked in 2010, when in fact they are still climb­ing.)

“It is a mat­ter of con­sid­er­able con­cern that we are not sure how to do this” on the scale needed, Myles Allen, head of the Univer­sity of Ox­ford’s Cli­mate Re­search Pro­gramme, told AFP.

Michael Tay­lor, an at­mo­spheric sci­en­tist from the Univer­sity of West In­dies, un­der­scored the ur­gency in the af­ter­math of the two Cat­e­gory Five hur­ri­canes — pro­jected to in­crease in fre­quency — that re­cently rav­aged the Caribbean. “The re­gion’s cli­mate will be so sig­nif­i­cantly al­tered that it will not just be un­fa­mil­iar,” he told col­leagues. “It will be un­prece­dented.”

Two cat­e­gories

One of two broad cat­e­gories un­der the geo­engi­neer­ing um­brella, car­bon diox­ide re­moval (CDR) schemes in­clude “en­hanced weather­ing” of rocks that soak up CO2; large-scale pro­duc­tion of char­coal from or­ganic waste; se­ques­ter­ing CO2 cast off from burn­ing bio­fuel plants; and suck­ing car­bon diox­ide di­rectly from the air with high-tech ma­chines.

Even the mas­sive plant­ing of trees — which store CO2 as they grow — is seen as part of the “CDR” ar­se­nal.

The other, far more con­tro­ver­sial ap­proach to cli­mate en­gi­neer­ing, known as so­lar ra­di­a­tion man­age­ment, would deflect enough sun­light back into space to cool the planet a de­gree or two.

This, pro­po­nents say, could be done by in­ject­ing bil­lions of tiny re­flec­tive par­ti­cles into the strato­sphere, or chem­i­cally bright­en­ing mir­ror-like ocean clouds.

“It will be very dif­fi­cult to meet the Paris Agree­ment goal of even stay­ing be­low 2 de­grees Cel­sius with­out re­sort­ing to at least one, if not both, of these forms of cli­mate en­gi­neer­ing,” said Mark Lawrence, sci­en­tific direc­tor of the In­sti­tute for Ad­vanced Sus­tain­abil­ity Stud­ies in Pots­dam, Ger­many, which is host­ing the four-day con­fer­ence.

Some sci­en­tists think cli­mate en­gi­neer­ing of any kind is a slip­pery slope. “It di­verts at­ten­tion away from the need to re­duce emis­sions,” Jean-Pas­cal van Ypersele, a pro­fes­sor at the Catholic Univer­sity of Lou­vain in Bel­gium, and a for­mer vice-chair of the UN In­ter­gov­ern­men­tal Panel on Cli­mate Change, told AFP.

“CO2 re­moval gives the il­lu­sion that we can con­tinue us­ing fos­sil fu­els in­def­i­nitely,” he said.

Other ex­perts who have re­luc­tantly em­braced the ne­ces­sity of geo­engi­neer­ing to help fix the cli­mate are more ner­vous about fid­dling with the sun’s ra­dia­tive force.

“This is the first time since the devel­op­ment of nu­clear weapons that we have a set of tech­nolo­gies which has the po­ten­tial of im­pact­ing Earth, as well as hu­man so­ci­ety, at a plan­e­tary scale,” said Arun­abha Ghosh, chief ex­ec­u­tive of the Coun­cil on En­ergy, En­vi­ron­ment and Wa­ter in New Delhi.

So­lar ra­di­a­tion man­age­ment could dis­rupt rain­fall pat­terns, and thus agri­cul­ture, say crit­ics who also worry about what is some­times called “ter­mi­na­tion shock” — a sud­den warm­ing if the sys­tem were to fail.

There is also the dan­ger of con­flicts over side-ef­fects — real or per­ceived, Allen said. “Coun­tries that are suf­fer­ing from drought will blame who­ever is do­ing so­lar ra­di­a­tion man­age­ment for their trou­bles,” he said.

Be­cause such tech­nolo­gies could be de­ployed uni­lat­er­ally by a sin­gle coun­try, or even a com­pany, they also raise ques­tions about who should set the rules.

Cli­mate sci­en­tist

AFP

Emis­sions spew out of a large stack at the coal-fired Morgantown Gen­er­at­ing Sta­tion in New­burg, Mary­land. Green­house gas emis­sions are still climb­ing glob­ally.

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