Using tech to con­trol the wea­ther

Les tech­no­lo­gies pour contrô­ler la mé­téo.

Vocable (Anglais) - - Sommaire - OLI­VIA SOLON

C’est bien connu, un gros orage de grêle suf­fit à mettre à mal une ré­colte qui était pour­tant as­su­rée. Les ca­prices de la mé­téo ne datent pas d’hier, et nos ef­forts pour ten­ter de les contrô­ler non plus... Les pre­miers ca­nons an­ti-grêle sont ap­pa­rus dès le XIXe siècle et, au fil du temps, les sys­tèmes per­met­tant de contrô­ler la mé­téo se sont mul­ti­pliés et sont de­ve­nus de plus en plus com­plexes. Mais leur ef­fi­ca­ci­té est-elle prou­vée ?

Far­mers in Mexi­co have ac­cu­sed Volks­wa­gen of rui­ning their crops by ins­tal­ling “hail can­nons”, which fire sho­ck­waves in­to the at­mos­phere in an ef­fort to prevent hail storms from da­ma­ging the cars rol­ling off the pro­duc­tion line. The de­vices are being bla­med for cau­sing a drought du­ring months when far­mers near the Ger­man car­ma­ker’s plant in Pue­bla ex­pec­ted plen­ty of rain. 2. While some may be convin­ced of the hail can­non’s po­wer, scien­ti­fic re­search has cast doubt on these ob­ser­va­tions. But ef­fec­tive or not, the tech­no­lo­gy re­pre­sents hu­ma­ni­ty’s la­test at­tempt to con­trol the wea­ther – rain dan­cing 2.0 – and has rai­sed concerns about the lack of re­gu­la­tion and the as­sump­tion that there is a quick fix for com­plex me­teo­ro­lo­gi­cal phe­no­me­na. Both hail can­nons and hail ro­ckets emit loud noises in the sky, and ma­nu­fac­tu­rers claim this dis­rupts the for­ma­tion of hail so that it falls ins­tead as rain or slush.

HAIL CAN­NONS

3. In 2005, Nis­san ins­tal­led 20ft hail can­nons at its plant in Mis­sis­sip­pi af­ter a hail­storm, much to its neigh­bours’ an­noyance. When ac­ti­va­ted, the sys­tem fi­red off gun­shot sounds

in­to the sky eve­ry six se­conds. “It was like ha­ving a boom­box in my dri­ve­way,” said one neigh­bour at the time. Far­mers have al­so used hail can­nons to try to prevent their crops from being cru­shed.

4. Ho­we­ver, a re­view by the Dutch me­teo­ro­lo­gist Jon Wie­rin­ga conclu­ded that these tech­no­lo­gies were “a waste of mo­ney and ef­fort” – a sen­ti­ment echoed by the World Me­teo­ro­lo­gi­cal Or­ga­ni­za­tion. “The on­ly be­ne­fi­cial ef­fect of fi­ring ex­plo­sive ro­ckets and gre­nades at hail clouds may be the emo­tio­nal sa­tis­fac­tion of the gun­ners, who have fi­red at the ene­my,” he wrote.

CLOUD SEEDING

5. Cloud seeding has been shown to be more ef­fec­tive at control­ling pre­ci­pi­ta­tion. It in­volves shoo­ting che­mi­cals in­to clouds – of­ten from a

boom­box gros ra­dio­cas­sette (por­table) / dri­ve­way al­lée (de ga­rage) / at the time à l'époque / cru­shed écra­sé; ici, dé­truit. 4. re­view ici, étude / dutch hol­lan­dais / waste gas­pillage / gun­ner ar­tilleur. 5. cloud seeding en­se­men­ce­ment des nuages / to in­volve im­pli­quer; ici, consis­ter à / che­mi­cal ici, sub­stance chi­mique / small air­craft – to cause rain­fall or snow. It’s done in more than 50 coun­tries world­wide for va­rious rea­sons in­clu­ding dis­per­sing fog at air­ports, re­du­cing pro­per­ty da­mage from giant hail­stones in Ca­na­da and to in­crease snow­fall in Co­lo­ra­do and sum­mer rain­fall in Texas.

6. “You have to be ve­ry ca­re­ful about what types of clouds and what you are trying to do,” said William Cot­ton, a pro­fes­sor of at­mos­phe­ric science at Co­lo­ra­do State Uni­ver­si­ty. Seeding win­ter­time moun­tain clouds can, he said, in­crease pre­ci­pi­ta­tion by 6-8%. “That’s en­ough for a lot of wa­ter users to be hap­py and willing to pay for it,” Cot­ton said. The evi­dence to sup­port sum­mer­time cloud seeding seems to be much more sha­ky, with the Na­tio­nal Re­search Coun­cil conclu­ding in 2003 that “there is still no convin­cing scien­ti­fic proof of the ef­fi­ca­cy of in­ten­tio­nal wea­ther mo­di­fi­ca­tion ef­forts”.

7. Cri­tics are concer­ned that ma­ni­pu­la­ting the wea­ther is on­ly trea­ting the symp­toms of drought ra­ther than ta­ck­ling the un­der­lying causes. “Even if it’s lo­cal, it’s wor­rying that in the face of cli­mate change these kinds of al­ter­na­tives come up,” said Sil­via Ri­bei­ro, the La­tin Ame­ri­ca di­rec­tor of ETC Group, which exa­mines the so­cio-eco­no­mic and eco­lo­gi­cal im­pact of new tech­no­lo­gies. “We con­trol the symp­toms ins­tead of mo­di­fying what is pro­du­cing the ef­fect.”

A WHOLE NEW SCALE

8. That hasn’t stop­ped states and bu­si­nesses from conti­nuing to seed clouds, in some cases on a diz­zying scale. The Chi­nese go­vern­ment is de­ve­lo­ping the world’s most am­bi­tious cloud seeding pro­ject to boost rain­fall across the Ti­be­tan pla­teau, an area span­ning 620,000 sq miles – three times the size of Spain.

9. The state-ow­ned Chi­na Ae­ros­pace Science and Tech­no­lo­gy Cor­po­ra­tion has de­si­gned and construc­ted cham­bers that use mi­li­ta­ry ro­cket en­gine tech­no­lo­gy that burn fuel to pro­duce the cloud-seeding agent sil­ver io­dide. When the cham­bers are ins­tal­led on moun­tain ridges, the par­ticles tra­vel up in­to the clouds and trig­ger rain­fall in one of the driest places on Earth.

10. Be­cause of the large area co­ve­red, some are concer­ned that the Ti­bet pro­ject tee­ters from wea­ther mo­di­fi­ca­tion in­to geoen­gi­nee­ring ter­ri­to­ry. “Wea­ther mo­di­fi­ca­tion tends to be quite lo­cal. You do it, it hap­pens. You stop and it’s gone. Geoen­gi­nee­ring, or mo­di­fi­ca­tion of the cli­mate, means you do so­me­thing in a way that it stays like that,” ex­plai­ned Ja­nos Pasz­tor, the exe­cu­tive di­rec­tor of the Car­ne­gie Cli­mate Geoen­gi­nee­ring Go­ver­nance Ini­tia­tive, which seeks to create ef­fec­tive go­ver­nance for cli­mate en­gi­nee­ring tech­no­lo­gies. “If [wea­ther mo­di­fi­ca­tion in Ti­bet] were done long en­ough, it will have an im­pact on the cli­mate, not just the wea­ther,” he said.

11. Medd­ling with the cli­mate in this way is high­ly contro­ver­sial and raises all sorts of ethi­cal and lo­gis­ti­cal ques­tions. “We have one at­mos­phere so we must get it right,” said Pasz­tor.

“We con­trol the symp­toms ins­tead of mo­di­fying what is pro­du­cing the ef­fect.”

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