Leapfrog the chem­i­cal tread­mill

Go straight to cli­mate­friendly op­tions for re­frig­er­ants

Down to Earth - - OZONE DAY SPECIAL - CHAN­DRA BHUSHAN

THE WORLD is at a cross­roads. Just like in 1990. That year, coun­tries agreed to phase out the use of gases like chlo­roflu­o­ro­car­bons (cfcs) that de­plete the ozone layer of the at­mos­phere. Ozone pro­tects the earth by block­ing ul­tra­vi­o­let ra­di­a­tion that can cause dis­eases like skin can­cer, dam­age crops and threaten the lives of other or­gan­isms.

cfcs, used as re­frig­er­ants, are also su­per green­house gases. A mol­e­cule of the most com­monly used cfc—cfc-12—is 10,600 times more po­tent in caus­ing global warm- ing than a mol­e­cule of car­bon diox­ide (CO2).

Un­der the Mon­treal Pro­to­col, an in­ter­na­tional treaty to pro­tect the ozone layer, de­vel­oped coun­tries phased out the pro­duc­tion and con­sump­tion of cfcs by 2000 and de­vel­op­ing coun­tries by 2010. Coun­tries moved from cfcs to hy­drochlo­roflu­o­ro­car­bons (hcfcs). hcfcs were touted as an in­terim so­lu­tion as they were less harm­ful to ozone than cfcs.But they too caused global warm­ing. The global warm­ing po­ten­tial (gwp) of hcfcs is a thou­sand times that of CO2 but com­par­a­tively less than that of cfcs.

But in 1990,coun­tries had the op­tion to

Past

High-GWP/ODP CFCs

Present

High-GWP HFCs

Fu­ture

Low-GWP al­ter­na­tives

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