Michael Hart, muaka-tiko wa San Diego, u hehliwe hi ku tlula milawu ya mfumo wa US leyi kongomisiweke eka ku sivela ku tirhisiwa ka tigasi ta greenhouse. A swi le nawini ku nghenisa tihydrofluorocarbons (HFCs) handle ka mpfumelelo wo hlawuleka lowu humesiweke hi Environmental Protection Agency (EPA) Hart u hehliwa hi ku xava swihalaki swo titimerisa eMexico kutani a swi ngungumerisa swi ya eUS hi ku swi tumbeta ehansi ka tarpaulin na switirhisiwa.