<prompt> tafadhali geuza maudhui haya ya swahili kwenda kwa kiingereza.mara tu viwango vya kaboni dioksidi vilipokuwa vya chini karibu sehemu 300 kwa milioni kati ya miaka milioni mbili na tatu iliyopita, mzunguko wa sasa wa barafu ulianza, lakini ongezeko la joto joto zetu husababisha ni kubwa kuliko mwenendo wa baridi wa asili.  <response>: once carbon dioxide concentrations became low enough around 300 parts per million between two and three million years ago, the current ice age cycle began, but the warming our emissions are causing is larger than the natural cooling trend. 