The climate crisis is largely due to the increase of global temperature from the greenhouse gases. Although the global mean for CO2 has surpassed the 400 ppm, in the urban environment of Athens during winter and especially during nighttime values can even exceed the 650 ppm! The anthropogenic burden in Athens compared to background values is estimated to around 3.5% for the whole year while during winter it may reach even 20% (average ~7%) when during summer values drop to background levels. On the other hand methane appears enhanced by 3.5% compared to the background, with persistent sources throughout the year that are associated with natural gas, oil refineries, industry and livestock farming.