>>24155344 lb/pb
There is a well-studied phenomenon called 'aircraft-induced cirrus' which transforms aircraft contrails into continuous cloud cover. It's not 'chemtrails', the issue is increased air traffic, especially in the US SW and other major flight routes:
"Air traffic is known to have an immediate and noticeable effect on clouds in the upper troposphere. New clouds that form due to aircraft effluent are called contrails, and may develop into more persistent and widespread contrail cirrus. Boucher was the first to realize that aviation might have a strong influence on the occurrence rate of cirrus clouds."
"Aircraft emissions and contrails at cirrus altitudes have the potential to either cause optically thin cirrus clouds to form (that would have a warming effect on surface temperatures) or increase the optical thickness of existing clouds (or induce new optically thick clouds), thus, causing a net cooling effect. "
https://www.nature.com/articles/ncomms12016