Modern Farmer published an interesting short article last week about how early agricultural practices changed the local and global climate.  Slash and burn techniques caused big changes in land use and injected a lot of carbon into the atmosphere, both as carbon dioxide and as black soot, both of which change the climate in different ways.  You might enjoy reading about it here.

Source: mattmangum, Commons Wikimedia
An example of slash and burn agriculture in Thailand.  Source: mattmangum, Commons Wikimedia