Irresponsible use of campfires.
Slash and burn farming doesn’t impact global climate. We would be hearing about it instead of cow farts, SUVs, and air conditioning.
https://en.wikipedia.org/wiki/Slash-and-burn
Slash-and-burn agriculture, or fire–fallow cultivation, is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. (Preparing fields by deforestation is called assarting.)
In subsistence agriculture, slash-and-burn typically uses little technology. It is often applied in shifting cultivation agriculture (such as in the Amazon rainforest) and in transhumance livestock herding.[1]
Slash-and-burn is used by 200–500 million people worldwide.[2][3] In 2004 it was estimated that in Brazil alone, 500,000 small farmers each cleared an average of one hectare (2.47105 acres) of forest per year[4]. The technique is not scalable or sustainable for large human populations.
...Historically, slash-and-burn cultivation has been practiced throughout much of the world, in grasslands as well as woodlands.
During the Neolithic Revolution, which included agricultural advancements, groups of hunter-gatherers domesticated various plants and animals, permitting them to settle down and practice agriculture, which provides more nutrition per hectare than hunting and gathering. This happened in the river valleys of Egypt and Mesopotamia. Due to this decrease in food from hunting, as human populations increased, agriculture became more important. Some groups could easily plant their crops in open fields along river valleys, but others had forests blocking their farming land.
In this context, humans used slash-and-burn agriculture to clear more land to make it suitable for plants and animals. Thus, since Neolithic times, slash-and-burn techniques have been widely used for converting forests into crop fields and pasture.[8] Fire was used before the Neolithic as well, and by hunter-gatherers up to present times. Clearings created by the fire were made for many reasons, such as to draw game animals and to promote certain kinds of edible plants such as berries.
...Southern European Mediterranean climates have favored evergreen and deciduous forests. With slash-and-burn agriculture, this type of forest was less able to regenerate than those north of the Alps. Although in northern Europe one crop was usually harvested before grass was allowed to grow, in southern Europe it was more common to exhaust the soil by farming it for several years.
Classical authors mentioned large forests,[12] with Homer writing about “wooded Samothrace,” Zakynthos, Sicily, and other woodlands.[13] These authors indicated that the Mediterranean area once had more forest; much had already been lost, and the remainder was primarily in the mountains.[14]