Earlier this week, Jeff Masters explained that global warming is causing rats to take over the earth, and The Washington Post announced that the vermin have already taken over Washington DC.
John Cook has followed up with this by theorizing that rats cause global cooling.
Little Ice Age Causes
The Black Death caused a decrease in the human populations of Europe, East Asia, and the Middle East during the 14th century and a consequent decline in agricultural activity. A similar effect occurred in North America after European contact in the 16th century. Ruddiman (2003) suggests reforestation took place as a result of this reduced human population and agricultural activity, allowing more carbon dioxide uptake from the atmosphere to the biosphere, thus having a cooling effect.
h/t to Tom Nelson
Does this mean that rats are a negative feedback?