We then examine climate impacts during the past few decades of global warming and in paleoclimate records including the Eemian period, concluding that there are already clear indications of undesirable impacts at the current level of warming and that 2 °C warming would have major deleterious consequences. (journals.plos.org)
Verdon, D. C., Franks, S. W., 2006, Long - term behaviour of ENSO: Interactions with the PDO over the past 400 years inferred from paleoclimate records, Geophysical Research Letters, Volume 33, Issue 6, March 2006, DOI: 10.1029 / 2005GL025052 (watertechbyrie.com)
Indeed, it is slow feedbacks that cause long - term climate sensitivity to be high in the empirical paleoclimate record [51]--[52]. (journals.plos.org)