Climate science and consensus evidence is now moving to a position that natural climate change causes unprecedented warming (global and/or regional) - a major refutation of IPCC's denial of natural climate impacts
Read here and here. The IPCC's political agenda requires a denial dogma that is built on the concept that natural climate change is minor, thus the recent warming of the 1980's and 90's is a result of human CO2 emissions.
Of course, the lack of global warming over the last 17 years has made a shambles of the AGW hypothesis, plus new research continues to bolster the climate science thesis that natural climate change actually drives unprecedented temperature change. New research by Chen et al. confirms the power of natural climate forcings.
"...they state, in this regard, that "one of the most intriguing questions within the climate debate is if the present temperature rise is unique in the late Holocene or if there have been pre-industrial time intervals where comparable climatic perturbations occurred," noting that "one of these time intervals where historical records suggest that climate conditions might have been similar to today is the so called 'Roman Warm Period' (~200 BC - AD 400)."...developed high-resolution climatic and environmental reconstructions "based on a dinoflagellate cyst record from a well dated site in the Gulf of Taranto located at the distal end of the Po River discharge plume." ...determined that the dinoflagellate cyst warm/cold ratio suggests that sea surface temperature (SST) was "relatively high and stable between 60 BC and AD 200," which they say is suggestive of "slightly higher SST than today." In fact, they say that the association that is observed between 60 BC and AD 90 is equivalent to modern regions that are characterized by higher SST than those in the present day Gulf of Taranto. And noting that "Versteegh et al. (2007) showed that SST in the region is strongly related to local air temperature," they go on to suggest that the region's air temperature "might have been warmer during the Roman Period as well."" [Liang Chen, Karin A.F. Zonneveld, Gerard J.M. Versteegh 2011: Quaternary Science Reviews]