New Research: Medieval Warm Period Was As Warm As Today
New research papers suggest Northern hemisphere temperatures during the Medieval Warm Period were as warm as recent decades.
Other NH Reconstructions Indicate Pre-Industrial Temps Were Highly Variable, 1940s As Warm As 2000s
New Paper: Models Need ‘Forcing’ Adjustment…Underestimate Past Warmth, Internal Variability…Instrumental Record ‘Biased’
Spanning the period 1186-2014 CE, the new reconstruction reveals overall warmer conditions around 1200 and 1400, and again after ~1850. The coldest reconstructed summer in 1258 (-4.4°C wrt 1961-1990) followed the largest known volcanic eruption of the CE. The 20th century is characterized by pronounced summer cooling in the 1970s, subsequently rising temperatures until 2003, and a slowdown of warming afterwards. Little agreement is found with climate model simulations that consistently overestimate recent summer warming and underestimate pre-industrial temperature changes.
[W]hen it comes to disentangling natural variability from anthropogenically affected variability the vast majority of the instrumental record may be biased. … Although the causes of the recently measured slowdown in global and regional warming during the last decade are still debated (Karl et al. 2015; Fyfe et al. 2016), our study provides the first long-term proxy evidence for this temperature decline over the western Mediterranean basin. This finding is in line with local, regional and sub-continental meteorological observations, and consistent with the observations by Gleisner et al. (2015) that the post-2003 pause in rising mean surface temperatures is most strongly expressed at mid-latitudes.
The reconstructed long-term variability exceeds the pre-industrial multi-decadal to centennial variability in four state-of-the-art climate model simulations.