During 2017, there were 150 graphs from 122 scientific papers published in peer-reviewed journals indicating modern temperatures are not unprecedented, unusual, or hockey-stick-shaped — nor do they fall outside the range of natural variability. We are a little over 4 months into the new publication year and already 81 graphs from 62 scientific papers undermine claims that modern era warming is climatically unusual.
“In this study we present a detailed GDGT data set covering the last 13,000 years from a peat sequence in the Changbai Mountain in NE China. The brGDGT-based temperature reconstruction from Gushantun peat indicates that mean annual air temperatures in NE China during the early Holocene were 5–7°C higher than today. Furthermore, MAAT records from the Chinese Loess Plateau also suggested temperature maxima 7–9°C higher than modern during the early Holocene (Peterse et al., 2014; Gao et al., 2012; Jia et al., 2013). Consequently, we consider the temperatures obtained using the global peat calibration to be representative of climate in (NE) China. … The highest temperatures occurred between ca. 8 and 6.8 kyr BP, with occasional annual mean temperatures >8.0 ± 4.7°C, compared to the modern-day MAAT of ∼3°C.”
“We estimate that air temperatures were 2.5–3.0 °C higher during the Holocene Thermal Maximum than the local 1960–1990 average. … Between 1700 and 1925 CE temperatures were likely 0.6–0.8 °C lower than the 1950–2015 reference temperature.“
“Iceland’s terrestrial HTM [Holocene Thermal Maximum] has previously been constrained to ~7.9 to 5.5 ka based on qualitative lake sediment proxies (Larsen et al., 2012; Geirsdottir et al., 2013), likely in association with progressive strengthening and warming of the Irminger Current (Castaneda et al., 2004; Smith et al., 2005; Olafsdottir et al., 2010). Numerical modeling experiments for Drangajokull suggest that peak air temperatures were 2.5 – 3°C warmer at this time relative to the 1961-1990 CE average (Anderson et al., 2018). … During the Little Ice Age(LIA, 1250-1850 CE), the Vestfirðir region entered the lowest multi centennial spring/summer temperature anomalies of the last 9 ka. Based on recent numerical modeling simulations, this anomaly is estimated to be 0.6-0.8°C below the 1950-2015 average on Vestfirðir (Anderson et al., 2018).”
“[C]limate anomalies appear to be reflected in the Tunu VA [vanillic acid]record, with elevated VA [vanillic acid] during the warm periods and lower levels during the colder periods. The data suggest a positive correlation between North American fire and hemispheric mean temperature. This relationship could be due to climate-driven changes in temperature or precipitation on burning extent, frequency, or location, as well as to changes in atmospheric transport patterns. … … [E]levated VA [vanillic acid] early in the record [Roman Warm Period] and around the MCA [Medieval Climate Anomaly]. It also emphasizes the decreasing trend from 1200-1900 CE [Little Ice Age] and the increase during the 20th century [Current Warm Period].”
“The record demonstrates a warming during the Roman Warm Period (~350 BCE – 450 CE), variable bottom water temperatures during the Dark Ages (~450 – 850 CE), positive bottom water temperature anomalies during the Viking Age/Medieval Climate Anomaly (~850 – 1350 CE) and a long-term cooling with distinct multidecadal variability during the Little Ice Age (~1350 – 1850 CE). The fjord BWT [bottom water temperatures] record also picks up the contemporary warming of the 20th century, which does not stand out in the 2500-year perspective and is of the same magnitude as the Roman Warm Period and the Medieval Climate Anomaly.”