Tropical volcanoes synchronize eastern Canada with Northern Hemisphere millennial temperature variability

Abstract

Although global and Northern Hemisphere temperature reconstructions are coherent with climate model simulations over the last millennium, reconstructed temperatures tend to diverge from simulations at smaller spatial scales. Yet, it remains unclear to what extent these regional peculiarities reflect region-specific internal climate variability or inadequate proxy coverage and quality. Here, we present a high-quality, millennial-long summer temperature reconstruction for northeastern North America, based on maximum latewood density, the most temperature-sensitive tree-ring proxy. Our reconstruction shows that a large majority (31 out of 44) of the coldest extremes can be attributed to explosive volcanic eruptions, with more persistent cooling following large tropical than extratropical events. These forced climate variations synchronize regional summer temperatures with hemispheric reconstructions and simulations at the multidecadal time scale. Our study highlights that tropical volcanism is the major driver of multidecadal temperature variations across spatial scales.

Stratospheric Aerosol and Ozone Responses to the Hunga Tonga‐Hunga Ha'apai Volcanic Eruption

“…These ash and gases can generally lift several kilometers with volcanic plumes into the upper troposphere and sometimes even into the stratosphere, where they can have a huge impact on climate change (Santer et al., 2015; Sigl et al., 2015; Toohey & Sigl, 2017). For example, when SO 2 is injected into the stratosphere, it is oxidized by hydroxyl radical ⸱OH and H 2 O to form sulfate aerosols, which scatter sunlight and reside for 1–3 years in the stratosphere (Wang et al., 2022). These stratospheric sulfate aerosols can be transported around the globe from low latitudes to high latitudes by the Brewer‐Dobson (BD) circulation (Kremser et al., 2016; Krishnamohan et al., 2019; Tilmes et al., 2017), cooling the troposphere and reducing the global average surface temperature, but warming the lower stratosphere (Timmreck, 2012; Toohey et al., 2011; Zuo et al., 2018).…”

Eastern USA summer temperatures since 1461 CE show connections to volcanic forcing and jet stream dynamics

“…Although the pre-instrumental period of overlap between the two records is short, both records demonstrate a cooler-thanaverage 1870s followed by average temperature conditions before the cooling of the turn of the 20 th century. Further, we find significant and positive multi-decadal coherence (r =0.40, p<0.001) with a maximum latewood density (MXD)-based reconstruction of mean May-Aug temperatures from northeastern North America (NENA) from 1461−2017-the common period of overlap between the two records (Wang et al, 2022) (Figure 3D). Although the length of our record precludes us from characterizing the historical context of modern warming as compared to the Medieval Climate Anomaly (MCA; ca.…”

“…Most MANE predictors are positioned considerably inland and at higher elevations compared to the coastal C. thyoides chronologies included in previous Northeast US temperature reconstructions (Pearl et al, 2017(Pearl et al, , 2020b, most likely explaining the differences in spatial imprint of SSTs. A multi-proxy network that combines the strong temperature proxies of C. thyoides (Pearl et al, 2020b) with the LWBIderived MANE network as well as other tree-ring width chronologies from the region shown to demonstrate a sensitivity to growing season temperatures (Patterson et al, 2016) would produce a potentially more robust pool of candidate predictors across a region known for diverse and complex relationships between tree species and temperature Pederson et al (2004) to the west and south and the combination with existing temperature-sensitive proxies across North America (Heeter et al, 2020(Heeter et al, , 2021Wilson et al, 2019;Wiles et al, 2019;Edwards et al, 2021;Trinies et al, 2022;Gennaretti et al, 2014;Wang et al, 2022;Heeter et al, 2019) will be critical for a more comprehensive understanding of spatiotemporal dynamics of temperature variability over the last millennium (e.g. values, trends, compound climate extremes).…”

Pine Maximum Latewood Density in Semi‐Arid Northern China Records Hydroclimate Rather Than Temperature

“…As tree‐ring latewood forms in the late growing season, the variability of maximum latewood density is likely affected by climate conditions during this period (Fuentes et al., 2017; Seftigen et al., 2020). Previous studies have revealed that the number and wall thickness of latewood cells, which govern tree‐ring MXD variations, are closely related to summer temperatures (Bräuning & Mantwill, 2004; Wang et al., 2022; Wilson et al., 2017). At high‐latitude/altitude sites, a lower‐than‐average growing season temperature can lead to less carbon and lignin allocated to tracheid cell walls, and thus low‐density rings.…”