Tropical volcanoes synchronize eastern Canada with Northern Hemisphere millennial temperature variability.

Area of Science:

• Paleoclimatology
• Climate Science
• Volcanology

Background:

• Global and Northern Hemisphere temperature reconstructions align with climate models over the last millennium.
• Regional temperature reconstructions often diverge from simulations, with causes unclear (internal variability vs. proxy limitations).

Purpose of the Study:

• To develop a millennial-long summer temperature reconstruction for northeastern North America.
• To investigate the drivers of regional temperature variations and their relationship with large-scale climate patterns.

Main Methods:

• Utilized maximum latewood density, a highly temperature-sensitive tree-ring proxy.
• Developed a high-quality, millennial-long summer temperature reconstruction for northeastern North America.

Main Results:

• A majority of coldest temperature extremes (31/44) were linked to explosive volcanic eruptions.
• Cooling was more persistent after large tropical volcanic events compared to extratropical ones.
• Volcanic forcing synchronized regional summer temperatures with hemispheric reconstructions and simulations on multidecadal timescales.

Conclusions:

• Tropical volcanism is identified as the primary driver of multidecadal temperature variations across different spatial scales.
• The study reconciles regional temperature peculiarities with large-scale climate forcing, emphasizing the role of volcanic activity.