Recent ground thermal dynamics and variations in northern Eurasia

<p><span>Ground thermal regime in cold environments is key to understanding the effects of climate change on surface&#8211;atmosphere feedbacks. The northern Eurasia, covering over half of terrestrial areas north of&#160;</span><span>40&#176;N, is sensitive to the ongoing climate change due to underlain permafrost and seasonal frost.&#160;Here, we quantify the recent ground thermal dynamics and variations over northern Eurasia by compiling measurements of soil temperature data over 457 sites at multiple depths from 1975-2016. Our analysis shows that the mean annual ground temperature has significant warming trends by 0.30&#8211;0.31&#160;&#176;C/decade at depths of 0.8, 1.6, and 3.2&#160;m. We found that the changes in annual maximum ground temperatures were more pronounced than mean annual ground temperatures with a weakened warming magnitude (0.40 to 0.31&#176;C/decade) from upper to lower ground. Our results also suggest the substantial differences in warming magnitudes through parameters and depths over different frost-related areas. The ground over continuous permafrost area warmed faster than non-continuous permafrost and seasonal frost areas in shallow ground (0.8 and 1.6&#160;m depth) but slower in deeper ground (3.2&#160;m). Our study highlights the varied ground temperature evolutions at multiple depths and different frost-related ground</span><span>, suggesting the importance of separated discussions on different frost-affected ground in application and future research. Noteworthy,&#160;</span><span>the results indicate that the significant ground warming can promote greenhouse gas emissions from soil to atmosphere, further accelerating climate change.</span></p>