Regional Hotspots of Change in Northern High Latitudes Informed by Observations from Space

Abstract

The high latitudes cover ˜20% of Earth's land surface. This region is facing many changes in thermal, moisture and vegetation properties, driven by climate warming. Here we leverage remote sensing-informed and climate reanalysis records to improve understanding of changes in key ecosystem indicators. To do so we applied non-parametric trend detections and Getis-Ord Gi* spatial hotspot assessments. We found substantial terrestrial warming trends across Siberia, portions of Greenland, Alaska, and western Canada. The same regions also showed increases in vapor pressure deficit, however changes in precipitation and soil moisture were variable. Vegetation greening and browning were widespread across both continents. Browning of the boreal zone was especially evident in autumn. Multivariate hotspot assessments indicated that Siberian ecoregions experienced the most substantial changes in thermal, moisture and vegetation status. Finally, we found that using regionally-based trends alone, without more local assessments, can yield incomplete views of high-latitude responses to climate warming. Key Points• This study identifies multiple changes in climatic and vegetation conditions across the high-latitude terrestrial domain. • Environmental changes occurring across the high-latitude domain are spatially complex, leading to a need for localized (i.e., pixel-based) trend assessments in addition to those based on regional averages.

An increasing Arctic-boreal CO2sink offset by wildfires and source regions

“…These studies have focused primarily on ecosystem CO 2 fluxes (i.e., not incorporating fire emissions), coarse annual or seasonal CO 2 fluxes (i.e., overlooking the intra-annual dynamics), and spatial patterns in CO 2 fluxes with data from only one to two decades. Most importantly, earlier studies have not extended into the 2020s, a period of time where warming has further accelerated and more fires have occurred 21 . Thus, we lack a comprehensive understanding of the regional and seasonal patterns in recent ecosystem CO 2 fluxes, including fire emissions, and their multidecadal trends, and the links to changing environmental conditions across the ABZ.…”