Pan-Arctic Climate and Land Cover Trends Derived from Multi-Variate and Multi-Scale Analyses (1981–2012)

Abstract

Arctic ecosystems have been afflicted by vast changes in recent decades. Changes in temperature, as well as precipitation, are having an impact on snow cover, vegetation productivity and coverage, vegetation seasonality, surface albedo, and permafrost dynamics. The coupled climate-vegetation change in the arctic is thought to be a positive feedback in the Earth system, which can potentially further accelerate global warming. This study focuses on the co-occurrence of temperature, precipitation, snow cover, and vegetation greenness trends between 1981 and 2012 in the pan-arctic region based on coarse resolution climate and remote sensing data, as well as ground stations. Precipitation significantly increased during summer and fall. Temperature had the strongest increase during the winter months (twice than during the summer months). The snow water equivalent had the highest trends during the transition seasons of the year. Vegetation greenness trends are characterized by a constant increase during the vegetation-growing period. High spatial resolution remote sensing data were utilized to map structural vegetation changes between 1973 and 2012 for a selected test region in Northern Siberia. An intensification of woody vegetation cover at the taiga-tundra transition area was found. The observed co-occurrence of climatic and ecosystem changes is an example of the multi-scale feedbacks in the arctic ecosystems.

The role of summer precipitation and summer temperature in establishment and growth of dwarf shrub Betula nana in northeast Siberian tundra

“…Local permafrost degradation resulting in thaw pond development and drowning of shrubs could have prevented net shrub expansion (Nauta et al 2015). The negative precipitation trend is not unique to the study area, but also occurred in some other locations, particularly in the High Arctic (Urban et al 2014). We used the KNMI Climate Change Atlas tool (http://climexp.knmi.nl/atlas) to generate a map of summer (JJA) precipitation trends over the years 1991-2015 for the Arctic land based on observations (CRU TS 3.22 dataset).…”

Environmental controls on the increasing GPP of terrestrial vegetation across northern Eurasia

“…Precipitation increases have also been observed over both North America and Eurasia over the past century (Nicholls et al, 1996;Groisman et al, 1991). Urban et al (2014) describe the co-occurrence of these climatic and ecosystem changes. Here we investigate increasing GPP of terrestrial ecosystems of northern Eurasia and determine the relative attribution arising through changes in several geophysical quantities, hereinafter referred to as "environmental variables", as they potentially drive observed temporal changes in vegetation productivity.…”

“…We consequently do not analyse the influence of CO 2 concentration. While some studies have focused on terrestrial ecosystems of the pan-Arctic (Urban et al, 2014;Myneni et al, 1997;Guay et al, 2014;Kim et al, 2014) or the high latitudes of North America (Goetz et al, 2005;Buermann et al, 2013;Thompson et al, 2006), few studies have investigated the relative role of different environmental variables on increasing GPP of northern Eurasia. Therefore, we assess in this study how vegetation productivity trends in northern Eurasia are influenced by the environmental variables air temperature, precipitation, cloudiness, and forest fire.…”

Trends in normalized difference vegetation index (NDVI) associated with urban development in northern West Siberia

“…Although the patterns are geographically fragmented (Elsakov and Teljatnikov, 2013;Barichivich et al, 2014;Guay et al, 2014), the northern biomes (tundra and foresttundra) demonstrate widespread increase of the vegetation productivity ("greening"). Its attribution to tall shrub and graminoids in tundra ecosystems (Frost and Epstein, 2014) and enhanced tree growth in forest-tundra ecosystems (Urban et al, 2014) suggested that we observe transitions to alternative, potentially more productive ecosystems rather than anomalously enhanced biological productivity in response to global warming Macias-Fauria et al, 2012). These environmental shifts have been unfolding for at least the last 3 decades (Keeling et al, 1996;Myneni et al, 1997) albeit at a slower pace since 2003 (Bhatt et al, 2013).…”