Ators of change are NDVI as well as the active layer thickness. Search phrases Alaska purchase NKL 22 Toolik Climate modify Ecological effects Greenland Zackenberg Medium pass filter VegetationINTRODUCTION Climate warming inside the Arctic, substantial more than recent decades and well-documented in IPCC reports (IPCC 2001, 2013), is reflected in adjustments inside a wide variety of environmental and ecological measures. These illustrate convincingly that the Arctic is undergoing a system-wide response (ACIA 2005; Hinzman et al. 2005). The altering measures variety from physical state variables, including air temperature, permafrost temperature (Romanovsky et al. 2010), or the depth of seasonal thaw (Goulden et al. 1998),to adjustments in ecological processes, such as plant growth, which can outcome in adjustments within the state of ecosystem components like plant biomass or modifications in ecosystem structure (Chapin et al. 2000; Sturm et al. 2001; Epstein et al. 2004). In spite from the huge number of environmental and ecological measurements created over current decades, it has established tough to discover statistically substantial trends in these measurements. This difficulty is brought on by the high annual and seasonal variability of warming inside the air temperature plus the complexity of biological interactions. One particular remedy to the variability issue is usually to carry out long-term studies. These studies are high-priced to carry out inside the Arctic with the result that many detailed research happen to be somewhat short-term (e.g., the IBP Arctic projects inside the U.S. and Canada), or happen to be long-term projects restricted in scope (e.g., the Sub-Arctic Stordalen project in Abisko, Sweden; Jonasson et al. 2012). Presently, there are but two projects underway that are each long-term and broad in scope: Toolik in the Low Arctic of northern Alaska and Zackenberg within the High Arctic of northeast Greenland (Fig. 1). Right here we use information from these web pages to ask which kinds of measures basically yield statistically considerable trends of effects of climate warming Additional, are there popular characteristics of these valuable measures that lessen variabilitySTUDY Web-sites The Toolik project (Table 1) is located at the University of Alaska’s Toolik Field Station (TFS) some 125 km inland in the Arctic Ocean. The Long-term Ecological Study (LTER)1 and connected projects at this web page havehttp:arc-lter.ecosystems.mbl.edu.The Author(s) 2017. This article is published with open access at Springerlink.com www.kva.seenAmbio 2017, 46(Suppl. 1):S160SFig. 1 Place of Toolik, Alaska (68o380 N, 149o430 W) and Zackenberg, Greenland (74o300 N, 21o300 W), 
long-term arctic study sitesTable 1 Ecological settings for Toolik and Zackenberg study internet sites Toolik field station Place Inland, Northern Alaska 68o380 N, 149o430 W, 719 m altitude Physical Rolling foothills, Continuous permafrost (200 m), annual setting temperature -8 , summer time (mid-June to mid-August) 9 , annual precipitation 312 mm Ecology Tussock tundra (sedges, evergreen PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21301389 and deciduous shrubs, forbs, mosses, and lichens). Low shrubs, birches, and willows develop between tussocks and along water tracks and stream banks. Low Arctic LTER (Long term Ecological Study), ITEX (International Tundra Experiment), NOAA’s Arctic Program, CALM (Circumpolar Active Layer Monitoring), and also the TFS environmental monitoring program Zackenberg Coast, Northeast Greenland 74o300 N, 21o300 W, 0 m altitude Mountain valley, Continuous permafrost (estimated 20000 m), annual temperature -8 , summer time (three months) four.five , an.