Key Findings

The Land Cover Change Initiative analysis showed that significant change is occurring in the Arctic’s terrestrial ecosystem and identified statistically significant temporal rates of change across several parameters. We need to determine how resilient the Arctic is to these changes and where there may be certain thresholds, ’‘tipping points’,’ beyond which an abrupt shift of physical or ecological states occur. Only with a combination of in situ data, remote sensing data, and an understanding of the processes occurring at different scales can we begin to understand change in the Arctic Therefore the analyses developed in the Land Cover Change initiative should be repeated regularly to support CBMP efforts to improve our understanding of status and trends in the Arctic biodiversity.

• An important outcome of this work is helping to develop an understanding of the status of spatial and temporal trends across multiple parameters simultaneously and serving as potential explanatory variables for in situ changes observed across FECs.
• The aggregated average annual pan-Arctic data showed significant temporal trends in land surface temperature and NDVI with both significantly increasing in CAVM (Fig 1-2) subzones A, B, D and E, and displaying a north–south variability in the seasonality of temperature change.
• The northernmost CAVM subzone experienced significant increasing temperatures in the autumn, winter, and spring, while the southernmost CAVM subzone showed a significant increase in temperature in late spring to early summer.
• Three parameters for phenology were analysed: green-up date, senescence date and growing season length. Results indicated an earlier green-up by approximately six days and a growing season length extended by approximately four days, from 2001 to 2014.
• No significant trends were observed in the average annual percent snow covered areas, although time series for individual months revealed significant trends—for example, significant declining trends were observed in subzones C and D for June, in subzone E for July and in subzones A and B for October.
• A set of five parameters were also analysed for the Arctic’s marine ecosystem—marine chlorophyll, coloured dissolved organic material, sea surface temperature, marine primary productivity, and sea ice extent. Both the terrestrial and marine environments experienced similar amounts of change with more statistically significant trends being observed in seasonal data. The rates of change of NDVI and sea ice were approximately the same.