Glacier area changes in Novaya Zemlya from 1986-89 to 2019-21 using object-based image analysis in Google Earth Engine

Climate change has had a significant impact on glacier recession, particularly in the Arctic, where glacier meltwater is an important contributor to global sea-level rise. Therefore, it is important to accurately quantify glacier recession within this sensitive region, using multiple observations of glacier extent. In this study, we mapped 480 glaciers in Novaya Zemlya, Russian Arctic, using object-based image analysis applied to multispectral Landsat satellite imagery in Google Earth Engine and quantify the area changes between 1986-89 and 2019-21. The results show that in 1986-89, the total glacierized area was 22 990 +/- 301 km(2), in 2000-01 the area was 22 525 +/- 308 km(2) and by 2019-21 the glacier area reduced to 21 670 +/- 292 km(2), representing a total of 5.8% reduction in glacier area between 1986-89 and 2019-21. Higher glacier area loss was observed on the Barents Sea coast (7.3%) compared to the Kara (4.2%), reflecting previously observed differences in warming trends. The accuracy of the automatically generated outlines of each layer (1986-89, 2000-01 and 2019-21) was evaluated by comparing with manually corrected outlines (reference data) using random sampling, resulting in an overall accuracy estimate of between 96 and 97% compared to the reference data. This automated approach in Google Earth Engine is a promising tool for rapidly mapping glacier change that reduces the amount of time required to generate accurate glacier outlines.