Shipping volumes in the Northwest Passage are likely to increase under climate change due to the distance advantage over traditional routes and the special strategic location of the Arctic. However, the harsh environment and poor channel conditions may pose a considerable risk to ship navigation. To ensure the safety of ships, understand the navigability of the route, and plan the sustainable use of the Northwest Passage, it is crucial to provide a quantitative risk assessment. Here, we present an analysis of several natural risks faced by ships in the Northwest Passage based on available datasets and use climate model simulations to project the navigability changes. The results showed that: (1) The sea-ice risk to ships in the Northwest Passage has been significantly reduced over the period 1979–2019, and the risk for Polar Class 6 (PC6) ships has decreased more rapidly than for general open-water (OW) ships. The difference in ice-breaking capacity further affects the seaworthy season, with the second seaworthy month being August for OW ships and October for PC6 ships, in addition to the commonly best September. (2) Low visibility is a more common form of adverse weather than strong wind for navigation in the Northwest Passage, mainly on the northern route, although pilotage conditions appear to be improving in September. (3) According to the comprehensive risk map, the distribution of risk is dominated by sea ice. The southern route of the Northwest Passage is superior to the northern route in terms of both sea ice and weather conditions, but there is a risk of shallow water. (4) For the northern route, which has greater transport potential, projections suggest that the sea-ice risk will be steadily lower than any extreme light ice year observed historically whether for the ship class OW or PC6 by 2050, with an increase of 50–80 navigable days, and the navigable period could be from June to January of the following year for PC6 ships by 2100. Our results provide valuable information for ships planning to pass through the Northwest Passage.
The glaciers in Arctic Archipelago of Svalbard, located in the hotspot of global warming, are sensitive to climate change. The assessment of glacier mass balance in Svalbard is one of the hotspots in Arctic research. In this study, we use the laser altimetry ICESat-2 data to investigate the elevation and mass change of Svalbard from 2019 to 2021 by a hypsometric approach. It is shown that the Svalbard-wide elevation change rate is −0.775 ± 0.225 m yr−1 in 2019–2021, corresponding to the mass change of −14.843 ± 4.024 Gt yr−1. All regions exhibit a negative mass balance, and the highest mass loss rates are observed at Northwestern Spitsbergen. Compared with ICESat/ICESat-2 (2003–2008 to 2019) and Cryosat-2 (2011–2017) periods, the elevation change from 2019 to 2021 has accelerated, with an increase by 158.3% and 31.5%, respectively, leading to equilibrium line altitude increasing to 750 m. Among the seven subregions, four are accelerated. It is shown that the overall accelerated glacier mass loss in Svalbard is expected to be caused by increasing surge events and temperature rise.
Glaciers play an important role in understanding the climate, water resources, and surrounding natural change. Baishui River Glacier No. 1, a temperate glacier in the monsoon-influenced Southeastern Qinghai–Tibet Plateau, has experienced significant ablation due to regional warming during the past few decades. However, little is known about the yearly changes in Baishui River Glacier No. 1. To investigate how Baishui River Glacier No. 1 has changed in recent years, digital orthophoto maps and digital elevation models were obtained from an unmanned aerial vehicle on 20 October 2018 and 22 July 2021, covering 84% and 47% of the total area, respectively. The results of the Baishui River Glacier No. 1 changes were obtained by differencing the digital elevation models, manual tracking, and terminus-retreat calculation methods. Our results showed that the surveyed area had a mean elevation change of −4.26 m during 2018 and 2021, and the lower area lost more ice than other areas. The terminus of Baishui River Glacier No. 1 has retreated by 16.35 m/a on average, exhibiting spatial variation with latitude. Moreover, we initially found that there was a high correlation between surface velocity and elevation gradient in this high-speed glacier. The surface velocity of Baishui River Glacier No. 1 was derived with the manual feature tracking method and ranged from 10.48 to 32.00 m/a, which is slightly smaller than the seasonal average. However, the snow coverage and ice melting of the two epochs led to the underestimation of our elevation change and velocity results, which need further investigation.
The mass balance of glaciers requires more detailed and continuous observations to understand their seasonal change in relation to climate. Here, we designed and installed an automated real-time monitoring platform at 4645 m a.s.l. on the Baishui River Glacier No.1 to collect continuous high-resolution observational data, and analyzed the seasonal dynamic from glacier movement and surface mass balance from glacier melting and snow accumulation. The results showed that the platform moved northeastward ~12.9 m at a rate of 0.06 ± 0.02 m d−1 between September 2021 and April 2022. The surface mass balance showed a varied temporal period. July and August were the main ablation periods, while ablation decreased and ceased in September. The glacier neither melted nor accumulated much between October and December, but began to have rapid snow accumulation in January. The glacier surface temperature varied with the air temperature and showed significant inter-seasonal differences among monsoon, post-monsoon and winter seasons. The surface mass balance also exhibited a strong response to the air temperature changes, with an average decrease of 1°C the point mass balance increased by 0.11 m w.e. from monsoon to post-monsoon and 0.22 m w.e. from post-monsoon to winter. Moreover, we found snowfall caused a decrease in the glacier surface temperature by increasing the surface albedo.