2018 Bering Sea Winter Sea Ice Lowest in At Least 5500 Years

Science Advances, September 2 Summer sea ice minimums receive the most attention; but Arctic sea ice has been declining year-round, and new reconstructions place the 2018 winter maximum in the Bering Sea as the lowest in at least 5500 years.  The 2018 and 2019 maximums were also 60-70% lower than the averages recorded since consistent […]

Large Reduction in Glaciers Under High Emissions Scenario in Central Himalayas

Journal of Glaciology, August 26 Up to 85% of the glaciers found in the Koshi River Basin could disappear by 2100 under the highest emission scenarios (RCP8.5). The Koshi River, a major tributary of the Ganges has a 50,000 km2 basin (the size of Costa Rica).  Over 5% is covered by glaciers, and spreads across India, Nepal, […]

Huge Pathways of Warm Water Found Under Major Antarctic Glacier

New maps collected under the floating tongue of Thwaites Glacier and further offshore reveal deep (> 1000 m) and wide (> 20,000 m) channels that guide warm ocean water under the ice, accelerating melt that eventually may lead to collapse. Thwaites, part of the West Antarctic Ice Sheet (WAIS) is the size of Great Britain, […]

2020 Arctic Fires Already One-third Higher Than 2019 Record High

Copernicus Atmosphere Monitoring Service, September 3 Arctic fire emissions – those directly caused by humans, as well as those from natural phenomena such as lightning strikes – already are one-third higher than the 2019 total, which itself broke the previous record.  The CO2 released from these fires through the end of August totalled around 244 […]

Majority of Antarctic Ice Shelves Sensitive to Meltwater Fracturing

Nature, August 26 Antarctic ice shelves – floating ice in contact with land ice – are both critical to maintaining ice sheet stability, and vulnerable to catastrophic fracturing from meltwater entering crevasses. Hydro-fracturing occurs when surface meltwater flows into and deepens pre-existing fractures, and is a potential mechanism driving sudden ice shelf collapse, as occurred with […]

Earlier Spring Rain on Arctic Sea Ice Accelerates Loss

The Cryosphere, August 28 Rain events on some portions of the Arctic Ocean have occurred nearly 4-6 days earlier for each recent decade, accelerating the onset of sea ice melt in the Pacific sector of the Arctic Ocean, and in the Eurasian Marginal seas above Siberia. This study combined limited field observations at Arctic coastal […]

Rapid Worldwide Growth in Glacial Lakes and Risk of Outburst Floods

Nature Climate Change, August 31 The global volume of glacier lakes increased 48% between 1990 and 2018, to 156.5 km3, a volume that would cover the country of Liechtenstein by a lake 1 km deep. Glacial lakes are bodies of water fed by a glacier’s meltwater, and subject to sudden outburst events that unexpectedly can […]

Ice Sheet Loss from Greenland and Antarctica Track Worst-case IPCC AR5 Projections

Nature Climate Change, August 31   The Greenland and Antarctic ice sheets have increased global sea level by 12.3 mm from 2007 and 2017, matching the most pessimistic predictions of the IPCC’s most recent assessment report (AR5). In particular, this study indicated that current models underestimate the contribution of ice sheet surface melt.  The comparison […]

Massive Amounts of Ice Loss in the Cryosphere

The Cryosphere Discussion/Review, August 14 A paper placed in open review notes that the cryosphere globally has lost a total of 28 trillion tonnes of ice (28,000 Gt) in the past 23 years, with a significant acceleration of mass loss since the year 2000. The largest losses have occurred to (in approximate order) Arctic sea […]

Reconstruction of Sea-level Rise Sources Closes the “Sea-level Budget”

Nature, August 19 For the first time, researchers have been able to close the “sea-level budget” (relative sources of sea-level rise), gaining new insights on the drivers of observed global mean sea-level rise over the past century. By re-examining the contributions of glaciers, ice sheets, thermal expansion, and land water storage, this study was able […]

Unexpected Basal Ocean Melting in East Antarctica

Nature Communications, August 24 The floating Shirase Ice Tongue (a long and narrow projection of ice, connected an ice basin about the size of the United Kingdom) in Queen Maud Land, East Antarctica, has revealed surprisingly high basal melt rates of 7 to 16 m per year. These rates equal or surpass the melting rate underneath […]

Satellite Data Confirms Accelerating Greenland Ice Sheet Loss

Nature, August 20   The Greenland Ice Sheet lost a record-breaking 532 (± 58 Gt) of ice in 2019, up around 200 Gt in the early 2000s, when it first became clear that the ice sheet was losing mass. The two GRACE satellite missions also provided new insights on the sensitivity of the Greenland Ice Sheet to climate-related changes in […]

Ice Mass Loss from Greenland Will Continue Even After Stabilized

Nature, Communications Earth & Environment, August 13 Acceleration of outlet glaciers from the Greenland ice sheet, not compensated by accumulation above makes it the current largest contributor to sea level rise. Through the 1980s and 1990s, losses through iceberg calving and melting were replaced by snowfall, keeping the ice sheet in balance. However, starting in […]

Basal Melting of Antarctic Ice Shelves

Nature Geoscience, August 10 Between 1994 and 2018, Antarctic ice shelves (floating ice connected to the land-based Antarctic ice sheet) lost close to 3960 Gt of ice. Many ice shelves bordering Antarctica lose mass through ocean-driven melting at their base. This study builds on previous work by using higher density satellite radar measurements, enabling far […]

Emissions from Thawing Peatland Permafrost 30-50% Greater than Previous Estimates

Proceedings of the National Academy of Sciences, August 10 Under high emissions scenarios, northern hemisphere permafrost and peatlands will show a 30-50% greater contribution to warming than previously projected, with emissions impacts equivalent to 1% of all anthropogenic radiative forcing this century – and this takes into account both peatland carbon uptake and permafrost thaw […]

Arctic Sea Ice More Sensitive to Emissions: Ice-Free Arctic During Last Interglacial Points to Rapid Future Loss

Nature Climate Change, August 10 The Arctic Ocean could be seasonally ice-free at temperatures only slightly above today’s, once land-based Arctic summer temperatures average 4 to 5°C above pre-industrial. This would occur by summer 2035 under high emissions scenarios; parts of the Arctic were already far warmer this summer. These new simulations using CMIP6, by […]

New Global Estimate of Rock-Debris Cover on Glaciers Helps Improve Projections of Glacier Melt and Sea Level Rise

Nature Geoscience, August 3 An updated approach is required to estimate the melting of global glaciers due to rock debris partially insulating the glaciers’ surface. As glaciers shrink, eroded rock from surrounding mountain slopes becomes exposed and slides down, forming a layer on the surface of glaciers which, if thick enough, reduces the rate at […]

Extreme Glacier Loss in New Zealand Undeniably Linked to Human-Caused Climate Change

Nature Climate Change, August 3 In New Zealand’s Southern Alps, anthropogenic forcing has made extreme loss of glacier ice at least 6 times more likely to occur in 2011 and 10 times in 2018 (>90% confidence). These were two of the highest mass-loss years ever recorded in that region. This increased likelihood is driven by […]

Canadian Ice Shelf Collapse in the Canadian Arctic, and Glacier Collapse in the Alps

Water and Ice Research Laboratory, August 7 This extremely warm summer is driving some dramatic collapses: one of the last remaining Canadian Ice Shelves, the Milne Ice Shelf lost 43% of its area (80 km2, greater than the size of Manhattan) in a dramatic collapse on July 31st, compromising nearby ecosystems as well as threatening […]

Emissions To-date Consistent with Worst-Case Scenario for Global Warming

Proceedings of the National Academy of Sciences, August 3 Despite recent progress on bending the emissions curve and the global pandemic, cumulative CO2 emissions measured between 2005 and 2020 place us on track (within 1%) of RCP8.5, the most aggressive scenario in assumed fossil fuel use. Between 2030 and 2050, human CO2 emissions will likely […]