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 […]

Loss of Outdoor Ice Skating in Coming Decades

The Canadian Geographer, July 16 Outdoor ice-skating is an important cultural pastime in many northern regions and holds a firm foothold in North American identity. Using citizen science data collected in six cities across Canada and the US, researchers estimated backyard skating conditions in past winters for which historical observations do not exist. They found […]

Arctic Ocean Experiences Significant Shifts in its Ecological Structure

Science, July 10 Growth of phytoplankton biomass in the Arctic Ocean increased by 57% between 1998 and 2018. This surge in biomass at the base of the food chain was triggered in part by retreating Arctic sea ice and the influx of new nutrients from adjoining oceans. In the future, the compositions of European and […]

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