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 […]

Increased Episodic Flooding by 2100 Under High Emissions Scenarios

Scientific Reports, July 30 Under the high emissions RCP8.5 scenario, and with no adaptation such as sea walls or inland migration, increases of 48% in total land area, 20% of global GDP and an additional 23 million people could face periodic risk of flooding by 2100, significantly increasing previous estimates. Regions in northwestern Europe, Asia, […]

Current Arctic Warming Closer to Past Abrupt Climate Events than Models

Nature, July 29 Over the past 40 years, the rate of change in large portions of the Arctic appears comparable to past rapid warming events, going back to the last interglacial period as reflected in this analysis of Greenland ice cores. These past warming events were typically characterized by warming rates of 1-2°C per decade […]

Record High Temperatures in Northernmost Arctic Human Settlements

While the Siberian heatwave drove large wildfires in July, other parts of the Arctic also saw record-breaking temperatures. On July 25, the town of Longyearbyen in Svalbard, an archipelago in the Norwegian High Arctic saw temperatures reach 21.7°C, breaking the previous record by 0.4°C; with daily temperatures exceeding 20°C for four days in a row. […]

First Active Methane Leak Observed off Antarctica

Proceedings of the Royal Society B, July 22. A team of scientists has discovered the first active leak of methane through the Antarctic seafloor, in the Ross Sea. Researchers monitored microbial communities that can consume the greenhouse gas before it reaches the atmosphere, and therefore play an important role within the methane cycle. Their work reveals […]

South Pole Warming Three Times the Global Average

Nature Climate Change, June 29. Surface air temperatures at the South Pole over the past 30 years, as measured at the Scott-Amundsen station and across the Antarctic plateau, reached record-high warming levels of 0.61 ± 0.34 °C per decade, more than three times the global average. Scientists found that stronger low-pressure systems in the Weddell Sea carry warmer […]

East Antarctic Ice Sheet Vulnerable to Melting Within Paris 2°C Goal

Nature, July 22 Large sections of the massive Wilkes Basin ice sheet of East Antarctica, holding 3-4 meters of SLR collapsed only 400,000 years ago, retreating over 700 km inland from the current ice margin – dispelling theories that it had been stable for millions of years. This glacial retreat, measured through traces of uranium-234 in […]

Climate Sensitivity to CO2 Emissions: More Accurate and Higher Level

AGU, July 21, 2020 Earth’s global “climate sensitivity” to CO2 emissions remains a fundamental question in predicting the future climate.  Until now, scientists relied on a 1979 estimate of 1.5‐4.5°C per doubling of atmospheric carbon dioxide (assuming no other climate forcing).  For the first time in 40 years, this consensus report – part of preparation […]

Global Methane Emissions Reach ‘Record High’ Levels

Global Methane Budget, 2000-2017 (2020), July 15, 2020. A new consensus update to global methane emissions reveals that atmospheric methane increased by 8.5ppb and 10.7ppb in 2018 and 2019, respectively – two of the highest annual values of the 21st century. The current concentration of atmospheric methane is more than 2.5 times higher than pre-industrial […]