Monday, July 27, 2020

Arctic sea ice could disappear completely within two months' time

Arctic sea ice fell by 3.239 million km² in extent in 25 days (i.e. from July 1 to 25, 2020). Melting will likely continue for another two months. If it continues on its current trajectory, the remaining 6.333 million km² of Arctic sea ice could disappear completely within two months' time.

The fall in extent over the next two months' time may not remain as as steep as it was in July, yet the sea ice still could disappear completely. One reason for this is that, over the years, sea ice thickness has been declining even faster than extent. The rapid decline in sea ice thickness is illustrated by the sequence of images below.

The image on the right further illustrates that sea ice is getting very thin, which threatens the latent heat tipping point to get crossed. 

Sea currents and the Coriolis force will make that the influx of warm, salty water into the Arctic Ocean will continue. With no buffer of sea ice left underneath the surface of the sea ice to absorb incoming ocean heat, more heat will accumulate in the Arctic Ocean, threatening that the methane hydrates tipping point will get crossed.

The animation below was run on August 3, 2020, and shows sea ice thickness over 30 days (last 8 frames are forecasts for August 4 - August 11, 2020). 

Here's another indication that the buffer is disappearing fast. North of Greenland and of the Canadian Arctic Archipelago, less than 700 km from the North Pole, the sea ice is disappearing, precisely where the thickest sea ice used to be located. 

High greenhouse gas levels are causing high temperatures over the Arctic and high ocean temperatures. 

On July 25, 2020, sea surface temperatures in the Arctic Ocean were as high as 20.8°C or 69.4°F (at the green circle on above image).

At that same location, on July 22, 2020, sea surface temperatures in the Arctic Ocean were as much as 17°C or 30.5°F higher than the daily average during the years 1981-2011. 

This location is where the Pechora River flows into the Barents Sea (the green circle pointed at by the white arrow on above image).

Distortion of the jet stream is causing more extreme weather, resulting in the recent lengthy heatwave over Siberia that has heated up the water of rivers flowing into the Arctic Ocean.

A cyclone was visible over the Arctic Ocean on July 28, 2020, as illustrated by the image on the right. 

Underneath on the right is a forecast for August 7, 2020, showing rain over the North Pole. 

In summary, Arctic sea ice may disappear completely over the next two months, and there are at least six reasons why this could occur:
• Low Arctic sea ice extent;
• Low Arctic sea ice thickness;
• High ocean temperature;
• High greenhouse gas levels;
• High temperatures over the Arctic;
• Distorted jet stream causing extreme weather such as storms that can break up the sea ice. 
As the image below shows, sea surface temperatures in the Arctic Ocean on August 1, 2020, were as much as 11.5°C or 20.7°F higher than 1981-2011 (at green circle, off the coast of Siberia, opposite Greenland). 

Ominously, the MetOp-1 satellite recorded peak methane levels of 2933 ppb, at 469 mb, on the afternoon of July 30, 2020.

The situation is dire and calls for immediate, comprehensive and effective action, as described in the Climate Plan.


• NSIDC Arctic sea ice

• Polar Portal - sea ice volume

• NASA Worldview

• Arctic Hit By Ten Tipping Points

• Fast Path to Extinction

• 2020 Siberian Heatwave continues

• Climate Plan

Thursday, July 9, 2020

Global warming and ice sheet melting: Portents of a Younger dryas-like stadial event

Global warming and ice sheet melting:
Portents of a Younger dryas-like stadial event
by Andrew Glikson

Linear climate projections by the IPCC are difficult to reconcile with the paleoclimate evidence of stadial cooling events which closely succeeded warming peaks, including the Younger dryas (12.9–11.6 kyr ago), Laurentian melt (~8.3 kyr) and earlier interglacial stadials. Each of these events followed peak interglacial temperatures, leading to extensive melting of the ice sheets and transient stadial cooling events. Current global temperature rises in the range of ~ +1.19 ± 0.13 °C (Northern Hemisphere) and higher in the Arctic are consistent with this pattern, leading to the build-up of ice melt pools south of Greenland and around Antarctica. The growth of these pools is likely to progress toward large-scale to a global stadial, inducing differential warming and cooling effects leading to major weather disruptions and storminess, possibly analogous to the Younger dryas and Laurentian melt events.

Linear temperature rise projections by the IPCC are unlikely in view of (1) amplifying feedbacks of greenhouse gases and global warming on land and ocean, and (2) stadial cooling effects due to the flow of ice melt water from the large ice sheets into the North Atlantic Ocean and the circum-Antarctic ocean (Figure 1). Apart from the absolute GHG level (~500 ppm CO₂-equivalent), the high rise rate of ~2-3 ppm CO₂/year and thereby temperature is driving dangerous weather events. The extreme rise in greenhouse gases in the atmosphere is evident from a comparison with past climate events (Figure 6). Linear temperature projections and thereby environment change are complicated by storminess due to collisions between air masses of contrasted temperatures. As the Arctic jet stream weakens, warm air currents from the south and freezing air masses from the north cross the boundary, a pattern already manifested by Arctic heat waves and fires and by penetration of freezing air masses into mid-latitudes, i.e. the “Beast from the East” snow storms. The increasing extent of cold ice melt pools around Greenland and Antarctica (Figure 1) suggest such a process is already in progress, signifying an onset of an interglacial stadial, as modelled by Hansen et al. 2016 and Bronselaer et al. (2016).

Figure 1 A. The cold ocean region south of Greenland visible on the NASA's 2015 global mean
temperatures (NASA/NOAA; 20 January 2016), the warmest year on record since 1880;
B. Circum-Antarctic summer surface temperatures, showing the large Weddell Sea and other
cold Sub-Antarctic ocean anomalies related to the flow of ice melt water into the ocean, and a seasonal
warming anomaly in the Ross Sea due to upwelling of warm salty water from the circum-Antarctic current.

Stadial events

Late Pleistocene climate cycles were controlled by orbital parameters of the Milankovitch cycles including eccentricity (~100,000 years), obliquity to the ecliptic plane (~41,000 years) and precession/wobble of the Earth’s axis (~19,000 and ~23,000 years). The Younger dryas of 12,900 to 11,600 years ago following the Allerod BÖlling warm peak and marked by cooling of near -20°C in Greenland and (Figure 2A, B), has major implications for climate change projections for the 21-23rd centuries.

The Younger dryas is the longest of three late Pleistocene stadials (Figure 2A) associated with abrupt climatic changes that took place over the last 16,000 years. According to Steffensen et al. 2008 based on deuterium isotopes in ice cores the abrupt onset of the Younger dryas in Greenland occurred over less than 1 year and ended over less than 3 years (Figure 2B), or about 50 years based on stable water isotopes representing the air temperature record. Evidence for the effects of the Younger dryas stadial has also been identified in tropical and subtropical regions (Shakun and Carlson, 2010) (Figure 3). The underlying factors for the Younger dryas and Laurentian (Figure 4) stadial events are the deglaciation of Northernmost America, flow of cold ice melt water into the North Atlantic Ocean and into North American lakes (Lake Agassiz), and the retreat southward of the North Atlantic Thermohaline Current.

Suggestions of a comet impact origin of the Younger dryas are inconsistent with (1) the recurrence of stadial events following peak interglacial temperatures over the last 420,000 years (Figure 5) and (2) the paucity of clear evidence for a large extraterrestrial impact contemporaneous with the Younger dryas, including the little known age of the radar-detected crater below the Hiawatha Glacier In northwest Greenland.

Figure 2A Air temperatures at the Last glacial maximum (20-16 kyr), BÖlling-Allerod warm peak,
Younger dryas (12,900 to 11,600 years ago) and 8.2 kyr Laurentian stadial event. This image
shows temperature changes, determined as proxy temperatures, taken from the central region

of Greenland's ice sheet during the Late Pleistocene and beginning of the Holocene.

Figure 2B. deuterium evidence for onset cooling temperature and terminal
warming of the Younger dryas stadial event (14,740-11,660) (Steffensen et al. 2008).

Figure 3. Magnitude of late Holocene glacial-interglacial temperature changes
in relation to latitude. Black squares are the Northern Hemisphere (NH),
gray circles the Southern Hemisphere (SH) (Shakun and Carlson, 2010).

The youngest recorded stadial, the Laurentian melt, between ~8,500 and ~8.000 years ago (Figure 4), is indicated by distinctive temperature–CO₂ correlation with global CO₂ decline of ≈25 ppm by volume over ≈300 years, consistent with the lowering of North Atlantic sea-surface temperatures and weakening of the AMOC (Atlantic Meridional Ocean Circulation).

Figure 4 A. The ~8.2 kyr Laurentian stadial event in a coupled climate model (Wiersma et al. 2011);
B. Reconstructed CO₂ concentrations for the interval between ~8,700 and ~6,800 BP, based on
CO 2 extracted from air in Antarctic ice of Taylor Dome (Wagner et al. 2002).
The Younger dryas and the Laurentian stadials are not unique, as peak temperatures in every interglacial event over the last 420,000 years were followed by sharp cooling events (Figure 5). Apart from the absolute level of greenhouse gases (GHG) in the atmosphere the high rate at which GHG concentrations are rising, as shown by comparisons with previous extreme warming events (Figure 6), enhances extreme weather events, as well as retards the ability of fauna and flora to adapt to the new conditions.

Figure 5 (a) Evolution of sea surface temperatures in five glacial-interglacial transitions recorded in
1089 at the sub-Antarctic Atlantic Ocean (Cortese et al. 2007). Grey lines – δ 18 O measured on
Cibicidoides plankton; Black lines – sea surface temperature. Marine isotope stage numbers are 
indicated on top of diagrams. Note the stadial following interglacial peak temperatures; (b) the last 
glacial maximum and the last glacial termination. Olds- Oldest dryas; Old – Older dryas; Yd – Younger dryas.

Figure 6 (A) Reconstructed atmospheric CO₂ variations during the Late Cretaceous–early Tertiary
derived from the Stomata indices of fossil leaf cuticles calibrated by using inverse regression
and stomatal ratios (Beerling et al. 2002);
(B) Simulated atmospheric CO₂ at and after the Palaeocene-Eocene boundary (after Zeebe et al. (2009).
Compare the CO₂ ppm/year values with the current rise of 2 to 3 ppm/year;
(C) Global CO₂ and temperature during the last glacial termination (After Shakun et al., 2012)
(LGM - Last Glacial Maximum; OD – Older dryas; BA - Bølling–Allerød; YD - Younger dryas);

The average global land and ocean surface temperature for March 2020 was 1.16°C above the 20th century average global level of 12.7°C. Current CO₂ rise and warming rates exceed that of the Last Glacial Termination (LGT) (21–8 kyr) (Figure 6C), the Paleocene-Eocene Thermal Maximum (PETM) (55.9 Ma) (Figure 6B) and the Cretaceous-Tertiary boundary (K-T) (64.98 Ma) impact event (Figure 6A). The relations between warming rates and the migration of climate zones toward the poles (Figure 7), including changes in the atmosphere and ocean current systems, are in the root of the major environmental changes in these zones.
Figure 7. Expansion of the tropical African climate zone (vertical red lines) into subtropical and Mediterranean
climate zones to the north and south (Migration, Environment and Climate Change, International Organization
for Migration, Geneva, Switzerland (Regional Maps on Migration, Environment and Climate Change.

Future Stadial events

IPCC climate change projections for 2100-2300 portray linear to curved temperature progressions (SPM-5). However, amplifying feedbacks and transient cooling events (Stadials) ensuing from the flow of ice melt water into the oceans during peak interglacial warming events, impose abrupt temperature variations (Figure 5). The current flow of ice melt water from Greenland and Antarctica (Figures 8, 9) is leading to regional ocean cooling in the North Atlantic and around Antarctica (Rahmstorf et al, 2015; Hansen et al. (2016); Bronselaer et al. 2018; Purkey et al. 2018; Vernet et al. 2019) (Figures 1, 8). Under high greenhouse gas and temperature rise trajectories (RCP8.5) this implies future stadial events as modelled by Hansen et al. (2016) (Figure 10) and Bronselaer et al. (2018) (Figure 11).

Depending on different greenhouse emission scenarios (IPCC 2019; van Vuren et. al. (2011), including the CO₂ forcing-equivalents of methane (CH4) and nitrous oxide (N2O), the total CO₂–equivalent rise has reached 496 ppm (NOAA, 2019). As the oceans heat contents is rising, upwelling of warm sublayers is melting the leading edges of continental glaciers (Figure 8). This factor and the flow of ice meltwater from leading glacier fronts and grounding lines lead to stratification of the sub-Antarctic ocean and an incipient onset of a southern ocean stadial (Figure 8).

Figure 8. The transition from grounded ice sheet to floating ice shelf and icebergs

Figure 9. Greenland and Antarctic ice mass change. GRACE data are extension of Velicogna et al. (2014)
gravity data. MBM (mass budget method) data are from Rignot et al. (2011). Red curves are gravity data
for Greenland and Antarctica only; small Arctic ice caps and ice shelf melt add to freshwater input.
Satellite and mass balance measurements of the large ice sheets indicate their rapid reduction (Figure 9). Variations in ice thickness, ice drainage and ice velocity data in 176 Antarctic basins between 1979 and 2017 indicate a total mass loss rise from 40 ± 9 Gt/year in 1979–1990 to 50 ± 14 Gt/year in 1989–2000, 166 ± 18 Gt/year in 1999–2009, and 252 ± 26 Gt/year in 2009–2017 (Figure 9). This amounts to an increased melting by more than 6-fold in about 40 years, contributing an average sea level rise of 3.6 ± 0.5 mm per decade, with a cumulative 14.0 ± 2.0 mm since 1979 (Rignot et al. 2019). The mass loss concentrated in areas closest to warm, salty, subsurface, circumpolar deep water (CDW), consistent with enhanced polar westerlies pushing CDW toward Antarctica.

The Greenland ice sheet contains approximately 2,900,000 GtI of ice. During the exceptionally warm Arctic summer of 2019, Greenland lost 600 GtI of ice. Under global GHG and temperature rise this rate is likely to be exceeded. The Greenland ice sheet may not last much longer than a Century. The Antarctic ice sheet weighs approximately 26,500 Gigaton. For a loss greater than ~250 GtI/year it could last for 105 years or less. For accelerated ice melt rates under rising GHG concentrations it could last for significantly shorter time, except for possible negative feedbacks associated with stadial cooling?

Hansen et al. (2016) suggest that, depending on ice melt rates of the polar ice sheets, transient cooling events (stadials) can be expected to develop over periods dependent on the rates of ice melt (Fig. 10). Stadial cooling of about -2°C lasting for several decades (Figure 10) may affect temperatures in Europe and North America. The model is consistent with a slowdown of the Atlantic Meridional Ocean Circulation (AMOC) (Weaver et al. 2012) and the exceptional growth of a cold water region southeast of Greenland, (Rahmstorf et al, 2015).
Figure 10. A. Model surface air temperature (◦C) change in 2096;
B. Surface air temperature (◦C) relative to 1880–1920 for several ice melt scenarios.

According to Bronselaer et al. (2018) temporal evolution of the global-mean surface-air temperature (SAT) shows meltwater-induced cooling translates to a reduced rate of global warming (Fig. 11), with a maximum divergence between standard models and models which include the effects of meltwater-induced cooling of 0.38 ± 0.02°C in 2055. As stated by the authors “We demonstrate that the inclusion in the model of ice-sheet meltwater reduces global atmospheric warming, shifts rainfall northwards, and increases sea-ice area”, and “Antarctic meltwater is therefore an important agent of climate change with global impact, and should be taken into account in future climate simulations and climate policy.”
Figure 11. The 2080–2100 meltwater-induced sea-air temperature anomaly relative to the standard
RCP8.5 ensemble. Hatching indicates where the anomalies are not significant at the 95% level.


Based on the paleoclimate record, global warming, penetration of cold and warm air masses across weakened polar boundaries, increased ice melting rates, sea level rise and near-surface cooling of large ocean tracts (Figures 10, 11), collisions between warm and cold air and water masses and thereby storminess are likely to determine the future climate of large parts of Earth. With rising greenhouse gas levels and their amplifying feedbacks from land and oceans these developments are likely to persist in the long term. The continuing migration of climate zones toward the poles is likely to be disrupted by developing stadial effects and differential warming and cooling effects, leading to major weather disruptions and storminess. Continuing release of greenhouse gases and their amplifying feedbacks could lead to tropical Miocene-like conditions about 4 to 5 degrees Celsius warmer than late Holocene climate conditions which allowed agriculture and thereby civilization to emerge.

Andrew Glikson
Dr Andrew Glikson
Earth and Paleo-climate scientist
ANU Climate Science Institute
ANU Planetary Science Institute
Canberra, Australia

The Asteroid Impact Connection of Planetary Evolution
The Archaean: Geological and Geochemical Windows into the Early Earth
Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene
The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth
Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon
From Stars to Brains: Milestones in the Planetary Evolution of Life and Intelligence
Asteroids Impacts, Crustal Evolution and Related Mineral Systems with Special Reference to Australia

Wednesday, July 8, 2020

Arctic Sea Ice at Record Low for Time of Year

As temperatures keep rising, should the IPCC raise the alarm?

Some 1,750 jurisdictions in 30 countries have now declared a climate emergency, according to this post dated July 8, 2020. The United Nations does acknowledge the Climate Emergency, but its description is sourced from the IPCC Global Warming of 1.5°C report that was approved back in 2018. A lot has happened since, as described in many posts at Arctic-news. When a state of emergency is declared, doesn't one expect such a declaration to result in action, complete with updates on the effectiveness of the action?

Described below are some events taking place right now.

Arctic Sea Ice at Record Low for Time of Year

Arctic sea ice looks set to reach an all-time record low in September 2020.

In an earlier post, Paul Beckwith describes a Blue Ocean Event (BOE) and some of the consequences of the changes taking place in the Arctic. A BOE occurs when sea ice extent gets below 1 million km², which is important regarding the amount of sunlight absorbed/reflected in the Arctic (albedo feedback).

[ from earlier post ]
Arctic sea ice extent on July 20, 2020, was well below the minimum of the 1979-1990 average (the orange line among the blue lines on the image below).

If it continues on its current trajectory, Arctic sea ice may well be gone altogether in September 2020.

A BOE is one of the many tipping points that threaten to get crossed in the Arctic.

[ click on images to enlarge ]
As illustrated by the image on the right, sea ice is getting very thin, which threatens the latent heat tipping point to be crossed, meaning there is no buffer of sea ice left underneath the surface of the sea ice to absorb ocean heat.

Furthermore, the temperature rise in the Arctic is accelerating and the Arctic Ocean is getting very hot, threatening that the methane hydrates tipping point will get crossed.

The animation below run on July 20, 2020, shows the fall in sea ice thickness over 30 days (last 8 frames are forecasts for July 21-28, 2020).

The combination image below illustrates the speed at which Arctic sea ice is disappearing, with sea ice thickness shown in meters from left to right at June 1, June 18, July 1 and July 18, 2020.

Meanwhile, fires and smoke are visible at a distance of as little as 1970 km or 1224 miles from the North Pole.

The image below shows open water on the edge of the sea ice, north of Greenland and the Canadian Archipelago, where the thickest sea ice used to be located.

Alarming acceleration of heating continues

The image below shows the global temperature rise through to June 2020.
[ click on images to enlarge ]
The red trend supports fears that the 2°C above preindustrial threshold has already been crossed this year, while loss of the aerosol masking effect and an emerging El Niño could trigger a huge further temperature rise.

Global temperature anomalies are typically lower in June (yellow circles) than the annual anomaly. The Copernicus image below shows twelve-month averages of global-mean surface air temperature anomalies relative to 1981-2010.

The shape of current anomalies is very similar to the peak reached around 2016. This is alarming because the peak around 2016 was reached under El Niño conditions, whereas the current temperatures are reached under conditions that are leaning toward La Niña, as illustrated by the images below.

In conclusion, one may wonder how much stronger the temperature rise will be once El Niño conditions do arrive.

[ click on images to enlarge ]
Furthermore, one may wonder how much current temperatures are elevated by a decrease in emissions due to COVID-19 restrictions, which in turn makes one wonder how much higher the temperature will be when the aerosol masking effect will fall away even further as the world phases out coal-fired power plants, bunker oil for shipping, etc. Guy McPherson concludes that a 1°C rise in global-average temperature will occur within a few days or weeks after industrial activity is reduced by as little as 20%.

Very high sea surface temperature anomalies in the Arctic Ocean

Sea surface temperature anomalies in the Arctic Ocean are very high. As discussed in a recent post, sea surface temperatures in the Bering Strait were as much as 15.1°C or 27.2°F hotter than 1981-2011 on June 20, 2020 (in Norton Sound, Alaska, at the green circle).

As the image below shows, the sea surface temperature at green circle used to be 0.3°C (32.6°F). It was 12°C (53.6°F) on July 18, 2020.

Much of the Arctic Ocean is quite shallow, making that the water can warm up very quickly during summer heat peaks and heat can reach the seafloor, which comes with the risk that heat will penetrate cracks in sediments at the seafloor. Melting of ice in such cracks can lead to abrupt destabilization of methane hydrates contained in sediments.

Very high peak methane levels

Ominously, as the 2020 Siberian heatwave continues, very high peak methane levels show up over the Arctic Ocean. The NOAA 20 satellite recorded a peak methane level of 2728 ppb at 399 mb on the afternoon of July 16, 2020.

The MetOp-1 satellite recorded a peak methane level of 2726 ppb on the afternoon of July 16, 2020. Also, a mean methane level of 1897 ppb was recorded at 469 mb and a mean methane level of 1908 ppb at 293 mb.

The situation is dire and calls for immediate, comprehensive and effective action, as described in the Climate Plan.


• Arctic Data archive System

• Polar Portal - sea ice volume

• Fast Path to Extinction

• NASA Worldview

• Surface air temperature for June 2020

• ENSO: Recent Evolution, Current Status and Predictions - NOAA, July 6, 2020

• Arctic Hit By Ten Tipping Points

• The Myth of Sustainability - by Guy McPherson

• 2020 Siberian Heatwave continues

• Climate Plan