Arctic News: melt

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Friday, December 22, 2023

Too late to save the climate?

by Andrew Glikson

“Without major action to reduce emissions, global temperature is on track to rise

by 2.5°C to 4.5°C by 2100” (NASA 2023)

“We Will Not Sign Our Own Death Warrant” (a delegate at COP28)

Whether anything can be done by humans to arrest or reverse global warming and its consequences for the habitability of planet Earth remains an open question, for which neither climate science nor the ignorant hordes of politicians and economists, oblivious to the basic laws of physics, have the answer. However, it is likely that over the next centuries or longer the flow of cold water from the melting of the Greenland and Antarctica ice sheets will lead to a transient slowdown of the rate of warming before the large ice sheets are exhausted.

Having ignored climate science, dismissed climate scientists and repeatedly confected untruths, while global heating accelerates with deleterious consequences, Homo “sapiens” finds itself on track toward carbon poisoning of the atmosphere, the lungs of the inhabitable Earth, acidification of the hydrosphere and coating of the land with carbon and plastics.

In a new paper, a group of leading climate scientists (Hansen et al., 2023) indicates mean global temperature is currently accelerating toward 2.0°C above pre-industrial temperature by the middle of the decade (Figure 1). The Arctic is warming nearly four times faster than the rest of the world over the last 43 years, on average around 3℃ warmer than it was in 1980. Over the past 30 years Antarctica has been one of the fastest-changing places on Earth, warming more than 3 times faster than the rest of the world.

[ Figure. 1. Global temperature relative to 1880-1920 based on the GISS
(Goddard Institute of Space Studies) analysis - by James Hansen et al., 2023. ]

As the polar regions warm, the tropical climate zones expand and the mid-latitudes, where the most fertile soils are and where the bulk of the population lives, are contracting.

Thus (Figure 2.):

Agro-climate zones in eastern Europe experienced a northward migration velocity of 100 km per 10 years over the past 40 years.
Northward migration of climate zones in Europe may be up to two times faster in the next decades.
Negative impacts of heat stress are expected to non-linearly increase in large parts of southern and southeastern Europe.

[ Figure 2. (a) Agro-climate zonation of Europe based on growing season length (GSL) and active temperature sum (ATS) for the period between 1975 and 1995.The identified agro-climate zones are named as follows (going from north to south): boreal north (BON), boreal south (BOS), nemoral (NEM), continental (CON), Pannonian (PAN), northern maritime (NMA), southern maritime (SMA) and Mediterranean (MED). (b) The migration of agro-climate zones between the 1975–1995 and 1996–2016 periods. For better distinction, only the areas affected by migration of agro-climate zones are displayed (colored areas), while gray color denotes the areas where the agro-climate zones have not changed - Ceglar et al. 2019. ]

A projection by NOAA states: “While we cannot stop global warming overnight, we can slow the rate and limit the amount of global warming by reducing human emissions of heat-trapping gases and soot (“black carbon”). This projection takes neither the amplifying feedback, i.e. from warming of the oceans, melting ice sheets, melting of the permafrost, migrating climate zones, nor the time factor into account.

Factors rendering a potential reversal of global warming in the short term unlikely include:

The rise of mean global heating above a level of ~1.5^oC and much higher at the poles above pre-industrial temperatures, polar-ward migration of climate zones, melting of the Greenland and Antarctic ice sheets, intensification of extreme weather events, requiring major cooling of the Earth, which is unlikely within the time frame of a tribal-conflicted civilization.
Where scientific breakthroughs would allow effective climate mitigation, for example global cooling by CO₂ drawdown, it is questionable whether Homo sapiens ─ recorded by history as an invasive blood-stained tribal species ─ would be able to avoid destroying its home planet.

The apparent absence of radio signals from technological civilizations in the Milky Way may suggest that advanced civilizations tend to undergo self-destruction, consistent with local observations, referred to as the “Fermi Paradox”.

A factor rarely taken into account emerges from the key paper “Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modelling, and modern observations that 2°C global warming could be dangerous”, by Hansen et al. (1996) (Figure 3.).

[ Figure 3. Surface air temperature (°C) relative to 1880-1920 for several scenarios - by James Hansen et al. 2016. ]

Here the flow of cold ice-melt water results in formation of large cold pools in the Atlantic Ocean and Southern Ocean (Figure 3), related to an overall decline in mean global temperatures to -0.33°C by 2096 (Figure 4.) due to the flow of cold ice-melt water from Greenland and Antarctica.

While the collision between the cold air and water fronts and the tropical war air mass would lead to intense storms over large tracts of Earth, such transient cooling may allow Home "sapiens" a respite from global warming before its home becomes an uninhabitable planet.

[ Figure 4. Surface air temperature (◦C) relative to 1880–1920 in (a) 2065, (b) 2080, and (c) 2096. Top row is IPCC scenario A1B. Ice melt with 10-year doubling is added in other scenarios - James Hansen et al. 2016. ]

A/Prof. Andrew Y Glikson
Earth and Paleo-climate scientist

Andrew Glikson

Books:

The Asteroid Impact Connection of Planetary Evolution
https://www.springer.com/gp/book/9789400763272
The Archaean: Geological and Geochemical Windows into the Early Earth
https://www.springer.com/gp/book/9783319079073
The Plutocene: Blueprints for a Post-Anthropocene Greenhouse Earth
https://www.springer.com/gp/book/9783319572369
The Event Horizon: Homo Prometheus and the Climate Catastrophe
https://www.springer.com/gp/book/9783030547332
Climate, Fire and Human Evolution: The Deep Time Dimensions of the Anthropocene
https://www.springer.com/gp/book/9783319225111
Evolution of the Atmosphere, Fire and the Anthropocene Climate Event Horizon
https://www.springer.com/gp/book/9789400773318
From Stars to Brains: Milestones in the Planetary Evolution of Life and Intelligence
https://www.springer.com/us/book/9783030106027
Asteroids Impacts, Crustal Evolution and Related Mineral Systems with Special Reference to Australia
https://www.springer.com/us/book/9783319745442
The Fatal Species: From Warlike Primates to Planetary Mass Extinction
https://www.springer.com/gp/book/9783030754679
The Trials of Gaia. Milestones in the evolution of Earth with reference to the Antropocene
https://www.amazon.com.au/Trials-Gaia-Milestones-Evolution-Anthropocene/dp/3031237080

Friday, August 15, 2014

Heatwave to hit Greenland

A heatwave with temperature anomalies exceeding 36°F (20°C) is expected to hit Greenland between August 16 and 22, 2014, as illustrated by the image on the left and the animation on the right.

Such heatwaves can be expected to hit the Arctic more frequently and with greater intensity, as temperatures in the Arctic are rising faster than elsewhere on Earth.

Such heatwaves can result in massive melting on Greenland, as persistent heat changes the texture of the snow and ice cover, in turn reducing its reflectivity. This makes that less sunlight is reflected back into space and is instead absorbed.

The image below illustrates what a difference the presence of sea ice can make.

from: Arctic Warming due to Snow and Ice Demise

As the NSIDC/NOAA graphs below shows, melting on Greenland has been relatively modest this year when compared to the situation in 2012. By July 12, 2012, 97% of the ice sheet surface had thawed, according to this NASA analysis and this NOAA Arctic Report Card.

Melting on Greenland directly affects sea level rise, and melting on Greenland is accelerating due to a number of factors.

Projections of melting on Greenland have long been based on a warming atmosphere only, ignoring the warmer waters that lubricate glaciers and that warm Greenland's bedrock canyons that sit well below sea level.

Furthermore, there are growing quantities of black carbon deposits as a result of burning of fossil fuel and biomass. High temperatures have recently caused ferocious wildfires in Canada that have in turn caused a lot of black carbon to go up high into the atmosphere.

And of course, the atmosphere over the Arctic is warming up much faster than most models had projected. This in turn causes triggers further feebacks, including more extreme weather events such as heatwaves and rain storms that can be expected to hit Greenland with ever more frequency and ferocity. Further feedbacks include methane eruptions from the heights of Greenland, as discussed at the Arctic Feedbacks Page.

When also taking into account the accelerating impact of such factors on melting in Greenland, sea levels could rise much faster than anticipated, as illustrated by the image below.

from: more than 2.5m sea level rise by 2040?

Note that sea level rise is only one of the many dangers of global warming, as discussed in the 2007 post Ten Dangers of Global Warming.

The image on the right shows a temperature forecast for August 16, 2014, with parts of Greenland changing in color from blue into green, i.e. above the melting point for snow and ice.

Such high temperatures are now hitting locations close to the North Pole ever more frequently, due to the many feedbacks that are accelerating warming in the Arctic, as discussed at this Feedbacks page.

One of the most dangerous feedbacks is a sudden eruption of huge quantities of methane from the seafloor of the Arctic Ocean, as discussed in a recent post.

The impact of such feedbacks can be accumulative and interactive, resulting in self-reinforcing feedbacks loops that can escalate into runaway warming.

Below is another forecast by ClimateReanalyzer for August 16, 2014, showing the remarkable ‘greening’ of Greenland, as well as the very high temperatures reaching the higher latitudes of North America.

Also see the very high sea surface temperatures around Greenland on the image below, created with ClimateReanalyzer.

Sea surface temperature anomalies on August 15, 2014.

In conclusion, the situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan blog.

Post by Sam Carana.

Tuesday, July 29, 2014

More than 2.5m Sea Level Rise by 2040?

A warming period more than 400,000 years ago pushed the Greenland ice sheet past its stability threshold (which may have been no more than several degrees above pre-industrial temperatures). This resulted in a nearly complete deglaciation of southern Greenland, raising global sea levels some 4.5-6 meters, found a recent study by Reyes et al. Due to melting elsewhere, global mean sea level then was 6 to 13 metres above the present level. Indeed, melting of the entire West Antarctic Ice Sheet can add a further 6-meter rise in sea levels. If the East Antarctic Ice Sheet (EAIS) were to melt as well, sea levels would rise by around 70 metres.

Sea level is now rising by 3.1mm (0.122 inch) per year. Much of this rise is due to rising temperatures, but there are also other factors. One quarter of the rise results from groundwater depletion, while run off from melting ice and glaciers adds another quarter and the remainder is attributed to thermal expansion of sea water. Furthermore, as temperatures rise, feedbacks start to kick in, e.g. the kinetic energy from stronger waves and more intense storms can speed things up.

Clearly, a rapid multi-meter rise would be devastating as it would flood many coastal cities, as well as much of the land now used to grow food. By how much have sea levels been rising recently and how fast can they be expected to rise in the near future?

NASA image, data by the JPL PODAAC, in support of the NASA's MEaSUREs program.

Sea levels have risen by some 60 mm over the past 20 years, as above NASA image shows, which has a linear trendline added. The question is whether a linear trendline is the most appropriate trendline, given that it suggests that a similar rise could be expected over the next 20 years. A polynomial trendline appears to fit the data better, as the animation below shows.

Such a polynomial trendline, however, points at a similar rise (of some 50 mm) in just four years time, with an even more steeper rise to follow, as illustrated by the image below.

And indeed, such a rise doesn't slow down there. A polynomial trendline applied to the data points at a sea level rise of more than 2.5 m (8.2 ft) by the year 2040.

The image below gives an idea of what a sea level rise of six feet (1.829 m) would do to the City of New York. Of course, this is only the sea level rise. Storm surge would come on top of this, as discussed at Ten Dangers of Global Warming.

So, what would be more appropriate, to expect sea levels to continue to rise in a linear way, or to take into account feedbacks that could speed things up? Where such feedbacks could lead to is illustrated by the image below.

[ from: How many deaths could result from failure to act on climate change? click on image to enlarge ]

This calls for comprehensive and effective action, as discussed at the Climate Plan blog.

References

- South Greenland ice-sheet collapse during Marine Isotope Stage 11, Reyes et al. (2014)
http://www.nature.com/nature/journal/v510/n7506/full/nature13456.html

- Nonsustainable groundwater sustaining irrigation: A global assessment, Yoshihide Wada et al. (2012)
http://onlinelibrary.wiley.com/doi/10.1029/2011WR010562/abstract

- Groundwater Depletion Linked to Rising Sea Levels
http://www.waterworld.com/articles/2010/11/groundwater-depletion-linked-to-rising.html

- Assessment of the Jason-2 Extension to the TOPEX/Poseidon, Jason-1 Sea-Surface Height Time Series for Global Mean Sea Level Monitoring, Beckley et al. (2010)
http://www.tandfonline.com/doi/abs/10.1080/01490419.2010.491029

- Feedbacks in the Arctic
http://climateplan.blogspot.com/p/feedbacks.html

- How many deaths could result from failure to act on climate change? (2014)
http://arctic-news.blogspot.com/2014/05/how-many-deaths-could-result-from-failure-to-act-on-climate-change.html

Post by Sam Carana.

Saturday, April 5, 2014

River ice reveals new twist on Arctic melt

A new study led by Lance Lesack, a Simon Fraser University geographer and Faculty of Environment professor, has discovered unexpected climate-driven changes in the mighty Mackenzie River’s ice breakup. This discovery may help resolve the complex puzzle underlying why Arctic ice is disappearing more rapidly than expected.

Lance Lesack,
photo by Simon Fraser University

Lesack is the lead author on Local spring warming drives earlier river-ice breakup in a large Arctic delta. Published recently in Geophysical Research Letters, the study has co-authors at Wilfrid Laurier University, the University of Alberta and Memorial University.

Its goal was to understand how warming global temperatures and the intensifying Arctic hydrological cycle associated with them may be driving increasing water discharges and more rapid ice breakup in the Arctic’s great rivers.

But the researchers stumbled upon an unexpected phenomenon while trying to figure out why the Mackenzie River’s annual ice breakup has been shortening even though its water discharge isn’t increasing, as in Russian rivers.

Just slightly warmer springs with unexpected snowfall declines — rather than warmer winters or increasing river discharge, as previously suspected — can drive earlier-than-expected ice breakup in great Arctic rivers.

The Mackenzie exemplifies this unexpected phenomenon. The researchers discovered this by accessing records dating back to 1958 of the river’s water levels, snow depths, air temperatures and times of ice breakup.

This finding is significant, as Arctic snow and ice systems are important climate-system components that affect the Earth’s ability to reflect solar radiation.

Mackenzie delta river, before (top) and after
(bottom, one day later) onset of dynamic ice
breakup in the central Mackenzie's delta middle
channel. Photos by Simon Fraser University.

“Our surprising finding was that spring temperatures, the period when river-ice melt occurs, had warmed by only 3.2 degrees Celsius. Yet this small change was responsible for more than 80 per cent of the variation in the earlier ice breakups, whereas winter temperatures had warmed by 5.3 degrees but explained little of this variation,” says Lesack.

“This is a strong response in ice breakup for a relatively modest degree of warming, but further investigation showed that by winter’s end snow depths had also declined by one third over this period. The lesser snow depths mean less solar energy is needed to drive ice breakup.”

Lesack says this is the first field-based study to uncover an important effect of reduced winter snowfall and warmer springs in the Arctic — earlier-than-expected, climate-change-related ice breakup.

“The polar regions have a disproportionate effect on planetary reflectivity because so much of these regions consist of ice and snow,” says Lesack. “Most of the planetary sea ice is in the Arctic and the Arctic landmass is also seasonally covered by extensive snow. If such ice and snow change significantly, this will affect the global climate system and would be something to worry about.”

Lesack hopes this study’s findings motivate Canadian government agencies to reconsider their moves towards reducing or eliminating ground-based monitoring programs that measure important environmental variables.

There are few long-term, ground-based snow depth records from the Arctic. This study’s findings were based on such records at Inuvik dating back to 1958. They significantly pre-dated remote sensing records that extend back only to 1980. Without this longer view into the past, this study’s co-authors would still be in the dark about the more rapid than expected Arctic melt and planetary heat-up happening.

Arctic Death Spiral - Evolution to July 2013

Image by Andy Lee Robinson, from http://haveland.com/share/arctic-death-spiral.png

The video below is a visualization of the Arctic Death Spiral showing the evolution of the volume of sea-ice over time from 1979 to July 2013.

The rate of ice loss in the Arctic is staggering. Since 1979, the volume of Summer Arctic sea ice has declined by more than 80% and is accelerating faster than scientists believed it would, or even could melt.

Pitch of the notes are proportional to the average sea-ice volume for each month. Spectral filters are derived from the average sea-ice volume for each year. Produced using Perl and PovRay, Midi perl and Reason and Virtualdub on a cluster of Linux servers.

Above image is another way to visualize the data. It is a screenshot from the video below, by Andy Lee Robinson, illustrating the dramatic decline since 1979 until July 2013.

Andy Lee Robinson

The soundtrack "Arctic Requiem" also by Andy Lee Robinson, is available for free download: http://haveland.com/share/Arctic-Requiem.mp3

Sea Ice Volume is calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) developed at APL/PSC.

Source data is available from:
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

http://www.youtube.com/watch?v=oFMDmS783Ro

Thursday, February 7, 2013

Arctic Sea ice Volume and Greenland Melt Update

Arctic Sea Ice Volume

The image below, from the ArctischePinguin site, shows the current volume of Arctic sea ice, updated with PIOMAS data from the Polar Science Center of the University of Washington.

As the above image shows, a minimum volume of 3000 cubic km is expected to be reached in September 2013 (red dotted line), with a margin of error that allows for the sea ice to disappear altogether in a few months time.

The image below updates the exponential trends for each month.

Greenland Melt

Meanwhile, the National Snow and Ice and Data Center (NSIDC) has started a page with daily updates of the extent of the Greenland melt. The image below pictures the Greenland melt in 2012 on the left, and the situation up to February 6, 2013 on the right.

Friday, December 28, 2012

Albedo changes in the Arctic

How global warming and feedbacks are causing huge albedo changes in the Arctic.

Snow cover decline

Decline of the snow cover on land in the northern hemisphere is accelerating, as illustrated by the image below and the image underneath on the right. (1)

Image credit: Rutgers University

Fresh snow can have an albedo as high as 0.85, meaning that up to 85% of the sunlight falling on snow can get reflected back into space. As the snow melts, its structure changes making it less reflective, i.e. its albedo will go down, to as low as 40%. (2)

As a result, more sunlight gets absorbed, accelerating the melting process. Eventually, where snow melts away, spots of bare soil become exposed, and dark wet soil has a very low albedo, reflecting only between 5% and 15% of the sunlight. Thus, even more sunlight gets absorbed and the soil's temperature increases, causing more of the remaining snow to melt. (2)

Changes in vegetation can further accelerate this process. Russia's boreal forest - the largest continuous expanse of forest in the world - has seen a transformation in recent years from larch to conifer trees. Larch trees drop their needles in the fall, allowing the vast, snow-covered ground in winter to reflect sunlight and heat back into space and helping to keep temperatures in the region very cold. But conifers such as spruce and fir retain their needles, which absorb sunlight and increase the forest's ground-level heat retention. (3)

Albedo, from Wikipedia

A conversion from larch to evergreen stands in low-diversity regions of southern Siberia would generate a local positive radiative forcing of 5.1±2.6 W m−2. This radiative heating would reinforce the warming projected to occur in the area under climate change. (4)

Tundra in the Arctic used to be covered by a white blanket of snow most of the year. However, as the landscape is warming up, more trees and shrubs appear. Scientists who studied part of the Eurasian Arctic, found that willow and alder shrubs, once stunted by harsh weather, have been growing upward to the height of trees in recent decades. They now rise above the snowfall, presenting a dark, light-absorbing surface. This increased absorption of the Sun's radiation, combined with microclimates created by forested areas, adds to global warming, making an already-warming climate warm even more rapidly. (5 & 6)

Furthermore, encroachment of trees onto Arctic tundra caused by the warming may cause large release of carbon to the atmosphere, concludes a recent study. This is because tundra soil contains a lot of stored organic matter, due to slow decomposition, but the trees stimulate the decomposition of this material. (7)

Sea ice decline

In the Arctic, sea ice volume has fallen dramatically over the years, as illustrated by the image on the right. The trend points at 2014 as the year when Arctic sea ice will first reach zero volume for some time during that year. (8)

The Arctic Ocean looks set to be ice-free for a period of at least three months in 2015 (August, September and October), and for a period of at least 6 months from the year 2020 (June through to November). (9)

Decline of the Arctic sea ice is accelerating, due to numerous feedbacks. As the Arctic atmosphere warms up, any snow cover on top of the ice will melt away ever quickly, decreasing the surface albedo and thus reinforcing the warm-up. As melt ponds appear on top of the ice, the albedo will drop even further.

Sam Carana's Diagram of Doom pictures ten feedbacks that jointly work to accelerate sea ice decline. (10)

The image below shows the three areas where albedo change will be felt most in the Arctic, i.e. sea ice loss, decline of albedo in Greenland and more early and extensive retreat of snow and ice cover in other areas in the Arctic. (8)