Climate Models Out Of Whack …Also Warming From Arctic Soot Underestimated

What follows is another report on how it’s “back-to-the drawing-board” for climate models.

Climate models underestimate soot amounts and their warming effect in the Arctic

By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(Translation/editing of German text by P Gosselin)

Soot (black carbon aerosol) is a climate warming aerosol. Some years ago we recognized that soot warms far more than earlier assumed. Thus we should have deducted a part of the warming of the past 150 years from CO2 and assigned it to soot. But that was not allowed politically, and so the models were fudged to make CO2 a powerful climate factor in the end. A rotten compromise which we already described 5 years ago in our book “Die kalte Sonne”.

What’s the latest in the research of soot? Already in 2013 in PNAS a paper appeared authored by von Thomas Painter et al investigating the surprisingly early and abrupt glacier retreats in the Alps. When studying the ice they found a strong increase in soot from this time, which had something to do with the start of the Industrial Revolution in the mid 19th century.

The authors concluded that the melting of the Alps glaciers was impacted significantly by the rise in soot. Here’s the abstract:

End of the Little Ice Age in the Alps forced by industrial black carbon
Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Alpine temperature and precipitation records suggest that glaciers should instead have continued to grow until circa 1910. Radiative forcing by increasing deposition of industrial black carbon to snow may represent the driver of the abrupt glacier retreats in the Alps that began in the mid-19th century. Ice cores indicate that black carbon concentrations increased abruptly in the mid-19th century and largely continued to increase into the 20th century, consistent with known increases in black carbon emissions from the industrialization of Western Europe. Inferred annual surface radiative forcings increased stepwise to 13–17 W⋅m−2 between 1850 and 1880, and to 9–22 W⋅m−2 in the early 1900s, with snowmelt season (April/May/June) forcings reaching greater than 35 W⋅m−2 by the early 1900s. These snowmelt season radiative forcings would have resulted in additional annual snow melting of as much as 0.9 m water equivalent across the melt season. Simulations of glacier mass balances with radiative forcing-equivalent changes in atmospheric temperatures result in conservative estimates of accumulating negative mass balances of magnitude −15 m water equivalent by 1900 and −30 m water equivalent by 1930, magnitudes and timing consistent with the observed retreat. These results suggest a possible physical explanation for the abrupt retreat of glaciers in the Alps in the mid-19th century that is consistent with existing temperature and precipitation records and reconstructions.”

Today thanks to satellite measurements, we have a more exact, full surface picture of glacier albedo. However here there are “cases” that dodge this. This is how Dartmouth College im October 2015 admitted that the supposed changes in albedo in northern Greenland were not in any way real, but could be traced back to a worsening of the satellite sensors, i.e. an artefact of measurement.

In March 2016 a more precise evaluation by a team led by Marco Tedesco appeared in the The Cryosphere. They found a slight decrease in albedo in Greenland over the time period 1981-2012, whereby during the 1981-1996 period there was no detectable trend. Soot measurements from northern Finnland provided hope. In the last 40 years soot concentration in the atmosphere dropped steadily thanks to falling emissions.

The Japanese research center RIKEN made a complaint in May 2016 that climate models assumed too little soot in the Arctic regions. In reality there was far more:

Current atmospheric models underestimate the dirtiness of Arctic air

Black carbon aerosols—particles of carbon that rise into the atmosphere when biomass, agricultural waste, and fossil fuels are burned in an incomplete way—are important for understanding climate change, as they absorb sunlight, leading to higher atmospheric temperatures, and can also coat Arctic snow with a darker layer, reducing its reflectivity and leading to increased melting. Unfortunately, current simulation models, which combine global climate models with aerosol transport models, consistently underestimate the amount of these aerosols in the Arctic compared to actual measurements during the spring and winter seasons, making it difficult to accurately assess the impact of these substances on the climate.

To find out if these inaccuracies could be mitigated, a team of scientists decided to use the Japanese K computer to perform fine-grained simulations of how black carbon aerosols are transported to and distributed in the Arctic region. By using smaller grids—with spacing of just a few kilometers rather than several tens of kilometers as in conventional current models—they were able to show that they could more realistically model the amount of black carbon aerosols, mitigating the underestimation in more coarse-grained models. Their finest model used 3.5 kilometer grids broken up vertically into 38 layers, so that it required 1.6 billion grids to cover the globe. The simulation, done on the 10-petaflop K computer, still required 17 hours to perform the two week simulation.

According to Yousuke Sato of the RIKEN Advanced Institute for Computational Science (AICS), ‘this research shows that powerful supercomputers, by performing more fine-grained simulations, can help us to model weather and climate patterns in a more realistic way. We have to note, however, that while our model reduced the underestimation, it did not completely eliminate it. Further generations of even more powerful computers will allow us to run simulations that may be able to make even more realistic simulations and help us to understand the mechanism through which these aerosols are transported.’

‘It is also known,’ continues Sato, ‘that current models do not realistically model the vertical distribution of the aerosols, and we believe that finer measurements could help there as well. Unfortunately there were no vertical measurements taken in November 2011, the time we chose to model, so we plan in the future to do simulations for time periods for which actual measurement data exist.’

The research, published in Scientific Reports, was carried out by AICS in collaboration with the University of Tokyo, the National Institute of Environmental Studies, Kyushu University, and the Japan Aerospace Exploration Agency.

Reference: Yousuke Sato, Hiroaki Miura, Hisashi Yashiro, Daisuke Goto, Toshihiko Takemura, Hirofumi Tomita, and Teruyuki Nakajima, ‘Unrealistically pristine air in the Arctic produced by current global scale models’, Scientific Reports, doi: 10.1038/srep26561″

The consequences of the climate model misassumptions are clear: Less soot in the models also means less warming by soot. This is how the observed Arctic warming can be foremost assigned to CO2.

If one now increases the soot in the models, then it becomes necessary to deduct a part of the warming effect from CO2, and of course CO2-climate sensitivity drops accordingly. No matter where one looks, CO2 keeps taking a greater share of the climate cake than it should. It’s an error that is systematic.


8 responses to “Climate Models Out Of Whack …Also Warming From Arctic Soot Underestimated”

  1. tom0mason

    Also of note is the algae growth in the Greenland ice.
    There is little understanding of how this is mediated, IMO as CO2 levels rise this phenomena will happen more but as the actual alga’s history is poorly understood. I can not imagine that this will be put down to anything more than ‘global warming’ as it is here —

    Like changes in corals, this is an entirely natural effect for which we have little to no historical records.
    Indeed a case may be made for investigating whether the algae blooms, CO2 levels, and the soot deposits are linked in some manner. However I can not foresee much research in that direction as many are already willing to put these events down to man-made climate change.

  2. tom0mason

    Also of note is this —
    This discussion paper about Greenland ice sheet (GrIS) and light-absorbing impurities (LAI), the presence of soot (black carbon, BC), dust, organic matter, algae, and other biological material in snow or ice and the reducing albedo, with potentially accelerating melting.

    To date, most surface-based observations have been made in the dry-snow zone or the percolation zone,and they have generally focused on measuring the mixing ratios of BC (Hagler et al., 2007; McConnell et al., 2007; Polashenski et al., 2015) or of the spectral light absorption by all particulate components collectively (Doherty et al., 2010; Hegg et al., 2009, 2010). The regions of Greenland that are darkening the most rapidly are within the ablation zone. Here, there is no direct evidence that the rate of atmospheric deposition of LAI has been increasing. In view of the cumulative effect of snowmelt leaving impurities at the surface, the intra-seasonal variation of deposition may not be as important as the exposure of LAI by melting. Changes in the abundances of light-absorbing algae and other organic material with warmer temperatures may also be contributing to declining albedo, particularly for the ice, but this is an essentially unstudied source of darkening.
    Until measurements are made that quantify and distinguish the relative roles of each of these factors in the darkening of the GrIS, it is not possible to reduce the uncertainty in their contributions to the acceleration of surface melt. In addition to the need for targeted ground observations, it is necessary for the models that simulate and project the evolution of surface conditions over Greenland to start including the contribution of surface LAI, their processes, and their impact on albedo, as well as aerosol models that account for their deposition. Concurrently, space-borne sensors or missions capable of separating the contributions from the different processes (with increased spatial, spectral, and radiometric resolution) should be planned for remote sensing to become a more valuable tool in this regard.

  3. tom0mason

    My second comment is in the spam bin?

    1. AndyG55

      The algae is eating the spam. 🙂

      1. tom0mason

        Reduced to soot?

        1. AndyG55

          that’s not soot 😉

  4. tom0mason

    I find this paper probably the most interesting when it come to soot and dust effects on Greenland and the global climate overall.
    Modulation of ice ages via precession and dust-albedo feedbacks
    by Ralph Ellis, Michael Palmer (with special thanks to Prof. Michael Palmer and also Prof. Clive Best, who supplied the summary graphic in Fig. 14.)

    China University of Geosciences (Beijing) published Geoscience Frontiers.
    DOI: 10.1016/j.gsf.2016.04.004

    An interglacial is only initiated when eccentricity is rising and northern Great Summer Milankovitch insolation is enhanced. Following this temporary warm period, the rate of polar ice regrowth and its associated increase in albedo, controls the cooling-rate of the oceans and climate. These steadily reducing temperatures control the equally steady oceanic absorption and sequestration of atmospheric CO2, which in turn eventually controls the exponential increase in dust production, which then lowers ice-sheet albedo and primes the world for another interglacial warming. Thus one of the primary climatic regulators of interglacial periodicity is the steady rate of increase in polar ice extent. And since it takes about 70 kyr before the ice-sheets are large enough for temperatures and CO2 to reach a minima, this coincidentally places the increased dust production era close to the next eccentricity minima.
    Thus the rate of ice-sheet regrowth plays a key role in determining the w100kyr length of the glacial cycle. If temperatures and CO2 have not reached their critical minimum values before the onset of an eccentricity-enhanced Great Summer, there would be no dust-ice albedo feedbacks. And so the world would wait patiently until the next enhanced Great Summer, when hopefully all the participants in this stand-off between orbital forcing and climate feedbacks are ready to play their part. The glacial world’s dust-ice Achilles heel needs to be primed and ready to fire before an interglacial can be fully successful, otherwise the result is merely a ‘flash in the pan’ one of the many minor warming events of no consequence in the paleo-climatic record. In which case, interglacial warming is eccentricity and polar ice regrowth regulated, Great Summer forced,and dust-ice albedo amplified. And the greenhouse-gas attributes of CO2 play little or no part in this complex feedback system.

  5. yonason

    “Climate Models Out Of Whack …”

    Given that it’s impossible to model a non-linear chaotic system (like earth’s weather) which is dependent on a non-linear chaotic driver (like the sun), it has never been, nor will it ever be IN whack.