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Prof Ian Simmonds on melting permafrost and the latest climate science.
Professor Ian Simmonds of the School of Earth Sciences at The University of Melbourne is an expert in climate science and atmospheric carbon dioxide and methane budgets. His recent research has focused on the dramatic record melting permafrost in the Arctic and extreme weather events relating to climate change.I'd say we've got the measure of the prof. right away, wouldn't you? What "dramatic record melting permafrost in the Arctic" exactly?
The permafrost has started warming at 50m depth by about 2 degrees. This is significant because the permafrost is very close to freezing and 2 degrees will start to thaw it and this increases the potential for chemical reactions and leakage of methane and carbon emissions from the frozen organic matter inside the permafrost."Very close to freezing"? Very close to thawing, surely? If "2 degrees will start to thaw it" and it's already warmed by 2 degrees then it's at thawing point already innit? Except that at 50m depth it's not at -2 degrees and not close to thawing. If there's only "potential for chemical reactions and leakage of methane and carbon emissions" where's the "dramatic record melting permafrost" then?
Par for the course for this sort of article - the writer can't even see the built-in contradictions in what they write. Which brings me directly to a rather glaring contradiction in "Policy Implications of Warming Permafrost", in the executive summary right at the start.
Two global networks monitor permafrost status: the Thermal State of Permafrost (TSP) network measures permafrost temperature at various depths in 860 boreholes, and the Circumpolar Active Layer Monitoring (CALM) network measures the thickness of the active layer at 260 sites. The active layer thickness is the maximum surface thaw depth in summer . The TSP and CALM networks are the two components of the Global Terrestrial Network for Permafrost (GTN-P), under the auspices of the Global Climate Observing System (GCOS). The International Permafrost Association (IPA) currently coordinates international development and operation of the TSP and CALM networks for the GTN-P . TSP observations indicate that permafrost temperatures have risen over the past few decades. CALM observations are less conclusive due to the melting of ice layers and lenses in near surface permafrost, but show increases in active layer thickness at many sites. Overall, these observations indicate that large-scale thawing of permafrost may have already started.The "active layer" is the unfrozen (in summer) layer above the permafrost layer. Microbial decay of plant matter can only take place in that active layer when it's unfrozen. Temperature monitoring at depths well below the active layer says nothing about any actual increase in the depth of that layer, which is what indicates additional thawing and subsequent decay and release of (mostly) CO2. Yet the summary implies that warming at depth is a more conclusive indicator than CALM (active layer) observations which are "less conclusive"? This is clutching at straws big time. I hope those straws don't decay and release an element of objectivity and truth.
So "large-scale thawing of permafrost may have already started"? Here's the contradiction in the next-but-one paragraph (my bold);
Carbon dioxide (CO2) and methane emissions from thawing permafrost could amplify warming due to anthropogenic greenhouse gas emissions. This amplification is called the permafrost carbon feedback. Permafrost contains ~1700 gigatonnes (Gt) of carbon in the form of frozen organic matter, almost twice as much carbon as currently in the atmosphere. If the permafrost thaws, the organic matter will thaw and decay, potentially releasing large amounts of CO2 and methane into the atmosphere. This organic material was buried and frozen thousands of years ago and its release into the atmosphere is irreversible on human time scales. Thawing permafrost could emit 43 to 135 Gt of CO2 equivalent by 2100 and 246 to 415 Gt of CO2 equivalent by 2200. Uncertainties are large, but emissions from thawing permafrost could start within the next few decades and continue for several centuries, influencing both short-term climate (before 2100) and long-term climate (after 2100).However that's the dumbed-down version in the Executive Summary. The main report section 2.4 "Current State of Permafrost", after discussing changes and trends in atmospheric and permafrost temperatures states
Trends in active layer thickness are less conclusive, with some sites showing increases, but others showing no trend at all. Active layer thickness has increased in the Russian European North, but not in West Siberia (Mazhitova 2008; Vasiliev et al. 2008). Increases in summer air temperature have increased the active layer thickness on the Qinghai-Tibet Plateau (Wu andZhang 2010; Zhao et al. 2010). Although active layer thickness has increased in the Alaskan and Canadian interior, there is no obvious trend near the Arctic coastline (Streletskiy et al. 2008; Shiklomanov et al. 2010; Smith et al. 2009; Burn and Kokelj, 2009; Smith et al. 2010). Melting of excess ground ice might explain the lack of consistent trends in active layer thickness even though permafrost temperatures show clear signs of warming. Year-to-year variability in active layer thickness due to variations in summer air temperature also makes it difficult to detect long-term trends (Smith et al. 2009; Popova and Shmakin 2009). However, radar measurements near Prudhoe Bay indicate the surface has subsided by several centimeters since 1992, even though nearby CALM sites showed no obvious increases in active layer thickness (Liu et al. 2010, 2012). The excess ground ice in near-surface permafrost, if present, melts slowly over several years, the water drains away and the ground surface settles, a process that is difficult to detect using mechanical probing at CALM sites.So there's a "lack of consistent trends in active layer thickness", which is the only sign that permafrost is melting on a large scale. Note that "Although active layer thickness has increased in the Alaskan and Canadian interior, there is no obvious trend near the Arctic coastline". That's it then? There's no mention of monitoring CO2 and methane emissions on the ground, in the air, or by satellite. If emissions are the bottom line then it's emissions which should be monitored above all else, something that would appear to be essential to my mind. Wait - aren't CO2 and methane already monitored by satellite? Wouldn't increasing emissions over permafrost areas show up, and wouldn't this report show them? Yes, yes, and yes to those questions.
Something occurred to me while I was writing my previous post. Surely microbial digestion of plant matter would produce heat, and act as a feedback, accelerating the melt? No mention of it in the report, but I did manage to find a reference in Amount and timing of permafrost carbon release in response to climate warming (2011), lead author one Kevin Schaefer, who also happens to be the lead author of the UNEP report:
A regional model projection with permafrost carbon predicts a complete thaw of permafrost in eastern Siberia by 2300, fuelled by the heat of microbial decay (Khvorostyanov et al., 2008).I'm not just a pretty face then, I have some insight.
There's a distinct lack of data in these 30 report pages, and the maps are dreadful - here's the first intended to show the various areas of permafrost types (actual size, extracted from the pdf)
... and here's how it appears in the pdf - a scientific report intended for international consumption.
Here's one i found from the same original source, the International Permafrost Association.
|Source: National Snow and Ice Data Center (NSIDC)|
So there we have it - an inconclusive report, despite what's being "spun" about it in the media and on the 'net. A big nothing.
How objective is the report's lead author, Kevin Schaefer? NBC News quotes him in "Melting permafrost being ignored at climate talks, experts warn"
"Permafrost has begun to thaw," lead author Kevin Schaefer, a researcher at the National Snow and Ice Data Center at the University of Colorado-Boulder, told a news conference in Doha.You don't even deserve my bullshit button, Kev, you're putting politics above science. Your report doesn't say that - at best it's a gross over-simplification, at worst a lie, and you know it.