Comments by "Old Scientist" (@OldScientist) on "What happens when the permafrost thaws? | BBC Ideas" video.
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In the current interglacial Svalbard has been far warmer than today. Using biomarker evidence (for example, the Early Holocene presence of sea creatures unable to survive below fixed warmth thresholds) and glacier melt extent measurements (for example, sea shells buried 6 km inside a glacier), scientists have discovered that much of Arctic Svalbard was about 7°C warmer than today during the Early Holocene, when CO2 concentrations were much lower (near 260 ppm) (Farnsworth et al, 2020. Leopold et al, 2019. van der Bilt et al, 2019. Łacka et al, 2019. Beierlein et al, 2015).
Anyway the Arctic has already been ice free in the current interglacial. It was certainly warm enough during the Holocene Climatic Optimum, being upto 7°C warmer on the shores of the Arctic during that time, with trees growing on the shores of the ocean, far to the north of the current treeline.
The northern coast of Greenland was, during parts of the Pleistocene, warmer by double figures when compared to today. The summer and winter average minimum temperatures of 10 degrees Celsius and 17 degrees C, respectively, were more than 10 degrees C warmer than present day. I think it was a maximum of 19 °C warmer than today. So no ice in the ocean, and the world survived. These changes emerged in the Earth's climate system without any human input.
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@astronautical1082 Extinction rates (1500-2009) peaked around 1900 at 50 per decade. Extinction rates have declined dramatically to around 4 to per decade in the 2000s. So the extinction rate is very low: 900 known lost species for 2.1 million known species in 500 years (IUCN), so from observations there are an average of slightly less than 2 species lost every year. Out of a known species total of over 2 million. That gives an annual percentage loss of less than 0.0001%. That's background extinction. At that frequency it will take over 930,000 years to reach 80% extinction of species experienced at the K-T boundary that saw the extinction of the dinosaurs. Of course, extinction is a natural part of the evolution of life on this planet with the average lifespan of a species thought to be about 1 million years (cf 930,000). It is estimated that 99.9% of all plant and animal species that have existed have gone extinct. It should also be noted that no taxonomic families have become extinct in the last 500 years. In fact marine diversity at the taxonomic level of families is the highest it has ever been in the Earth's long history (see Sepkoski Curve). In a review of 16,009 species, most populations (85%) did not show significant trends in abundance, and those that did were balanced between winners (8%) and losers (7%) (Dornelas et al, 2019). There have been only 9 species of continental birds and mammals confirmed extinct since 1500 (Loehle, 2011). No global marine animals have become extinct in the past 50 years (McCauley et, 2015 using IUCN data).
There is no climate crisis.
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The Arctic minimum summer sea ice trend is zero for the past 17 years. In the past few years it was almost as high as 1995. The probability that this could be due to chance has now dropped to 10% (after Swart et al calculations, 2015). If the hiatus continues until 2027, it will become statistically significant (p<0.05, or less than 5%) and no longer explainable by chance. Using National Snow and Ice Data Centre (NSIDC) information for September minima (million km²):
2007 4.16
2008 4.59
2009 5.12
2010 4.62
2011 4.34
2012 3.39
2013 5.05
2014 5.03
2015 4.43
2016 4.17
2017 4.67
2018 4.66
2019 4.19
2020 3.82
2021 4.77
2022 4.67
2023 4.23
Plot the trend line for this data and it will be flat. ZERO net change in 17 years. The linear trend since 2007 is indistinguishable from zero ( around -0.17% per year ).
In the early 1950s the sea ice concentration anomaly was lower than it is at present. The sea ice anomaly then rose during the 50s, 60s and 70s. This was followed by a decline. This is demonstrated in Arctic and Antarctic Research Institute (AARI) data, which is based on historical sea ice charts from several sources (aircraft, ship, and satellite observations).
The AARI data shows the sea ice concentration anomaly was lower in 1952 (-5%) than 2005 (-3%). The anomaly increased in the 50s, 60s and 70s. In the 80s, 90s and early 2000s it decreased. Since 2007 the trend has been flat.
JAXA (Japanese Aerospace Exploration Agency) satellite data from 2002 to 2024 Arctic Sea Ice Extent (365 day running average) shows no noticeable trend with values close to 10,000,000km² throughout. Their minimum extent for daily values was in 2012. No other year since has come close.
MASIE (Multisensor Analyzed Sea Ice Extent - Northern Hemisphere) shows something similar to JAXA. From 2005 to 2024 Arctic Sea Ice Extent (365 day running average) shows no noticeable trend with values close to 10,000,000km² throughout. Their minimum extent for daily values was in 2012. Again no other year since has come close. It also shows a marked increase in Ice in the Greenland Sea since 2018.
Polyakov et al (2003) show "ice extent (1900-2000) in the Kara, Laptev, East Siberian, and Chukchi Seas provide evidence that long-term ice thickness and extent trends are small and generally not statistically significant". Trend -0.5% per decade (±0.7%).
Vinje (2001) shows a deceleration in the rate of ice loss from 1864 to 2000.
Recent sea ice extent is very high when compared to the last 10,000 years. Also changes in sea ice extent and the speed of those changes were greater in the past (Stein et al, 2017).
NOAA's Global Time Series Average Temperature Anomaly monthly data (1995-2004) for the Arctic region shows the peak anomaly occurred in January 2016 (+4.99°C), another El Niño year, and the trend is now downwards (-0.42°C per decade) as of June 2024.
HadCRUT4 Arctic (70N - 90N) monthly surface air temperature anomalies record (1920-2021) shows the greatest number and magnitude of positive temperature anomalies occurred between 1930-49. All anomalies in excess of 5°C, including +7°C (referenced to 1961-1990) are from that period. No temperature anomalies from 2000-2019 exceeded 5°C. It shows no decade warmed faster than the 1930s and the current 'warming' finished in 2005.
JRA55 SAT (2010-2020) shows most of the Canadian Arctic and Greenland cooling with parts of Canada cooling by 3°C and western Greenland cooling by 2.5°C in a decade.
KNMI data (Twentieth Century Reanalysis V2c, 1851-2011, 68°N-80°N, 25°W-60°W, so Greenland) shows the most pronounced warming took place in the 1870s, and when comparing temperature anomalies, highest are in the 1930s and comparison of that period with recent temperature anomalies shows no net warming.
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There is no objective observational evidence that we are living in a global climate crisis.
The UN's IPCC AR6 WG1, chapter 12 "Climate Change Information for Regional Impact and for Risk Assessment", page 1856, section 12.5.2, table 12.12 confirms there is a lack of evidence or no signal that the following have changed:
Air Pollution Weather (temperature inversions),
Aridity,
Avalanche (snow),
Average precipitation,
Average Wind Speed,
Coastal Flood,
Agricultural drought,
Hydrological drought,
Erosion of Coastlines,
Fire Weather (hot and windy),
Flooding From Heavy Rain (pluvial floods),
Frost,
Hail,
Heavy Rain,
Heavy Snowfall and Ice Storms,
Landslides,
Marine Heatwaves,
Ocean Acidity,
Radiation at the Earth’s Surface,
River/Lake Floods,
Sand and Dust Storms,
Sea Level,
Severe Wind Storms,
Snow, Glacier, and Ice Sheets,
Antarctic Sea Ice,
Tropical Cyclones.
How about some quotes from the UN's IPCC AR6?
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@astronautical1082 As regards ocean acidification, it is estimated that the ocean’s global mean surface pH may have declined (i.e., become less alkaline and thus more “acidic”) by -0.07 to -0.08 in the last 200 years — from pH8.12 during pre-industrial times to 8.04 to 8.05 today (Wei et al, 2015). N.B. The decline in pH occurred before 1930.
However, and very importantly when you look the data after CO2 emissions began rising precipitously in the 1930s, the oceans have become less “acidic”!!!
By way of comparison, from one season to the next, or over the course of less than 6 months, pH levels naturally change by ±0.15 pH units, or twice the overall rate of the last 200 years. On a per-decade scale, the changes are even more pronounced. Oceanic pH values naturally fluctuate up and down by up to 0.6 U within a span of a decade, with an overall range between 7.66 and 8.40. This decadal rate of pH change is larger than the overall 200-year span (0.07-0.08) by a factor of 8. Indeed the daily noted maximum pH range of 0.7 (Santos et al. 2011) is far greater than the overall change predicted between now and the end of the century.
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@astronautical1082
Warming events in the Cenozoic do not correlate to mass extinction. The Paleocene-Eocene Thermal Maximum PETM (55mya), a time when the Earth warmed rapidly to temperatures far in excess of today's, only resulted in a noticeable extinction of some benthic foraminifera. That was so small of an event it doesn't even show up on a marine extinction intensity chart for the Phanerozoic. There was, in fact, a more general flourishing of life at that point, especially terrestrial. Many major mammal groups appeared and spread around the globe including hyaenodontids, artiodactyls, perissodactyls, and primates. So if he's right we've got that to look forward to. The next largest extinction event, since the dinosaurs bit the big one, is the Eocene-Oligocene transition ("Grande Coupure" = The Great Rupture). This seems to have been connected with cooling (rapid Antarctic glaciation), not warming.
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