Comments by "Old Scientist" (@OldScientist) on "Astrum Earth"
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The AMOC tipping point is a scare story about things you cannot see.
To quote the Chief Scientist at the National Oceanography Centre, Professor Penny Holliday, "There hasn't been a slow down. There hasn't been a slowing of the AMOC."
Actual observations using the RAPID-MOCHA array from 2004 to 2023 show, that although there can be a great deal of variability of flow in the ocean from month to month or even day to day, there has been no decline in the Gulf Stream, with flow oscillating around 32Sv (32 million cubic metres per second) throughout the period of observation.
Continuous section measurements of the AMOC, available since 2004 at 26°N from the RAPID-MOCHA array, have shown that the AMOC strength decreased from 2004 to 2012, and thereafter, it has strengthened again. No relationship to CO2.
MOC spanning the North Atlantic at 27°N derived from RAPID/MOCHA/WBTS, satellite altimeter, and Argo floats for 1994 to 2020 shows no statistically significant decline (-0.06 Sv per decade). Furthermore blended meridional overturning basin-wide circulation (MOC) trend estimates (Sv) based on combinations of satellite altimetry and in situ hydrography data exist for the South Atlantic for 1994 onwards: at 34.5°S (often referred to as SAMBA) is +0.48Sv per decade. This is a significant positive trend, so no decline, no tipping point, no correlation to CO2. (GLOBAL OCEANS G. C. Johnson and R. Lumpkin, Eds., 2021)
The OSNAP MOC Timeseries of observations from Canada to Greenland and across to Scotland, although a shorter timescale (from 2014), show no decline in MOC with the flow fluctuating around 17Sv.
"Florida Current transport observations reveal four decades of steady state" Volkov et al, 2024 (published in Nature). This paper shows that a key component of AMOC, the Florida Current, has remained remarkably steady for over 40 years.
There is no climate crisis.
The North Atlantic current has doubled its velocity over the course of a quarter of century (Oziel et al, 2020). This is based on actual satellite observations.
The idea the AMOC is going to shut down is based on modelling. There is minimal real world evidence to support these outlandish claims. It relies upon climate models. You know, those Magical Truth Machines that keep making false predictions. It claims with 95% certainty that the AMOC with collapse by the end of the century. Come on! Really? These numerical models produce ocean circulations that are far from what we actually observe. These models can't even replicate one of the key physical processes, Convection, in ocean currents "because convection is a small-scale process, it is not captured well in most current models (Jackson et al (2023)" (Rahmstorf, 2024). So they can't model Convection. So they can't model ocean currents.
The most recent research into the AMOC confirms it is not weakening. From a 2024 paper by Terhaar et al published in Nature Communications "Based on the here identified relationship and observation-based estimates of the past air-sea heatflux in the North Atlantic from reanalysis products, the decadal averaged AMOC at 26.5°N has not weakened from 1963 to 2017". So not even close to a tipping point or collapse.
Sea surface temperatures (SST) were trending downwards 2000-2018 (HadSST 4), and from 1950-1980, and from 1880-1910. The oceans warmed at a faster rate 1910-1940 than 1980-2010. Remember CO2 has been accumulating in the atmosphere at an accelerating rate all the time, so there is little correlation between the two.
Also the 'Cold Blob' has disappeared from North Atlantic surface temperatures -Rahmstorf must be gutted - when annual anomalies for 2013-2023 are compared to the average for the period 1979-2010 (ECMWF ERA5). The International Comprehensive Ocean-Atmosphere Data Set (ICOADS) shows a Sea Surface Temperature departure of over +2°C exactly where the Cold Blob used to be. It may have been there but it's gone. Looking more carefully using NOAA ERSST V5 data for North Atlantic Sea Surface Temperature anomalies (50N-65N, 50W-10W) shows in 1942 a +1°C anomaly declining to -0.7°C in 1992 then rising to almost +1°C in 2010, declining again to -0.6°C in 2010, and of course rising again to +0.75°C in 2023. There are also oscillations in the data back to the 1850s, but there is no trend overall up or down, and no correlation to CO2. The same is true for the heat content in the North Atlantic down to 1000m (Met Office data). No correlation to CO2, just a natural variability. That's the data. The Cold Blob is an artefact.
The North Atlantic ocean has cooled and warmed rapidly and repeatedly during the current interglacial with no correlation to CO2 e.g. 10,300-10,200 years before the present (y BP), 9,500y BP, 6,000-5,900y BP, 5,400-5,300y BP, 2,500-2,300y BP, 1,700-1,600y BP (Berner et al., 2008. See Figure 8 in the paper). There is a high frequency (18 events) of SST variability on the order of 1-3°C during a 10-50 year time resolution throughout the Holocene in the North Atlantic with no correlation to CO2. And Life just carried on.
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The North Atlantic ocean has cooled and warmed rapidly and repeatedly during the current interglacial with no correlation to CO2 e.g. 10,300-10,200 years before the present (y BP), 9,500y BP, 6,000-5,900y BP, 5,400-5,300y BP, 2,500-2,300y BP, 1,700-1,600y BP (Berner et al., 2008. See Figure 8 in the paper). There is a high frequency (18 events) of SST variability on the order of 1-3°C during a 10-50 year time resolution throughout the Holocene in the North Atlantic with no correlation to CO2. And Life just carried on.
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@edwardbrown8933 The whole of East and West Antarctica is cooling, and has been for 40 years. East Antarctica has cooled by an impressive 0.7°C per decade. Resulting in an overall substantial and statistically significant decline of 2.8°C since 1980. So much for "Global" warming. I am referring to a paper by Zhu et al (2021) that looked at the reanalysed ERA5 satellite dataset. Check out table 4. Furthermore, the Antarctic Peninsula ice has since been shown to be on the increase “The eastern Antarctic Peninsula Ice Sheet has grown in area over the last 20 years, due to changing wind and sea ice patterns.” (University of Cambridge, May, 2022.)
In reality, "there have been statistically significant positive trends in total Antarctic sea ice extent since 1979." (Fogt et al, 2022. Published in Nature) "since 1979 is the only time all four seasons demonstrate significant increases in total Antarctic sea ice in the context of the twentieth century".
A study of Antarctic ice shelves from 1980 to 2021 (Banwell et al, 2023) showed meltwater volume dropped with "decreasing trend in both annual melt days and meltwater production volume over the 41 years.”
"Overall, the Antarctic ice shelf area has grown by 5305 km² since 2009, with 18 ice shelves retreating and 16 larger shelves growing in area. Our observations show that Antarctic ice shelves gained 661 Gt of ice mass over the past decade." (Andreasen et al, 2023). It is from a paper entitled "Change in Antarctic Ice Shelf Area from 2009 to 2019". They use MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data to measure the change in ice shelf calving front position and area on 34 ice shelves in Antarctica from 2009 to 2019. Also, as the mass gain (661Gt) was given, you could calculate the volume of the ice gained using the formula: Volume = Mass ÷ Density (assume Density of glacier ice 0.9167 Gt/km³). This would give you (well not you obviously) an Ice Gain Volume ≈721km³. That's how much extra of the lovely white stuff there is around Antarctica. Imagine standing in the centre of this extra ice. It would stretch beyond the horizon in all directions and would be 45 storeys high.
Antarctica contributes 0.36mm to sea-level rise per year (that's essentially nothing as well). At the current rate it will take well over ¼ million years to melt, but we are due for two more glacial periods in that time. That ice is here to stay.
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@batsy3 There is no objective observational evidence that we are living in a global climate crisis.
Even the biased UN's IPCC AR6 WG1 (Sixth Assessment Report, The Physical Science Basis, The Working Group 1 contribution), 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),
Mean 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.
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@jordaneggerman4734 The AMOC tipping point is a scare story about things you cannot see.
To quote the Chief Scientist at the National Oceanography Centre, Professor Penny Holliday, "There hasn't been a slow down. There hasn't been a slowing of the AMOC."
Actual observations using the RAPID-MOCHA array from 2004 to 2023 show, that although there can be a great deal of variability of flow in the ocean from month to month or even day to day, there has been no decline in the Gulf Stream, with flow oscillating around 32Sv (32 million cubic metres per second) throughout the period of observation.
Continuous section measurements of the AMOC, available since 2004 at 26°N from the RAPID-MOCHA array, have shown that the AMOC strength decreased from 2004 to 2012, and thereafter, it has strengthened again. No relationship to CO2.
MOC spanning the North Atlantic at 27°N derived from RAPID/MOCHA/WBTS, satellite altimeter, and Argo floats for 1994 to 2020 shows no statistically significant decline (-0.06 Sv per decade). Furthermore blended meridional overturning basin-wide circulation (MOC) trend estimates (Sv) based on combinations of satellite altimetry and in situ hydrography data exist for the South Atlantic for 1994 onwards: at 34.5°S (often referred to as SAMBA) is +0.48Sv per decade. This is a significant positive trend, so no decline, no tipping point, no correlation to CO2. (GLOBAL OCEANS G. C. Johnson and R. Lumpkin, Eds., 2021)
The OSNAP MOC Timeseries of observations from Canada to Greenland and across to Scotland, although a shorter timescale (from 2014), show no decline in MOC with the flow fluctuating around 17Sv.
"Florida Current transport observations reveal four decades of steady state" Volkov et al, 2024 (published in Nature). This paper shows that a key component of AMOC, the Florida Current, has remained remarkably steady for over 40 years.
There is no climate crisis.
The North Atlantic current has doubled its velocity over the course of a quarter of century (Oziel et al, 2020). This is based on actual satellite observations.
The idea the AMOC is going to shut down is based on modelling. There is minimal real world evidence to support these outlandish claims. It relies upon climate models. You know, those Magical Truth Machines that keep making false predictions. It claims with 95% certainty that the AMOC will collapse by the end of the century. Come on! Really? These numerical models produce ocean circulations that are far from what we actually observe. These models can't even replicate one of the key physical processes, Convection, in ocean currents "because convection is a small-scale process, it is not captured well in most current models (Jackson et al (2023)" (Rahmstorf, 2024). So they can't model Convection. So they can't model ocean currents.
The most recent research into the AMOC confirms it is not weakening. From a 2024 paper by Terhaar et al published in Nature Communications "Based on the here identified relationship and observation-based estimates of the past air-sea heatflux in the North Atlantic from reanalysis products, the decadal averaged AMOC at 26.5°N has not weakened from 1963 to 2017". "Based on the results, the AMOC is more stable than we thought," Vogt said (one of the authors on the paper). "This might mean that the AMOC isn't as close to a tipping point as previously suggested." So not even close to a tipping point or collapse.
Sea surface temperatures (SST) were trending downwards 2000-2018 (HadSST 4), and from 1950-1980, and from 1880-1910. The oceans warmed at a faster rate 1910-1940 than 1980-2010. Remember CO2 has been accumulating in the atmosphere at an accelerating rate all the time, so there is little correlation between the two.
Also the 'Cold Blob' has disappeared from North Atlantic surface temperatures -Rahmstorf must be gutted - when annual anomalies for 2013-2023 are compared to the average for the period 1979-2010 (ECMWF ERA5). The International Comprehensive Ocean-Atmosphere Data Set (ICOADS) shows a Sea Surface Temperature departure of over +2°C exactly where the Cold Blob used to be. It may have been there but it's gone. Looking more carefully using NOAA ERSST V5 data for North Atlantic Sea Surface Temperature anomalies (50N-65N, 50W-10W) shows in 1942 a +1°C anomaly declining to -0.7°C in 1992 then rising to almost +1°C in 2010, declining again to -0.6°C in 2010, and of course rising again to +0.75°C in 2023. There are also oscillations in the data back to the 1850s, but there is no trend overall up or down, and no correlation to CO2. The same is true for the heat content in the North Atlantic down to 1000m (Met Office data). No correlation to CO2, just a natural variability. That's the data. The Cold Blob is an artefact.
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