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climate-debate

New Study: Antarctic Sea Ice Completed Half Its Deglacial Retreat 1000s Of Years Before CO2 Began Rising

by K. Richard, Nov 16, 2023 in NotricksZone

The timing of the dramatic Antarctic sea ice decline during the last deglaciation suggests solar forcing and sea ice retreat “instigated” century-scale climate warming and atmospheric CO2 change. This would appear to challenge the perception CO2 plays a causal role in glacial-interglacial sea ice and climate changes.

From ~21,000 to 19,500 years ago, when CO2 was thought to have been at its lowest point in the Quaternary ice age (~180 ppm), the sea ice surrounding East and West Antarctica completed 50% of its eventual deglaciation-era decline (Sadatzki et al., 2023).

“[I]ndependent lines of evidence supporting that early sea ice and surface ocean changes in the Southern Ocean initiated as early as ~19.5 ka ago (with signs of summer sea ice retreat in our reconstruction as early as ~21 ka ago) and thus (at least) about 2 ka before major deglacial changes in global ocean circulation, climate, and atmospheric CO2.”

The increase in 65°S insolation during these millennia was deemed sufficient to drive this magnitude of sea ice retreat.

“This early increase in local integrated summer insolation at 65°S, which is independent of the longitude, may have thus provided enough energy to initiate melting of the near-perennial sea ice cover in late glacial.”

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better to know...?, climate-debate

While Media Obsess About Some Warmth, Globe Seeing Plenty Of Unusual Cold Events

by P. Gosselin, Nov 17, 2023 in WUWT

Surface temperatures measured where people live show there’s as much cold as there ‘s warmth, see temperature.global.com.

Christian Freuer’s Cold Report (EIKE)

and Electroverse.com

Snowpack extent in US reaches record levels!

America’s first Arctic air blast of the season broke hundreds of low temperature records and led to the largest snowpack extent there in early November in NOAA records.

A high snowpack blanketed the Rocky Mountains, northern Plains, Great Lakes and northern New England, resulting in 17.9% of the Lower 48 under a blanket of snow as the calendar turned to November – a new record in the books dating back to 2003.

Many places recorded their snowiest Halloweens ever.

At 22 inches, Muskegon, MI, not only recorded the snowiest Halloween ever, but also the snowiest October day and month. Glasgow, MT, recorded the snowiest start to the season with 36 inches.

The cold broke hundreds of low temperature records across the country, from Texas to Maine, dropping the average temperature in the Lower 48 to -0.5°C – more than 5 degrees Celsius below normal.

Historic November cold grips Argentina, Australia

A late cold spell has hit large parts of South America, especially Argentina. The country recorded the lowest November temperatures since records began.

A number of records for highs and lows have fallen. New lows include the 0.1°C at Córdoba Airport, which broke the record of 2°C set on November 4, 1992, the 1.6°C in Chamical, which broke the record of 4.5°C set on November 9, 2010, and the 2.8°C in Mendova, which beat the 3.2°C set in 1992.

New lows include Gualeguaychú’s 13.8°C, which broke the old record set in 1992, and Paraná’s 13.5°C, which beat the record set in 1936.

The cold was severe, up to 24 degrees Celsius below normal, and it was also widespread, affecting most of Argentina:

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unclassified

Can we trust projections of AMOC weakening based on climate models that cannot reproduce the past?

by G.D. McCarthy & L. Caesar, Nov 2023 in PhilosophicalTransactions

The Atlantic Meridional Overturning Circulation (AMOC), a crucial element of the Earth’s climate system, is projected to weaken over the course of the twenty-first century which could have far reaching consequences for the occurrence of extreme weather events, regional sea level rise, monsoon regions and the marine ecosystem. The latest IPCC report puts the likelihood of such a weakening as ‘very likely’. As our confidence in future climate projections depends largely on the ability to model the past climate, we take an in-depth look at the difference in the twentieth century evolution of the AMOC based on observational data (including direct observations and various proxy data) and model data from climate model ensembles. We show that both the magnitude of the trend in the AMOC over different time periods and often even the sign of the trend differs between observations and climate model ensemble mean, with the magnitude of the trend difference becoming even greater when looking at the CMIP6 ensemble compared to CMIP5. We discuss possible reasons for this observation-model discrepancy and question what it means to have higher confidence in future projections than historical reproductions.

This article is part of a discussion meeting issue ’Atlantic overturning: new observations and challenges’.

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