The issue with ice science

When I was about ten, there was a camp I'd been chosen for, can't even remember and one of the lessons interested the kids greatly - ZPG was the big issue then:

In the late 1960s ZPG became a prominent political movement in the U.S. and parts of Europe, with strong links to environmentalism and feminism.

Uh huh. Nobody ever asked him what about the billion in China - were they ZPGing or was it just us? Until Covid took over recently, warble gloaming was the fashion. There are issues I have with all this: 

https://everythingclimate.org/topics/antarctic-ice-melt/

It would require several thousands of years of detailed ice mass data to accurately determine the natural trends and fluctuations of Antarctic and Greenland ice masses that would allow an accurate comparison to ice mass fluctuations since the 1.3 part per ten thousand increase in atmospheric carbon dioxide since 1850.  This is the period during which human activity contributed CO2 to the atmosphere, most of which occurred since 1940.

Despite the lack of long-term historical data, short term data contradicts theories of rapidly increasing ice mass loss due to increases in atmospheric CO2 levels. 

 

Thirty years ago, Antarctica was barely losing ice mass, and this remains so. In 2019 and 2020, media outlets began claiming the Antarctic ice cap is melting six times faster than 30 years ago. “Six times” almost no ice loss remains almost no ice loss. When recent ice loss measurements are compared to the full entire Greenland and Antarctic ice caps, the loss is so small that it is barely detectable.

Writing in the journal Nature, scientists at Columbia University and the University of Victoria, British Columbia report:

The Antarctic continent has not warmed in the last seven decades, despite a monotonic increase in the atmospheric concentration of greenhouse gases. ”The scientists also observe that over the past several decades, “Antarctic sea ice area has modestly expanded.”

https://www.nature.com/articles/s41612-020-00143-w

My issues are not to do with the slow changes in cycles themselves and that we're not in imminent danger this way - no issues with that - the issues are with the modelling. We are assailed with models, trotted out as absolute fact but who said radio-carbon dating was accurate anyway?  They do back projections in millions of years - how?

I'm not dismissing RCD outright any more than dismissing metaphysical entities - seems both have things going for them - I'm just saying that the dogma on the science side approaches that of the metaphysical side and yet rationalists will have none on't.

So where do they get these super accurate back projections from, so utterly convinced of their complete accuracy?