[Hot Tabasco]

the magnetic shifts in the Sun mimic those that occurred during the mini-Ice Ages of the 17th century

For the life of me I can never figure out how they know what happened 300 years ago when there were no instruments to record such events...........

[hattend]

The evidence is in the polar ice core samples. Always the polar ice core samples.

Or tree rings...always the tree rings if the ice cores don’t pan out.

[ApplegateRanch]

For the life of me I can never figure out how they know what happened 300 years ago when there were no instruments to record such events.

Even more amazing is the fact that they know exactly, down to the third decimal place, what the correction factor is for 200-300 year old recorded measurements, such as temperatures and tides/sea levels.

Using those correction factors, they can even prove that purported contemporary reports of the Thames flowing in winter are bogus: it was 2.795C too cold; it never thawed out year round until the Industrial Age created the beginnings of Global Warming. /sarc>

[Vermont Lt]

People observed things. And they wrote them down. These observations, such a water temps, air temps, sunspots, etc. can be used to infer relationships. It is not exact measurement, but cause and effect can be suggested.