The long view; There is climate change and there are fluctuations in sea level, the questions is how much, why and what can be attributed to human activity. I was taught in school that Glacial periods were regular Geolocial events, and that we were in a warm period between ice ages and sooner or later it would get cold again. (1950-1960s). Twelve or thirteen thousand years ago with ice covering Canada and northern Europe. I grew up living on a Terminal moraine at the situated at the southern end of Lake Michigan so something caused that melting and it wasn't industrial pollution. (They will return at some point!)
There are places that were dry land that now underwater...Doggerland in the the saddle between England and France that is now the English Channel, The Mediterranean sea was a lake , the Black Sea, a low land bridge between India and Ceylon. At some point the Glaciers broke up, and sea levels rose (most recently) by something like 90 meters inundating any ancient seacoast human settlement.
https://www.e-education.psu.edu/earth107/node/1496
The primary driver of weather is the amount of sun. Here is something that discusses one of the longest solar cycles and the periodic fluctuation in the amount of sunlight we recieve:
https://www.britannica.com/science/precession-of-the-equinoxes
More in depth and with some Art Bell flavoring!
https://consciouscalendars.com/precession-of-the-equinoxes-greatyear/
http://www.ancient-wisdom.com/precession.htm
And these: A PBS You tube; The Mediterranian as a dry salt sea!
https://www.youtube.com/watch?v=HooZ84rpovQ
And the Sahara with lakes and water and greenery..
https://www.youtube.com/watch?v=ZQP-7BPvvq0