Global warming is real. It is caused by the oceans heating up due to increased tectonic activity (subsea rifting and undersea volcanoes). They also release alot of Carbon Dioxide, hence the historical increased Carbon Dioxide concentrations in the atmosphere AFTER the temperature rise. The correlation is perfect, but the CO2 lags the temperature record.
The world's major (and some minor) navies know this. Ocean temperature profiles are critical to ASW (Anti-Submarine Warfare) so these have been measured at least since WWI. Ambient subsea noise and directionality is also important to ASW and these too have been measured for a long time. Undersea volcanoes and rifting generate massive changes in both local temperatures and ambient noise. The navies of the major powers and many of the secondary powers are all well aware of this. Unfortunately that data is almost always "classified" as state secrets.
