At the dawn of the Industrial Era in the middle of the eighteenth century, atmospheric CO2 concentrations were about 280 parts per million (ppm). Today, atmospheric CO2 concentrations are well above 400 ppm and show no sign of peaking. Even the global coronavirus pandemic, which seriously hurt the global economy, did not prevent it from continuing to grow to new record highs. The best-known world meteorological station measuring CO2 levels in the atmosphere—Mauna Loa on the Hawaiian Islands—reported a CO2 concentration of about 425 ppm in July 2024, up from 422 ppm in July 2023, 419 ppm in July 2022, 417 ppm in July 2021 and 415 ppm in July 2020. The last time our planet experienced similar CO2 levels was in the middle part of the Pliocene epoch, approximately 3.0–3.3 million years ago. During that past geological epoch, global temperatures were 2–3 °C and global sea levels were up to 25 meters higher than today. As discussed in Sect. 2.1 , scientific evidence suggests that the Earth’s climate system is well along on a trajectory of repeating the mid-Pliocene climatic conditions. Taking into account the rapid acceleration of global warming and climate change, some scientists estimate that it will take the Earth’s climate only 10–20 years to enter the mid-Pliocene epoch again [1]. Then, it will only be a matter of time before the Earth reaches similar air temperatures and sea levels, although raising sea levels to the very high mid-Pliocene levels will take many centuries if not millennia, due to the huge thermal inertia of the vast and deep ocean.