Going Up?
There have been a flood of articles over the past couple days with the same overarching message: the climate crisis is irreversible and we have already moved beyond the threshold we’d need to stay below if we have any hope of avoiding the worst of the effects.
Most of the articles dwell on the rise of sea level, and the inevitable disruptions this will cause to coastal communities around the globe. Here’s one quote that summarizes the sentiment:
The international target to keep global temperature rise below 1.5C is already almost out of reach. But the new analysis found that even if fossil fuel emissions were rapidly slashed to meet it, sea levels would be rising by 1 centimeter a year by the end of the century, faster than the speed at which nations could build coastal defenses.
I encourage you to do your due diligence regarding the topic, but until then, I refer you to a blog post I offered in March of 2023 with the snappy title “Climate Change and Sea Level Rise” to fill you in on the salient details.
Going up and going down…rocks and water in a symphony of earth history. I just got back last night from a visit to the obducted Kalmiopsis ultramafics to see their signature flowers in bloom. So I drove past your old core shack again. Talk about some big ups and downs – from over 40,000′ down in Jurassic to 4000′ up now…
Global and local sea level change and related climate change are confusing topics for scientists, so they are almost impenetrable for the masses.
To put a finer point on what you are talking about, most of the post-glacial eustatic (global) sea level rise took place from 20,000 to 6,000 years ago. Only about 15 feet of the 400+ feet of rise has taken place in the last 6,000 years. So, it had much bigger effect on paleolithic geoman than on modern geoman. It’s just that there are so many more of us modern humans to panic and run around. In fact, sea level between the last two glacial maxima was about 16 feet higher than it is now – a depressing benchmark that we are steadily carbonizing our way towards.
“Refining the eustatic sea-level curve since the Last Glacial Maximum using far- and intermediate-field sites”, 1998, Earth and Planetary Science Letters 163 (1-4): 327-342
Natural variations of sea level and climate over long periods of time have been much larger than what humans are currently causing. There have been times in the more modern version of Earth (Phanerozoic) when carbon in the atmosphere was way more than 5 times more abundant or less than half as much as there is now. Temperatures varied accordingly. Nitrous oxide, a way more potent greenhouse gas, hit excessive highs at times in the Cretaceous. Inoxicated dinosaurs?
Relative sea level change (ie local land level vs local sea level) is confounding. It is analogous to the relation of global climate change to local weather. Global seal level is a rising signal on average because of global warming, but there are other signals to consider. Because the Atlantic is heating up quicker than the rest of the oceans, causing higher thermal expansion, the current relative sea level change along our east coast is more than along the other big oceans. Relative sea level is going DOWN in northern Canada due to glacial rebound, pushing the displaced water to rise more on other coasts. Man-made redirection of sedimentation and underground fluid withdrawals from coastal areas accentuate sea level rise in local areas, like the Gulf of Mexico/America/Trump. The lowered lateral gravity attraction of melting ice masses moves water around, following Newton and Einstein. Confusing, but real.
Same water, different reservoirs…