Interesting what you find sometimes when you start riding a Google Train. One thing leads to another and then you find out that in the prior interglacials it was WARMER than today. All Natural.
While we saw some of that in the Florida Rising posting, this posting looks at new work done on Bering Sea sediments. From 4 to 5 Million years back, not just a few hundred thousand.
Which page is riddled with AGW Double Speak. A favored bit?
Scientists have identified many primary forcing mechanisms that contribute to the current global warming, but there is uncertainty about the relative impact of each forcing and associated feedbacks. The mid- Piacenzian presents the reverse situation: global data sets reveal the mature state of a warmer world, but the forcings that led to Pliocene warming are only partially identified. The data so far compiled by the Pliocene Research, Interpretation and Synoptic Mapping group (PRISM) suggest a combination of increased greenhouse gases and increased ocean heat transport acted concurrently through undetermined feedback relationships.
So it happened all by itself in the past, and we have little clue why, but “This time it’s different and MUST be because of us”. Yeah, right.
How about this one instead: Natural changes in ocean currents and solar output caused a warming cycle that liberated a load of CO2 from the oceans (which showed up with an 800 year lag after the warming as the deep ocean water turned over). That’s how I’d expect it to work. So what were the conditions then?
From this article:
Bering Sea was ice-free and full of life during last warm period, study finds
December 13, 2010 By Donna Hesterman
UCSC ocean scientist Christina Ravelo and Alan Mix of Oregon State University show off a record-breaking sediment core section during the Bering Sea expedition. Ravelo (below) was co-chief scientist of the expedition on the RV Joides Resolution. Photo credit: Carlos Alvarez Zarikian, IODP/TAMU.
Deep sediment cores retrieved from the Bering Sea floor indicate that the region was ice-free all year and biological productivity was high during the last major warm period in Earth’s climate history.
Gee. It was a lot warmer then. “Biological productivity” was higher. As in “more food” and “easier living”…
And it was all natural
The researchers drilled down 700 meters through rock and sludge to retrieve sediments deposited during the Pliocene Warm Period, 3.5 to 4.5 million years ago.
“Evidence from the Pliocene Warm Period is relevant to studies of current climate change because it was the last time in our Earth’s history when global temperatures were higher than today,” Ravelo said.
Carbon dioxide levels during the Pliocene Warm Period were also comparable to levels today, and average temperatures were a few degrees higher,
I’m sure the Warmistas will try to spin this that the CO2 caused the warming, but who was burning all the oil and driving SUVs then? Hmmm? Oh, and there is the little problem of the 800 year lag between warming and when the CO2 shows up…
So to me it’s pretty dramatic confirmation that CO2 levels NATURALLY were higher at the same time it NATURALLY was warmer; and the warmth drove the CO2 out of the ocean just as the gas laws predict.
And it all happened with NO human intervention as the only “people” around then were more like smart chimpanzees than modern humans.
Current observations show more rapid warming in the Arctic compared to other places on Earth and compared to what was expected based on global climate models.
Ravelo’s team found evidence of similar amplified warming at the poles during the Pliocene Warm Period. Analysis of the sediment samples indicated that average sea surface temperatures in the Bering Sea were at least 5 degrees Celsius warmer than today, while average global temperatures were only 3 degrees warmer than today.
Gee, and the Arctic was a whole lot hotter than now. So the hotter Arctic now is caused by us but the hotter Arctic then was caused by nature? But the good news is that with a 5 C hotter Arctic, we didn’t hit any “tipping point”. We have an “existence proof” now that it doesn’t exist.
Samples from the expedition showed evidence of consistently high biological productivity in the Bering Sea throughout the past five million years.
This I find quite fascinating. They don’t say much about when the higher productivity stopped. But “throughout the past five million years” says it had to be “recently” on a geological time scale. Something has changed about the North Pacific water flow.
In addition, samples from the Pliocene Warm Period include deep-water organisms that require more oxygenated conditions than exist today, suggesting that the mixing of water layers in the Bering Sea was greater than it is now, Ravelo said.
“We usually think of the ocean as being more stratified during warm periods, with less vertical movement in the water column,” she said. “If the ocean was actually overturning more during a period when it was warmer than today, then we may need to change our thinking about ocean circulation.”
Well, so much for yet more “Settle Science”. If we “need to change our thinking about ocean circulation” we don’t know diddly about what makes this system work. Looks like we can put to bed all the paranoid fantasies about stagnation and stratification of the ocean as well. Oh, and the “acidification” of the ocean arguments. Since we have had similar high CO2; and everything, well, lived (and lived well from the looks of it) that whole “ocean can’t take it” angle is toast. Can you say “Existence Proof”? I knew you could…
Today, the Bering Sea is ice-free only during the summer, but the sediment samples indicate it was ice-free year-round during the Pliocene Warm Period. According to Ravelo, the samples showed no evidence of the pebbles and other debris that ice floes carry from the land out to sea and deposit on the seafloor as they melt. In addition, the researchers didn’t find any of the microorganisms typically associated with sea ice, she said.
Well, so much for the idea that if we lose the Arctic Ice Cap all hell breaks lose and that we’ve never had the North Pole ice free. It was hotter. There was no ice. Then it got colder and we went back into the subsequent Glacial period.
I’ve not used this particular graph before. I usually start with the second graph that shows the history of the most recent ice ages. But since this story is about times further back in history, a bit more context will be in order.
OK, the time we’re talking about is back about that 4 Million Years Before Present point (MYBP).
Look at the chart for a moment. Notice the trend. From upper left to lower right. Cooling. Think about it.
Notice that about 2.5 MYBP to 1 MYBP we used to pop up to warmer about every 41,000 years and had less extreme cycles. Now it’s only about every 100,000 years. As were getting steadily colder, we’re also slowing down the rate of cycles and the frequency with which we have a brief warm period. Again, think about it…
Now look at that period between about 3 MYBP and 5.25 MYBP. It was fairly uniformly within 2 C of, well, right now. The “natural state” for the last 2.5 MY has been Ice Ages. Most of Europe, Asia, and North America under glacial ice. Brief visits to our present world of green and warm. Then a plunge back into the freezer. The only “tipping point” is to the downside. To freezing. That first couple of million years says so. Warmer than now and things just steady out and dampen. Colder and things go unstable with wider ranges to the downside. Think about it some more.
So, if we tried Really Really hard, and managed to create horrible global warming with scads of CO2 just like back in the 5 MYBP Pliocene, it MIGHT get 2 C warmer. And basically the world would stay about like it is now. If it cools off just a bit, we plunge back into an Ice Age Glacial at 8 C to 10 C colder than now as a global average.
OK, got that context?
Here’s that last bit blown up larger so you can see each of those little peaks spread out to 100,000 year saw tooth shaped events.
We’ve seen this one before, but just as a reminder, the ice is “upside down” so a “peak” is when there is no ice during an interglacial. Most of the time the ice volume is very large (the curve is below the dotted line by a lot).
Notice that the prior “Interglacial warm spikes” have been higher than this one. Warmer. We didn’t spike as high, but we’re spreading it out a bit more; about the same interval of time as the other spikes had above the dotted line, just we’re staying closer to “smack on” that line. Next stop, however, is down.
It looks to me like we have absolutely nothing to fear from a warmer world. The world has been there before, even as recently as 120,000 years ago. It stayed there for several millions of years during the years that formed our species (and during the time that most species on this planet developed – they have nothing to fear from a warmer world either). But over the last 5 million years the climate has become more unstable and volatile due to our consistent cooling trend.
The recent interglacials all show us that this present warm time will not last. We’re near the end as it is. They also show us that it’s a rapid ride down to cold, then 80,000 years or so of accumulating ice and increasing dustiness. Dust? Yeah, dust:
(Note that time runs “the other way” in this graph. “Now” is on the left.)
Each warm spike ends with a plunge to cold, then a partial recovery from the overshoot, back onto the sawtooth pattern down. And the added cold starts washing the CO2 out of the air, back into ices and cold oceans. (CO2 dissolves much better in cold water – a known gas law.)
Look at those low CO2 levels. Below 200 PPM plants basically suffocate. Productivity drops dramatically. Cold oceans don’t evaporate well, and extreme polar cold sucks moisture from the air to make those giant glacier sheets. Which grow steadily until the glacial ends. I would also note that with each cycle the dust has gotten worse (it’s a harder drought) and the ‘high ice period’ is longer. We gain ice faster and sit ‘fully frozen’ a bit longer. The ice age glacials are each just a little worse than the last.
An Ice Age Glacial is a cold, dead, dry, dusty desert place.
So, we have a warm, pleasant, stable, life filled world when it’s warm, or a volatile, hostile, cold, dry, dead, dusty desert when it’s cold.
Ah, I think I’d rather have a bit of the warm, please…
Now ‘the bad news’ is that this cycle runs all on it’s own. Even the CO2. Not a thing we can do about it as near as I can tell. The good news is that it takes a few thousand years before anything really bad happens.
If by some fantastic means we find that liberating CO2 DOES warm the globe, it will be the greatest blessing we could bestow upon the planet to preserve it in the present state. Canada and Europe under a mile of ice will not have much “biodiversity”.