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Another great podcast!

I feel like I should share this with the people here because it was something that got me so excited to find and it might excite the people here too!

This is not an ad:

I recently discovered a handful of what are being called “ethical banks.” These banks are using their resources to tackle important issues. The one that I switched to is trying to help the climate change issue. The bank is called Aspiration. What got me excited about them is that for every transaction made on their debit card, they will have a tree planted! This is one of the many cool things they are doing including helping their customers to invest in “green” technologies. I’ll stop talking now. But if you are looking for something like that, go give them a look.

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That chevron video was hilarious I thought it was real for half of it. Which was terrifying and angered me thinking how the fuck can chevron get away with this bullshit. This type of comedy reminds me of the Yes Men

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A wonderful conversation. I would love to know Charlie's take on Graham Hancock's new TV series on Netflix "Ancient Apocalypse," which posits the end of the Younger Dryas was caused by a cometary impact.

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@Junkie Thanks for your question. I did not know who Graham Hancock was until I looked him up just now. From what I've just read, it seems that "Ancient Apocalypse" attacks the viewpoint of most archaeologists and paleoclimatologists who study this fascinating climate period. The show has attracted widespread attention and skepticism. My viewpoint is influenced by my profession (climate science) which has been under overt and covert attack by conspiracy theorists funded by the petrochemical industry for decades. Their goal is raise uncertainty and doubt about the findings of climate "experts" (like me), often to promote their own agenda ("drill, baby, drill!"). I feel sympathy for the archaeologists whose careful, career-long, evidence-based work is now questioned by millions of viewers of Hancock's sensational-sounding theories, at least those about an "advanced ice age civilization". It's a poor comparison since Hancock is probably not backed by any deep-funded industry, yet his tactics of repeating claims with only cherry-picked evidence (and neglecting the bulk of the countervailing evidence) seem similar to those of climate-change-deniers.

Unless/until I see the documentary, I can't add any specific comments about the robustness of Hancock's theories. It's important for scientists to understand the public's perceptions about our fields' great questions, because they fund us (through taxes) and deserve the best answers we can give. I like a good story so I'll probably do with Hancock's special what I did with "The Day After Tomorrow": watch it (with popcorn) and then turn it into a teaching experience. Doubtless many of my students will have seen it so I can ask them to support or refute specific links in his chain of reasoning based on the climate physics that we have learned in class.

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Hey Charlie. Thanks so much for dropping in to respond to questions. I was considering reaching out to you on some of these topics, but decided it would be asking too much to do so. I've had Graham on the podcast, and I've read one of his books. He's a nice guy, but I'm unconvinced by his arguments. Of course, I don't have the expertise to evaluate every claim, but I'm sympathetic with the argument that his theories have an unspoken context of racial superiority (How could those primitives have possibly figured out how to build such advanced temples/calendars/roads, etc.?). People are fucking smart, and have been for a long time (contemporary brains are about 10% smaller, by volume, than the brains of our ancestors 20,000 years ago). As for conspiracies, I just learned yesterday, from this review, that Hancock's son is the head of the department that contracts shows like this at Netflix.

https://www.theguardian.com/tv-and-radio/2022/nov/23/ancient-apocalypse-is-the-most-dangerous-show-on-netflix

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"The most dangerous show on Netflix"? Come on, more dangerous than The Great British Baking Show?! ;)

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These are the episodes I really enjoy!

I was surprised to hear Charlie say the 100k to 12k year glacial cycle stretched back 2 million years. I was under the impression that before the mid-Pleistocene Transition (between 1.2 million years and 700,000 years ago) the cycle was closer to 40k glacial and ~12k interglacial. This would have major implications in human evolution.

Regardless, this was a really important discussion to have. The science behind climate change needs to be disseminated far and wide to strengthen the average person's confidence in the science. Charlie really opened the world of climate to us!

There are two images from two different climate studies that I go back to again and again. They give you a sense of the earth's climatic past and answer many questions that might materialize. Plus its fun just exploring them.

The second figure, in particular, shows how long lasting the Antarctic ice sheets have been and how if they disappear we are probably really fucked...

Here's a link to the two figures if anyone is interested https://dawnofsapiens.com/climate/ If anyone needs access to the research papers themselves leave a comment.

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@Andrew, thanks for pointing out that the glacial cycles were shorter in the early-to-mid than in the mid-to-late (i.e., today) Pleistocene. One of the dangerous opportunities of speaking outside the realm of my direct expertise is ... learning from those who know more. Indeed, the 100-thousand year cycle only "emerged" from the shorter 40-thousand year cycle about a million years ago. During this part of the podcast we were discussing the large climate changes that have occurred only due to natural causes, such as orbital periods. So it's interesting to note how the internal dynamics of Earth's climate switch from one periodicity to another without any human influence. In other words, climate is a chaotic system where small impulses can produce large responses, like the "butterfly effect". Wikipedia also has an abundance of further paleoclimate information, including here https://en.wikipedia.org/wiki/Marine_isotope_stages

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No worries Charlie! More than anything I was wondering out loud if my impression was outdated. Its been several years since I went down the rabbit hole of paleoclimate and these days research moves at the speed of light.

I'm curious how you perceive time when it comes to your research and discussing it. I've noticed that when it comes to climate, and especially evolution, points of interest are discussed in a linear fashion but the space (time) between these points, or even the width of the points (events) themselves, are discounted. For instance, on a geological timescale the mid-Pleistocene Transition is a blink of an eye (~500 ky) but from a human evolutionary perspective the span of all H. sapiens existence fits within the same amount of time. In other words the totality of our species existence fits inside this single event (or point) of glacial cycles transitioning from 40k year cycles to 100k year cycles.

If the MPT is compared to the current climate situation (100s or maybe several thousand years?) and its projection, isn't the climate change orders of magnitude faster? Does it make sense to talk about "changing climates" without acknowledging the time scale of the specific events?

Just to be clear, I'm referring to how the general public tends to perceive and discuss events on different time scales and not how you accurately described them in the episode.

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> If the MPT is compared to the current climate situation (100s or maybe several thousand years?) and its projection, isn't the climate change orders of magnitude faster?

Yes, most natural climate change (including the MPT) is slow, not abrupt like current (human-made) climate change. The current "forcing" is anthropogenic pollution, 99% of which has been been emitted in the last century. Natural abrupt climate changes have occurred (e.g., the Younger Dryas), and are fascinating because, unless there is a smoking gun (e.g., traceable impact event or eruption), we don't know what caused them. The abrupt natural climate change tells us Nature has tipping points that we need to better understand, which makes the current anthropogenic climate change all the more dangerous.

> Does it make sense to talk about "changing climates" without acknowledging the time scale of the specific events?

Everyone, though especially non-experts, can become overwhelmed by the number of qualifiers and bounds needed to make a statistically robust statement about climate. Climate scientists are prettly likely to specify the relevant timescales in journal articles, and less likely to in public discussions for lay audiences to avoid drowning them in details. That said, present day greenhouse gas concentrations (a proxy for climate "forcing") are at their highest level in the past few million years. On the podcast we stuck to the pleistocene (last ~2 million years) during which our species evolved, and the rate and magnitude of present day climate change is comparable to or greater than ANY changes during this period.

It's strange to me that some people are apparently unperturbed by the fact that humans are creating a climate unlike any our species has ever experienced. The accelerated pace of this change is itself a problem, since ecosystems that have evolved slowly may crash (e.g., cod fisheries, coral reefs, ice shelves) if pushed too hard. So it is important to emphasize the consequences of both the magnitude and the pace of climate change.

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Cheers Charlie,

The implications of your last paragraph are morbidly fascinating.

I'm thinking of wet-bulb temperatures and the limits of human thermoregulation via evaporative sweating. In the not too distant future there may be "humidity deserts" (even if transitory in nature) in regions that are too hot and humid for humans to survive. Forced migration out of these areas will run head first into the current anti-migrant political climate. There's all sorts of upheavals on the horizon.

This New York Times feature captures how this process is already starting:

https://www.nytimes.com/interactive/2022/11/18/world/middleeast/extreme-heat.html

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Lovely episode - Charlie is a good speaker :)

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