Comment by echelon | Hacker News Reader

Comment by echelon | Hacker News Reader

We're technically still in an ice age [1]. How far does this need to go to reach the end of that ice age [2]?

The Cretaceous period was over ten degrees warmer than our current period [3,4,5]. It supported a lot (though much different) biodiversity. How long would it take us to push into these temperature ranges? And how long to exceed them?

How much species diversity will we lose at each half degree increment from this point forward? Will we see some species better equipped (increased as opposed to decreased fitness) by temperature increases? Will we see any quick evolution to support climage changes?

When will temperatures be incompatible with ranges necessary to sustain society? When will they be incompatible with human life? And all terrestrial and aquatic animal life? Will runaway heating (clatrate gun [6], etc.) be capable of achieving any of these?

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[1] https://en.wikipedia.org/wiki/Ice_age "Earth is currently in the ice age called Quaternary glaciation."

[2] https://en.wikipedia.org/wiki/Quaternary_glaciation "To geologists, an ice age is defined by the presence of large amounts of land-based ice." (So my question in terms of heating and time - how long until we exit the ice age?)

[3] https://en.wikipedia.org/wiki/Cretaceous "Mean annual temperatures at the poles during the MKH exceeded 14 °C.", "deep ocean temperatures were as much as 15 to 20 °C (27 to 36 °F) warmer than today's"

[4] https://en.wikipedia.org/wiki/Cretaceous_Thermal_Maximum "Late Cenomanian sea surface temperatures (SSTs) in the equatorial Atlantic Ocean were substantially warmer than today (~27-29°C). Turonian equatorial SSTs are conservatively estimated based on δ18O and high pCO2 estimates to have been ~32°C, but may have been as high as 36°C."

[5] https://www.nature.com/articles/ngeo1081 "During this period, we find sea-surface temperatures exceeding 32 °C at 15°–20° N and averaging 26 °C at ∼53° S. These temperatures substantially exceed modern temperatures at equivalent latitudes,"

[6] https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis (truly horrifying)

Climate change deniers tell each other we are coming out of The Little Ice Age that started in 1200AD. Which is technically correct.

What they don’t tell each other is that “Little” is an understatement and we shot way past the prior “Medieval Warm Period” long ago and are only accelerating.

https://en.m.wikipedia.org/wiki/Little_Ice_Age#/media/File%3...

People believe we are coming out of an ice age?

This means they deny climate is changing.

The more you know…

It's not belief...This is a pretty accepted fact, the debate amongst the educated is about the speed and causes of the change (man-made vs not)

I just checked on them a few days ago.

Their current messaging is back to:

“Climate change is a hoax for science grants and political power”

Many issues over humanity it has been the case that someone lied for power.

Insane that these idiots picked the one time a problem is actually really real as the time they decided to call out the tactic.

> Insane that these idiots picked the one time a problem is actually really real as the time they decided to call out the tactic.

If you take every shot you're probably going to miss a lot.

Latest trend is "warming (which is normal) is increasing co2, but the other way around". From the same people who think co2 levels are too low to be significant and that water vapor is more problematic.

I read what you wrote several times and I still don't understand what your point is.

Can you please elaborate?

eschelon said that we are in an ice age and multiple people asked “how can you call this an ice age?” I either didn’t see the linked reference or it wasn’t there when I read eschelon’s comment.

Either way, I’ve seen the Little Ice Age come up enough lately to be extremely irritating. So, I knee-jerked the rebuttal.

Now I think eschelon was actually asking if we are overriding the https://en.m.wikipedia.org/wiki/Quaternary_glaciation which would normally take millions of years to happen.

> I either didn't see the linked reference or it wasn't there when I read eschelon's comment.

It wasn't there. echelon added the references later, presumably en lieu of responding to everyone. Everything below the -- is new.

Thank you for the honesty

I'm not a climate change denier. I'm very interested in climate science, I'm just not informed as I'd like to be.

I edited my comment to include sources for things I knew off-hand. I left the core comment largely intact, just changing a few words to better flow with the sources.

I want more information and reading around the questions I asked.

From my understanding, it looks like we're about to enter a period that is actually slightly more sustainable for humans on average (increases in arable land, easier to access hydrocarbons - yikes) [1].

But from there, we may quickly slip into ranges that kill everything. Especially if the Clathrate gun hypothesis [2] or similar runaway mechanisms turn out correct.

And obviously even if slightly warmer temperatures are better for people on average, every temperature increment results in enormous and permanent erasure of species diversity. That's an incalculable loss that we cannot recover.

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[1] https://www.nytimes.com/interactive/2020/12/16/magazine/russ... "And no country may be better positioned to capitalize on climate change than Russia. Russia has the largest land mass by far of any northern nation. It is positioned farther north than all of its South Asian neighbors, which collectively are home to the largest global population fending off displacement from rising seas, drought and an overheating climate. Like Canada, Russia is rich in resources and land, with room to grow. Its crop production is expected to be boosted by warming temperatures over the coming decades even as farm yields in the United States, Europe and India are all forecast to decrease. And whether by accident or cunning strategy or, most likely, some combination of the two, the steps its leaders have steadily taken — planting flags in the Arctic and propping up domestic grain production among them — have increasingly positioned Russia to regain its superpower mantle in a warmer world." (There are lots of other geopolitical takes on climate change that cite similar outcomes for a host of other countries.)

[2] https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis

Considering that the tropics only contain a third of the land mass it makes sense for humanity to not fight this warming.

Its possible to think that, but at the aame time the cost of adjustment would be trememndous.

I would think food costs would skyrocket before canada and siberia are pumping out grain in massive quantity.

Adjustment at that scale can also carry other risk such as disease and civil war.

Or nothing at all may happen

It really does depend on the rate of change.

It's going to happen slowly enough. Right now we enjoy a few extra days growing season.

That chart covers a very short duration. Here's a more complete chart of Earth's temperature:

https://en.wikipedia.org/wiki/Geologic_temperature_record#/m...

As you can see, we are indeed coming out of one of the coldest periods ever in Earth's history.

... and based on that chart are now hotter than any time in the last 100k years, heading into the last few million. A few 10s (of million) years at +25c are going to be the "new normal"? I'm trying to understand the point. The rate of change is quite dramatic, and the last time (Eemian) there was anything like this there were "rapid" 12c oscillations.

Humans didn't exist. I suspect most current plant/animal species are "devolved" by such swings.

Don't know about op's point, but seeing those kinds of graphs makes you really think twice about the hypothesis that stopping any kind of human activity will have any effect on a phenomenon that's been naturally occuring for hundreds of millions of years, on one order of magnitude greater than what we're observing (talking about degrees variation, not taking speed into account).

> talking about degrees variation, not taking speed into account

If you discount this of course we aren't effecting anything unprecedented. We were once a ball of magma. But, as has been pointed out here, rate and cause of change is incredibly important. A swing set and an explosion will both launch you into the air.

>and based on that chart are now hotter than any time in the last 100k years, heading into the last few million. A few 10s (of million) years at +25c are going to be the "new normal"?

No, the chart does not say that. The 2050 and 2100 dots are projections from the IPOC RCP8.5 “high emissions” scenario. Also, absolutely nothing on that says we’re going to +25c. That part of the chart (that goes to 25) is in F, and it still doesn’t say we’re going to 25f either.

Lots of people wonder why we have so many climate deniers. A lot of the reason is because of guys like this ^ on the opposite end of the spectrum, spewing their fears into a hyperbolic, warped reality. What we need more of is a balanced, realistic, objective view. That will allow us to get to work on a solution.

Thank you for pointing out that the right side of the graph is labeled in F and the left label is in C.

> Humans didn't exist. I suspect most current plant/animal species are "devolved" by such swings.

The first apes evolved about 20 million years ago, when the world was much hotter. I suspect we can survive those conditions again.

And regardless of climate change, most current plant/animal species will go extinct (or already have) due to habitat destruction and mass exploitation. As a cause of mass extinction, that's a much bigger problem than climate change.

Looks to me more like we were in a very long, very cool period and are suddenly popping out of it and are only accelerating. That’s fine for the planet. But, sucks pretty hard for any life forms that evolved to fit the Earth in the last 10 million years according to that chart.

It looks very long because of the scale of the chart. But everything on the right half of the chart would fit in a few pixels on the left side.

no, scientists do too.

https://www.space.com/climate-change-termination-event-end-i...

Even if that is the case, the agriculture needed to feed the amount of people on the planet doesn't seem like it will survive and be efficient if this keeps on going. It doesn't matter if it's human-made or not, if we don't get it under control, a whole lot of people will die and the current amount of refugees will seem quaint in comparison.

The planet will probably be fine in a few hundred thousand years, it's just us humans that are not going to be here.

> agriculture needed to feed the amount of people doesn't seem like it will survive and be efficient if this keeps on going

The earth is getting greener, rapidly. The maximum human carrying capacity is probably higher than ever and populations are shrinking at the same time.

https://www.nasa.gov/feature/goddard/2016/carbon-dioxide-fer...

That is irrelevant to the quote you cited.

Hint: The green stuff is food, for either humans or animals humans can eat.

Yes, good job. Let’s dig a little deeper though.

In terms of useful agricultural output, how many acres of “greening” do you think we might need to offset the loss of one well maintained acre of arable farmland?

> The earth is getting greener, rapidly

https://skepticalscience.com/co2-plant-food-basic.htm

https://skepticalscience.com/co2-plant-food-advanced.htm

> The maximum human carrying capacity is probably higher than ever

https://www.mdpi.com/2673-4060/4/3/32

The Human Ecology of Overshoot: Why a Major ‘Population Correction’ Is Inevitable

> Plants cannot live on CO2 alone

Not my claim. We also have plenty of fossil fuels to put into the Haber process until we transition into fusion, even if that's in the distant future.

> The Human Ecology of Overshoot: Why a Major ‘Population Correction’ Is Inevitable

> Homo sapiens has evolved to reproduce exponentially

Sure, humans do that until they industrialize, then they slow down.

>> (OP) the agriculture needed to feed the amount of people on the planet doesn't seem like it will survive

> (you) The earth is getting greener, rapidly. The maximum human carrying capacity is probably higher

The actual myth (read beyond the title):

"CO2 is actually the "food" that sustains essentially all plants on the face of the earth, as well as those in the sea. And the more CO2 they "eat" (absorb from the air or water), the bigger and better they grow"

As I understand this exchange, you've challenged the claim that climate change will negatively impact agriculture by pointing out that Earth is getting greener, supported by yours

> Hint: The green stuff is food, for either humans or animals humans can eat.

The page I've linked debunks exactly this.

> A specific plant’s response to excess CO2 is sensitive to a variety of factors, including but not limited to: age, genetic variations, functional types, time of year, atmospheric composition, competing plants, disease and pest opportunities, moisture content, nutrient availability, temperature, and sunlight availability. The continued increase of CO2 will represent a powerful forcing agent for a wide variety of changes critical to the success of many plants, affecting natural ecosystems and with large implications for global food production. The global increase of CO2 is thus a grand biological experiment, with countless complications that make the net effect of this increase very difficult to predict with any appreciable level of detail.

> Sure, humans do that until they industrialize, then they slow down.

Overshoot is not only about population, but also about consumption and pollution.

Commenters seem to be taking these questions as rhetorical (which they may well be, I can’t really tell), but I’d actually be intellectually interested in genuine answers to them.

It’s pretty useless to debate biodiversity and keeping it intact because the real killer is not the temperature increase by a degree or two but the speed.

Here is a climate professor's site he and his associates are warning of imminent mass human extinction. https://arctic-news.blogspot.com/ Dig back through his posts they are horrifying.

As far as I can tell this site is run by an amateur, not a "climate professor".

It is written by an actual Rutgers Professor who writes it under a pseudonym to insulate themselves from doxing. With occasional guest contributions from an Australian professor.

I think it’s an ice age while any point on earth (not counting mountains etc.) has year-round ice. We’ll be in serious trouble long before that changes.

As I understand it, there was no glacial ice on earth during the Cretaceous. Water covered much more of the earth's surface. There were lots of dinosaurs, insects, and other biodiversity that thrived during this time.

Our current biodiversity evolved to fit cooler temperatures, obviously, so the quick change is a huge fitness gradient challenge that many species will not overcome. And in certain food webs, it may result in much larger scale collapse.

I think humans are one of those species, as they cannot survive wet bulb over 95f nor can current populations survive across the collapse of agriculture, hence the problem

That doesn't take technology into account, though. Not arguing one way or the other, but humans are well advanced beyond any species, and are ingenious and inventive to boot. I don't think humans are so easy to wipe out, not on the timeline predicted.

Not at all. Many humans are definitely surviving this no matter what. It's just the extra 2 billion or so that won't have access to whatever new "technology" is needed to survive.

Yeah, it is a mistake to worry about the earth in regards to climate change. It will be fine. Biodiversity may in fact increase after the bottleneck. Humans though, or at least human civilization...

That's what I'd really like to read an abundance of information on. Timelines, milestones, etc.

At what stages do fishing and agriculture end? When do our brains overheat? Etc.

In the short term, we're possibly going to have an even better time of sustaining human life and society (see my other comments' sources). Until things progress even further and we severely damage our civilization and possibly kill ourselves off.

What are the things we can do to cope, what are the things we can do to slow or reverse the temperature trend, and what ranges do these things happen?

Can we stop? How? Where should we stop? Should we return back to where we were? Or should we keep going further and then stop? At some point this becomes a biogeoengineering problem.

I have so many questions.

> no glacial ice on earth during the Cretaceous

That’s not quite what the evidence shows. The Cretaceous shows evidence for forest near the poles and it’s missing evidence for multiple mile thick ice sheets such as those that recently covered Manhattan Island etc. However currently there’s a glacier 170 km from the equator as altitude drops the temperature, such glaciers likely existed in the Cretaceous.

> The Cretaceous period was over ten degrees warmer than our current period [3,4,5]. It supported a lot (though much different) biodiversity.

Humans don’t evolve very fast, it’s going to be very very uncomfortable to be part of that “much different” biodiversity and kill a lot of people

What is your source for saying that we're in an ice age? And do you mean ten degrees C or F?

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