Current name is relative to current date because it talks about an event 4200 years ago. Any literature discussing this will be stuck with this relative name and eventually will become incorrect.
I understand why they don't want to use BC to name a global event that touched all cultures, and far before C was a thing.
Maybe it would make sense to adopt kurzgesagt's Human Era calendar, starting at approximate time of first human settlements. They call current year 12019.
EDIT: Early Modernity began around 1500 and Late Modernity (allegedly) ended in 1989. I think Postmodernity still has a few years left to play out.
Also, the radiocarbon dating itself (and thus the beginning of effective absolute dating) was invented around 1950, and nuclear weapon tests made everything after that point unsuitable for the radiocarbon dating. It would be natural to have that point as a reference for the "present" at least for now.
The calibration is there because the global 14C/12C ratio is not constant over the time, and the same procedure can be used given the recent history of ratios (that we do have). As far as I know, though, resulting error bars might be much larger than usual because the function from uncalibrated ("14C") years to calendar years is no more regular. For example see  where uncalibrated t2 and t3 can correspond to much larger periods than t1's; historically this happened only locally, but after 1950 it would be far more common. Still the radiocarbon dating can be used with this caveat .
That way we can have another shot at it being 1957.
Moreover, even our calendar and epoch has changed. Since Jesus pbuh was conceived nine months before he was born, the English used to record the beginning of the year as the 25th March OS before they adopted the Gregorian calendar. Therefore, the 20 March and the 30 March of the same year would have different numbers. (The general public still celebrate new years on the 1 January in this period, which can make dates between new years and lady day ambiguous.)
So unless you circuitously define a "calendar year" to mean "the calendar used for measuring compared to C", your statement is false. If you circuitously define it, it is a useless statement which says nothing more than "true statements which can be made about calendar length are true", which is unnecessarily specific while being at the same time redundant.
I thought he was conceived 4-5 years before he was born, if you're going to nitpick.
But the date of this event was determined by radioactive calibration. It's not measuring the same thing. It measures something that approximates human years.
This might seem like a trivial distinction to lay people, but it's relevant to the field, and the 4.2 k BP year event is a technical term.
This is subjective.
On the other hand going with a generic choice helps create a well defined universal language. This makes scientific cooperation across cultures easier.
Sample difficulties of going with culture-specific naming: https://en.m.wikipedia.org/wiki/Comparison_of_the_imperial_a...
> Maybe it would make sense to adopt kurzgesagt's Human Era calendar, starting at approximate time of first human settlements.
So what about calling it the settlement era, as humans were around before the first settlement, making "human era" a bad name to begin with. :)
It's not in the list you link, but it's a pretty neat read. Basically, the Mediterranean dried up and refilled about 6 million years ago.
Earth's climate has varied greatly over time but its the current rate of change that is so alarming. During the last ice age it was about 4.5 degrees colder but it took 10,000 years to reach modern temperatures. We're currently on a path to changes of that magnitude within the next 70-100 years.
And then more recently, after the last glacial period had ended, you had incidents like the Younger Dryas, for example, where temps plunged to near ice age levels (up to 6C drop in a few decades) and then rapidly warmed all of a sudden. If you read https://en.wikipedia.org/wiki/Younger_Dryas) some are suggesting that a warming episode at the end of the Younger Dryas occurred in as little as a few years and warmed global temps by 7C.
Note, that by the end of the Younger Dryas, the Arctic was as much as 7C hotter than it is today (https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019...).
There's thousands of papers on the Little Ice Age. It certainly shows up all over the world in the fossil record. https://www.sciencedirect.com/search/advanced?qs=little%20ic...
Those rapid global warming events were almost always highly destructive for life, causing mass extinctions such as at the end of the Permian, Triassic, or even mid-Cambrian periods. The symptoms from those events (huge and rapid carbon emissions, a big rapid jump in global temperatures, rising sea levels, ocean acidification, widespread oxygen-starved zones in the oceans) are all happening today with human-caused climate change. The outcomes for life on Earth were often dire. The end Permian extinction saw around 90% of species go extinct, and it left tropical regions on the planet lethally hot, too hot for complex life to survive. The Triassic extinction was another, one of the 5 biggest mass extinctions in the geological record. Even in the end Cretaceous extinction, in which dinosaurs were finally wiped out by an asteroid impact, a major global-warming extinction event was already underway causing a major extinction within 150,000 years of the impact. That global warming 66 million years ago was due to catastrophic eruptions in India, which emitted a pulse of CO2 that sent global temperatures soaring by 7°C (13°F).
So yes, the climate has changed before, and in most cases scientists know why. In all cases we see the same association between CO2 levels and global temperatures. And past examples of rapid carbon emissions offer no comfort at all for the likely outcome from today’s climate change."
I could have phrased it better, I'm talking about the temperature difference between the end of the last age and the current day.
> ...Dansgaard-Oeschger events
The recorded temperature swings are local rather than global, global temperature does not rise by five degrees in a matter of decades unless something catastrophic happens.
> There's thousands of papers on the Little Ice Age. It certainly shows up all over the world in the fossil record.
Yes, but average global temperatures were barely affected.
Even if you solve atmospheric conditions, CO2 and temperature, still you have the pollution of the waters, mass extinctions due to habitat loss, car-tyres rubbering off everywhere, unknown untested toxins even on your cloths. Thats like, not talked about.
EDIT: Cant believe somebody downvoted you. Yes nature has done fast changes, faster than human-induced change currently, and "nature" has mass-exterminated most of its life several times over, and other forms of life caused the deaths and biological disaster for most of other life on earth as well. These are facts.
Somehow these Greata climate activists, would like to believe that humans are more powerful in their destruction than cyanobacteria. Wishful thinking really.
Also, it is easy to pinpoint this issue to a little girl from Sweden, but unfortunately she is just repeating the general scientific consensus. Harder to argue against that, is it?
I'm beginning to think that countering illogical arguments with logical ones is actually some kind of tactical error in many situations - I have no idea what the alternative is but I increasingly feel that it is too easy to goad people (particularly those with some kind of scientific training) into types of arguments that really don't resonate with a lot of people.
My argument is, fuck the climatists, and their self-good crusade, since its not good, and their suggested solutions would actually cause more poverty and hurt poor people more.
My argument is, the rich are the problem, not pollution per se. 0.1% of the world population can pollute and destroy the environment of the rest. They can even ensalve the rest without destroying the environment.
Thats where the problem lies, oppression of the very few on the many, thats the problem we need to solve. The "climate atmospherists" are a side-show, stealing the light from the real issues.
EDIT: scientific consensus
Im not arguing against sci consensus, this climate issue is not "science" its politics, and should be treated as such. Everything is politics, remember that.
They are trying to use soft means like climate meetings and "targets of CO2", instead of spurring eco terrorism and beginning violence to save the planet. Thats a terrible path to take, to just "lets hold each others hands and sign really nice and come to a solution".
When the problem is caused by the same oppressive relationships now as it was 2000 years ago - slavery, and can only be solved with violence.
Have you been living under a rock? They're talked about all the time.
Kidnap CEOs of the fossil fuel industry, and citizen-jail Monsanto managers, you know... disruption.
This is how I know you've never engaged seriously with climate activists. These things are definitely talked about.
For example, leaf area index has increased by 8% since the 80s. CO2 is fertilizing plant growth.
If you listen to a lot of the hype, it seems it's all bad, when really it's a mixed bag of complex trade offs.
We currently track the "average annual daily global mean temperature" to somewhere around 4 digits of precision, with an accuracy of around 3 digits of precision (back in the day my university TAs would fail any lab report with inverse precision like that, but I'm no PhD in climate science), and with a time frame of hours. Estimated historic temperatures are presented with 2 or 3 digits of precision over a timeframe of centuries or kiloyears.
Saying current trends are unprecedented is motivational and technically correct, but not scientifically sound given the actual data. Well, science as in hard sciences like chemistry and physics in which we could run controlled experiments to generate confidence in our understanding; not soft sciences like economics or nutrition where controlled experiments would be unethical and results are only as good as the next product you're selling.
My point is that you can see the current short-term trends because we have precision and accuracy to be able to do that. We lack the precision and accuracy of historical data to be able to do that, which makes it an argumentum ad ignorantiam.
What this means is that the frequency and/or the intensity of these local outlier events can increase significantly. This is what man-made climate change means and we can still avoid most of the negative effects if we want to.
Often these local climate change events are taken as proof that 'climate has always changed'. Well, yes of course - but not on a global scale during human civilization as we know it.
Personally, imagining these events occuring during our lifetime, maybe several at once or just a couple of decades apart scares the crap out of me.
There is (possibly a minority) view that no, we can't, and things are far, far worse than people think. That contrary to the idea that people exaggerate the threat, in fact it's been minimized to the point where we are about as prepared for it as we would be for a large asteroid strike.
1.「4.2 Kiloyear event」 - A severe aridification event, occurring around 2200 B.C., that greatly contributed to the fall of the Akkadian empire.
2.「Medieval Warming Period」 - A warmer climate experienced especially in the Northern Hemisphere when Vikings and Inuit were moving to Greenland, around 800-1300 A.D.
3.「Little Ice Age」 - A cooler climate that eventually caused the demise of the Vikings, lasting from circa 1300-1850 A.D.
4.「The Holocene Era」 - Starting about 10,000 years ago, this era includes the Medieval Warming Period, the Little Ice Age, and continues all the way up until today!
How do you rule out random climate variation scientifically? I'm curious, do we have enough data to say one way or the other?
I'm hesitant to post this, since it seems like detached scientific conversation about climate change has been in short supply. But perhaps.
One does not preclude the other. Was the climate different, often hotter and drier, in the past? Sure. Evidence shows that it was.
But does that mean that we aren’t leading ourselves in to a short/medium-term catastrophe by dumping enormous amounts of CO2 in to the environment now? No. The two are unrelated.
Imagine if we determined that the climate was on a natural cycle, such that the entire Earth would warm, fires and droughts would become commonplace, and that sea levels would rise as a result of global temperature. Would we just do nothing? I’d hope not. I’d hope that it would spur us in to action, to realise that our quality of life is about to radically change, that human migration will necessarily increase, that people living near the sea, or depending on water, will have their lives irrevocably changed.
That has happened in the past. We just didn’t have such a complicated society at the time, so the impacts were less. If you count the extinction of the Egyptian society as “less”.
It’s also happening now, except we are doing it. Voluntarily, with full knowledge of the ultimate result.
That seems, to people like me, a bit silly.
People always seem to talk as though it's one or the other, but it seems to me essentially impossible that it's not both.
> and there is an underlying natural trend,
> and that adds significant uncertainty to the magnitude and sign of those two factors?
Ooh you were so close to the trifecta.
This isn't disputable as randomness any more than an object can be said to have randomly fallen to the ground when dropped.
Here is one of countless sources you can find that explain this principle and the consequences: https://www.climate.gov/news-features/understanding-climate/...
Doesn't this mean that the correlation between CO2 levels and temperatures isn't that big?
1. Our current carbon levels haven’t been high long enough for their total effects in temperature to be felt yet, given the size of the system they must affect. 50 years is a blip on geological timescales.
2. There are cascading effects to high CO2 levels that will take longer to manifest themselves and which will raises the temperatures further. Permafrost melting and releasing methane is a possible example.
Ozone depletion measured CFCs in parts per trillion (US short scale).
You ask "do we have enough data". Well, the same data that gives us evidence of prior climate events is the same data that shows human emissions are climatologically significant. So if we have enough data to study random changes, we have enough to study the changes we are causing.
If you want to take a stance against man-made climate change, you'll actually need to do your own research first and have a really good reason why it's wrong. Can you yourself list all the data sources that go into climatology and why they aren't adequate?
I had a longer comment prepared, but as you say, responding to accusations tends to get boring.
If you want to have a conversation about this, though, it would be nice.
Look sonny, I've been on HN since 2008. I guarantee you that people in the early days would have been nice about this topic.
My options here are to sit quietly and let people take turns kicking me in the stomach merely for asking a question, or to exit the conversation. I'll do the latter.
Have a good week.
In this thread you've been responding more to the meta comments than to the actual data people have posted. In a hot-button topic like this, that leads people to believe you are acting in bad faith. Do you have any response to the IPCC report, or to the other comments about CO2 and temperature data?
To me, it seems like (strong) evidence that climate can change.
And that there is a cause of this change, and that the cause that can be found. Maybe volcanic, meteoric, related to vegetation levels, or other?
Which is, I think, the _opposite_ of random. It is understandable and predictable.
> How do you rule out random climate variation scientifically?
Outside of quantum physics, "it was random" is not a scientific explanation. Science finds causes.
When applied to "our current climate change", the idea that climate can change and change a lot, in response to causes, well, that provides the opposite conclusion to yours doesn't it: we can see the causes this time.
Negative. It's quite possible (even likely) that the odds of a major hurricane hitting Florida next week are down to "a non-linear, dynamic system" and you're tying to predict which why the storm will "veer off wildly", while the average number and total intensity of storms over the next ten years is neither of those.
That allows us to reduce your question to how do we rule out that the increases in greenhouse gases are due to random variation?
For CO2, we can answer that by looking at different carbon isotopes. CO2 in living plants, CO2 in long dead plants, CO2 in volcanic gas emissions, and CO2 from weathering rock all have distinctly different ratios of carbon isotopes. By looking at the isotope distribution on the carbon in the atmosphere, we can show that most of the increase is from long dead plants--in other words, from burning coal and oil.
I am interested in the scientific methodology that rules out such variations and confirms that fossil fuels are in fact responsible.
The time period is an obvious one: we seem to be seeing spikes in one century vs millennia. But the details of those spikes matter in comparison to our total historical record; hence the curiosity.