Did you know that over the last 450,000 years there have been four Ice Ages lasting around 100,000 years each?
And five interglacial periods lasting around 12,000 years each?
Look at this graph of temperature data derived from the Vostok ice core from Antarctica.
What it means is that for around 90 percent of the last 450,000 years Earth has been in an Ice Age, where global temperatures have slumped to as low as 10 deg C colder than in the relatively brief interglacial periods.
The current interglacial period (the fifth) began about 11,600 years ago, suggesting it may not last much longer. It corresponds to the time when human beings began farming and building cities and civilizations.
It is notably cooler than the previous four interglacial periods. If we ‘zoom in’ on it (see the upper graph, below)
We can see that it has been getting progressively cooler for the last 3,500 years, ‘presumably indicating the early stages of the coming Ice Age,’ says climate scientist Ole Humlum.
We also see that it is punctuated by periods warmer than the rest, most recently the Minoan warm period, the Roman warm period and the medieval warm period.
The current warm period after the ‘Little Ice Age’ of 1300-1850 (not shown as the graph ends in 1854), which according to Humlum has currently reached around the same temperature as the medieval warm period, may well be part of this natural pattern rather than driven by carbon dioxide emissions.
The lower graph shows CO2 concentration over the current interglacial period, and there is no obvious relationship with temperature.
Over a longer period, CO2 is seen to lag temperature by several thousand years rather than lead it, suggesting higher temperatures may drive greater CO2 concentrations rather than vice versa.
However, it is true that in the past 150 years CO2 concentrations have climbed from around 280 ppm to 395 ppm, a level unprecedented in the past 12,000 years [and a mere blink in Earth’s five-billion-year history].
Furthermore, since the end of the upper graph (in 1854) the temperature has risen to around the same balmy levels last seen in the Middle Ages. (This is assuming that the recent temperature data has not been misleadingly adjusted, as some believe is the case.)
This in itself is not alarming – the reported temperature rise is hardly unprecedented in the current interglacial period, and warmer temperatures (and higher carbon dioxide concentrations) provide better conditions for life to flourish.
However, if it is the case that current levels of carbon dioxide are driving runaway warming, that would obviously be deeply concerning.
That is the question current climate science is sharply focused on, though more often than not with only one acceptable answer, it seems.
Since the cost of cutting carbon dioxide emissions is huge, and will negatively affect the environment in other ways, it is well worth being sure that this is the case before taking any significant action to reduce emissions.
Despite much alarmism about a present ‘climate emergency,’ time does seem to be on our side.
While temperatures appear to have been rising on and off over the last century by about 0.15 deg C per decade, they did fall in the 1960s and 70s, and paused between 1998 and 2013, suggesting a degree of natural variability.
If temperatures continue to rise and eventually reach levels unprecedented in this (or any recent) interglacial period, then we’ll know there’s something to consider taking concerted action about, as there may be a risk that human emissions have initiated a positive feedback loop resulting in unsustainable temperature rises.
Though what counts as unsustainable is also an open question, as on a longer geological timescale we are currently in an extended ‘icehouse’ age of around 30 million years, whereas for 91 percent of the last 550 million years the Earth had no permanent ice caps at the poles at all.
From this perspective, how warm is too warm?
On the other hand, if we find temperatures stabilizing for a while, oscillating a bit, maybe falling again, then we can be more confident that we have not left the natural cycles.
Whether that is itself a good thing is a matter of debate.
In the 1970s, scientists were warning about the onset of a new Ice Age when Iceland was blocked with ice and ‘climate change’ meant global cooling. That turned out to be a false alarm, but the reasoning wasn’t entirely unsound.
The present interglacial period, if history is any guide, may have just about run its course. And what then? Human civilization has appeared and endured only during the present interglacial warmth.
How will more than 8 billion people cope with the much harsher conditions of a climate chilled by 6-8 deg C, one much less conducive to life, abundance and comfort?
Let us watch and wait for now, then, and see how things look in 2030. In the meantime, we shouldn’t take the present warmth for granted. We’ll miss it when it’s gone.
Read more at Conservative Woman
ice ages devolope very slowly.
Our infrastructure anyhow has to be rebuilt every few hundred years.
In an ice age, the population will live mainly underground.
Nuclear energy will provide power for greenhouses and synthetic meat factories.
I don’t want to be around for the next asteroid strike. Won’t be slow, or adaptable
In the meantime, we are approaching the weakest solar cycle in two centuries.
If the graphs above tell the truth, a new neoglacial stage may return.
https://urbancoldspots.blogspot.com/2020/01/verso-il-ciclo-solare-piu-debole-da-due.html
“How will more than 8 billion people cope with the much harsher conditions of a climate chilled by 6-8 deg C, one much less conducive to life, abundance and comfort?”
They will not. When we enter the next glaciation cycle, billions will starve. Malthus, from his vantage in Hell, will rejoice.
Really? Are you serious? We’ll ADAPT. We always do.
Not if we don’t have abundant inexpensive energy sources to deal with the much shorter growing seasons as well as a much smaller area to live and grow food.
A harshly colder planet will great reduce Earth’s food production capacity. Humans will adapt as much as they can but they’ll also seek life-sustaining condition in other parts of the solar system. That may also simply mean habitating in highly controlled biospheres drifting through interplanetary or even interstellar space.
You are an idiot Wilson, good thing is you are not alone.
It is a serious mistake to assume that ice core CO2 measurements are empirical measurements. Far from it. Jaworowski, a leading authority on ice cores, has described the trauma ice cores undergo during extraction from the high pressures of an ice sheet’s depths. Microfracturing could cause the loss of 30-50% of the gases in the trapped bubbles, let alone other chemical reactions which might remove CO2 from the bubbles. If you back calculate 40% into the ice core CO2 readings, we end up with CO2 concentrations exactly the same or even much higher than today. It is a mistake to compare ice core CO2 data with current atmospheric concentrations—apples and oranges.
The coincidental rise in CO2 and temperature in the late twentieth century is just that – coincidental. The simple fact that CO2 has risen to concentrations not seen in twelve million years while temperatures remain smack in the middle of our Holocene interglacial twelve thousand years proves that CO2 has an insignificant effect on climate. CO2 is, however, the basic ingredient molecule of life on earth, along with water. Water is abundant. CO2 is within 30ppm of lethal lows during glacial phases and the LOWEST level in 600 million years. A little more has been a Godsend for life on earth.
And to see that CO2 variation during our current ice age, you would have to examine the 180-280ppm variation of CO2 between the glacial and interglacial phases. (all life begins to die at CO2 levels of 100-150ppm) Multicellular life began ~600 million years ago in CO2 levels of 7000ppm. Never in that entire 600 million year (Phanerozoic) has there been “runaway global warming” in spite of CO2 levels up to twenty times that of today.
Excellent synopsis Will Jones. A few points… 1) The Vostock ice core 400,000 year period is part of our ONGOING Pleistocene/Holocene ice age (three million years long so far). This ice age is composed of both glacial and interglacial phases. They are likely caused by Milankovitch Eccentricity. CO2 does indeed lag temperature but by several hundred (not thousand years). CO2 solubility varies with temperature.
Let’s get the terms correct here.
An Ice Age is about 12 million years with alternating glacial and interglacial periods, roughly 80-90/10-12 in thousands of years, respectively. The interglacials were about 40k years apart until 500+k years ago when every other interglacial did not reach warm enough to be a true interglacial—these are called interstadials. The glacial periods on either side of an interstadial would be called stadials. Let’s just hope that the remaining interglacials do not start failing and we have 180k year glacial periods. That’s a long wait.
This is comedic. No-one with a formal education will EVER believe this shit. You will be irrelevant soon enough and fade away or eventually end up in prison like the dotard Racist-in-Chief. Shame on you for your role in spreading disinformation. Enjoy it while it last’s FUCKER. HAHAHAHAHAHHA🖕🏾
Let’s face it. Your response is neither helpful or demonstrates the “formal education” you tout. PLENTY of qualified climate scientists do not agree with the idea that the modest warming over the past 150 years constitutes a “climate crisis.” You cannot produce a “97% consensus” in this regard. Just FACT. Folks who subscribe to the scientific method understand the purpose of the null hypothesis and it’s value in physical science, NOT political science. So, I’m challenging YOUR critical thinking. If the alarmists have such a strong climate position, then engage in scientific debate. Further, offer a CLEAN, SCALABLE & SUSTAINABLE alternative to transition our energy system. A constructive SOLUTION to the alleged problem. Resorting to 5th grade play ground behavior is not constructive or WORTHY of serious consideration…
This is climate science Terry Wilson. Take some time to actually learn a little of it and you won’t be so hell bent to disgard the energy that provides the best fed, most prosperous, longest living conditions that human beings have ever enjoyed. Time to grow up now Terry. Barry Bateman, B.Sc. (biology)
Watch out where the Huskies go don’t you est that yellow snow. Lets hear it for Russia!! They know some real “stuff” when they step in it.
What an imbecile.
Warm = good. Lots of plant growth. Humans flourish.
Cold = death.
This is how the alarmist react when actual science is discussed. Devolve into foul violent language.
Trump is still The President. He keeps winning in every aspect. And he’ll have landslide reelection. And you are a really stupid moron and will be a really stupid moron forever. You waste of DNA you.
Terry Wilson – Why is that narrow-minded fools like yourself and so many others in positions high and low within our society choose to be idiotic in public? It takes more than a formal education to be smart and insightful. It takes presence of mind, analytic thinking and proper perspective to see things as they really are. Obviously, you either cannot or will not do so. Intelligent people who understand science and deep time can easily see the wisdom that has been described in this article. The Earth has been both very cold and very warm for very long periods of time, with episodes within each that were opposingly warmer and colder than the ongoing trends. IN all cases, carbon dioxide was not the driver of these climatic behaviors, but an indicator that they happened. It takes an understanding of cause-and-effect scenarios to grasps these concepts.
Just why should the author, Will Jones, go to jail? This not only violates freedom of speech but also undermines the free exchange of ideas which is the best way to converge on the truth. I guess that is the problem. The truth doesn’t support the climate political movement. If people were put in jail for spreading disinformation the prisons would be even more crowded. Consider all of the claims that hurricanes, wild fires, floods, and draughts are caused by climate change. Consider the claims that food production has suffered when the exact opposite is true. There are many other false claims. Terry, for the sake of people who have similar views to your self, be glad that they are not held accountable for their lies.