There is a new study out that indicates that the rate at which climate change could occur is much higher than previously known or assumed.
Those of us who study actual (historical) evolution, looking at fossils and geological layers and such, have always known that the possible rates of change in earth systems and biological systems are much higher than what we can estimate by looking at the present day. There are two reasons for this. One is a glitch in the uniformitarianism principle, the idea that processes in the past must have been the same as processes we observe today. The glitch has to so with bias. Rare events, which likely include rapid change, are rarely observed, and the time range over which scientists have been observing and recording things is too short to have seen very many such events. So, in effect, processes in the past may have features that we do not observe today, not because they can't happen today but because they are rare and we've only been closely watching for a few generations.
The second reason is that we happen to have been, until recently, living in a period of less rapid change because of the nature of the Earth's climate. Consider living on the Nullarbor Plain of southern Australia during the end of the last glacial, when sea level rise was very rapid for a few thousand years. This is one of the flattest places on earth, and is divided into two parts. The upper part makes up part of modern Australia's landscape, but the lower part rests beneath the sea. It is very likely that even moderately fast sea level rise on that lower plain, which was exposed during the last glacial maximum, would have been noticed by anyone living there (and there were people living there). The most rapid sea level rise across an essentially flat region may have even been catastrophic. The tide goes in. It does not go out. Take a trip inland to hunt some kangaroo because you are tire of seafood, and the sea follows you. Since we don't see such events today, we have a hard time relating to them, and in particular, we have a hard time estimating just how fast they can happen.
Meanwhile, the fossil record of both species (newly evolved, newly extinct, or just moved in or out of a region) and ecological conditions tends to show a lot of abrupt change. We assume most of that abruptness is because the readable geological record is formed during certain periods of time, and during other times, things that happen are not recorded. We are less likely to spot a period of change in the geological record than a period of stasis. Add to this the fact that many geological columns are broken up by disconformities, periods where the record that may have been of some change or another is simply eroded away. From these effects we get a geological record that tends to show abrupt change but that only rarely means abrupt change actually happened.
There may be yet another factor. Rapid change may simply leave little evidence. Slower change may accumulate clearer evidence. The degree to which this happens may depend a great deal on the kind of change involved.
The upshot of the new research is to confirm that change in the past sometimes happens more quickly than we can know from our current experience. Also the research attempts to estimate the rate of some past changes, looking specifically at global surface temperature change. The logic is pretty straight forward. Imagine you want to know how many people per 10 minute time slice enter a shopping mall. You count the number of people in the mall every hour from 8:00 opening time to noon. You then estimate the rate by dividing the increase in number of people per hour by six. But what if a particular store opened at 10:30 and had a big sale that day? Well, your estimate for the 10:00 to 11:00 period would be higher than the rest of the hours. But isn't it true that a lot of people would show up for the sale right around 10:30? To get a better estimate, you need to make more observations, say every 20 minutes. The 20 minute period including 10:30 would yield a number, divided by 2, that would be higher than the hour-long data divided by 6. From the paper:
The scaling relationship predicts that for every 10-fold increase in measurement timespan, there is an approximately 8-fold decrease in the recorded rate of temperature change. The logical explanation for this scaling is that climate change does not proceed in a linear, monotonic manner, but is instead characterized by transient stasis and reversals, even during episodes of extreme warming. Similar explanations have been put forward for observed timespan-dependent scaling in other Earth system processes, notably sedimentation rates16 and evolution. Geological temperature changes defined at typically centennial to multimillennial timespans cannot capture the full variance of the climate system operative at shorter timescales; aliasing variability that is readily apparent from higher resolution and more recent records.
The paper draws two conclusions that could be regarded as good news, though not really. First, when we look at modern rapid global warming, and say, "look, this is happening faster than anything in the past," we ma be overstating the case. Past temperature change could have been faster than we were thinking. Second, when we look at future likely rapid climate (and related ecological) change, and say "this rapid change will be bad for species," we may be overstating the case. Past rapid change probably happened, so species must be adapted to rapid change.
Unfortunately, it does not work that way. We know that pretty much every ecosystem we examine over long periods of time involves repeated and significant disturbance and turnover. Also, we know from evolutionary theory and observation that species do not adapt to rapid change that happens now and then. There is no known mechanism for that adaptation to occur. So, unfortunately, these implications of the research are invalid. Rapid change has always been bad, and in the future, nothing is going to change that.
This research does show us something very important. How fast global surface temperatures can rise is not well known. We see very rapid increases in temperature (and sea level rise) now and then, but there are also decreases now and then. The forces that increase temperature and decrease temperature are always playing against each other, with the trend for many decades now being that the increases outweigh the decreases. But just how fast can change happen if, say, the forces that increase surface temperature get a few decades without mitigation from the opposing forces? This recent paper may indicate that very rapid change, much more rapid than we see now, could happen. I personally think this difference in observed rate of change and possible rate of change is more important with ice sheet melting and deterioration than it is with temperature. We might be thinking of a few feet of see level rise over several decades as likely, but this research could indicate that while that might be the total final effect, the paleorecord does not rule out that a large amount of that change may happen in just short segment of that multi-decade horizon.
David B. Kemp,Kilian Eichenseer & Wolfgang Kiessling. 2015Maximum rates of climate change are systematically underestimated in the geological record. Nature Communications.
“Those of us who study actual (historical) evolution, looking at fossils and geological layers and such, have always known that the possible rates of change in earth systems and biological systems are much higher than what we can estimate by looking at the present day…
a glitch in the uniformitarianism principle, the idea that processes in the past must have been the same as processes we observe today…
The upshot of the new research is to confirm that change in the past sometimes happens more quickly than we can know from our current experience.”
Amen to that, Greg.
I agree that fast climate change has happened in the past and that species have adapted to this rapid change in the past.
For example, polar bears are around 650,000 years old (as a species) and have clearly been through warm periods and cold before and have survived to today.
Corals have survived past bleaching events and have survived to today.
Just looking at sea level rise, one can see a huge slope from 20k to 8k years ago, which is far faster than the current rate, and polar bears and corals survived that.
So this new paper makes a great deal of sense to me.
RickA, your logic boils down to saying this:
"Humanity, as a species, will possibly survive such a potentially very high rate of climate change. This is a reassuring thing, so we don't need to even think about doing anything to stop the deaths of millions of individual humans, nor worry about the massive property damage and capital destruction, because species survival does not depend on those things.
Here's to your line going extinct, RickA. Humanity will indeed survive just fine without those individuals, and as you point out, only humanity surviving is important.
Brainstorms continues to cnfuse the exinctionof lifestyles and species.
Polar cultures , from Lapland to Alaska, came into being in consequence of holocene climate change.
The evolutionary outcome remains to be discovered , because thus far all of the participants remains H. sap.
@RickA -- 650,000 years isn't a long time in evolutionary time scales. The last of the five great extinctions happened about 450 million years ago, and plenty of species at the time failed to adapt to it. We may now be entering a sixth mass extinction, and the first one to be triggered internally. That sucks, but also means it's the only one that has the potential of being prevented. It all depends on what we do.
Not for the polar bears though. They're doomed.
Indeed the outcome for human evolution remains to be discovered — as does the outcome for human civilization. There are many dystopian novels. Many of them posit a collapse of civilization. I think civilization has value, and I think it should be preserved. I think that preserving it requires limiting the effects of climate change, to the extent we are able.
On the other hand, those who think civilization is just another lifestyle can sit back, consume away, and sing "Don' worry; be happy."
Russell appears to join RickA in discounting the extinction of cultures and civilization, noting that such loss may have worthy effect of bringing new ones into being to replace them.
I think most of us join Christopher Winter in valuing the ones we have and deeming it worthwhile to sacrifice the lifestyles in order to preserve them.
No confusion there.
Greg C #5:
125000 years ago the temperature was 6C higher than today in Antarctica (according to ice core data).
I will assume it was also warmer in the Arctic.
The polar bears did fine - as demonstrated by the fact they are still here.
So I doubt the polar bears are doomed.
It is all about cost/benefit.
I am all for civilization - but if the cure is worse than the disease then you have to skip the treatment and roll the dice, and see if the dire forecasts were overstated.
It doesn't make sense to crash the entire world economy to avoid .17C of warming by 2100.
I am not sure it would make sense even if we could avoid 1C of warming by 2100.
It is about 1C warmer than it was 135 years ago and the weather is great in Minnesota.
RickA clearly demonstrates the influence of confidence of personal belief over those pesky scientists and their knowledge.
Worse: RickA is willing to kill (those who are toddlers now) because he thinks the effort needed to keep them alive, which poses an inconvenience to himself, is worse than the inconvenience those toddlers today will experience when they are his age... by experiencing their own premature deaths. Deaths that will not be as fun as RickA's fun lifestyle.
RickA can justify this because he doesn't have to look them in the eye as he condemns them. He cites "personal belief" to defend himself. Science exposes him. No wonder he has no respect for Science (and its pesky scientists).
I am all for science.
But science is saying that fast changes have occurred before and life adapted better than we maybe thought.
I am merely agreeing with the science.
Saying polar bears are doomed is an opinion - not science.
Look - what I want is not that difficult to understand.
First, we need a plan.
Second, we need to subject it to a cost benefit analysis.
Bjorn Lomborg took a "plan" - all the commitments the various countries are making before Paris - and is looking at the benefits, under various scenarios.
The costs to achieve those benefits need to be looked at also.
Then policy makers decide what to do.
I am weighing in with my opinion that the costs seem high and the benefits low.
That is all.
I have not called for killing anybody.
Unlike yourself - who hopes my "line" is killed off.
But please - engage in hyperbole - it works so well.
Warming during past interglacials, including the Eemian, was *much* more gradual than that resulting from the current spike in anthropogenic forcing. That's why the polar bear population had time to adapt (spatial reorganisation) and survive.
Please stop spouting nonsense with such unwarranted confidence.
It doesn’t make sense to crash the entire world economy to avoid .17C of warming by 2100.
A nonsensical argument from assertion followed by a factually incorrect claim per Lomborg. More worthless verbiage.
Corals have survived past bleaching events and have survived to today.
You have no idea at all what you are talking about. See Veron (2008):
The five mass extinction events that the earth has so far experienced have impacted coral reefs as much or more than any other major ecosystem. Each has left the Earth without living reefs for at least four million years, intervals so great that they are commonly referred to as ‘reef gaps’ (geological intervals where there are no remnants of what might have been living reefs). The causes attributed to each mass extinction are reviewed and summarised. When these causes and the reef gaps that follow them are examined in the light of the biology of extant corals and their Pleistocene history, most can be discarded. Causes are divided into (1) those which are independent of the carbon cycle: direct physical destruction from bolides, ‘nuclear winters’ induced by dust clouds, sea-level changes, loss of area during sea-level regressions, loss of biodiversity, low and high temperatures, salinity, diseases and toxins and extraterrestrial events and (2) those linked to the carbon cycle: acid rain, hydrogen sulphide, oxygen and anoxia, methane, carbon dioxide, changes in ocean chemistry and pH. By process of elimination, primary causes of mass extinctions are linked in various ways to the carbon cycle in general and ocean chemistry in particular with clear association with atmospheric carbon dioxide levels. The prospect of ocean acidification is potentially the most serious of all predicted outcomes of anthropogenic carbon dioxide increase. This study concludes that acidification has the potential to trigger a sixth mass extinction event and to do so independently of anthropogenic extinctions that are currently taking place.
* * *
I am all for science.
You appear to know next to nothing about the relevant science. It's embarrassing.
"It doesn’t make sense to crash the entire world economy to avoid .17C of warming by 2100."
Thou shalt not take Lomborg's claims at face value and then also add unsupported alarmism.
I find the confidence with which certain parties predict that effective action to limit climate change would "crash the entire world economy" intriguing. The behaviour of the world economy is at least as difficult to predict as that of the climate (arguably significantly more so), and yet I am not aware of any rigorous attempts to model the economic impacts of various climate change mitigation strategies. The best attempt that I am aware of is the 2006 Stern Review, which concluded that the economic impacts of uncontrolled climate change were almost certain to be far worse than the costs of mitigation.
What evidence does anyone have for the contention that attempts to limit climate change would "crash the entire world economy"?
(Aside: the evidence to date seems to indicate that the world economy is perfectly capable of crashing itself without any help, so there's a rather large question as to how you would distinguish an economic crash from "natural variation" from one "forced" by intervention, such as climate change mitigation policies. Attribution is even more difficult in economics than in climatology.)
What evidence does anyone have for the contention that attempts to limit climate change would “crash the entire world economy”?
As far as I am aware (I am not an economist) there is *no* evidence supporting this contention. This would explain why it is is invariably presented as an argument from assertion.
Recent ecological responses to climate change support predictions of high extinction risk.
Ilya M. D. Maclean, Robert J. Wilson.
Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1017352108
Rates of projected climate change dramatically exceed past rates of climatic niche evolution among vertebrate species.
Ignacio Quintero, John J. Wiens.
Ecology Letters, 2013; DOI: 10.1111/ele.12144
Accelerated modern human–induced species losses: Entering the sixth mass extinction
Gerardo Ceballos,1* Paul R. Ehrlich,2 Anthony D. Barnosky,3 Andrés García,4 Robert M. Pringle,5 Todd M. Palmer6
"Bjorn Lomborg took a “plan”..."
There is a problem: you assume that he is both qualified and honest enough to do a competent evaluation. Evidence indicates that neither of those conditions is met.
I would be surprised if warming was more gradual.
Take a look at the slope of the sea level rise about 15k or 10k years ago:
That does not look like more gradual warming to me.
If you think that orbital forcing can cause rapid warming, then you have to propose a physical mechanism. How does a slight and incremental change over millennia drive surface temperature increase temperature as rapidly as an unprecedented spike in anthropogenic CO2 forcing?
How does that work, RickA?
You can learn a lot from palaeoclimate if you pay attention.
I suppose I should have said that the deglacial SLR figure you link shows SLR for almost 15,000 years.
You call that fast?
Yes - the rate over those 15,000 years is twice the rate we are currently experiencing and in the steep parts of the graph (you know the almost vertical portions) the rate is even higher than that.
If sea level rise over that period averaged 6 mm/ year and in parts 12 mm / year - that is evidence that warming was less gradual in the past 15,000 years than currently (because the rate of sea level rise was higher then than now).
If sea level rise over that period averaged 6 mm/ year and in parts 12 mm / year – that is evidence that warming was less gradual in the past 15,000 years than currently (because the rate of sea level rise was higher then than now).
No, it's evidence that the great ice sheets of the LGM were collapsing. That happened with far less rapid warming than we are seeing now during an interglacial.
Please stop bullshitting about palaeoclimate; it makes you look silly.
You did not answer the question. Let's try again:
If you think that orbital forcing can cause rapid warming, then you have to propose a physical mechanism.
How does a slight and incremental change over millennia drive surface temperature increase temperature as rapidly as an unprecedented spike in anthropogenic CO2 forcing?
How does that work, RickA?
Answers please. Physical climatology does not work by magic. Describe the physical mechanism required by your argument. If you cannot or will not do this, you concede that you were mistaken by default.
As I have said before, I don't know the answer to your question.
All I know is that rapid warming did occur, as evidenced by the sea level rise graph I showed you.
What caused that rapid warming?
I don't know - but it did happen.
For all I know it could have been some lady with a hair dryer (grin - just kidding).
It was more rapid than the current warming because the sea rose more than twice as fast as currently.
It is not my job to explain what happened - but merely to note that it did.
I will leave it to the climate scientists to figure out why it warmed rapidly in the past.
But my lack of knowledge and inability to provide an explanation sufficient for you does not change the facts.
It did warm more rapidly from 20,000 years ago to 8,000 years ago than it is right now. That is a fact.
Or at least the rate of sea level rise was double during that period than it is today (using sea level rise as a proxy for arming).
What I find interesting is that you are disagreeing that it did warm more rapidly - why is that?
As I have said before, I don’t know the answer to your question.
Then you have no argument. You are just making a meaningless noise.
What I find interesting is that you are disagreeing that it did warm more rapidly – why is that?
Because there's no evidence that it did. I've already explained that you are mistaken to use SLR as a direct proxy for temperature because in deglacial climates it is indicative of the collapse of the major land ice sheets. This process is heavily influenced by ice sheet dynamics, not solely dependent on the rate of warming.
You cannot compare deglacial climate SLR directly with modern climate SLR but that is exactly what you are doing. It's wrong. I'm not going to repeat this again.
I will leave it to the climate scientists to figure out why it warmed rapidly in the past.
Orbital forcing that entrained strong positive feedbacks, mainly ice albedo and GHGs.
And of course, if the rate of warming were much higher in the past, given the known orbital forcings, that would imply much stronger positive feedbacks, which in turn would imply a much higher value for ECS... Which I don't think is where RickA wants the argument to end up.