
Why natural cycles only play small role in rate of global warming - okket
https://www.carbonbrief.org/guest-post-why-natural-cycles-only-play-small-role-in-rate-of-global-warming
======
apo
The first graph ("External factors explain nearly all global temperature
change") shows what appears to be temperature precisions of less than 0.1
degree C, yet reports no error bars.

How is it that a graph like this is even acceptable, given the importance of
the conclusions? How does this study account for the inevitably poorer
precision and accuracy of measurements made over 100 years ago? How are
systematic errors (differences in measuring procedure, differences in time of
day precision, etc.) accounted for?

A paper from Cowton/Way is available, but it appears to focus on filling in
gaps from lack of data at the poles:

[https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.22...](https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.2297)

Where is the readily-accessible explanation for how the underlying dataset
accounts for so many unknown factors?

~~~
mikekij
I'm so glad to see you bring this up. In my graduate physics training, I was
taught to be extremely cautious about statistical significance, error
propagation, and error bars. I remain skeptical of our conclusions about AGW,
not because I have a political view on the subject, but because I'm skeptical
that our temperature measurements from 120 years ago have a precision of less
than 1 degree C.

But I (sincerely) assume that the climate scientists working in this space
have compensated for this lack of precision in their conclusions. Right?

~~~
tasty_freeze
Hyperskepticism run wild. You, an outsider, doubt the science because you
think that the people who have specialized in the field and have spent their
careers collecting data are not as smart as you and have overlooked the
quality of their data sets.

I'll go farther and say nobody better understands the limits of their data
sets than the people who work with them.

~~~
lostmymind66
I think my problem with the whole thing is how politicized AGW has become.
There are supporters saying 'temperature is not climate when it comes to
disproving climate change, yet try to use the same argument when proving that
it exists.

Many supported laws for trying to reduce emissions are nothing more than
wealth transfer schemes used by one group to take power from another.

I also would like to know how so many experts in their field missed the fact
that they were using incorrect data sets for so many years. Google 'climate
gate'. Nobody talks about it anymore, but it was a serious enough problem that
hundreds of universities had to come out with retractions/explanations.

If you are a scientist that doesn't support the current narrative about
climate change, you will have a difficult time getting funding and your career
will most likely be over the second you submit anything for review. I've
noticed that scientists that do have contrary theories are either retired or
plain on retiring..for this very reason.

If scientists are going to be the authority now, what about things like the
definition of sex/gender? Is it only an authority when it suits our political
needs?

I don't deny that climate change is happening. There is just too much noise to
really know the actual truth about the extent of the damage and what we can do
to prevent it.

~~~
snowwrestler
> Eight committees investigated the allegations and published reports, finding
> no evidence of fraud or scientific misconduct. The scientific consensus that
> global warming is occurring as a result of human activity remained unchanged
> throughout the investigations.

[https://en.wikipedia.org/wiki/Climatic_Research_Unit_email_c...](https://en.wikipedia.org/wiki/Climatic_Research_Unit_email_controversy)

------
Roark66
The headline of this post is bullshit. The author of the article doesn't prove
"natural cycles" play small role. He claims that the data he analyses points
to the conclusion one specific 60-70 year old cycle of oceanic origin has far
less impact on climate than commonly accepted. He talks about one mechanism,
there are plenty of other natural mechanisms that affect the climate in
various ways.

Quoting the article: >This means that ocean cycles on timescales of 60-70
years are unlikely to be a factor in the observed evolution of global
temperatures since 1850. Instead, external factors, such as periods of strong
volcanic activity and the release of aerosol particles (air pollution), have
caused temperatures to fluctuate.

~~~
ocschwar
There are other cycles, most of which are right now in a cooling phase, and
yet we are warming. So those cycles (i.e. Milankovich cycles) can be written
off already

~~~
User23
Plate tectonics are another huge factor. When Pangea existed there was just
one ocean to distribute heat and no polar continent for glaciers to form on
and increase the Earth’s albedo. That meant a much warmer planet.

The Quaternary glaciation is still ongoing because of those tectonic factors.

Another fun fact is that the warmest period in human existence was the
Holocene maximum about 8000 years ago[1].

Geology is a fascinating field and thankfully lets us look at climate through
a lens that isn’t intensely politicized.

[1]
[https://en.m.wikipedia.org/wiki/Holocene_climatic_optimum#/m...](https://en.m.wikipedia.org/wiki/Holocene_climatic_optimum#/media/File%3AHolocene_Temperature_Variations.png)

------
f00_
Have been reading the late and great David MacKay's Sustainable Energy -
Without the Hot Air lately (completely free on withouthotair.com)

[https://www.withouthotair.com/c1/page_5.shtml](https://www.withouthotair.com/c1/page_5.shtml)

 _> The climate-change motivation is argued in three steps: one: human fossil-
fuel burning causes carbon dioxide concentrations to rise; two: carbon dioxide
is a greenhouse gas; three: increasing the greenhouse effect in- creases
average global temperatures (and has many other effects)._

 _> Fossil fuel burning increases CO2 concentrations signiﬁcantly. But does it
matter? “Carbon is nature!”, the oilspinners remind us, “Carbon is life!” If
CO2 had no harmful effects, then indeed carbon emissions would not matter._

 _> However, carbon dioxide is a greenhouse gas. Not the strongest greenhouse
gas, but a signiﬁcant one nonetheless. Put more of it in the atmosphere, and
it does what greenhouse gases do: it absorbs infrared radiation (heat) heading
out from the earth and reemits it in a random di- rection; the effect of this
random redirection of the atmospheric heat trafﬁc is to impede the ﬂow of heat
from the planet, just like a quilt. So carbon dioxide has a warming effect.
This fact is based not on complex historical records of global temperatures
but on the simple physical properties of CO2 molecules. Greenhouse gases are a
quilt, and CO2 is one layer of the quilt._

 _> One last thing about the climate-change motivation: while a range of human
activities cause greenhouse-gas emissions, the biggest cause by far is energy
use. Some people justify not doing anything about their energy use by excuses
such as “methane from burping cows causes more warming than jet travel.” Yes,
agricultural by-products contributed one eighth of greenhouse-gas emissions in
the year 2000. But energy-use contributed three quarters (ﬁgure 1.9). The
climate change problem is principally an energy problem._

Watched Merchants of Doubt recently, point that stuck with me most is that
people against global warming are motivated by libertarianism, and anti-
communism. lots of the contrarian scientists worked during the cold war. Will
be checking out the book version soon

I don't think you even need the climate change motivation to get behind moving
off fossil fuels (supply chain security is another huge one, I find climate
change deniers often also in the peak oil camp). The way David MacKay presents
the numbers allows people to come up with realistic plans to move off fossil
fuels on their own instead of reciting someone else's dogma

Teasing out cause and effect is difficult especially with something that we
can't perform randomized experiments on. I'd like to read more about
counterfactuals and causal analysis of climate change

Judea Pearl has a great little bit about this in The Book of Why

 _> Until recently, climate scientists have found it very difficult and
awkward to answer questions like “Did global warming cause this storm [or this
heat wave, or this drought]?” The conventional answer has been that individual
weather events cannot be attributed to global climate change. Yet this answer
seems rather evasive and may even contribute to public indifference about
climate change.

> Counterfactual analysis allows climate scientists to make much more precise
> and definite statements than before. It requires, however, a slight addition
> to our everyday vocabulary. It will be helpful to distinguish three
> different kinds of causation: necessary causation, sufficient causation, and
> necessary-and-sufficient causation.

> Using these words, a climate scientist can say, “There is a 90 percent
> probability that man-made climate change was a necessary cause of this heat
> wave,” or “There is an 80 percent probability that climate change will be
> sufficient to produce a heat wave this strong at least once every 50 years.”
> The first sentence has to do with attribution: Who was responsible for the
> unusual heat? The second has to do with policy. It says that we had better
> prepare for such heat waves because they are likely to occur sooner or
> later. Either of these statements is more informative than shrugging our
> shoulders and saying nothing about the causes of individual weather events

> Climate scientists can get counterfactuals very easily from their computer
> models: just enter in a new number for the carbon dioxide concentration and
> let the program run. _

and one of my favorite quotes from MacKay:

 _> Please don't get me wrong: I'm not trying to be pro-nuclear or anti-wind.
I'm just pro-arithmetic_

------
yeahitslikethat
Why do we continue to debate climate change focusing on centuries old data
when the carbon cycle takes hundreds of millions of years? _Any_ data we've
collected amounts to less than a rounding error.

------
Bucephalus355
This was an interesting article and the author has strong data. I would want
to know about the Younger Dryas [1] period though. This is a warming period
about 12,000 years ago when some of the most devastating geological events we
know of happen. This includes the outburst floods of glaciers holding back
bodies of water larger than Lake Erie (Lake Agassiz [2] for example) and a
temperature differential in Greenland of 27 degrees Fahrenheit cooler compared
to today.

Human being play a huge role in climate change, but I don’t want to also write
off the absolute enormous shifts than can occur naturally. We need to take
those just as seriously for our own security.

[1]
[https://en.wikipedia.org/wiki/Younger_Dryas](https://en.wikipedia.org/wiki/Younger_Dryas)

[2]
[https://www.dmr.nd.gov/ndgs/ndnotes/agassiz/](https://www.dmr.nd.gov/ndgs/ndnotes/agassiz/)

~~~
GorgeRonde
It was almost certainly caused by one or multiple comet fragment impacts.

Sources:
[https://scholar.google.fr/scholar?as_ylo=2018&q=hiawatha+cra...](https://scholar.google.fr/scholar?as_ylo=2018&q=hiawatha+crater&hl=fr&as_sdt=0,5)

~~~
lenticular
No, speaking as a former glaciologist, that's not likely to be true. The
parent poster is correct. Younger Dryas featured multiple advances and
retreats, which is inconsistent with an impact. Multiple impact over many
centuries just isn't that statistically likely, and we would see better
evidence of it.

Instead, the most probably cause is freshwater pulses coming out of the
melting Laurentide ice sheet changing circulation in the Atlantic. This is
actually quite well supported.

Younger Dryas was also confined to the parts of the northern hemisphere,
mainly in higher latitudes. A large enough impact to significantly alter
climate would see the resulting particulates globally mix in the atmosphere,
resulting in more uniform cooling.

Instead, the fact that it was confined to parts of the northern hemisphere
also supports the freshwater pulse hypothesis, since it is only a change in
the transport of heat from the tropics to the pole, not a change in total
heat.

The fact that freshwater pulses from the Laurentide ice sheet caused so much
cooling is actually a concern with climate change. It's _possible_ that it
could happen again with melting of the Greenland Ice Sheet, at least a
weakened version of it (the Laurentide Ice Sheet dwarfed the GIS).

~~~
pmayrgundter
A report was published in Nature in spring of this year showing multiple lines
of evidence for impact-related effects in the YDB layer in southern Chile:

"In the most extensive investigation south of the equator, we report on a
~12,800-year-old sequence at Pilauco, Chile (~40°S), that exhibits peak YD
boundary concentrations of platinum, gold, high-temperature iron- and
chromium-rich spherules, and native iron particles rarely found in nature. A
major peak in charcoal abundance marks an intense biomass-burning episode,
synchronous with dramatic changes in vegetation, including a high-disturbance
regime, seasonality in precipitation, and warmer conditions. This is anti-
phased with northern-hemispheric cooling at the YD onset, whose rapidity
suggests atmospheric linkage. The sudden disappearance of megafaunal remains
and dung fungi in the YDB layer at Pilauco correlates with megafaunal
extinctions across the Americas. The Pilauco record appears consistent with
YDB impact evidence found at sites on four continents."

[https://www.nature.com/articles/s41598-018-38089-y](https://www.nature.com/articles/s41598-018-38089-y)

~~~
lenticular
That just means that there was an impact at around the same time. There's been
numerous impacts like this that have been claimed to be the cause of Younger
Dryas in the past. However, just because there was an impact doesn't mean it
had anything to do with YD.

The Atlantic meridional overturning current shutdown from a freshwater pulse
is much more parsimonious, and is exactly what we would expect from the
physics of the Laurentide melt going into the Atlantic.

Impacts still don't explain the multiple advance and retreats during the
Laurentide, but it is obvious why that would occur with the AMOC shutdown
explanation:

Melting causes the AMOC to shut down, causing nothern hemisphere cooling. The
cooling reduces melting, inducing the AMOC to start back up, increasing
melting once again.

~~~
pmayrgundter
I accept part of what you're saying, which I believe is that the Laurentide
melt was probably happening anyways, with the associated effects on the AMOC.
Glacial oscillation are their own cycle, clearly.

But the YD impact scenario hardly seems irrelevant to the YD. I'm curious what
other impacts you're aware of that you deem irrelevant.

The best candidate I'm aware of for the YD impact would possibly/probably be
related to the Hiawatha crater [1], which is 31km after likely boring through
a km or so of ice. This puts it amongst the largest impacts on Earth, e.g.
since back to the Chesapeake/Siberian impact around 35mya, (if not beyond
after the ice impact is taken into account, e.g. to Chicxulub) [2]. It's not
solidly dated yet, but according to the authors the evidence at the site is
consistent with an impact during the Pleistocene, and they even say it may
still be hot, despite being packed in ice!

If we're talking about the same event, with evidence across 24-53 sites on 4
continents that includes continent-wide fires, impact winter and floral and
megafaunal extinction, then I'd be hard-pressed to see how this doesn't have
to do with the main climate change event of that period; that's the definition
of what makes the YD significant: the drastic floral changes (e.g. of Dryas
octopetala) at the boundary. The impact seems a more likely candidate cause
for the abrupt global changes.

Or put another way, I think the question is back to you of how changes in the
AMOC during the YD somehow caused the characteristic extinctions and charcoal
residue observed in southern Chile at the YDB.

The contemporaneous, global inferno and impact winter going seems too much to
chalk up to coincidence. That's where I see the parsimony breakdown for a
simple Laurentide melting/AMOC change being responsible for the YDB.

[1]
[https://advances.sciencemag.org/content/4/11/eaar8173](https://advances.sciencemag.org/content/4/11/eaar8173)

[2]
[https://en.wikipedia.org/wiki/List_of_impact_craters_on_Eart...](https://en.wikipedia.org/wiki/List_of_impact_craters_on_Earth#Larger_craters_\(1_Ma_to_10_Ma\))

------
briantakita
This article's claims fail the smell test. Ultimately we don't know what we
don't know & simplistic overarching models are probably missing key
components, many of which are non-linear. 200 years is a tiny window when it
comes to cosmological time. The methodology of measurement & extrapolation of
data also needs public scrutiny. Interpretations of geological events are
ridden with conjecture to fit an overarching narrative.

Here's what we have evidence of. Earth receives the majority of it's energy
from the Sun. The Sun has significant fluctuations. Earth is affected not only
by infrared & visible EM, but also by higher frequencies of EM. Earth is also
affected by magnetism from the Sun. Earth's Magnetosphere is affected by the
Heliosphere. A weaker Magnetosphere means less protection from Cosmic Rays,
Coronal Holes, CMEs, & other space weather. Cosmic Rays perturbs water, seeds
clouds, induces volcanic eruptions & earthquakes. Volcanic ash & cloud cover
increase albedo, which cools the earth.

The "year without a summer" in 1816 (~200 years ago), was caused by the Mt.
Tambora eruption. The Carrington Event happened in 1859.

~~~
breakyerself
The planets been breaking temperature records like hotcakes while solar
irradiance has been declining for decades. There is zero evidence for
magnetosphere driven climate change. What you've written is just some sciencey
sounding BS that rationalizes an irrational position.

~~~
instantwhat
If, tomorrow, NASA, NOAA, and the UN IPCC held a joint press conference to
announce surprising new evidence which indicated that anthropogenic effects on
the climate were minimal, that we could not noticeably affect the climate,
regardless of our emissions, and that the climate was essentially out of our
control, what would your reaction be? Would that be good news or bad news?
Why?

~~~
breakyerself
I suppose it would be nice to know we can worry less about how we impact
things, but I don't see what the point is in wishful thinking.

~~~
briantakita
Actually, global cooling & a wet spring means decreased crop yields around the
world. This is a serious matter that we need to properly prepare for. Not be
distracted by pseudoscience of "Anthropogenic Global Warming".

We are seeing an increase of Earthquakes & Volcanic Eruptions, driven by space
weather. We need to prepare accordingly. The next few winters will continue to
get colder.

