Reprise — Why I Don’t Deny: Confessions of a Climate Skeptic — Part 1

Guest Essay by Kip Hansen — 4 February 2023

NOTE: I wrote this original two-part series nearly five years ago now.  This reprise has been prompted by a conversation with a colleague who’s only understanding of Climate Change or Global Warming has been gleaned from NPR/CNN/PBS and Main Stream Media.  I thought to update this essay to see if I would have the same opinions today as I did five years ago.  Updated text will be in this lighter blue color.  Changed or added images will be clearly labelled.

I have often been asked “Why do you deny climate change?”  I am always stumped by the question.  It is rather like being asked “Why do you torture innocent animals?”  The questioner is not merely asking for information, they are always making an accusation — an accusation that they consider very serious and a threat to themselves and others. 

The reason it stumps me is that, as you have guessed already, I do not deny climate change (and I do not torture innocent animals — nor even guilty ones).  And there is nothing about me or my behavior, present or past, that I am aware of, that would lead any reasonable person to think such a thing of me. 

I am thoroughly guilty though of being very skeptical of what is generally referred to as the Climate Consensus — usually said to be represented by the latest reports and policy recommendations put out by the Intergovernmental Panel on Climate Change (IPCC) and its supporters; political, ideological and scientific.  I suppose it is this that leads to the false accusation of “denying climate change”.       

Note: My colleague had been indoctrinated to believe that the two sides of the issue consisted of only two positions:  The IPCC Consensus team opposing those who think Global Warming is a hoax.

And there is the crux of the matter — it is something in the mind of the accuser, not any action of the accused, which leads to the false accusation.

MY DENIAL:

I deny that I am a Climate Denier, a Global Warming denier or any other kind of a  “denialist”.  And I do not think that Global Warming is a hoax.

WHY I DON’T DENY:

I do not deny either of the two primary claims of the Global Warming Movement:

1.  Global Warming is happening

2.  Human activity causes [some of] it.

Here’s why I don’t deny #1: Global Warming is happening.

There is no need to update this section very much as it is long-term historical data – though at end of section I will put in a current Global Temperature graphic for completeness.

I am perfectly happy to accept that the “world” (the “global climate”) has warmed since the late 1800s.   We know that the date of 1880/1890 is picked for the starting point of most of the contemporary consensus view plots — purportedly because it represents “the start of the modern industrial era”, this despite the fact that even the IPCC does not claim that “CO₂ induced global warming” started at that date.    Let’s take a closer look at Lamb and ”Lamb_modified_by_Jones”:

Note: This image cleaned up a bit.  CET is Central England Temperature, which is used because the record is actual measurements continuous since mid-17^th century.

We know that Lamb was showing a stylized “schematic” view of Central England temperatures — and Jones 2007 re-does the analysis with very slightly different results, then overlays (in blue) the measured Central England through 2007.    This graph contains the seed of my certainty that “global warming is happening” — which, in un-politicized language would be something like:  “The Earth’s general climate has warmed since a bit before 1700 CE — i.e., for the last 300+ years.”    Here’s Spencer 2007:

And if you prefer, here’s the NOAA version with comparisons of various reconstructions :

Note:  The link to the file above is no longer valid.  But there is a similar graphic used in the report of the National Research Council’s Committee on Surface Temperature Reconstructions for the Last 2,000 Years below:  

This graphic is new to this essay. 

They all show cooling to approximately 1650 – 1700 and general warming since then.

From where does my skepticism arise then?  Well, there is no more — general warming started about 1650-1700, maybe a little earlier, and has been ongoing.  When warming doesn’t start is 1880/1890 — it starts one hundred and fifty to two hundred years earlier — earlier  than the start of the increased CO₂ output of the modern Industrial Revolution.  This makes me very skeptical indeed of the claim that the industrial revolution and modern warming are intrinsically entwined. 

And I think that it is a good thing that it has warmed since 1700.  The Little Ice Age years, up thru  the 16 and 17 hundreds,  were hard times for farmers (and thus whole populations) in North America and Europe,  as attested to by contemporary accounts of crop failures and hard winters. 

To my knowledge, this point is not controversial or even contested.  In the Consensus Worldview, it is simply over-looked and not mentioned.   Truthfully, since the facts don’t match the narrative — the narrative that global warming was caused by the start of the Industrial Revolution and its subsequent CO2 emissions —  this fact seems to have been down-played or ignored. 

Most current temperature graphics:

The above is Global Temperature Anomalies since 1880, with the vertical scale set to a spread of 5°C – the range recommended by U.S. OSHA for office temperature comfort.

What does the IPCC say? “Warming of the climate system is unequivocal.”  — IPCC AR5 SPM 1.1 

 Well, I couldn’t agree more  — moreover, it has been warming since about 1650-1700, two hundred years before the Industrial Revolution starts pouring out CO₂.

What else does the IPCC say?  “ … recent anthropogenic emissions of green-house gases are the highest in history.” — IPCC AR5 SPM 1

Again, I don’t disagree:

Without arguing about when “history” began, and looking at atmospheric CO2 concentrations rather than emissions, we can stipulate that the graph the European Geophysical Union gives us is an “accurate enough” picture of CO2 concentrations over the last thousand years.   CO2 remains a shaky 275-290 ppm for 800 years and then begins to show a rise around 1850, finally breaking into new territory  circa  1880-1890 — the start of the modern Industrial Era.    The Wiki offers us the following, again confirming that CO₂ does not begin to rise until 1890-1900, long after temperatures begin to rise.

It is simply a fact that atmospheric CO₂ concentration has been rising since 1880-1890-1900 (close enough for my purpose today) and that it is now higher than it has been in a long time.   Some think that this is a good thing, as it has brought about a resurgence in plant life on Earth’s surface and some think it is a bad thing.

Atmospheric CO₂  has been rising — but is there doubt about this? — “ … recent anthropogenic emissions of green-house gases are the highest in history.” ?

While it is not easy to measure atmospheric CO₂ concentrations, it has been being done for quite some time….and we have been able to guess about human greenhouse-gas emissions and their sources.  [These are naturally abject guesses, but we needn’t argue with them on that account — they are our “best guesses”).

The IPCC’s AR5 includes this graphic:

We see that recent emissions are highest, at least in this history, but notice that cumulatively up to 1970 (see the right hand inset bar graph), Forestry and other land use accounts for more than 50% of all CO₂ emissions.  This surprised even me — I was expecting a pretty big contribution from the clear-cutting and conversion into pasture and farmland of much of Europe and North America east of the Mississippi River — but I had no idea that Forestry and Land Use accounts for >50% all the way to 1970 –and that’s nineteen seventy, not eighteen seventy.   By some proxies, global surface temperature had been rising for 300 years by 1970. 

Keeping that fact in mind, let’s see what else the IPCC has to say about causes:

IPCC AR5 SPM 1.2 — “Anthropogenic greenhouse gas emissions have increased since the pre-industrial era, driven largely by economic and population growth, and are now higher than ever. This has led to atmospheric concentrations of carbon dioxide, methane and nitrous oxide that are unprecedented in at least the last 800,000 years.  Their effects, together with those of other anthropogenic drivers, have been detected throughout the climate system and are extremely likely to have been the dominant cause of the observed warming since the mid-20th century.”

This language is not found in AR6 – the most recent Assessment Report.  AR6 Summary for Policy Makers says “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.”  AR6 stands by the AR5 statement above without changes.

The IPCC in their synthesis report for policy makers says that human emissions of greenhouse gases and “other anthropogenic drivers,” are  “extremely likely to have been the dominant cause of the observed warming since the mid-20th century.”

Well, OK.  This is where my Climate Skepticism begins to gain some traction.  Dr. Judith Curry, president and founder of Climate Forecast Applications Network, recently offered the following graphic in an essay entitled “Fundamental disagreement about climate change”:

I would have used slightly different points and alternate wordings — but the essence would be the same.

The IPCC Consensus general position is shown on the left — CO₂  (and other greenhouse gases) are the primary “forcing” of climate — with changes in CO₂ causing changing climate (basically warming) —  this warming amplified by feedbacks, like increased water vapor and clouds.

On the right is Dr. Curry’s general view — I share much the same viewpoint.  I would have placed more emphasis on this: 

(corrected typos h/t John H)

Climate is Chaotic:  It is composed of  highly complex, globally coupled, spatio-temporal chaotic, resonant systems.

So far, I agree with all the facts, but don’t agree with recent CO₂ (and other) emissions being “the dominant cause of the observed warming since the mid-20th century.” — I agree neither with the attribution or the effect size.

Today, five years later, I still find myself with the same position:  There is no scientific reason to accept the IPCC position and the IPCC offers only that global temperatures have risen (stipulated: the factual matters are not in dispute) and CO2 concentrations have risen (also stipulated).

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If you aren’t yet bored to tears, you can find out more on my reasons for that in Part 2, to be published in the next day or so.

The reprise of Part 2 should appear here in about a week.

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Author’s Comment Policy:

I have tried to use examples, graphs, that would be generally acceptable to both sides of the Climate Divide, and to avoid controversial minor or fringe sources.  I didn’t need to — I am happy with the data presented and that’s Why I Don’t Deny.

I suppose that many readers will disagree with my lack of denial or agree but have different reasons.  That is how it should be in a new young field of science like Climate.  Feel free to tell all in your comments.   I may reply to rational, collegial remarks, questions and requests for clarification.

I am, however, too old to argue. (and five years older now)

The latest IPCC assessment report, AR6, adds nothing that changes my opinions from those of five years ago.  There are no new facts that show anything other then the simple “the climate has warmed” and “atmospheric CO₂ concentrations have risen” and “are higher than they have been in a long time” – both of which I am happy to agree with.  In fact, I think that both are “good things”.

I invite your comments on anything I have written above or on the data presented.

Address comments to “Kip…” if you expect a response.

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