LeverLabs

On Being Skeptical of Climate Change

written by Onne Gorter on 2016/09/01

(This article replaces a previous version which was grossly misunderstood.)

The the IPCC 2013 report represents our current body of knowledge on climate change. Only a climate expert can add to that knowledge. And if ever our understanding changes, that change would come from the experts.

It might be tempting to listen to other voices. Perhaps because a different message fits our world view better. But that is not how science, and therefor not how knowledge works. Unless that voice is about to win a nobel price, that voice is most likely wrong. We non-experts do not get to choose a voice.

The High Level Picture

But the IPCC summary, or NASA very informative site, or other media, all sketch a high level picture of climate change. And that picture is not convincing to me. That puts me in an awkward position: trusting the science for what it shows, but at the same time needing to ignore my own gut.

Here is an excellent video by Richard Alley explaining a lot and very well. He uses the high level picture of CO2 is a thermostat.

One time he states: Half of the world ignored its own sunshine, because CO2 was more powerful than sunshine in controlling its temperature (21:19).

But you can also find negative examples, where the thermostat is set high, but temperature goes down. For instance, just after the holocene climactic optimum CO2 went up but temperature went down. A cursory look might identify three such negative examples.

Richard Alley shows one himself: The ice ages recently were not caused by CO2 (18:12). Those, he shows, had to do with Milankovitch cycles. (Earths orientation and orbit, see Milankovitch cycles)

And so the main question is this: Sometimes the thermostat is ignored. So how sensitive is it, how high does it go, and how do we know?

For that answer, please trust the experts, and expect the answer along the lines of: it is complicated.

But we get the high level discussion, I would expect that last question to be included in the high level discussion.

Skepticism and Religion

This last statement was the point of the article that was replaced. But it was misunderstood. Largely that was my own fault for trying to be too edgy. But also partly because the climate change issue has become like a religion, with fanatics on both sides.

To check if you are leaning towards dogmatic belief:

If you can give a tweet sized explanation that a twelve year old can understand. I'll concede it is a stupid question. But consider not what ends an ice age, but what ends a warm peak.

Also consider it is not about the question. It is about the lack of discussion. The question pops up after a certain level of details. But it seems to be left unanswered at that level or the next.

One Example and One Answer

Below is a picture showing "alarming" decline in ice, since 1780. A good 150 years before human made green house gasses became a strong climate change factor.

Glaciers melting at "alarming" rate since 1780!

It is a picture climate change deniers like to feature as "proof". And it seems unexplainable by the high level story non-experts get. So score for the deniers.

But there is a perfectly good explanation. A drop in solar radiation and heightened volcano activity had caused what is known as the little ice age. There is even a year known as the year without a summer. There was a small period of global cooling around 500 to 250 years ago. (See Little Ice Age, 1816 The Year Without a Summer, bottom of the NASA page)

The picture is only surprising when given half the information. Deglaciation reversed and later resumed at the end of the little ice age. Deglaciation today is not about ice melting, it is about ice melting at an accelerated pace, or in places where it should not. (See Deglaciation, Retreat of Glaciers since 1850)

This is probably the easiest one to answer. And there is something deeply interesting in the answer. Namely it gives clues on how much glaciation the earth should have for its temperature. And that likely all the little ice age glacier growth was gone by around 1950.

Too bad most people will hear about Glacier Bay from the climate change deniers.

(The original article)

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