2012-01-16 06:03:49We've been through climate changes before
Sarah
Sarah Green
sarah@inlandsea...
67.142.177.26

Here I aim to address the fact that some people have very little sense of time. They have an idea that humans have lived through numerous ice ages and other climatary ebs and flows, without a clear notion of the actual time scales of those event relative to human civilization.

So, here's an attempt to simplify human pre-history and climate:

http://www.skepticalscience.com/humans_survived_previous_changes.html

I have not included local/regional cliamte changes (mini-ice age, etc) in an effort to keep it simple.

Corrections please. This is not my field.

Sarah

2012-01-17 06:11:43Graphic?
BaerbelW

baerbel-for-350@email...
93.193.104.10

Hi Sarah,

how about collaborating with jg (John Garrett) to create a visual timeline with relevant figures/events/animals/people...? Your summary might gain a lot by not just relying on words.

Cheers
Baerbel

2012-01-17 11:33:35Good idea
Daniel Bailey
Daniel Bailey
yooper49855@hotmail...
97.83.150.37

His email:  garrjohn@gmail.com

2012-01-17 12:06:21
KR

k-ryan@comcast...
68.34.93.62

With due hat-tipping to the Debunking Handbook - you need the 'true story' right up there with the skeptic argument. Perhaps "Previous climate changes have understood causes - current climate changes, in addition to being much faster than past climate change, have well understood causes as well, which include human influences via greenhouse gases.", if that is indeed the aim of the posting.

It's a reasonable overview, 'tho it could use more 'meat', more examples, but I feel (personal opinion) that it needs more direction. What is the point you are trying to make with this posting? Basic historical overview? Time scales? Sequencing? Relation of (natural) causes for past climate change to (natural + anthropogenic) causes for current climate change? What we can learn about current change from the past? Dangers of climate change? It's not evident to me from your post...

Your post needs introductory and final paragraphs that state the reason for the post and then tie the various bits together.

2012-01-30 11:50:31
Sarah
Sarah Green
sarah@inlandsea...
67.142.177.22

Thanks all.

I've updated a bit and tried to focus. I'll ask John if he'd like to illustrate. I certainly do need a picture.

 

 

2012-01-30 12:42:37
Rob Painting
Rob
paintingskeri@vodafone.co...
203.96.196.190

Sarah - I think the explicit take-home point should be that generally global climate in the past changed extraordinarily slowly by human time frames, nothing like the rapid warming within a few hundred years we are currently experiencing. A recurrent feature of those slower ancient changes is that many plants and animals adapted by becoming dead.

2012-02-01 12:48:58
Sarah
Sarah Green
sarah@inlandsea...
67.142.177.23

Rob-

I'm trying to balance the KISS (Keep It Simple Stupid) principle against the level of detail to include (my scratch file is many pages longer).

Thus the two main things I pruned out are:

(i) rates of change, as you mention

(ii) relatively recent "small" regional climate changes such as: 100+ year droughts in the Americas, the "General Crisis of 17th Century Europe",  failed monssons in years 700-900 in China, etc, all of which were devastating for the resident populations.

To add back more of (i) I've added more "gradually"s, and this phrase: "Each transition from warm to glacial ages and back took thousands of years, giving humans and prehumans many generations to adjust."

thanks

-s

2012-02-01 15:36:33
Rob Painting
Rob
paintingskeri@vodafone.co...
118.93.210.64

Sarah - I think it still can be simple. This logical fallacy equates enormously slow rates of change with the present 'geological blink of an eye'. That's the meme that's needs to be scuttled because they are not the same. Everything else is just dressing.

2012-02-08 07:47:09timeline draft
jg
John Garrett
garrjohn@gmail...
98.112.44.167

Hi Sarah,

this is to let you know I got started on your timeline and to invite comments on the scope of the timeline. I started with a 1 million year scale since I have EPICA temperature data and at a 1 million span you can still see a range for our 6k years of civilization. I thought I'd draw icons for the milestones, e.g, aurignacian art, cave paintings, then city states and pyramids, etc. Let me know if the format and scope works for you. This will need significant cleanup.

jg

2012-02-19 09:49:10
jg
John Garrett
garrjohn@gmail...
96.229.221.76

Here's an update to the image:

2012-02-24 09:36:54
Sarah
Sarah Green
sarah@inlandsea...
173.174.112.26

Rob-

it seems that rate of change issue is more complicated than I had thought. There have been other rapid, if shorter-lived T changes. Obviously on the geological scale we are headed to uncharted territory, but like many things it depends on scale. Drastic swings of 1-3 degrees that last only a few hundred years won't show up on long time scale, but may certainly be catostrophic for anyone living at the time. This is rather facinating to dig into.

See for example: 

Shuman, B. (2012). Patterns, processes, and impacts of abrupt climate change in a warm world: the past 11,700 years. Wiley Interdisciplinary Reviews: Climate Change, 3(1), 19–43. doi:10.1002/wcc.152

In particular:

The most-widely examined abrupt change of the Holocene is the ‘8200 year BP event,’ which appears to represent the final episode of ice-ocean- atmosphere interactions typical of the Pleistocene.41,42 The event stands out as the most prominent negative anomaly in oxygen isotope records from Arctic ice cores (Figure 4(a)), and represents a rapid cooling of 3.3 ± 1.1C over Greenland in <20 years at 8175 ± 30 cal year BP, although the event was initiated earlier. The cool conditions, as well as associated changes in the hydrologic cycle, lasted only 150 years and extended throughout much of the Northern Hemisphere. The North Atlantic region contains the most pronounced cooling with 1–2C depressions typical of many European records and 3C cooling evident as far eastward as central Europe.

3.3 degrees cooling in <20 years!! That's alarming evidence of the possibility of drastic swings in a short time. 

Zhang et al looked at ecomonic and human effects of smaller temp fluctuations (+/- 1°C) in Europe and found:

Results show that cooling from A.D. 1560–1660 caused successive agro-ecological, socioeconomic, and demographic catastrophes, leading to the General Crisis of the Seventeenth Century

Also, remarkably:

The average height of Europeans followed temperature closely (Fig. 1F red line) and declined 2 cm in the late 16th century. It increased slowly with rising temperatures only after A.D. 1650.

So, obviously, following this trend, in a warmer climate we will all become giants!

(Zhang, D. D., Lee, H. F., Wang, C., Li, B., Pei, Q., Zhang, J., & An, Y. (2011). The causality analysis of climate change and large-scale human crisis. Proceedings of the National Academy of Sciences, 108(42), 17296–17301. doi:10.1073/pnas.1104268108) 

I can send copies of these articles if you can't get to them

-sarah

2012-02-24 09:37:44
Sarah
Sarah Green
sarah@inlandsea...
173.174.112.26

I'm ready to be done with this- thanks to John's lovely image.

Last question: does the image need numbers for T? I think it's ok the way it is.

Any other suggestions??

-sarah