The Holocene Climate
(Public Input Loudoun County Board of Supervisors, 7 March, 2017)
Figure 1 shows the climate variation over the last million years. The low points on the curve correspond to ice ages when glaciers up to a mile thick covered New York. The high points correspond to interglacial periods such as the climate during the Holocene, the last 10,000 years. As shown in the figure, the Holocene encompasses all of human civilization. Prior to that species and subspecies of humans were hunter gatherers. There are at least four reasons why humans and other animals and plants were able to survive prior ice age/interglacial abrupt climactic shifts.
- These were not as dramatic as the current human-caused climate change, unfolding ten to hundred times slower. In fact over any individual’s lifetime there might have generally been no discernable change in many regions.
- Human populations were less than a few tens of millions globally or equivalent to the population of one modern city. There was room to move about.
- Humans were all hunter/gatherers independent of immobile infrastructure.
- There were no artificial barriers to mobility for wildlife which humans depended upon such as farms, roads, cities and pipelines.
Today, there are 7.5 billion humans or one human per every four acres of land, including deserts, mountains and Antarctica. There is no place to go. Humans, especially Loudoun County citizens are highly dependent on immobile and vulnerable infrastructure and global systems of finance, trade and commerce. Because of these differences, human civilization likely could not survive a glacial/interglacial shift much less the climate catastrophe we are now causing. Figure 2 shows that the global Holocene climate within 1? limits has not varied more than 1 degree. This includes the Little Ice Age, the Medieval Warm Period and other climactic shifts. Yet even these modest shifts throttled various civilizations  as described by anthropologists such as Jared Diamond in his book “Collapse” and historians such as Peter Frankopan in his recent “The Silk Roads” when there were still only a few 100 million people and only modest dependence on immobile and complex infrastructure and global commerce as compared to today. And these temperature shifts were much slower than what is happening due to human emissions today.
It seem just a little foolish to assume that human civilization, upon which Loudoun County citizens clearly depend can survive such a rapid large magnitude climate shift as we are causing .
 Michael McCormick, Ulf Büntgen, Mark A. Cane, Edward R. Cook, Kyle Harper, Peter Huybers, Thomas Litt, Sturt W. Manning, Paul Andrew Mayewski, Alexander F. M. More, Kurt Nicolussi, Willy Tegel, Climate Change during and after the Roman Empire: Reconstructing the Past from Scientific and Historical Evidence, Journal of Interdisciplinary History, xliii:2 (Autumn, 2012), 169–220.