The Fall Of California
Over 4,000 years ago, the Harappan Civilization of the Indus Valley faded and disappeared. Never heard of the Harappans? Theirs was a Bronze-Age civilization located where Pakistan and northwest India are today. With large, well-planned cities, municipal sewage systems and writing that has never been deciphered, they had a civilization equal to Egypt, Mesopotamia, and Greece. But the Harappans fell victim to what most view as a modern horror—climate change. Sometime around 2,100 BC the monsoon cycle, vital to all of South Asia, faltered. The reliable rains stopped, and man's earliest civilizations fell. Now we are told that California—that progressive paradise on the Pacific—is poised on the brink of its own drought spawned disaster. So desperate have things become that one restaurant chain has threatened to stop serving guacamole and vintners are turning to witchcraft. Can the total collapse of Californian civilization be far behind?
It has been well established that several of humanity's earliest civilizations suffered significant decline around the start of the second millennium BC. This reversal of human fortunes has been attributed to a long-term drought that began around 2400 BC and peaked around 2100 BC. In a new paper in the journal Geology, a team of palaeoclimatologists suggest the enigmatic Harappan Civilization suffered a similar fate. Based on isotope data from the sediment of an ancient lake, Yama Dixit, David A. Hodell and Cameron A. Petrie claim to have found an interruption of the yearly monsoon cycle 4,100 years ago. In “Abrupt weakening of the summer monsoon in northwest India ∼4100 yr ago,” the researchers document a climatic smoking gun. They state their case in the paper's typically understated abstract:
Climate change has been suggested as a possible cause for the decline of urban centers of the Indus Civilization ∼4000 yr ago, but extant paleoclimatic evidence has been derived from locations well outside the distribution of Indus settlements. Here we report an oxygen isotope record of gastropod aragonite (δ18Oa) from Holocene sediments of paleolake Kotla Dahar (Haryana, India), which is adjacent to Indus settlements and documents Indian summer monsoon (ISM) variability for the past 6.5 k.y. A 4‰ increase in δ18Oa occurred at ca. 4.1 ka marking a peak in the evaporation/precipitation ratio in the lake catchment related to weakening of the ISM. Although dating uncertainty exists in both climate and archaeological records, the drought event 4.1 ka on the northwestern Indian plains is within the radiocarbon age range for the beginning of Indus de-urbanization, suggesting that climate may have played a role in the Indus cultural transformation.
The authors claim that the collapse of the Old Kingdom in Egypt, the Early Bronze Age civilizations of Greece and Crete, and the Akkadian Empire in Mesopotamia are linked to a similar decline in the Indus Valley—a widespread aridiﬁcation event that occurred ~4.2 thousand years (ka) before the present. “The 4.2 ka aridiﬁcation event is regarded as one of the most severe climatic changes in the Holocene, and affected several Early Bronze Age populations from the Aegean to the ancient Near East,” they state in their concluding remarks. Imagine, an instance of natural climate change that brought down civilizations all over the ancient world.
The paleoclimate study was based on proxy data gathered from a dried lake site known as Katla Kahar, shown on the map above. “Holocene paleoclimate records suggest that Indian summer monsoon (ISM) variability occurred at centennial and millennial time scales, but the instrumental record (post-1871) is generally too short to document the full range of variability,” the authors state. “Thus, paleoclimate studies are necessary to evaluate past changes in ISM intensity and their potential societal implications.”
This highlights one of the problems with climate change and associated human disasters—our records just don't go back long enough to make accurate judgments. The same can be said for the current drought in the great state of California. As reported in this blog, conditions have been parched in the Golden State for several years, leading to the predictable cry of “global warming!” from climate alarmists everywhere. The trouble is, California is a semi-arid region that is prone to drought, some times lasting for decades and even centuries. Scientists have documented ancient Megadroughts that occurred between 850 to 1090 and 1140 to 1320.
Things have gotten so bad all sorts of people have taken to blaming unrelated problems on climate change. Supposedly the demand for water witches has gone through the roof (see “California’s drought is so bad people are turning to witchcraft”). Even those who do not believe in the mystical arts are panicking. For instance, the west coast restaurant chain Chipotle stirred up the media and guacamole lovers with news that it could “suspend” guacamole from its menu due to global warming. For those unfamiliar with Mexican and Southwestern cuisine, guacamole is made from avocados, a large fruit that grows on trees.
“Increasing weather volatility or other long-term changes in global weather patterns, including any changes associated with global climate change, could have a significant impact on the price or availability of some of our ingredients,” the chain opined in its annual report. Chipotle uses 97,000 pounds of avocado daily to make its guacamole and salsa, which translates to 35.4 million pounds of avocados yearly. That is a lot of avocados. Is this the end for California? First the indigenous cuisine is destroyed; soon there is no longer enough water to grow food or water lawns in Beverly Hills; surely the collapse of civilization (such as it is) will soon follow. Or perhaps not.
According to PBS, avocados have shrunk in size in recent harvests but the number of fruits have actually increased. Avocados seem to be in plentiful supply despite vagaries of climate change that have resulted in “lemon sized” Hass avocados. Chipotle, which recently absorbed a significant price increase in beef and introduced a new vegetarian tofu option, might be taking proactive steps to address how the climate could affect its business long term. After a flurry of unwanted attention in the media, the company has walked back the guacamole crisis.
Besides, global warming does not seem to be a direct threat to the world's avocados. The condition most limiting to growing an avocado tree is cold weather, according to the Texas A&M System AgriLife Extension website. All three primary avocado species are tropical plants: West Indian (P. americana Mill. var. americana), Guatemalan (P. nubigena var. guatamalensis L. Wms.) and Mexican (P. americana var. drymifolia Blake). Mexican varieties are the most cold-hardy, but they can tolerate cold temperatures to only about 20°F (-6.7°C). So it is global cooling that the guacamole aficionados should be concerned with.
But what about the global warming drought connection? Should we fear a return of the dust bowl that ravaged the southwest in the 1930s? According to the US government, “The most widespread and severe drought conditions occurred in the 1930s and 1950s. The early 2000s were also characterized by severe droughts in some areas, notably in the western United States... The trends averaged over all of North America since 1950 are similar to U.S. trends for the same period, indicating no overall trend.”
Moreover, the Intergovernmental Panel on Climate Change (IPCC) conducted a survey of global drought in 2012 (pdf), and concluded:
There is not enough evidence at present to suggest high confidence in observed trends in dryness due to lack of direct observations, some geographical inconsistencies in the trends, and some dependencies of inferred trends on the index choice. There is medium confidence that since the 1950s some regions of the world have experienced more intense and longer droughts (e.g., southern Europe, west Africa) but also opposite trends exist in other regions (e.g., central North America, northwestern Australia).
If the IPCC finds no compelling evidence of a link then those espousing one are on the fringe of the fringe of climate science. The chaos continues, however, with all sorts of scientific ignoramuses—John Kerry and Barrack Obama to name two—continuing to spout unsupported nonsense at every opportunity. This public prattle is driving real climate scientists to distraction, and pissing quite a few of them off. Here is how Roger Pielke Jr. put it on his blog:
The amount of nonsense in public debate on extreme events and climate change remains at a high level. This is great news for me because it provides plenty of opportunities to discuss what the actual science says and how we think we know what we know. As I have long argued, accurate representations of the state of science of extremes is far more important as a matter of scientific integrity than to the hyper-politiczed debate over climate change. Put another way, it is highly unlikely that misrepresentations of the state of science will do much to move action on energy policies, but they could damage the integrity of leading institutions of science.
For more from Dr. Pielke, check out his “Handy Bullshit Button on Disasters and Climate Change.” It should be required reading for all politicians and news reporters.
The bottom line on all of this drought nonsense is that droughts happen. Indeed, sometimes they last for centuries. There is nothing we can do about droughts because we do not control the climate, no matter what green agitators and climate change alarmists say. California will have to muddle through regardless. The only thing its people can do is adapt to the changing conditions. I suggest they all have some guacamole, a couple of margaritas, and chill out.
Be safe, enjoy the interglacial and stay skeptical.
Grab some guacamole, a margarita and chill out on your favorite beach.