Peru, Nazca and Climate Change

On December 8th, whilst the Lima climate talks were in progress, Greenpeace activists unfurled a message at the historic landmark of Nazca in Peru (Picture above). Little did the activists know at the time that their action would blow up into a major international incident causing considerable embarrassment to Greenpeace. 

But lets bring this incident into context by asking a few questions. A major ancient artefact may have sustained superficial damage as a result of Greenpeace's actions. This superficial damage may result in in further damage. At the moment nobody knows until an investigation has been conducted and completed. Until then what we have is pure speculation. The Guardian has summed up the situation between the Peruvian Authorities and Greenpeace.

Clearly a well intentioned action by Greenpeace was miscalculated and not properly planned out. But how does this compare with the totally misguided policies of so called political 'leaders' who intentionally act in favour of corporations and institutions who have placed the planet in pearl and have presided over policies that has resulted in the deaths of millions of people?

What then of the future of the Nazca lines? How will climate change affect these artefacts in the future? And what about the constant demand for land and resources?

What is clear from this incident is the unnecessary distraction from the inconvenient reality of climate change as a serious threat to humanity. In other words an ancient monument has taken precedence over the future survival of the human race. It has brought into sharp relief the immense gulf between scientific reality and subjective human perception.

Nazca offers a fascinating insight into an ancient civilisation. Preservation of site is rightly of paramount importance. It is unfortunate that the Greenpeace incident took place. But then it is equally unfortunate that there is a chronic lack of ability of our current civilisation to come to terms with what is going on. The fate of those who made the artefact may be a fate that we will all share. It is therefore worth delving into the history of this remarkable site. 

According to an article in Popular Archaeology: 'a recent genetic study that suggests that the evidence indicates periods of migration in pre-Columbian Andean societies in Peru, spurred on by local climate changes. It supports the archaeologists, who for years have been saying that the excavated evidence hints of such shifts by the Nasca, Wari and Tiwanaku peoples'.

As for the peoples themselves, it would appear that their lifestyle was based on sustainability: 'Perhaps because of the adversity they faced, the Nasca people seem to have been remarkably "green." The creation of the puquios displayed a sophisticated sense of water conservation, since the underground aqueducts minimized evaporation. The farmers planted seeds by making a single hole in the ground rather than ploughing, thus preserving the substructure of the soil. During a visit to a Nasca site called La Muña, Isla pointed out layers of vegetative matter in the walls of buildings and terraces that marked the rocky hillside settlement. The Nasca, he said, recycled their garbage as building material. "It's a society that managed its resources very well," he said. "This is what Nasca is all about." '

The National Geographic (NG) article goes on to say: 'There is little question that water—or more precisely, its absence—had assumed paramount importance by the endgame of the Nasca culture, roughly between A.D. 500 and 600. In the Palpa area, geophysicists have traced the creep of the eastern margin of the desert about 12 miles up the valleys between 200 B.C. and A.D. 600, reaching an altitude of some 6,500 feet. Similarly, the population centres in the river oases around Palpa moved farther up the valleys, as if they were trying to outrun the arid conditions. "At the end of the sixth century A.D.," Eitel and Mächtle conclude in a recent paper, "the aridity culminated and the Nasca society collapsed." By A.D. 650, the more militaristic Wari (Huari) Empire, which expanded from its base in the central highlands, had supplanted the Nas­ca in the southern desert region.

"It wasn't just climate conditions that caused the collapse of the early Nasca culture at Cahuachi, and we can say the same thing for the end of Nasca culture in general," Johny Isla told me. "A state of crisis was provoked because water was more prevalent in some valleys than in others, and the leaders of different valleys may have been in conflict." '

More information on the site and its world heritage status can be found at UNESCO.

The location of the Nazca lines lies at the north western fringes of the Atacama Desert. As such the climatic conditions are very similar.

Another NG article considers the role - past and present - of the Atacama desert. It points out subtle climatic changes that have occurred in the region over the past 10,000 years: 'More than 10,000 years ago when the Atacama's climate was more moderate, humans stated to populate the region. Archaeologists have long known about the deserts coastal civilisations... , and have recently found evidence of settlements in some of the Atacama's driest caves and valleys. Life could not exist at these inland sites today: An immense and permanent high-pressure cell over the pacific Ocean fends off weather systems from the west and to the east Andean peaks, drain moisture from clouds formed in the Amazon basin. On the coast the cold water Peru current streams in from Antarctica and chills the desert air, creating a temperature inversion that further inhibits rain clouds'. 

A detailed explanation of the region from a geological historical perceptive can be found in a series of articles referred to in Vignettes. The general conclusion is that hyper-aridity developed in the area about 19 - 13 million years ago, with recent changes occurring as noted above.

The western coast of South America at mid latitudes certainly exhibit unique geographical and climatic features. This poses the question as to how would future climate change affect the region? 

The current local climate in the region is influenced by the Humboldt (Peru) current (see below) and a subtropical high pressure system. The El Nino Southern oscillation (ENSO) is another important factor in determining climate fluctuations.

 

 

The Humboldt current has a considerable cooling influence on the climate of Chile, Peru and Ecuador. It is also largely responsible for the aridity of Atacama Desert in northern Chile and coastal areas of Peru and also of the aridity of southern Ecuador. Marine air is cooled by the current and thus is not conducive to generating precipitation (although clouds and fog are produced). 

The United Nations Global International Waters Assessment (GIWA), is an in-depth study of the Humboldt Current. With respect to climate change, 'It is expected that extreme natural events, such as El Niño, will increase in frequency and intensity as a result of global change. The El Niño Southern Oscillation (ENSO) is a global ocean-atmospheric event responsible for significant climate, oceanic, biological and ecological changes. The countries of the region particularly affected by El Niño are Ecuador and Peru'. 

Although the report doesn't document whether a changing climate would directly affect the desert regions, its clear that it could impact the socio-economics of the region, which depends on tourism and the fishing industry and that the ENSO will be an influencing factor in the region.

The article, The impact of ENSO in the Atacama Desert and Australian arid zone: Exploratory time-series analysis of Archaeological Records, from The Journal of Chilean Anthropology, offers an informative insight into the effects of ENSO in the region over the past 5000 years. 

It's analysis of past impacts appear to tally with the potential impacts warned by the UN in its GIWA report: 'In northern Chile, historical El Niño events are recorded as having a major impact on coastal waters, causing the collapse of local fisheries, mass mortality of marine organisms and birds, red tide, torrential rainfall, erosion of coastal lowlands and widespread flooding. The major effects of ENSO are on the marine biomass along the coast. El Niño events disrupt the trophic structure of marine ecosystems; create a pulse of severe drought in the highlands; and extreme rain in coastal regions of Peru and northern Chile. Between 1819 and 1991 historical records show 32 episodes of rain in the normally dry Atacama Desert. Of these, 21 were linked to El Niño.

'In contrast, on the altiplano -SOI [Southern Oscillation Index] events are associated with dry years. An intensified subtropical jetstream blocks the advection of moisture from the Amazon Basin and Gran Chaco during El Niño events'. 

Another paper, Late Quaternary hydroclimatology of a hyper-arid Andean watershed: Climate change, floods, and hydrologic responses to the El Niño-Southern Oscillation in the Atacama Desert, published in the journal Geomorphology, offers a detailed technical and scientific analysis of research conducted in the region (NB: Paywall). 

It considers paleo-climatic change in the region over the defined period, with a reference to anthropological activities.

The paper notes that the region has 'experienced significant climatic changes over contemporary, Quaternary, and geologic timescales where the development of hyper-aridity during the Mid-to-Late Tertiary has been punctuated by drier and wetter periods over timescales of 101 –103 years and where the effects of the El Niño-Southern Oscillation (ENSO) have been climatically profound throughout the Holocene and longer (Keefer et al., 1998; Magilligan and Goldstein, 2001; Keefer et al., 2003). Despite these extreme climatic conditions, this region has been an important environmental setting for sophisticated cultural development through intensive and extensive irrigated agriculture and other cultural adaptations such as terracing and raised fields in highland or riverine settings (Dillehay and Kolata, 2004; Diaz and Stahle, 2007).  

The paper details the effects of ENSO on the climate variations in the region: 'The extreme climatic conditions in this geographic setting are exacerbated by the occurrence of El Niños and La Niñas. Significant flooding across the Atacama and Peruvian coastal deserts and droughts in the Andean highlands and Altiplano are linked to the magnitude of the El Niño-Southern Oscillation (the pressure difference between Darwin, Australia and Tahiti). The Atacama Desert lies in a latitudinal belt from ~°15 S to °25 S on the western side of the Andes, and its hyper-aridity is controlled by the rainshadow effect of the Andes which limits the transfer of moisture from the Atlantic Ocean trade winds westward across the topographic high of the Andes. This orographic effect is further compounded by the position and strength of the Pacific cell of the STHP [sub-tropical high pressure cell] that, in concert with the normally cool waters off the eastern Pacific, establishes an inversion layer of ~ 800 m on the western side of the Andes ultimately blocking eastward transfer of Pacific-sourced moisture. Moreover, the relative strength and position of the upper-level Bolivian High also modulates precipitation amount across the Altiplano (Lenters and Cook, 1997, 1999; Vuille, 1999; Vuille et al., 2000b; Garreaud, 1999; Garreaud and Aceituno, 2001; Garreaud et al., 2003). During El Niño years, the Pacific STHP weakens and trade winds diminish, which limit the upwelling of deep cool water off the eastern Pacific and ultimately allow rainfall on the arid western slopes of the Andes and dryer conditions across the normally wetter Altiplano (Fig. 1A), and disrupting most agricultural and cultural systems. At the other extreme of ENSO, strengthened La Niña's permit wetter conditions to prevail across the Altiplano but maintain dry conditions across the Andean western slopes, exacerbating normal patterns (Fig. 1B)'. The figures are reproduced below.

The paper makes a reference to exceptionally strong El Niño events known as Mega Niños. These appear to be associated with rarer but catastrophic flooding events. 

The paper concludes with this observation: 'El Niños have a catastrophic dimension associated with floodplain stripping (Manners et al., 2007), erosion of
important irrigation canals (Huckleberry, 1999; Huckleberry and Billman, 2003), and wiping out villages (Keefer et al., 2003), but they also can provide cultural opportunities and serve a vital role in replenishing and maintaining groundwater resources across the Atacama Desert'.  

The NG article El Niño/La Niña Nature’s Vicious Cycle, gives a detailed account of the effects of the intense El Niño that caused severe flooding in 1997/98. Yet, according to paleo-climate record, this would not be defined as a catastrophic event. 

There is little doubt in as far as the evidence goes that a warming climate could lead to more intense ENSO events. Peru is particularly vulnerable to such events. The potential for a catastrophic event occurring is more likely, especially if global warming follows a more extreme trajectory.

From the perspective of Nazca, a flood event could completely destroy the region, as noted in an article in The Independent. The cause is attributed to deforestation and industrial activities: 'the Unesco World Heritage site could be destroyed or damaged beyond repair within a matter of years, says Viktoria Nikitzki of the Maria Reiche Centre. The organisation, based in the nearby city of Nazca, is dedicated to researching and protecting the Lines.

"There has been deforestation everywhere so water from the highlands comes down to the Lines in streams and rivers. The Lines themselves are superficial, they are only 10 to 30cm deep and could be washed away," she said. "There is no maintenance or any sort of care for the Lines. Also there is threat by the weather. Nazca has only ever received a small amount of rain. But now there are great changes to the weather all over the world. The Lines cannot resist heavy rain without being damaged."

Pollution and dust from a nearby iron mine and people trespassing and even driving vehicles over the 200 square-mile site are also causes for concern'. 

In the light of what has been discussed above, it could be argued that Greenpeace's infraction was a relatively minor incident in the grand scheme of things. The world is changing at so many levels. A fabulous heritage site could be lost in the future. But so could so many other things. There is some uncertainty as to the potential impacts of climate change. But the message from the past suggests that things could change quickly and suddenly.