History of Climate change – Flashcards

Minute to minute redistribution of solar energy as well as the state of the atmosphere at any given point in time and space.

The accumulation of long term patterns of energy redistribution

Creates seasons

James Croll articulates principles relating orbital forcing to glacial ice volume. Idea refined by Milutin Milankovich in 1930.

a parameter that determines the amount by which its orbit around another body deviates from a perfect circle. Difference between Earth's closest approach perihelion (jan. 3) and aphelion (furthest distance; July 4th) amounts to a 6.8% in coming solar radiation. When the orbit is highly elliptical, the amount of solar radiation at perihelion is 23% greater than at aphelion.

The angle between an object's rotational axis and it's orbital axis

21,000 cycle. The movement of the rotational axis of an object.

Ice sheets Disposition of continental land masses feedback from oceanic circulation Atmospheric variations (Co2, methane, dust particles) Uplift of Himalayas (2m.y.a) Volcanic eruptions Melting of ice packs

Last glacial Maximum (Freezing/dry)(2300.18,000 Bp) Bolling/Allerod (Warming and wetter)(15000) Younger Dryas (freezing and dry) (13000) holocene (warmer and wet) (11,700-present)

958 The Viking Sagas begin and continue through out 1350s when the western Greenland settlement is abandoned. This seems to track with a warmer period which may of lead to improved conditions along the northwest passage. Contrast this with the years of 1576-1610 with Frobisher, Hudson, Byolt, & Foxe probe the arctic regions west of Greenland but penetrate no further than Hudson bay. Conditions seems to have been minimal as the time frame tracks with a serious dip in temperatures during the little ice age. Not until 1903-06 did Amunndsen transit the passage which coincides with the beginning of a warming period.

Magnitude of events, duration, frequency, amplitude, periodicity

First order (less than 10 years): year to year oscillations. Including the Dust bowl (1934-9) and Sahel drought. Boundary between 1st and 2nd order marks the boundary between weather and climate. The duration between them is primarily based on the duration of the event.

Second order (several decades): short term anomalies, such as well defined trends in the instrumental record. Arctic warmup (1900-40); dry spells in East Africa

Third order (several centuries : Long term anomalies, such as the "little ice age" or the warm European "Little optimum" of sufficient amplitude to show up in geological records. Include repeated oscillations during the 10,000 years of the Holocene.

Fourth order (several millennia):

Fifth Order: Major perturbations, such as sever interruptions within the last interglacial, the stadical interstadial oscillations of the last glacial, and the warm and often drier millennia between 8,000 and 5,000 years ago.

Fifth Order

Cultural Ecology Political ecology Resilence theory

Climate change as observed in nature, within geological materials, such as oceans, lake sediments, tree rings, groth bands, ice cores, and cave deposits

Coral reefs, loess (wind blown dust)

The ratio (relative amount) of these two types of oxygen in water changes with the climate. Evaporation and condensation are the two processes that most influence the ratio of heavy oxygen to light oxygen in the oceans. Water molecules are made up of two hydrogen atoms and one oxygen atom. Water molecules containing light oxygen evaporate slightly more readily than water molecules containing a heavy oxygen atom. At the same time, water vapor molecules containing the heavy variety of oxygen condense more readily. Ocean waters rich in heavy oxygen: During ice ages, cooler temperatures extend toward the equator, so the water vapor containing heavy oxygen rains out of the atmosphere at even lower latitudes than it does under milder conditions. The water vapor containing light oxygen moves toward the poles, eventually condenses, and falls onto the ice sheets where it stays. The water remaining in the ocean develops increasingly higher concentration of heavy oxygen compared to the universal standard, and the ice develops a higher concentration of light oxygen. Thus, high concentrations of heavy oxygen in the ocean tell scientists that light oxygen was trapped in the ice sheets. The exact oxygen ratios can show how much ice covered the Earth. Ocean waters rich in light oxygen: Conversely, as temperatures rise, ice sheets melt, and freshwater runs into the ocean. Melting returns light oxygen to the water, and reduces the salinity of the oceans worldwide. Higher-than-standard global concentrations of light oxygen in ocean water indicate that global temperatures have warmed, resulting in less global ice cover and less saline waters. Because water vapor containing heavy oxygen condenses and falls as rain before water vapor containing light oxygen, higher-than-standard local concentrations of light oxygen indicate that the watersheds draining into the sea in that region experienced heavy rains, producing more diluted waters. Thus, scientists associate lower levels of heavy oxygen (again, compared to the standard) with fresher water, which on a global scale indicates warmer temperatures and melting, and on a local scale indicates heavier rainfall.

Calcium carbonate secreting animals the live on the ocean bottom. Oxygen to make shells comes from ocean water measure oxygen content of sediments in core (derived form theses shells) to get oxygen content of cean at time sediments were laid

Corals with annual growth rings are extraordinarily useful to paleoclimatologists because they combine an oxygen-isotope record with precise dating. This x-ray of a coral core shows the change in 18O concentration corresponding to the coral's growth. Because living organisms interact with their environment in complex ways, isotope measurements made from coral and other fossils must be carefully calibrated. (NASA figure by Robert Simmon, based on data provided by Cole et. al. 2000, archived at the World Data Center for Paleoclimatology.

Low heavy Oxygen 18 levels equals high sea level

originates from glacial out wash up to ca. 300 meters thick

sea core ice cores loess sequences

Pollen tree rings lake levels fauna and flora from archaeological sites stream terraces

Melting of the ice packs; Lake Agassiz

Starts during the mid 20th century. Markers are: Carbon isotopes from nuclear explosion and plastics. alternative dates: 1945; Atomic Bomb Testing, 1800 Industrial revolution well under way; 7,000 BP Increase in methane from paddy fields; 12,000 beginnings of reliance on agricultural economies; 500,000 first control of fire by ancestors.

Atmosphere: Green house gases and air pollution Hydrosphere: Water chemistry, draining water tables, alteration steam catchments Lithosphere: soil erosion, lanslides, mining activities Biosphere: biodiversity

Study the relationship between people and nature Adaptation and sustainability Interconnectedness Pristine environments? Domesticated landscapes People and the environment in the past Climate (Paleoclimate) Plants (Paleobotany) Animals (Zooarchaeology) Land surface (Geoarchaeology) Water (Palaeohydrology

between fifty and ten thousand years ago most large mammals became extinct except in Africa.

Environmental hypotheses Catastrophes Megadrought, rapid cooling, comet impact? Habitat loss Preferred habitat types lost or too fragmented Mosaic-nutrient hypothesis Loss of floras with high local diversity Co-evolutionary disequilibrium Disruption of coevolved plant-animal interactions due to flora rearrangement Self-organized instability Collapse of system due to intrinsic dynamics

Habitat alteration Loss or fragmentation of viable habitat due to human impacts, including fires Introduced predators Direct predation by dogs, rats, cats, pigs, etc. Hyper-disease Introduction of virulent diseases

Blitzkrieg Rapid loss of prey due to overhunting Protracted overkill Loss of prey after prolonged interaction with predator

Keystone megaherbivores Ecosystem collapse due to loss of landscape altering megaherbivores, perhaps with increase in fire Prey-switching Nonhuman carnivores switch prey as humans usurp preferred prey Predator avoidance Herbivores restricted to inviable refugia

Unusually warm ocean temperatures in the Equatorial Pacific. Normal trade winds die down causing warm water to accumulate off the western coasts of the Americas, with very reduced upwelling. A strong El Nino produces heavy rains all across the west and south central united states

Unusually cold ocean temperatures in the Equatorial Pacific A strong El Nina produces a drought in much of California and throughout the west

Trade winds blow west in the tropical pacific moving warm surface water away from the coasts of the Americas, causing colder (nutrient rich) water to upwell from the ocean depths.

upwelling ceases (Seriously affecting fisheries) Increased rainfall and storm activity leading to flooding in the Americas Drought conditions

Billman, Brian R, and Gary Huckleberry Deciphering the poltics of prehistoric El Nino events on the North coast of Peru

The Chimu? society was a four-level hierarchical system, with a powerful elite rule over administrative centers • The political power at Chan Chan is demonstrated by the organization of labor to construct the Chimu?'s canals and irrigated fields • In the middle were the craft-specialists (non-food producers) • At the bottom were the subsistence farmers • The Chimu? developed mainly through intensive farming techniques and hydraulic work, which joined valleys to form complexes.

• Patron-client relationships between hereditary rulers and groups of farmers, fishermen, and craft specialists. • The belief in the divinity of rulers. - Rulers were not only political leaders, they were responsible for maintaining the natural order and preventing El Nin?o Events

Archeological site dating to ca 4500 BC in the desert of Turkmenistan Central Asia

wrote "civilization and climate" 1915 Concepts accepted as fact throughout the teens and 20's of the early 20th century.

Pioneered by Franz Boas a sense developed that the particularities of individual cultures (particularism) were much more relevant for social changes than any environmental or climatic factors

scholar became one of the earliest anthropologists to stress the importance of the environment for understanding subsistence economies, settlement patterns, and technologies.

Environmental changes used as a monocausal Ignores the cultural complexity which allows some societies to successfully adapt to conditions Studying why some societies fail and others succeed teaches us more.

the degree to which systems are susceptible to, and unable to cope with, adverse impact.

the ability of a body that has been subjected to an external force to recover

assume that decomposition is an end state for all social forms.

change is ultimately inevitable and repeated adaptive cycles appear to occur across scales, although not continuously.

"Agency refers not to the intentions people have in doing things but to their capability of doing those things in the first place... Agency concerns events of which an individual is the perpetrator, in the sense that the individual could, at any phase in a given sequence of conduct, have acted differently" Free-Agency? an agent acts within the context of her or his norms and the structures that sustain the rules of society and within the limitations of the structural features that are available Values of limits? - Positive: Road map (social memory, institutional procedures, rules, etc.) - Negative: constrains flexibility/elasticity in face of novel situations

diversification of herds and crops

food storage

transformation of surplus food into non perishable goods

Extension of social networks

Consumption of chaff/ drought foods secret preparation and consumption of food Consuming deed populations of herds and grain

Access to goods and resources • Greater land resources • Access to stored resources • May benefit from short-term drought

a change in the amount of water present or else other processes not requiring any change in the amount of water: thermal effects tidal effects local tectonic effects changes, such as ocean floor spreading, affecting the volume of the sea water 'containers;'

refers to the amount of water available in the oceans- changes are often global in scale Rapid sea level rise during the early Holocene drowned significant portions of continental shelves and the settlements associated with them

Can change in response to different factors, not only eustatic ones: these include wind, tides, tectonic movements and isostatic adjustments in responce to change in crustal loading.

The lowest point of sea level during the last glaciation is now well attested but was 130 +- m below present sea level at approximately 22 +- 3 thousand years ago (last glacial maximum)

has led to several archaeological myths: The early postglacial period saw a significant increase in coastal sites (such as shell middens), with evidence of exploitation of coastal resources This coincided with a decline in "big game" animals, as terrestrial environments became less favorable to them Human subsistence patterns changes, exploiting a greater range of smaller animals and more wild plants. This "broad spectrum revolution" marked a significant shift in human perception of coastal environments and coastal food resources Many archaeologists saw this as indicating increased human population levels

In a thousand year time interval, sea level rose around 0.4 m every 20 years. Fast enough for it to have been noticed within a lifetime Such changes must have affected the perception of the world and symbolic sphere of these hunter gathers well before the forced the adoption of new subsistence strategies; these surprisingly did not change significantly as the Egadi were becoming islands.

Oriente B and C (the older samples) have higher amounts of nitrogen While Oriente X (younger) has higher levels of carbon and less nitrogen

Sea level rise did not cause local hunter gathers to develop strong marine oriented adaptations (such as those of their counterparts living on the Atlantic shores of Europe) They maintained a focus on terrestrial based strategies, possible due to: the continued availability of terrestrial resources, or the lack of rich resources in the Mediterranean sea.

based on the modern and ancient DNA records, Asia was the homeland of the first Americans, not Europe, lending no support to the recently proposed "Solutrean hypothesis", that the progenitors of Clovis were derived from an Upper Paleolithic population from Spain and Portugal.

Says their spread into the arctic occurred during a time of relatively warm climate during the lasst ice age, before the Late great migration

Early archaeological evidence south of the Canadian ice sheets starts with Clovis. They have many sites across N. America; some of the best in Texas & N. Mexico The apparent simultaneous appearance of Clovis across much of North America suggests that it rapidly expanded across the continent.

Clovis flourished during the late Allerod interstadial and quickly disappeared at the start of the Younger Dryas stadial

The presence of Human remains dating to 13.1 to 13 ka at arlington springs, on santa rosa island off the cast of California, indicates that the first Americans used watercraft.

Current evidence suggests that anatomically modern humans had colonized or explored several archipelagos in the eastern pacific by 50,000 to 30,000 years ago, islands that could only be reached by seaworthy boats. Between 18,200 and 14,700 years ago warming episodes in the northwestern pacific may have reduced seasonal sea ice cover significantly, increased human access to intertidal and near shore habitats, and facilitated the migration of maritime peoples from northeast Asia to Beringia

associated with collapse (freedom to invent is prevalent, social constraints minimal, new ways of doing things are prevalent and recalling old ways is also important)

greater constraints due to the increased connectedness. Level of control society has over individuals increases

even more connectedness in society, associated with large buraucracies; making decision making much slower.

says the cycle applies on multiple levels (such as in small groups like families, communal churches, and large scale ones like national governments.