Historical impacts of climate change
Encyclopedia
Climate
has affected human life and civilization
from the emergence of hominins to the present day. These historical impacts of climate change can improve human life and cause societies to flourish, or can be instrumental in civilization's societal collapse
.
to more arid
grasslands due to tectonic uplift
and changes in broader patterns of ocean and atmospheric circulation
. This environmental change is believed to have forced hominins to evolve for life in a savannah
-type environment. Some data suggest that this environmental change caused the development of modern homimin features; however there exist other data that show that morphological changes in the earliest hominins occurred while the region was still forested. Rapid tectonic uplift
likely occurred in the early Pleistocene
, changing the local elevation and broadly reorganizing the regional patterns of atmospheric circulation. This can be correlated with the rapid hominin evolution of the Quaternary period. Changes in climate at 2.8, 1.7, and 1.0 million years ago correlate well with observed transitions between recognized hominin species. It is difficult to differentiate correlation from causality in these paleopanthropological
and paleoclimatological
reconstructions, so these results must be interpreted with caution and related to the appropriate time-scales and uncertainties.
slowing of sea-level rise, many coastal urban centers rose to prominence around the world. It has been hypothesized that this is correlated with the development of stable coastal environments and ecosystems and an increase in marine productivity (also related to an increase in temperatures), which would provide a food source for hierarchical urban societies.
Climate change has been associated with the historical collapse of civilizations, cities and dynasties. Notable examples of this include the Anasazi, Classic Maya
, the Harappa
, the Hittites
, and Ancient Egypt
. Other, smaller communities such as the Viking
settlement of Greenland
have also suffered collapse with climate change being a suggested contributory factor.
There are two proposed methods of Classic Maya collapse: environmental and non-environmental. The environmental approach uses paleoclimatic evidence to show that movements in the intertropical convergence zone
likely caused severe, extended droughts during a few time periods at the end of the archaeological record for the classic Maya. The non-environmental approach suggests that the collapse could be due to increasing class tensions associated with the building of monumental architecture and the corresponding decline of agriculture, increased disease, and increased internal warfare.
The Harappa and Indus civilizations were affected by drought 4,500–3,500 years ago. A decline in rainfall in the Middle East and Northern India 3,800–2,500 is likely to have affected the Hittites and Ancient Egypt.
and the little ice age
. In the case of the Norse, the Medieval warm period was associated with the Norse age of exploration and arctic colonization, and the later colder periods led to the decline of those colonies.
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
has affected human life and civilization
Civilization
Civilization is a sometimes controversial term that has been used in several related ways. Primarily, the term has been used to refer to the material and instrumental side of human cultures that are complex in terms of technology, science, and division of labor. Such civilizations are generally...
from the emergence of hominins to the present day. These historical impacts of climate change can improve human life and cause societies to flourish, or can be instrumental in civilization's societal collapse
Societal collapse
Societal collapse broadly includes both quite abrupt societal failures typified by collapses , as well as more extended gradual declines of superpowers...
.
Role in human evolution
Changes in East African climate have been associated with the evolution of hominins. Researchers have proposed that the regional environment transitioned from humid jungleJungle
A Jungle is an area of land in the tropics overgrown with dense vegetation.The word jungle originates from the Sanskrit word jangala which referred to uncultivated land. Although the Sanskrit word refers to "dry land", it has been suggested that an Anglo-Indian interpretation led to its...
to more arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
grasslands due to tectonic uplift
Tectonic uplift
Tectonic uplift is a geological process most often caused by plate tectonics which increases elevation. The opposite of uplift is subsidence, which results in a decrease in elevation. Uplift may be orogenic or isostatic.-Orogenic uplift:...
and changes in broader patterns of ocean and atmospheric circulation
Atmospheric circulation
Atmospheric circulation is the large-scale movement of air, and the means by which thermal energy is distributed on the surface of the Earth....
. This environmental change is believed to have forced hominins to evolve for life in a savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
-type environment. Some data suggest that this environmental change caused the development of modern homimin features; however there exist other data that show that morphological changes in the earliest hominins occurred while the region was still forested. Rapid tectonic uplift
Tectonic uplift
Tectonic uplift is a geological process most often caused by plate tectonics which increases elevation. The opposite of uplift is subsidence, which results in a decrease in elevation. Uplift may be orogenic or isostatic.-Orogenic uplift:...
likely occurred in the early Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, changing the local elevation and broadly reorganizing the regional patterns of atmospheric circulation. This can be correlated with the rapid hominin evolution of the Quaternary period. Changes in climate at 2.8, 1.7, and 1.0 million years ago correlate well with observed transitions between recognized hominin species. It is difficult to differentiate correlation from causality in these paleopanthropological
Paleoanthropology
Paleoanthropology, which combines the disciplines of paleontology and physical anthropology, is the study of ancient humans as found in fossil hominid evidence such as petrifacted bones and footprints.-19th century:...
and paleoclimatological
Paleoclimatology
Paleoclimatology is the study of changes in climate taken on the scale of the entire history of Earth. It uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, ice sheets, tree rings, corals, shells and microfossils; it then...
reconstructions, so these results must be interpreted with caution and related to the appropriate time-scales and uncertainties.
Historic and prehistoric societies
The rise and fall of societies have often been linked to environmental factors.Societal growth and urbanization
Approximately one millennium after the 7 kaKa
-Language:* Ka * Ka * Georgian language, ISO 639-1 code ka* A glyph in the Brahmic family of scripts-Media and entertainment:* Ka * Kà, a Cirque du Soleil show* Mister Mosquito, a video game, known in Japan as Ka...
slowing of sea-level rise, many coastal urban centers rose to prominence around the world. It has been hypothesized that this is correlated with the development of stable coastal environments and ecosystems and an increase in marine productivity (also related to an increase in temperatures), which would provide a food source for hierarchical urban societies.
Societal collapse
Classic Maya collapse
The Classic Maya Collapse refers to the decline and abandonment of the Classic Period Maya cities of the southern Maya lowlands of Mesoamerica between the 8th and 9th centuries. This should not be confused with the collapse of the Preclassic Maya in the 2nd century AD...
, the Harappa
Harappa
Harappa is an archaeological site in Punjab, northeast Pakistan, about west of Sahiwal. The site takes its name from a modern village located near the former course of the Ravi River. The current village of Harappa is from the ancient site. Although modern Harappa has a train station left from...
, the Hittites
Hittites
The Hittites were a Bronze Age people of Anatolia.They established a kingdom centered at Hattusa in north-central Anatolia c. the 18th century BC. The Hittite empire reached its height c...
, and Ancient Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...
. Other, smaller communities such as the Viking
Viking
The term Viking is customarily used to refer to the Norse explorers, warriors, merchants, and pirates who raided, traded, explored and settled in wide areas of Europe, Asia and the North Atlantic islands from the late 8th to the mid-11th century.These Norsemen used their famed longships to...
settlement of Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
have also suffered collapse with climate change being a suggested contributory factor.
There are two proposed methods of Classic Maya collapse: environmental and non-environmental. The environmental approach uses paleoclimatic evidence to show that movements in the intertropical convergence zone
Intertropical Convergence Zone
The Intertropical Convergence Zone , known by sailors as The Doldrums, is the area encircling the earth near the equator where winds originating in the northern and southern hemispheres come together....
likely caused severe, extended droughts during a few time periods at the end of the archaeological record for the classic Maya. The non-environmental approach suggests that the collapse could be due to increasing class tensions associated with the building of monumental architecture and the corresponding decline of agriculture, increased disease, and increased internal warfare.
The Harappa and Indus civilizations were affected by drought 4,500–3,500 years ago. A decline in rainfall in the Middle East and Northern India 3,800–2,500 is likely to have affected the Hittites and Ancient Egypt.
Historical era
Notable periods of climate change in recorded history include the Medieval warm periodMedieval Warm Period
The Medieval Warm Period , Medieval Climate Optimum, or Medieval Climatic Anomaly was a time of warm climate in the North Atlantic region, that may also have been related to other climate events around the world during that time, including in China, New Zealand, and other countries lasting from...
and the little ice age
Little Ice Age
The Little Ice Age was a period of cooling that occurred after the Medieval Warm Period . While not a true ice age, the term was introduced into the scientific literature by François E. Matthes in 1939...
. In the case of the Norse, the Medieval warm period was associated with the Norse age of exploration and arctic colonization, and the later colder periods led to the decline of those colonies.