Historical climatology

Historical climatology is the study of historical changes in climate and their effect on human history and development. This differs from paleoclimatology which encompasses climate change over the entire history of Earth. The study seeks to define periods in human history where temperature or precipitation varied from what is observed in the present day. The primary sources include written records such as sagas, chronicles, maps and local history literature as well as pictorial representations such as paintings, drawings and even rock art. The archaeological record is equally important in establishing evidence of settlement, water and land usage.


In literate societies, historians may find written evidence of climatic variations over hundreds or thousands of years, such as phenological records of natural processes, for example viticultural records of grape harvest dates. In preliterate or non-literate societies, researchers must rely on other techniques to find evidence of historical climate differences.

Past population levels and habitable ranges of humans or plants and animals may be used to find evidence of past differences in climate for the region. Palynology, the study of pollens, can show not only the range of plants and to reconstruct possible ecology, but to estimate the amount of precipitation in a given time period, based on the abundance of pollen in that layer of sediment or ice.

Evidence of climatic variations

The eruption of the Toba supervolcano, 70,000 to 75,000 years ago reduced the average global temperature by 5 degrees Celsius for several years and may have triggered an ice age. It has been postulated that this created a bottleneck in human evolution. A much smaller but similar effect occurred after the eruption of Krakatoa in 1883, when global temperatures fell for about 5 years in a row.

Before the retreat of glaciers at the start of the Holocene (~9600 BC), ice sheets covered much of the northern latitudes and sea levels were much lower than they are today. The start of our present interglacial period appears to have helped spur the development of human civilization.

Human record

The 16th-century Skálholt Map of Norse America

Evidence of a warm climate in Europe, for example, comes from archaeological studies of settlement and farming in the Early Bronze Age at altitudes now beyond cultivation, such as Dartmoor, Exmoor, the Lake district and the Pennines in Great Britain. The climate appears to have deteriorated towards the Late Bronze Age however. Settlements and field boundaries have been found at high altitude in these areas, which are now wild and uninhabitable. Grimspound on Dartmoor is well preserved and shows the standing remains of an extensive settlement in a now inhospitable environment.

Some parts of the present Saharan desert may have been populated when the climate was cooler and wetter, judging by cave art and other signs of settlement in Prehistoric Central North Africa.

The Medieval Warm Period was a time of warm weather between about AD 800–1300, during the European Medieval period. Archaeological evidence supports studies of the Norse sagas which describe the settlement of Greenland in the 9th century AD of land now quite unsuitable for cultivation. For example, excavations at one settlement site have shown the presence of birch trees during the early Viking period. The same period records the discovery of an area called Vinland, probably in North America, which may also have been warmer than at present, judging by the alleged presence of grape vines. The interlude is known as the Medieval Warm Period.

Little Ice Age

Later examples include the Little Ice Age, well documented by paintings, documents (such as diaries) and events such as the River Thames frost fairs held on frozen lakes and rivers in the 17th and 18th centuries. The River Thames was made more narrow and flowed faster after old London Bridge was demolished in 1831, and the river was embanked in stages during the 19th century, both of which made the river less liable to freezing. Among the earliest references to the coming climate change is an entry in the Anglo-Saxon Chronicle dated 1046:

  • "And in this same year after the 2nd of February came the severe winter with frost and snow, and with all kinds of bad weather, so that there was no man alive who could remember so severe a winter as that, both through mortality of men and disease of cattle; both birds and fishes perished through the great cold and hunger."

The Chronicle is the single most important historical source for the period in England between the departure of the Romans and the decades following the Norman Conquest. Much of the information given in the Chronicle is not recorded elsewhere.

The Frozen Thames 1677
The Frozen Thames, 1677

The Little Ice Age brought colder winters to parts of Europe and North America. In the mid-17th century, glaciers in the Swiss Alps advanced, gradually engulfing farms and crushing entire villages. The River Thames and the canals and rivers of the Netherlands often froze over during the winter, and people skated and even held frost fairs on the ice. The first Thames frost fair was in 1607; the last in 1814, although changes to the bridges and the addition of an embankment affected the river flow and depth, diminishing the possibility of freezes. The freeze of the Golden Horn and the southern section of the Bosphorus took place in 1622. In 1658, a Swedish army marched across the Great Belt to Denmark to invade Copenhagen. The Baltic Sea froze over, enabling sledge rides from Poland to Sweden, with seasonal inns built on the way. The winter of 1794/1795 was particularly harsh when the French invasion army under Pichegru could march on the frozen rivers of the Netherlands, while the Dutch fleet was fixed in the ice in Den Helder harbour. In the winter of 1780, New York Harbour froze, allowing people to walk from Manhattan to Staten Island. Sea ice surrounding Iceland extended for miles in every direction, closing that island's harbours to shipping.

Hvalsey Church
The last written records of the Norse Greenlanders are from a 1408 marriage in Hvalsey Church — today the best-preserved of the Norse ruins

The severe winters affected human life in ways large and small. The population of Iceland fell by half, but this was perhaps also due to fluorosis caused by the eruption of the volcano Laki in 1783.Iceland also suffered failures of cereal crops and people moved away from a grain-based diet. The Norse colonies in Greenland starved and vanished (by the 15th century) as crops failed and livestock could not be maintained through increasingly harsh winters, though Jared Diamond noted that they had exceeded the agricultural carrying capacity before then. In North America, American Indians formed leagues in response to food shortages. In Southern Europe, in Portugal, snow storms were much more frequent while today they are rare. There are reports of heavy snowfalls in the winters of 1665, 1744 and 1886.

In contrast to its uncertain beginning, there is a consensus that the Little Ice Age ended in the mid-19th century.

Evidence of anthropogenic climate change

Through deforestation and agriculture, some scientists have proposed a human component in some historical climatic changes. Human-started fires have been implicated in the transformation of much of Australia from grassland to desert.[1] If true, this would show that non-industrialized societies could have a role in influencing regional climate. Deforestation, desertification and the salinization of soils may have contributed to or caused other climatic changes throughout human history.

For a discussion of recent human involvement in climatic changes, see Attribution of recent climate change.

See also


  1. ^ Miller GH, Fogel ML, Magee JW, Gagan MK, Clarke SJ, Johnson BJ (July 2005). "Ecosystem Collapse in Pleistocene Australia and a Human Role in Megafaunal Extinction". Science. 309 (5732): 287–290. Bibcode:2005Sci...309..287M. doi:10.1126/science.1111288. PMID 16002615.

External links

Anthony Watts (blogger)

Willard Anthony Watts (born 1958) is an American blogger who runs Watts Up With That?, a popular climate change denial blog that opposes the scientific consensus on climate change. A former television meteorologist and current radio meteorologist, he is also founder of the Surface Stations project, a volunteer initiative to document the condition of U.S. weather stations. The Heartland Institute helped fund some of Watts' projects, including publishing a report on the Surface Stations project, and has invited him to be a paid speaker at its International Conference on Climate Change from 2008 to 2014.

Atlantic hurricane

An Atlantic hurricane or tropical storm is a tropical cyclone that forms in the Atlantic Ocean, usually between the months of June and November. A hurricane differs from a cyclone or typhoon only on the basis of location. A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean.Tropical cyclones can be categorized by intensity. Tropical storms have one-minute maximum sustained winds of at least 39 mph (34 knots, 17 m/s, 63 km/h), while hurricanes have one-minute maximum sustained winds exceeding 74 mph (64 knots, 33 m/s, 119 km/h). Most North Atlantic tropical storms and hurricanes form between June 1 and November 30. The United States National Hurricane Center monitors the basin and issues reports, watches, and warnings about tropical weather systems for the North Atlantic Basin as one of the Regional Specialized Meteorological Centers for tropical cyclones, as defined by the World Meteorological Organization.In recent times, tropical disturbances that reach tropical storm intensity are named from a predetermined list. Hurricanes that result in significant damage or casualties may have their names retired from the list at the request of the affected nations in order to prevent confusion should a subsequent storm be given the same name. On average, in the North Atlantic basin (from 1966 to 2009) 11.3 named storms occur each season, with an average of 6.2 becoming hurricanes and 2.3 becoming major hurricanes (Category 3 or greater). The climatological peak of activity is around September 10 each season.In March 2004, Catarina was the first hurricane-intensity tropical cyclone ever recorded in the Southern Atlantic Ocean. Since 2011, the Brazilian Navy Hydrographic Center has started to use the same scale of the North Atlantic Ocean for tropical cyclones in the South Atlantic Ocean and assign names to those which reach 35 kn (65 km/h; 40 mph).

Cape Verde hurricane

A Cape Verde hurricane, or Cabo Verde hurricane is an Atlantic hurricane that originates at low-latitude in the deep tropics from a tropical wave that has passed over or near the Cape Verde islands after exiting the coast of West Africa. The average hurricane season has about two Cape Verde hurricanes, which are often the largest and most intense storms of the season due to having plenty of warm open ocean over which to develop before encountering land or other factors prompting weakening. A good portion of Cape Verde storms are large, and some, such as Hurricane Ivan and Hurricane Irma, have set various records. Most of the longest-lived tropical cyclones in the Atlantic basin are Cape Verde hurricanes. While many move harmlessly out to sea, some move across the Caribbean sea and into the Gulf of Mexico, becoming damaging storms for Caribbean nations, Central America, Mexico, Bermuda, the United States, and occasionally even Canada. Research projects since the 1970s have been launched to understand the formation of these storms.

Climate change in Japan

Climate change/global warming in Japan is being addressed at a governmental level.

The Intergovernmental Panel on Climate Change (IPCC) proposes two hypothetical future scenarios. One is Scenario "A1B" based on the assumption that a future world will have more global economic growth (the concentration of carbon dioxide will be 720ppm in 2100). The other is Scenario "B1" based on the assumption that a future world will have global green economy (the concentration of carbon dioxide will be 550ppm in 2100).

Earth Simulator calculations reveal the daily increase in mean temperature in Japan during the period of 2071 to 2100. The temperature will increased by 3.0 °C in Scenario B1 and 4.2 °C in A1B compared to that of 1971 to 2000. Similarly, the daily maximum temperature in Japan will increase by 3.1 °C in B1 and 4.4 °C in A1B. The precipitation in summer in Japan will increase steadily due to global warming (annual average precipitation will increase by 17% in Scenario B1 and by 19% in Scenario A1B during the period of 2071 to 2100 compared to that of 1971 to 2000).Currently, Japan is a world leader in the development of new climate-friendly technologies. Honda and Toyota hybrid electric vehicles were named to have the highest fuel efficiency and lowest emissions. The fuel economy and emissions decrease is due to the advanced technology in hybrid systems, biofuels, use of lighter weight material and better engineering.

As a signatory of the Kyoto Protocol, and host of the 1997 conference which created it, Japan is under treaty obligations to reduce its carbon dioxide emissions and to take other steps related to curbing climate change. The Cool Biz campaign introduced under former Prime Minister Junichiro Koizumi was targeted at reducing energy use through the reduction of air conditioning use in government offices.

Climate oscillation

A climate oscillation or climate cycle is any recurring cyclical oscillation within global or regional climate, and is a type of climate pattern. These fluctuations in atmospheric temperature, sea surface temperature, precipitation or other parameters can be quasi-periodic, often occurring on inter-annual, multi-annual, decadal, multidecadal, century-wide, millennial or longer timescales. They are not perfectly periodic and a Fourier analysis of the data does not give a sharp spectrum.

A prominent example is the El Niño Southern Oscillation, involving sea surface temperatures along a stretch of the equatorial Central and East Pacific Ocean and the western coast of tropical South America, but which affects climate worldwide.

Records of past climate conditions are recovered through geological examination of proxies, found in glacier ice, sea bed sediment, tree ring studies or otherwise.


Climatology (from Greek κλίμα, klima, "place, zone"; and -λογία, -logia) or climate science is the scientific study of climate, scientifically defined as weather conditions averaged over a period of time. This modern field of study is regarded as a branch of the atmospheric sciences and a subfield of physical geography, which is one of the Earth sciences. Climatology now includes aspects of oceanography and biogeochemistry. Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño–Southern Oscillation (ENSO), the Madden–Julian oscillation (MJO), the North Atlantic oscillation (NAO), the Northern Annular Mode (NAM) which is also known as the Arctic oscillation (AO), the Northern Pacific (NP) Index, the Pacific decadal oscillation (PDO), and the Interdecadal Pacific Oscillation (IPO). Climate models are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate. Weather is known as the condition of the atmosphere over a period of time, while climate has to do with the atmospheric condition over an extended to indefinite period of time.

Earth's energy budget

Earth's energy budget accounts for the balance between the energy Earth receives from the Sun, and the energy the Earth radiates back into outer space after having been distributed throughout the five components of Earth's climate system and having thus powered the so-called Earth’s heat engine. This system is made up of earth's water, ice, atmosphere, rocky crust, and all living things.Quantifying changes in these amounts is required to accurately model the Earth's climate.

Received radiation is unevenly distributed over the planet, because the Sun heats equatorial regions more than polar regions. "The atmosphere and ocean work non-stop to even out solar heating imbalances through evaporation of surface water, convection, rainfall, winds, and ocean circulation." Earth is very close to being in radiative equilibrium, the situation where the incoming solar energy is balanced by an equal flow of heat to space; under that condition, global temperatures will be relatively stable. Globally, over the course of the year, the Earth system—land surfaces, oceans, and atmosphere—absorbs and then radiates back to space an average of about 240 watts of solar power per square meter. Anything that increases or decreases the amount of incoming or outgoing energy will change global temperatures in response.However, Earth's energy balance and heat fluxes depend on many factors, such as atmospheric composition (mainly aerosols and greenhouse gases), the albedo (reflectivity) of surface properties, cloud cover and vegetation and land use patterns.

Changes in surface temperature due to Earth's energy budget do not occur instantaneously, due to the inertia of the oceans and the cryosphere. The net heat flux is buffered primarily by becoming part of the ocean's heat content, until a new equilibrium state is established between radiative forcings and the climate response.

Forest dieback

Forest dieback (also "Waldsterben", a German loan word) is a condition in trees or woody plants in which peripheral parts are killed, either by pathogens, parasites or due to conditions like acid rain and drought. Two of the nine tipping points for major climate changes, forecast for the next century, are directly related to forest diebacks.

Global Historical Climatology Network

The Global Historical Climatology Network (GHCN) is a database of temperature, precipitation and pressure records managed by the National Climatic Data Center, Arizona State University and the Carbon Dioxide Information Analysis Center.The aggregate data are collected from many continuously reporting fixed stations at the Earth's surface and represent the input of approximately 6000 temperature stations, 7500 precipitation stations and 2000 pressure stations.

This work has often been used as a foundation for reconstructing past global temperatures, and was used in previous versions of two of the best-known reconstructions, that prepared by the National Climatic Data Center (NCDC), and that prepared by NASA as its Goddard Institute for Space Studies (GISS) temperature set. The average temperature record is 60 years long with ~1650 records greater than 100 years and ~220 greater than 150 years (based on GHCN v2 in 2006). The earliest data included in the database were collected in 1697.

Greenhouse effect

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.If a planet's atmosphere contains radiatively active gases (i.e., greenhouse gases) they will radiate energy in all directions. Part of this radiation is directed towards the surface, warming it.

The intensity of the downward radiation – that is, the strength of the greenhouse effect – will depend on the atmosphere's temperature and on the amount of greenhouse gases that the atmosphere contains.

Earth’s natural greenhouse effect is critical to supporting life. Human activities, mainly the burning of fossil fuels and clearing of forests, have strengthened the greenhouse effect and caused global warming.The term "greenhouse effect" is a misnomer that arose from a faulty analogy with the effect of sunlight passing through glass and warming a greenhouse. The way a greenhouse retains heat is fundamentally different, as a greenhouse works mostly by reducing airflow so that warm air is kept inside, whereas the greenhouse "effect" is the increase in temperature inside of the "house" via the re-radiation of heat energy from its gaseous "windows" which allow light energy to pass in but then trap it and reflect it when it attempts to escape as heat energy.

Historical impacts of climate change

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.

Indian Ocean Dipole

The Indian Ocean Dipole (IOD), also known as the Indian Niño, is an irregular oscillation of sea-surface temperatures in which the western Indian Ocean becomes alternately warmer and then colder than the eastern part of the ocean.

Monsoon in India is generally affected by the temperature between bay of Bengal in the east and The Arabian sea in the west.

Instrumental temperature record

The instrumental temperature record provides the temperature of Earth's climate system from the historical network of in situ measurements of surface air temperatures and ocean surface temperatures. Data are collected at thousands of meteorological stations, buoys and ships around the globe. The longest-running temperature record is the Central England temperature data series, which starts in 1659. The longest-running quasi-global record starts in 1850. In recent decades more extensive sampling of ocean temperatures at various depths have begun allowing estimates of ocean heat content but these do not form part of the global surface temperature datasets.

Land use, land-use change, and forestry

Land use, land-use change, and forestry (LULUCF), also referred to as Forestry and other land use (FOLU), is defined by the United Nations Climate Change Secretariat as a "greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use such as settlements and commercial uses, land-use change, and forestry activities."LULUCF has impacts on the global carbon cycle and as such, these activities can add or remove carbon dioxide (or, more generally, carbon) from the atmosphere, influencing climate. LULUCF has been the subject of two major reports by the Intergovernmental Panel on Climate Change (IPCC). Additionally, land use is of critical importance for biodiversity.


Phenology is the study of periodic plant and animal life cycle events and how these are influenced by seasonal and interannual variations in climate, as well as habitat factors (such as elevation).

The word, coined by the Belgian botanist Charles Morren in 1849, is derived from the Greek φαίνω (phainō), "to show, to bring to light, make to appear" + λόγος (logos), amongst others "study, discourse, reasoning" and indicates that phenology has been principally concerned with the dates of first occurrence of biological events in their annual cycle.

Examples include the date of emergence of leaves and flowers, the first flight of butterflies and the first appearance of migratory birds, the date of leaf colouring and fall in deciduous trees, the dates of egg-laying of birds and amphibia, or the timing of the developmental cycles of temperate-zone honey bee colonies. In the scientific literature on ecology, the term is used more generally to indicate the time frame for any seasonal biological phenomena, including the dates of last appearance (e.g., the seasonal phenology of a species may be from April through September).

Because many such phenomena are very sensitive to small variations in climate, especially to temperature, phenological records can be a useful proxy for temperature in historical climatology, especially in the study of climate change and global warming. For example, viticultural records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years.

In addition to providing a longer historical baseline than instrumental measurements, phenological observations provide high temporal resolution of ongoing changes related to global warming.

Rising Tide North America

Rising Tide North America is a grassroots network of groups and individuals in North America organizing action against the root causes of climate change and work towards a non-carbon society. Rising Tide North America is part of an international network dedicated to building a climate justice and anti-extraction movement. Rising Tide generally takes a strongly "no compromise" stance on the environment and a vehement opposition to solutions proposed by corporations who, they say, are responsible for creating environmental problems in the first place.

The Hockey Stick Illusion

The Hockey Stick Illusion: Climategate and the Corruption of Science is a book written by Andrew Montford and published by Stacey International in 2010. Montford, an accountant and science publisher who publishes a blog called ‘Bishop Hill’ provides his analysis of the history of the "hockey stick graph" of global temperatures for the last 1000 years and the controversy promoted by mining exploration company director Steve McIntyre about the research which produced the graph. The book describes the history of the graph from its inception to the beginning of the Climatic Research Unit email controversy ("Climategate").

Timothy Ball

Timothy Francis "Tim" Ball (born November 5, 1938) is a Canadian public speaker and writer who was a professor in the Department of Geography at the University of Winnipeg from 1971 until his retirement in 1996. Ball has worked with Friends of Science and Natural Resources Stewardship Project, which oppose the consensus scientific opinion of significant anthropogenic global warming, and is a former research fellow at the Frontier Centre for Public Policy. Ball also rejects the consensus scientific opinion on climate change, stating that "CO2 is not a greenhouse gas that raises global temperature."

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