Little Ice Age volcanism refers to the massive volcanic activities during the Little Ice Age. Scientists suggested a hypothesis that volcanism was the major driving force of the global cooling among the other natural factors, i.e. the sunspot activities by orbital forcing and greenhouse gas. The Past Global Change (PAGES), a registered paleo-science association for scientific research and networking on past global changes in the University of Bern, Switzerland, suggested that from 1630 to 1850, a total of 16 major eruptions and cooling events had taken place. [2] When a volcano erupts, ashes burst out of the vent together with magma and forms a cloud in the atmosphere. The ashes act as an isolating layer that block out a proportion of solar radiation, causing global cooling. The global cooling effect impacts ocean currents, atmospheric circulation and cause social impacts such as drought and famine. Wars and rebellions were therefore triggered worldwide in the Little Ice Age. It was suggested that the crisis on Ottoman Empire [3] and Ming-Qing Transition [4] in China were typical examples that closely correlated with Little Ice Age.
Three large cooling periods caused by volcanic eruptions in 1641–1642, 1667–1694 and 1809–1831 respectively. [2] Also, some major volcanic eruptions caused the fall of the temperature. During the Little Ice Age, all major volcanic eruptions were stratovolcano, also known as composite volcanos. They were built by the escape of magma through separate vents over thousands of years, accumulated into layers. A large amount of sulfate and volcanic ashes escaped from the volcano, resulting in a significant decrease in temperature.
*All Volcanic Eruptions have a Volcanic Explosivity Index (VEI) of 5 or above. It means that the volume of gases and aerosols ejected were more than 1 km3 and the eruption column height was more than 25 km.
Volcano | Year | Region | Season | VEI | Effects/Features | Types of Volcanos |
---|---|---|---|---|---|---|
Komaga-Take Volcano | 31 July 1640 [11] | Japan | 3 | 6 | The Volcanic Eruption caused the Tsunami which reached Atokuchi-Yama. The thickness of the Ash deposition was up to 1–2 m. [11] | Stratovolcano |
Mount Villarica | February 1640 [4] | Chile | unknown | unknown | "Began to erupt with such force that it expelled burning rocks... So much burning ash fell into the river Alipen that the waters burned in such a way that it cooked all the fish here." (Parker, 2013) [4] | Stratovolcano |
Parker volcano | 1641 | Philippines | 1 | 5 | The eruption caused devastating pyroclastic flows and ash deposition and darkness over Mindanao Island. [12] | Stratovolcano |
Long Island | 1660 | New Guinea | unknown | 6 | The eruption was the largest eruption in Papua New Guinea's history, with an estimated air-fall volume in excess of 11 km3 [13] | Stratovolcano |
Usu | 1663 | Japan | 3 | 6 | 2.5 km3 rhyolitic pumice fall deposited in the east reaching about 1 m thick in Shiraoi coast. [14] | Stratovolcano |
Shikotsu (Tarumae) | 1667 | Japan | 4 | 5 | A small 1.5 km wide caldera formed during the eruption (Hokkaido's largest historical eruption) [15] | Stratovolcano |
Gamkonora | 1673 | Halmahera | 2 | 5? | A tsunami was produced which inundated villages. [16] | Stratovolcano |
Tongkoko | 1680 | Sulawesi | unknown | 5 | The escape of aerosols was high into the stratosphere and the proxies were found in Greenland Ice cores. [17] | Stratovolcano |
Fuji | 16 December 1707 | Japan | 1 | 5 | 800 million m3 of ashes were escaped and the ash reached and blanketed 100 km away. It caused a number of deaths. | Stratovolcano |
Shikotsu (Tarumae) | 1739 | Japan | 3 | 5 | The density of the yearly tree ring changed in 1740. Scientists believed that the eruption affected the climate. [5] | Stratovolcano |
St Helens | 1800 | United States | 1 | 5 | It began the Goat Rocks eruptive period and the continuous eruptions were relieved until the 1850s. [18] | Stratovolcano |
Tambora | 10 April 1815 | Indonesia | 2 | 7 | This was the world's greatest eruption since the end of the ice age. [19] The ash and smoke blanketed the Northern Hemisphere and caused "The year without summer" [20] | Stratovolcano |
Galunggung Volcano | 1822 | Indonesia | unknown | 5 | The mudflows killed over 4000 people and destroyed more than 114 villages. [21] | Stratovolcano |
Cosigüina Volcano | 1835 | Nicaragua | 1 | 5 | It was the largest volcanic eruption in Central America since Spanish Colonization. the total volume of deposits was about 6 km3 [22] | Stratovolcano |
Volcanoes are usually formed along plate boundaries or hotspots. Each eruption allows lava, volcanic ash and gases (toxic gases and greenhouse gases) to escape from the magma chamber under the surface. The escaped materials trigger the global cooling effect.
The temperature on the surface is affected by the greenhouse effect. During the Little Ice Age, volcanic eruptions produced ashes that blocked solar insolation. The Earth surface received less radiation, the temperature decreased significantly. The effect lasted for around 6–8 years (Fig. 5). [23] In addition, sulfur dioxide produced from eruptions reacted with the ozone layer to form sulfuric acid. Fine sulfate aerosols were formed in the atmosphere, which increased the reflection of solar and caused global cooling. [24]
Product | Formula | Causing global cooling |
---|---|---|
Volcanic ashes | Nil | |
Sulfur dioxide | SO2 | ✓ |
Carbon dioxide | CO2 | |
Hydrogen sulphide | H2S | ✓ |
Lava | Nil |
Scientists pointed out several natural causes of the Little Ice Age, e.g. volcanic activity, orbital cycles, decreased solar activity and Greenhouse gas. Gabriele C. Hegerl compared the different forcing of Little Ice Age based on various studies. [23] An energy balance model was simulated, with volcanic, solar and greenhouse gas signals as parameters. They created various models to calculate the correlation between natural forcing and temperature change. It showed natural forcing acted as an important role in temperature change (Fig. 5). Also, the research also compared the contribution of temperature change among three natural factors. [23] Volcanic activities was the main driver of the Little Ice Age (Fig. 7), [23] because volcanism was the largest forcing.
Little Ice Age Volcanism caused a temperature anomaly. It affected the climate system, i.e. the atmosphere, the hydrosphere. The influence of the climate system would cause the impact of the ecosystem and the society.
During the Little Ice Age, the northern hemisphere had a remarkable climatic shift. There was a nonlinear regime shift in the North Atlantic Ocean Circulation and changed ocean circulation. [26] There are two reasons for the change. Firstly, the cold climate reduced the melting rate of the Arctic sea ice in the summer, less freshwater remained in the Ocean, leading to a change of the stratification in the Ocean. [27] Besides, in Nordic Sea, the abrupt cooling showed a delay and gradual warming trend in contrast to a basin-wide cooling during the Little Ice Age [26] as the oceans take up heat and recharge their heat content. The scientists believed that it was a volcanically triggered regime shift. [26]
The massive volcanic eruption caused an abrupt cooling, the palaeoanalysis shows a significant decrease of mean global temperature. [8] It affects the global monsoon system, the system is the major wind system that dominates the climate pattern of the Earth by seasonally reverses its direction. Hence the climate patterns of different regions, i.e. precipitation and temperature were changed after the cooling.
African Monsoon Region is located between latitudes N10° and N20°, it is the major wind system which affected the West African Region. The temperature change weakened the African Monsoon system and Atlantic-European Hadley cell. [28] In the African Monsoon Region, the Intertropical Convergence Zone (ITCZ) shifted southwards. The ITCZ shifted to the position far from Doldrums (the low pressure air uplifting region in equator). [29] The air in the Atlantic converges with the drier air and causes a lower precipitation. [30]
Asian-Australian Monsoon is the major wind system affected the East Asia and Australia by the shift of prevailing wind between summer and winter seasons. However, the cooling weakened the Asian-Australian Monsoon. It affected the migration of the Intertropical Convergence Zone (ITCZ), the moist air could not reach southern Asia and tropical China. [31] Gallego's paper pointed out that there was a low DJF Australian monsoon index during Little Ice Age. [32]
South Asia Monsoon affects the Indian subcontinent annually The southward shift of the northern tropical belt (the boundary of Hadley cell and Ferrel Cell) [30] and the weaken Atlantic Multidecadal Oscillation [33] affected the South Asia Monsoon (a monsoon system mostly affects the climate of Indian subcontinent). Less precipitation occurred during the Little Ice Age.
El Niño, also named as El Niño-Southern Oscillation (ENSO), appeared in Pacific Ocean. It affects the walker circulation (an Atmosphere Circulation between East Pacific and Western Pacific). In normal conditions, the warm air developed in the Eastern Pacific, formed a low pressure system which blows the wind to the East Pacific Region. The uplifting air in the East Pacific Region enhances the precipitation.(Figure 8) However, when El Niño happens, the warm air shifts to the central Pacific causing the changes of precipitation and temperature. During the Little Ice Age, the increased volcanic activity triggered El Niño. In the mid-seventeenth century, it happened about once every five years, while the average frequency is every 20 years. [34] [ failed verification ] It caused droughts in different regions such as southern Africa, India and southern China. [4]
Earth scientists used a variety of proxies and instruments of climate indicator to measure the temperature changes and the proportion of natural forcing.
Tree ring dating, also known as dendrochronology, is an excellent indicator to measure the climate pattern. Each ring records a cycle of seasons. [35] Scientists can determine the age of the trees and the temperature of that particular period through the dating. The width of tree rings are thicker in warmer seasons and thinner in cooler environments. [36] During Little Ice Age, the radial stem growth was thinner than in medieval warm period (MWP), a warm climate period before Little Ice Age from c. 950 to c. 1250, which reflected a relatively low temperature between 1400 and 1800. [36] On the other hand, longer width of tree wings are found during Little Ice Age.
Carbon dating, also known as radiocarbon dating, is a method to determine the age and the temperature of organic material by measuring the carbon-14 activity. The organic material showed different carbon-14 activities in different climates. For the research of Little Ice Age, scientists collected samples of entombed plants such as moss in the Arctic region to measure the carbon-14 activity. They compared the obtained samples with that of the same existing species to get the result. [37]
Carbon dioxide (CO2) plays an important role in global greenhouse effect. It is an indicator to derive the global carbon cycle (the carbon exchange among the biosphere, geosphere, hydrosphere and atmosphere of the Earth). Before the industrial revolution, the concentration of CO2 was mainly regulated by the land use and the ecosystem of the world. [38] In cold climate, the low temperature affect the rate of photosynthesis and reduces a vast area of vegetation. [39] Scientist collected the ice core sample to measure the concentration of the CO2 and extrapolate the temperature to figure out the concentration of carbon dioxide is low during Little Ice Age. [38]
Sea ice is formed by seawater near the Arctic region. The volume of sea ice is determined by the temperature. In the Arctic region, sea ice has a regular annual melt and freeze cycle. The growing and melting of sea ice is an important parameter for scientists to study the climate. Through ice drilling in the Arctic region, scientists could understand the freezing situation of the sea ice. Gifford H. Miller and his research team have discovered that the sea ice froze rapidly at the beginning of the Little Ice Age (around 1400) and has not been melted. [37]
Modern temperature measurement has been adopted since 1770s. Mercury was widely used as a thermometric liquid to measure temperature. There were also different devices to measure pressure, wind direction and precipitation. [40] In the 1770s, there were more than 20 stations that collected the daily climatic data, which provided a more accurate record for the study. [8]
The scientific community has been investigating the causes of climate change for decades. After thousands of studies, it came to a consensus, where it is "unequivocal that human influence has warmed the atmosphere, ocean and land since pre-industrial times." This consensus is supported by around 200 scientific organizations worldwide, The dominant role in this climate change has been played by the direct emissions of carbon dioxide from the burning of fossil fuels. Indirect CO2 emissions from land use change, and the emissions of methane, nitrous oxide and other greenhouse gases play major supporting roles.
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. Climate change may refer to any time in Earth's history, but the term is now commonly used to describe contemporary climate change, often popularly referred to as global warming. Since the Industrial Revolution, the climate has increasingly been affected by human activities.
Paleoclimatology is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. As instrumental records only span a tiny part of Earth's history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate.
Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a heat source, usually internally generated, inside the body; the heat is generated by various processes, such as radioactive decay or tidal heating. This heat partially melts solid material in the body or turns material into gas. The mobilized material rises through the body's interior and may break through the solid surface.
Global cooling was a conjecture, especially during the 1970s, of imminent cooling of the Earth culminating in a period of extensive glaciation, due to the cooling effects of aerosols or orbital forcing. Some press reports in the 1970s speculated about continued cooling; these did not accurately reflect the scientific literature of the time, which was generally more concerned with warming from an enhanced greenhouse effect.
A volcanic winter is a reduction in global temperatures caused by droplets of sulfuric acid obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, sulfur-rich, particularly explosive volcanic eruption. Climate effects are primarily dependent upon the amount of injection of SO2 and H2S into the stratosphere where they react with OH and H2O to form H2SO4 on a timescale of a week, and the resulting H2SO4 aerosols produce the dominant radiative effect. Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation for several years. Moreover, the cooling trend can be further extended by atmosphere–ice–ocean feedback mechanisms. These feedbacks can continue to maintain the cool climate long after the volcanic aerosols have dissipated.
Global dimming is a decline in the amount of sunlight reaching the Earth's surface. It is caused by atmospheric particulate matter, predominantly sulfate aerosols, which are components of air pollution. Global dimming was observed soon after the first systematic measurements of solar irradiance began in the 1950s. This weakening of visible sunlight proceeded at the rate of 4–5% per decade until the 1980s. During these years, air pollution increased due to post-war industrialization. Solar activity did not vary more than the usual during this period.
Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 μm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This can affect the radiative properties of clouds and the overall atmosphere. Water vapour requires a non-gaseous surface to make the transition to a liquid; this process is called condensation.
Volcanic gases are gases given off by active volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating from lava, from volcanic craters or vents. Volcanic gases can also be emitted through groundwater heated by volcanic action.
Earth's climate system is a complex system with five interacting components: the atmosphere (air), the hydrosphere (water), the cryosphere, the lithosphere and the biosphere. Climate is the statistical characterization of the climate system. It represents the average weather, typically over a period of 30 years, and is determined by a combination of processes, such as ocean currents and wind patterns. Circulation in the atmosphere and oceans transports heat from the tropical regions to regions that receive less energy from the Sun. Solar radiation is the main driving force for this circulation. The water cycle also moves energy throughout the climate system. In addition, certain chemical elements are constantly moving between the components of the climate system. Two examples for these biochemical cycles are the carbon and nitrogen cycles.
Throughout Earth's climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth. Both climate states last for millions of years and should not be confused with the much smaller glacial and interglacial periods, which occur as alternating phases within an icehouse period and tend to last less than one million years. There are five known icehouse periods in Earth's climate history, namely the Huronian, Cryogenian, Andean-Saharan, Late Paleozoic and Late Cenozoic glaciations.
Mount Tambora is a volcano on the island of Sumbawa in present-day Indonesia, then part of the Dutch East Indies, and its 1815 eruption was the most powerful volcanic eruption in recorded human history. This eruption, with a volcanic explosivity index (VEI) of 7, ejected 37–45 km3 of dense-rock equivalent (DRE) material into the atmosphere, and was the most recent confirmed VEI-7 eruption.
Tectonic–climatic interaction is the interrelationship between tectonic processes and the climate system. The tectonic processes in question include orogenesis, volcanism, and erosion, while relevant climatic processes include atmospheric circulation, orographic lift, monsoon circulation and the rain shadow effect. As the geological record of past climate changes over millions of years is sparse and poorly resolved, many questions remain unresolved regarding the nature of tectonic-climate interaction, although it is an area of active research by geologists and palaeoclimatologists.
Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum, the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases.
Explosive volcanic eruptions affect the global climate in several ways.
The Late Antique Little Ice Age (LALIA) was a long-lasting Northern Hemispheric cooling period in the 6th and 7th centuries AD, during the period known as Late Antiquity. The period coincides with three large volcanic eruptions in 535/536, 539/540 and 547. The volcanic winter of 536 was the early phenomenon of the century-long global temperature decline. One study suggested a global cooling of 2 °C (3.6 °F). The period contributed to the decline of the Roman Empire and influenced the second wave migration period, primarily of the early Slavs.
In 1257, a catastrophic eruption occurred at Samalas, a volcano on the Indonesian island of Lombok. The event had a probable Volcanic Explosivity Index of 7, making it one of the largest volcanic eruptions during the Holocene epoch. It left behind a large caldera that contains Lake Segara Anak. Later volcanic activity created more volcanic centres in the caldera, including the Barujari cone, which remains active.
Ocean dynamical thermostat is a physical mechanism through which changes in the mean radiative forcing influence the gradients of sea surface temperatures in the Pacific Ocean and the strength of the Walker circulation. Increased radiative forcing (warming) is more effective in the western Pacific than in the eastern where the upwelling of cold water masses damps the temperature change. This increases the east-west temperature gradient and strengthens the Walker circulation. Decreased radiative forcing (cooling) has the opposite effect.
The Grindelwald Fluctuation is a period when glaciers in Grindelwald, Switzerland, expanded significantly. Temperatures were 1-2 degrees Celsius lower than twentieth-century averages during this period, which is thought to have lasted from the 1560s to the 1630s.