Climate change (general concept) in the context of "Carnian pluvial episode"

In April 1815, Mount Tambora, a volcano on the island of Sumbawa in present-day Indonesia (then part of the Dutch East Indies), erupted in what is now considered the most powerful volcanic eruption in recorded human history. This eruption, with a volcanic explosivity index (VEI) of 7, ejected 37–45 km (8.9–10.8 cubic miles) of dense-rock equivalent (DRE) material into the atmosphere, and was the most recent confirmed VEI-7 eruption.

Although the Mount Tambora eruption reached a violent climax on 10 April 1815, increased steaming and small phreatic eruptions occurred during the next six months to three years. The ash from the eruption column dispersed around the world and lowered global temperatures in an event sometimes known as the Year Without a Summer in 1816. This brief period of significant climate change triggered extreme weather and harvest failures in many areas around the world. Several climate forcings coincided and interacted in a systematic manner that has not been observed after any other large volcanic eruption since the early Stone Age.

The early Holocene sea level rise (EHSLR) was a significant jump in sea levelby about 60 m (197 ft) during the early Holocene, between about 12,000 and 7,000 years ago, spanning the Eurasian Mesolithic. The rapid rise in sea level and associated climate change, notably the 8.2 ka cooling event (8,200 years ago),and the loss of coastal land favoured by early farmers, may have contributed to the spread of the Neolithic Revolution to Europe in its Neolithic period.

During deglaciation since the Last Glacial Maximum, between about 20,000 to 7,000 years ago (20–7 ka), the sea level rose by a total of about 100 m (328 ft), at times at extremely high rates, due to the rapid melting of the British-Irish Sea, Fennoscandian, Laurentide, Barents-Kara, Patagonian, Innuitian and parts of the Antarctic ice sheets. At the onset of deglaciation about 19,000 years ago, a brief, at most 500-year long, glacio-eustatic event may have contributed as much as 10 m (33 ft) to sea level with an average rate of about 20 mm (0.8 in)/yr. During the rest of the early Holocene, the rate of sea level rise varied from a low of about 6.0–9.9 mm (0.2–0.4 in)/yr to as high as 30–60 mm (1.2–2.4 in)/yr during brief periods of accelerated sea level rise.

Patterns of solar irradiance and solar variation have been a main driver of climate change over the millions to billions of years of the geologic time scale.

Evidence that this is the case comes from analysis on many timescales and from many sources, including: direct observations; composites from baskets of different proxy observations; and numerical climate models. On millennial timescales, paleoclimate indicators have been compared to cosmogenic isotope abundances as the latter are a proxy for solar activity. These have also been used on century times scales but, in addition, instrumental data are increasingly available (mainly telescopic observations of sunspots and thermometer measurements of air temperature) and show that, for example, the temperature fluctuations do not match the solar activity variations and that the commonly-invoked association of the Little Ice Age with the Maunder minimum is far too simplistic as, although solar variations may have played a minor role, a much bigger factor is known to be Little Ice Age volcanism. In recent decades observations of unprecedented accuracy, sensitivity and scope (of both solar activity and terrestrial climate) have become available from spacecraft and show unequivocally that recent global warming is not caused by changes in the Sun.

Crucial to the survival of a glacier is its mass balance of which surface mass balance (SMB), the difference between accumulation and ablation (sublimation and melting). Climate change may cause variations in both temperature and snowfall, causing changes in the surface mass balance. Changes in mass balance control a glacier's long-term behavior and are the most sensitive climate indicators on a glacier. From 1980 to 2012 the mean cumulative mass loss of glaciers reporting mass balance to the World Glacier Monitoring Service is −16 m. This includes 23 consecutive years of negative mass balances.

A glacier with a sustained negative balance is out of equilibrium and will retreat, while one with a sustained positive balance is out of equilibrium and will advance. Glacier retreat results in the loss of the low elevation region of the glacier. Since higher elevations are cooler than lower ones, the disappearance of the lowest portion of the glacier reduces overall ablation, thereby increasing mass balance and potentially reestablishing equilibrium. However, if the mass balance of a significant portion of the accumulation zone of the glacier is negative, it is in disequilibrium with the local climate. Such a glacier will melt away with a continuation of this local climate.The key symptom of a glacier in disequilibrium is thinning along the entire length of the glacier. For example, Easton Glacier (pictured below) will likely shrink to half its size, but at a slowing rate of reduction, and stabilize at that size, despite the warmer temperature, over a few decades. However, the Grinnell Glacier (pictured below) will shrink at an increasing rate until it disappears. The difference is that the upper section of Easton Glacier remains healthy and snow-covered, while even the upper section of the Grinnell Glacier is bare, melting and has thinned. Small glaciers with shallow slopes such as Grinnell Glacier are most likely to fall into disequilibrium if there is a change in the local climate.

Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and the biomes of montane grasslands and shrublands, characterised by low-growing vegetation on acidic soils. Moorland today generally means uncultivated hill land (such as Dartmoor in South West England), but also includes low-lying wetlands (such as Sedgemoor, also South West England). It is closely related to heath, although experts disagree on the exact distinction between these types of vegetation. Generally, moor refers to highland and high rainfall areas, while heath refers to lowland zones which are more likely to be the result of human activity.

Moorland habitats are found mainly in tropical Africa, northern and western Europe, and South America. Most of the world's moorlands are diverse ecosystems. In the extensive moorlands of the tropics, biodiversity can be extremely high. Moorland is also related to tundra (where the subsoil is permafrost or permanently frozen soil), appearing as the tundra and the natural tree zone. The boundary between tundra and moorland constantly shifts with climatic change.

A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as genocide, speciocide, widespread violence or intentional culling. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring. Genetic diversity remains lower, increasing only when gene flow from another population occurs or very slowly increasing with time as random mutations occur. This results in a reduction in the robustness of the population and in its ability to adapt to and survive selecting environmental changes, such as climate change or a shift in available resources. Alternatively, if survivors of the bottleneck are the individuals with the greatest genetic fitness, the frequency of the fitter genes within the gene pool is increased, while the pool itself is reduced.

The genetic drift caused by a population bottleneck can change the proportional random distribution of alleles and even lead to loss of alleles. The chances of inbreeding and genetic homogeneity can increase, possibly leading to inbreeding depression. Smaller population size can also cause deleterious mutations to accumulate.

Lorraine Lisiecki is an American paleoclimatologist. She is a professor in the Department of Earth Sciences at the University of California, Santa Barbara. She has proposed a new analysis of the 100,000-year problem in the Milankovitch theory of climate change. She also created the analytical software behind the LR04, a "standard representation of the climate history of the last five million years".

Milutin Milanković (sometimes anglicised as Milutin Milankovitch; Serbian Cyrillic: Милутин Миланковић, pronounced [milǔtin milǎːnkoʋitɕ]; 28 May 1879 – 12 December 1958) was a Serbian mathematician, astronomer, climatologist, geophysicist, civil engineer, university professor, popularizer of science and academic.

Milanković gave two fundamental contributions to global science. The first contribution is the "Canon of the Earth's Insolation", which characterizes the climates of all the planets of the Solar System. The second contribution is the explanation of Earth's long-term climate changes caused by changes in the position of the Earth in comparison to the Sun, now known as Milankovitch cycles. This partly explained the ice ages occurring in the geological past of the Earth, as well as the climate changes on the Earth which can be expected in the future.

The environment is the subject of ministries at the federal and provincial level in Canada, with the current highest environmental government official being the national Minister of the Environment Steven Guilbeault. Canada's large landmass and coastline make it very susceptible to any climate changes, so any contemporary changes of climate in the country are of national concern. Of the factors caused by human intervention that can affect this environment, activities that sustain the economy of Canada such as oil and gas extraction, mining, forestry and fishing are influential. The increase in greenhouse gas emissions in Canada between 1990 and 2015 was mainly due to larger emissions from mining, oil, and gas extraction and transport. In 2011 United Nations said Canada's environment was the best in the world.

Several governmental programs have been created to mitigate 20th and 21st century climate change, such as the One-Tonne Challenge. In late 2005 Canada hosted the United Nations Climate Change Conference in Montreal, Quebec. Hundreds of environmental organizations have been founded in Canada.