Variations in the Earth's Orbital Characteristics The Milankovitch theory suggests that normal cyclical variations in three of the Earth's orbital characteristics is probably responsible for some past climatic change. The basic idea behind this theory assumes that over time these three cyclic events vary the amount of solar radiation that is received on the Earth's surface.
Pacific decadal oscillation to The ocean and atmosphere can work together to spontaneously generate internal climate variability that can persist for years to decades at a time. Due to the long timescales of this circulation, ocean temperature at depth is still adjusting to effects of the Little Ice Age  which occurred between the and s.
A schematic of modern thermohaline circulation. Tens of millions of years ago, continental-plate movement formed a land-free gap around Antarctica, allowing the formation of the ACCwhich keeps warm waters away from Antarctica.
Life Life affects climate through its role in the carbon and water cycles and through such mechanisms as albedoevapotranspirationcloud formationand weathering. Variations in CO2temperature and dust from the Vostok ice core over the lastyears Human influences Main article: Global warming In the context of climate variation, anthropogenic factors are human activities which affect the climate.
The scientific consensus on climate change is "that climate is changing and that these changes are in large part caused by human activities,"  and it "is largely irreversible". While much remains to be learned, the core phenomenon, scientific questions, and hypotheses have been examined thoroughly and have stood firm in the face of serious scientific debate and careful evaluation of alternative explanations.
This is due to emissions from fossil fuel combustion, followed by aerosols particulate matter in the atmosphereand the CO2 released by cement manufacture.
There is very little change to the area-averaged annually averaged sunshine; but there can be strong changes in the geographical and seasonal distribution.
Combined together, these produce Milankovitch cycles which affect climate and are notable for their correlation to glacial and interglacial periods their correlation with the advance and retreat of the Sahara and for their appearance in the stratigraphic record.
Upon seawater temperature change, the solubility of CO2 in the oceans changed, as well as other factors affecting air-sea CO2 exchange.
The period of extraordinarily few sunspots in the late 17th century was the Maunder minimum. The Sun is the predominant source of energy input to the Earth. Both long- and short-term variations in solar intensity are known to affect global climate.
However, there is evidence for the presence of water on the early Earth, in the Hadean   and Archean   eons, leading to what is known as the faint young Sun paradox. The Great Oxygenation Event —oxygenation of the atmosphere around 2.
Values since not shown. Solar output varies on shorter time scales, including the year solar cycle  and longer-term modulations. Some studies point toward solar radiation increases from cyclical sunspot activity affecting global warming, and climate may be influenced by the sum of all effects solar variation, anthropogenic radiative forcingsetc.
The next step is to find more about these trace vapours, including whether they are of natural or human origin.
The eruption of Mount Pinatubo inthe second largest terrestrial eruption of the 20th century, affected the climate substantially, subsequently global temperatures decreased by about 0. In climate modelling the aim is to study the physical mechanisms and feedbacks of volcanic forcing.
The US Geological Survey estimates are that volcanic emissions are at a much lower level than the effects of current human activities, which generate — times the amount of carbon dioxide emitted by volcanoes.
The annual amount put out by human activities may be greater than the amount released by supererruptionsthe most recent of which was the Toba eruption in Indonesia 74, years ago.
Plate tectonics Over the course of millions of years, the motion of tectonic plates reconfigures global land and ocean areas and generates topography.
This can affect both global and local patterns of climate and atmosphere-ocean circulation.
The locations of the seas are important in controlling the transfer of heat and moisture across the globe, and therefore, in determining global climate.
A recent example of tectonic control on ocean circulation is the formation of the Isthmus of Panama about 5 million years ago, which shut off direct mixing between the Atlantic and Pacific Oceans.
This strongly affected the ocean dynamics of what is now the Gulf Stream and may have led to Northern Hemisphere ice cover. Because of the stabilizing effect of the oceans on temperature, yearly temperature variations are generally lower in coastal areas than they are inland. A larger supercontinent will therefore have more area in which climate is strongly seasonal than will several smaller continents or islands.
Other mechanisms The Earth receives an influx of ionized particles known as cosmic rays from a variety of external sources, including the Sun.
A hypothesis holds that an increase in the cosmic ray flux would increase the ionization in the atmosphere, leading to greater cloud cover. This, in turn, would tend to cool the surface. The latter can increase the flux of high-energy cosmic rays coming from the Virgo cluster.Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years).
Climate change may refer to a change in average weather conditions, or in the time variation of weather . The Milankovitch Theory explains the 3 cyclical changes in Earth’s orbit and tilt that cause the climate fluctuations that occur over tens of thousands of years to hundreds of thousands of years.
Climate change news and analysis about global warming, energy, activism, media, renewables, politics, commentary, weather, trends, and polar life. Take Action Climate change is already having significant and widespread impacts on California's economy and environment.
California's unique and valuable natural treasures - hundreds of miles of coastline, high value forestry and agriculture, snow-melt fed fresh water supply, vast snow and water fueled recreational opportunities, as well as other natural wonders - are especially at risk.
The primary cause of climate change is the burning of fossil fuels, such as oil and coal, which emits greenhouse gases into the atmosphere—primarily carbon dioxide. Other human activities, such as agriculture and deforestation, also contribute to the proliferation of greenhouse gases that cause climate change.
Carbon dioxide is the primary greenhouse gas that is contributing to recent climate change. CO 2 is absorbed and emitted naturally as part of the carbon cycle, through plant and animal respiration, volcanic eruptions, and ocean-atmosphere exchange.