Solar Energy
The amount of solar energy reaching the Earth plays a huge role in its climate. Small changes in solar radiation over a long period of time can lead to climate change. For example, scientists suggest that the cold snap (known as the Little Ice Age) from the mid-17th to the mid-19th century was due to reduced solar activity. During these 200 years, Greenland was almost entirely covered by ice, and glaciers occupied much of the Alps. Conversely, warming in the first half of the 20th century is explained by more active solar radiation. Sunspot research allows scientists to predict how much solar energy the Earth will receive in the future, and hence to make some assumptions about whether and what climate change can be expected.
Changes in Earth's Orbit
Shifts in Earth's orbit are capable of causing major changes in the Earth's climate. As is well known, the Earth makes a complete orbit around the Sun in one year. The Earth's axis is inclined at an angle of 23.5 ° to the perpendicular plane of Earth's orbit. Slope changes can lead to small but important climate changes – a larger slope would mean warmer summers and colder winters, and a smaller slope would mean cooler summers and milder winters. But orbital changes are so gradual and slow that it takes thousands of years to become noticeable. For example, the last ice age ended 12,000 years ago, and such cooling due to a change in the slope of the earth's axis can be expected in about 30,000 years.
Volcanic eruptions
It is logical to assume that the eruption of hot volcanic lava would cause global warming, but this is not the case. The eruption of a volcano is accompanied by the release into the atmosphere of a huge amount of gases and ash, which are able to spread over large areas and significantly reduce the intensity of sunshine for months. The ash particles are relatively heavy and fall to the ground after 2-3 months. Their impact on the climate is relatively short-lived. This is not the case with sulfur dioxide emitted by volcanoes. This gas interacts with water vapor and dust in the atmosphere, forming sulfate aerosols that are able to form a cover above the ground within a few years, reflecting sunlight. An eloquent example is the eruption of Pinatubu volcano in the Philippines in 1991. About 20 million tons of sulfur dioxide emitted high into the atmosphere caused the formation of a huge cloud. It orbits the globe for 2 years and leads to a drop in global temperature of the planet by 0.5oC.
Ocean currents
Ocean currents circulate both on the surface and in depth. They are a major factor in climate formation. Wind, tides, sunshine, the Earth's rotation, and differences in water density are the main causes of ocean currents, both horizontally and vertically. The topography, shape of the oceans and nearby land masses also influence ocean currents. The density of ocean water is determined by its temperature, salinity and the depth at which it is located. As the temperature drops and the salinity increases, the density of the water increases. The greater the difference between the densities of the different aqueous layers, the more intense the processes of their mixing and circulation. As a result, two simultaneous processes are observed worldwide: warm surface currents carry less dense water from the equator to the poles, and deep ocean currents carry thicker water from the poles to the equator. This global circulation system plays a key role in the distribution of heat, the regulation of weather and climate in different regions of the Earth and the circulation of vital nutrients and gases.
