Climate is defined as a long-term weather condition. It is contingent on the energy balance of a particular location on the Earth‘s surface (i.e. the amount of energy coming from the Sun), the circulation of the atmosphere and ocean waters, and the nature of the Earth‘s surface, the chemical composition of the atmosphere and nowadays the activities of humans.

Energy and its flow

The low geographic latitudes gain more energy from the Sun than the area around the Poles. This fact is further emphasised by the tilt of the Earth axis. The excess of energy in the equatorial region and the lack of energy in the polar region lead to the transfer of thermal energy (further heat) from the Equator to the Poles. The atmosphere and the oceans mediate this heat transfer. This causes the inevitable air flow. The warm air heated from the luminated Earth surface is thinner, rises upward, and the cold air flows into its place at the Earth‘s surface. The result is the circulation of air masses. The air currents, with the influence of Earth‘s rotation, rotate and make spiral cyclones and anticyclones.

This causes changes in temperature and precipitation, i.e. what we call the weather. Similar processes happen in the oceans. The water at the surface is heated and warm sea currents flow from the Equator to the higher geographic latitudes. Deep ocean currents bring the cold water into equatorial areas in reverse. Warm surface currents bring heat to the Poles perhaps slower than the atmosphere, but more steadily. The Gulf Stream is an example of the warm sea currents in the Atlantic Ocean.

To explain the circulation in the atmosphere, it is necessary to realize the general model of circulation between the ocean and the mainland. In summer over the mainland, the rapidly heated air has smaller density and is pushed out by the cooler and therefore denser air that comes from the ocean. In winter, the surface of the mainland is cooled faster, and the denser air from the mainland flows into a relatively warmer and thus even thinner air over the oceans. Monsoons are traditionally frequently recurring air currents.

The nature of the Earth‘s surface

If the Sun-illuminated surface is dark, it receives (absorbs) more energy than a light surface. If there is snow and ice in the Polar Regions, the Earth‘s surface heats up less than the dark surface. The ocean is relatively dark compared to the mainland, therefore it absorbs more energy. The ocean also has higher thermal inertia than the mainland. That is why the oceans and seas hinder the heat fluctuations over the adjacent mainland, and the sea climate tends to be more thermally balanced than the centres of large landmasses.

Chemical composition of the atmosphere

Some gases in the atmosphere, especially carbon dioxide and methane, have a major influence on the maintenance of solar energy. A higher proportion of these gases in the atmosphere create so-called greenhouse effect causing an increase of the average temperature of the Earth‘s surface. These gases are „closed“ in the rock environment, from where they return to the atmosphere by ventilation and combustion (oxidation).

Climate zones

Different climate zones are distinguished on Earth: tropical, subtropical, temperate, subpolar and polar. Each of the zones has characteristic basic values of climatic elements: temperature, precipitation, sunlight. These factors, in particular the temperature and quantity of water, affect the plant cover and, both directly and indirectly, the size and appearance of the animals.

Climate change

In recent decades, climate change has been extensively debated on Earth. The causes of climate change are being sought in cosmic causes, in the arrangement of the continents and oceans, but it also discusses the direct influence of human civilization on climate change. The basic question is the stability of Earth‘s climate. There is evidence that the climate has been subject to long-term change without the contribution of humans.

The first influence of man on the climate could have begun to manifest between 2 to 3 thousand years ago in relation to changes in plant cover due to grazing, deforestation and agriculture. Compared to nearly 4 billion years of the atmosphere and solid Earth’s surface, it is clear that climate change on Earth in the geological past could not have been induced by man. They were caused by the geological processes themselves, the levels of life development and sometimes cosmic factors.