CAUSES OF CLIMATE CHANGE

Natural causes

A lot of  radical changes have taken place  in the global weather in a natural way because of the Earth rotation modifications, in the orbit and in the inclination. Also, human activities are changing the natural greenhouse, like the burning of fossil.

Scientists think the global warming trend observed since the mid-20th century is due to the human expansion of the "greenhouse effect" - warming that results when the atmosphere traps heat radiating from Earth toward space.

Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain in the atmosphere and do not respond physically or chemically to changes in temperature are described as "forcing" climate change..

On Earth, human activities are changing the natural greenhouse. Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2. The clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases.

The Role of Human Activity

The industrial activities  have raised atmospheric carbon dioxide levels from 280 parts per million to 400 parts per million in the last 150 years.  There's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in Earth's temperatures over the past 50 years.

Human activities contribute to climate change by causing changes in Earth's atmosphere in the amounts of greenhouse gases, aerosols (small particles), and cloudiness. The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere.

Greenhouse gases and aerosols affect climate by altering incoming solar radiation. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system.

Since the start of the industrial era (about 1750), the effect of human activities on climate has been a warming influence. The human impact on climate is causing solar changes and volcanic eruptions too.