Příčiny a následky změny klimatu

Climate change is not just a change in temperatures – this umbrella term covers several interrelated phenomena. Higher concentration of greenhouse gases in the atmosphere results in a long chain of interconnected impacts.

What causes climate change?

Human activity, particularly burning fossil fuels (coal, oil, and natural gas), leads to an increase in the concentration of carbon dioxide (CO₂) in the atmosphere. About 35–40 billion tons of CO₂ are produced annually in energy production, transportation, and industry, while deforestation adds another 4–5 billion tons. On average, every person on Earth accounts for about 5 tons of CO₂ per year. (See also: CO₂ concentrations and global greenhouse emissions.)

Other greenhouse gases include methane (CH₄), nitrous oxide (N₂O), and F-gases (fluorinated gases). Methane is produced in agriculture (livestock farming, rice cultivation, etc.) and released into the atmosphere from coal mining and oil and gas extraction. Nitrous oxide arises from the use of fertilizers and in some combustion processes. F-gases are used for refrigeration and air-conditioning. (See also: Which Greenhouse Gases Matter Most?.)

Higher concentrations of CO₂ and other greenhouse gases in the atmosphere lead to a stronger greenhouse effect. The natural greenhouse effect is necessary to sustain life on Earth – without it, the planet would be too cold – but a stronger greenhouse effect makes the planet warmer. (See also: The Greenhouse Effect and Energy Imbalance.)

What are the effects of climate change?

Atmospheric temperature has risen on average by 1.3 °C above pre-industrial levels as of 2025. However, most of the heat trapped by the stronger greenhouse effect has been absorbed by ocean water, and ocean temperatures have been rising steadily over the same period. (See also: How Much Is the Planet Warming? and Global Map of Temperature Changes.)

The warming of the planet leads to more frequent and more severe heat waves, more intense tropical storms and hurricanes, longer periods of drought, but also to heavier rains and floods – i.e. to more frequent extreme events. One event often leads to another, for example, prolonged droughts make forest fires more widespread and severe. (See also: Extreme Weather Is Growing More Severe.)

Atmospheric CO₂ partially dissolves in the ocean, where it forms carbonic acid. This leads to a drop in pH, or ocean acidification, which is dangerous for marine life.

Warmer sea water temperatures are disrupting marine ecosystems and causing a significant reduction in the area and thickness of sea ice in the Arctic Ocean. Most climate models predict that the first ice-free summers in the Arctic Ocean will arrive before 2050. This sea ice melt also accelerates the warming of the Arctic region, as dark sea water absorbs much more solar radiation than white sea ice.

The level of the world’s oceans is rising at a rate of 3–4 mm per year. Roughly half of this rise is caused by the melting of ice sheets in Greenland and Antarctica, while the other half is due to the warming of seawater which increases its volume with temperature. (See also: Accelerating Sea Level Rise and climate tipping points.)

Rising temperatures cause melting of mountain glaciers in the Alps, Himalayas, Andes, and other mountain ranges. This glacial melt will significantly impact water supplies and agriculture in the future, as rivers in many areas are fed by mountain glaciers. (See also: Map of Climate Tipping Points.)