The greenhouse effect is a process that occurs naturally in the Earth's atmosphere and results from the interaction between the energy that comes from the sun and some of the gases in the atmosphere called greenhouse gases. The natural greenhouse effect allows life to exist as we know it on the planet because, without it, the average temperature of the Earth would be below -18 °C.
The atmosphere is mainly composed of Nitrogen and Oxygen and only 1% by other components, including greenhouse gases. Most greenhouse gases have always existed in the atmosphere, and their cycle starts with natural processes such as:
- Water Vapor: The evaporation of water produces water vapor as it is an essential part of the hydrological cycle.
- Carbon Dioxide: Carbon dioxide is generated from the respiration of living beings, the decomposition of plants and animals, and natural fires, being part of the carbon cycle.
- Methane: Wetlands and ruminants mainly emit methane during their digestive process as it is the result of the anaerobic decomposition of organic matter.
- Nitrous Oxide: Nitrous oxide is a product of the bacterial breakdown of organic matter.
- Ozone: Ozone is the union of three oxygen atoms.
Unfortunately, there is another source of change in the global climate. This change is associated with human activities.
From the so-called Industrial Revolution to the present day, industrial processes are developed by burning fossil fuels (oil, gas, and its derivatives, such as gasoline) and by taking advantage of natural resources.
These activities are changing the composition of the Earth's atmosphere, emitting more greenhouse gases and compounds that can remain in the atmosphere for up to 50 years. Although more than half of the CO2 emitted today takes a century to be removed from the atmosphere, a part of the CO2 emitted (about 20%) remains in the atmosphere for many millennia.
In the last 800,000 years, atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to unprecedented levels. Moreover, the oceans have absorbed around 30% of the total emitted anthropogenic carbon dioxide, which has led to their acidification.
2. How does climate change affect us?
The effects of climate change are many, very diverse and, for the most part, very serious. The signs of the changes we are suffering are already evident, and we can see them in some situations such as:
The polar caps are melting. The sea surface covered by Arctic ice on the North Pole has decreased by 10% in recent decades, and the thickness of ice above water by almost 40%. Meanwhile, on the world’s other side, the ice sheet that currently covers the Antarctic continent has become largely unstable.