Final answer:
In the 20th century, man-made causes, predominantly the burning of fossil fuels and deforestation, have had the most considerable impact on the release of greenhouse gases, significantly strengthening the natural greenhouse effect and leading to global warming.
Step-by-step explanation:
Regarding the release of greenhouse gases in the 20th century and their impact on living organisms, it is the man-made causes that have had the biggest impact. This period saw a significant increase in the burning of fossil fuels and deforestation, enhancing the natural greenhouse effect and leading to global warming. Human activities have resulted in higher concentrations of carbon dioxide, methane, and nitrous oxide in the atmosphere, trapping more heat and perturbing the climate.
The increase in greenhouse gases, especially carbon dioxide (CO2), from human activities such as industrial processes, agriculture, and transportation, strengthens the natural greenhouse effect by trapping additional heat. This enhanced greenhouse effect is the main driver behind the unprecedented rates of global warming and climate change that we have been witnessing. Not only does this lead to rising temperatures but also to extreme weather events, melting glaciers, sea-level rise, and adverse impacts on biodiversity and ecosystems. Society is concerned about human activities because they are altering this natural balance and causing potentially irreversible damage to our planet. Reducing carbon emissions is crucial, and steps such as adopting renewable energies, improving energy efficiency, and preserving natural carbon sinks like forests can help mitigate this impact.