Increase in greenhouse gases since Industrial Revolution has caused which of the following environmental problem?

Global warming

The correct answer is option 2: Global warming

Since the Industrial Revolution, the concentration of greenhouse gases such as carbon dioxide and methane has increased significantly due to industrial activities, burning of fossil fuels, and deforestation. These gases trap heat in the atmosphere, leading to a rise in Earth’s average temperature, which is known as global warming.

Option 1: Ozone depletion :This is primarily caused by Chlorofluorocarbons (CFCs) and other ozone-depleting substances used in refrigeration and aerosols, rather than general greenhouse gases like $CO_2$. While related to atmospheric chemistry, it is a distinct environmental issue.

Option 3: Land degradation: This refers to the decline in soil quality and land utility, usually caused by over-farming, deforestation, and poor irrigation practices. While climate change (caused by GHGs) can worsen land degradation, it is not the direct environmental problem defined by the increase of these gases.

Option 4: Water contamination: This is caused by the discharge of industrial waste, sewage, and agricultural runoff (pesticides/fertilizers) into water bodies. It is an issue of chemical and biological pollutants rather than atmospheric greenhouse gases.

NCERT: Global warming is a gradual increase in the average temperature of the earth’s lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. Much of the recent observed and projected global warming is human-induced. It is caused by man-made increases in carbon dioxide and other greenhouse gases through the burning of fossil fuels and deforestation. Adding carbon dioxide, methane and such other gases (that have the potential to absorb heat) to the atmosphere with no other changes will make our planet’s surface warmer. The atmospheric concentrations of carbon dioxide and CH4 have increased by 31 per cent and 149 per cent respectively above pre-industrial levels since 1750. During the past century, the atmospheric temperature has risen by 1.1°F (0.6°C) and sea level has risen several inches. Some of the longer-term results of global warming are melting of polar ice with a resulting rise in sea level and coastal flooding; disruption of drinking water supplies dependent on snow melts; extinction of species as ecological niches disappear; more frequent tropical storms; and an increased incidence of tropical diseases."