NEET BIOLOGY

Detailed explanation-1: -Carbon dioxide concentrations have increased substantially since the beginning of the industrial era, rising from an annual average of 280 ppm in the late 1700s to 414 ppm in 2021 (average of five sites in Figure 1)-a 48 percent increase. Almost all of this increase is due to human activities.

Detailed explanation-2: -Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred.

Detailed explanation-3: -Carbon dioxide now more than 50% higher than pre-industrial levels | National Oceanic and Atmospheric Administration.

Detailed explanation-4: -Since 1970, CO2 emissions have increased by about 90%, with emissions from fossil fuel combustion and industrial processes contributing about 78% of the total greenhouse gas emissions increase from 1970 to 2011. Agriculture, deforestation, and other land-use changes have been the second-largest contributors.

Detailed explanation-5: -Since 2000, the global CO2 average has grown by 43.5 ppm, an increase of 12 percent. The atmospheric burden of CO2 is now comparable to where it was during the Mid-Pliocene Warm Period around 3.6 million years ago, when concentrations of carbon dioxide ranged from about 380 to 450 parts per million.