Q.13 The greenhouse gas which contributes maximum to global warming is
- CH4
- CFC5
- CO2
- N2O
Correct Answer: CO2
Carbon dioxide (CO2) contributes the maximum to global warming due to its highest atmospheric concentration and massive emission volumes from fossil fuels, despite lower potency per molecule compared to others.
Option Explanations
CH4 (Methane): Potent greenhouse gas (25x CO2 over 100 years) from agriculture and leaks, but lower total emissions limit its overall warming share to about 16%.
CFC5: Likely refers to chlorofluorocarbons (CFCs) or similar; extremely potent (thousands x CO2) but phased out by Montreal Protocol, now negligible (<1% contribution).
CO2: Dominant at ~74-80% of total anthropogenic warming; emitted vastly from energy (fossil fuels) and deforestation, with long atmospheric lifetime.
N2O (Nitrous oxide): Strong (265x CO2 over 100 years) from fertilizers, but only ~6% of warming due to low emissions.
The greenhouse gas which contributes maximum to global warming is CO2, accounting for ~74% of total emissions due to fossil fuel burning and land use. Others like CH4 and N2O add potency but far less volume.
GHG Warming Contributions
Total forcing depends on concentration x Global Warming Potential (GWP) x lifetime.
Gas % Total Warming GWP (100-yr) Main Sources CO2 74-80% 1 Fossil fuels, deforestation CH4 ~16% 25-28 Agriculture, gas leaks N2O ~6% 265-298 Fertilizers, industry CFCs <1% 1,000-10,000 Aerosols (phased out) Why CO2 Leads
CO2’s sheer volume (410+ ppm) overwhelms others’ higher GWPs; e.g., annual emissions exceed 35 Gt vs. CH4’s 0.4 Gt equivalent. Long persistence amplifies cumulative impact.
This breakdown clarifies IPCC data for environmental science students tackling climate questions.
