Previous Year Question

Statement 1 is incorrect. According to the IPCC, merely gradual and limited reductions in greenhouse gas emissions are not sufficient to limit climate change.

Greenhouse gases accumulate in the atmosphere. In particular, CO₂-induced warming is strongly related to cumulative emissions. Therefore, if emissions are reduced only slowly, additional greenhouse gases can continue accumulating in the atmosphere and global warming can continue increasing.

Statement 2 is correct. According to the IPCC Sixth Assessment Report, pathways that limit warming to around 1.5°C or 2°C require deep, rapid and sustained emission reductions.

All three terms are important:

Deep reductions → emissions must be reduced substantially, not marginally.
Rapid reductions → reductions need to occur soon rather than being postponed.
Sustained reductions → reductions must continue over time rather than being temporary actions.

According to the IPCC, limiting warming to 1.5°C requires deep, rapid and sustained greenhouse gas emission reductions across all sectors during this decade.

Pathways consistent with the 1.5°C goal indicate that global emissions need to be cut by almost half by 2030 while moving rapidly towards global net-zero CO₂.

Here, Net Zero CO₂ does not necessarily mean that absolutely no CO₂ is emitted. It means that the amount of CO₂ released into the atmosphere by human activities is balanced by anthropogenic removals of CO₂ from the atmosphere.

Along with CO₂, substantial reductions are also required in non-CO₂ greenhouse gases such as Methane (CH₄). Because methane has a shorter atmospheric lifetime than CO₂, rapid reductions in methane emissions can play an important role in slowing near-term warming.

Delaying emission reductions can require even steeper reductions later to achieve the same temperature goal and can also increase the lock-in of high-emission infrastructure.