Among greenhouse-gas emissions, CO2 must be curbed rapidly due to its problematic inertia in warming the planet.
CO2 accumulates in the atmosphere and oceans for centuries, persisting until vegetation and algae slowly convert it into solid carbon through photosynthesis. This means that CO2 emissions must not merely stop increasing in order to prevent global warming. Instead, they must fall rapidly to zero within the coming decades to stop further accumulation and ultimately halt global warming.
Any delay in cutting emissions would require large-scale CO2 capture in the future, which is particularly problematic at high altitude and relies on largely untested technologies. In fact, the IPCC already incorporates carbon capture in its pathways for limiting global warming.[1] Some scientists even argue that continuous carbon removal will be necessary to bring warming back below 1.2 °C, given the alarming ice-sheet melt already occurring at this level of warming, which could eventually inundate many coastal cities over the coming centuries.