Scientists and activists at COP26 have warned that the planet is heating up at an exceptional rate, but a 1.5 degree global warming target may give the world a lifeline.

Ella Ben Chorin

Limiting the global temperature rise to 1.5C above pre-industrial levels by the end of the century, the most optimistic target of the Paris Agreement, is seen as the only acceptable outcome for our 

Recent measurements from the Mauna Loa observatory in Hawaii show that for several days in February and March 2021, atmospheric CO2 levels exceeded 417 parts per million (ppm). Pre-industrial levels were about 278ppm.

Although the term "carbon neutral" is used, a carbon footprint also includes other greenhouse gases, measured in terms of their carbon dioxide equivalence. The term climate-neutral reflects the broader inclusiveness of other greenhouse gases in climate change, even if CO₂ is the most abundant. The term "net zero" is increasingly used to describe a broader and more comprehensive commitment to decarbonization and climate action, moving beyond carbon neutrality by including more activities under the scope of indirect emissions, and often including a science-based target on emissions reduction, as opposed to relying solely on offsetting.

The term net zero is important because – for CO2 at least – this is the state at which global warming stops. The Paris Agreement underlines the need for net zero, requiring states to ‘achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century’.