Understanding Carbon Budgets | WWF South Africa

Understanding Carbon Budgets



Posted on 01 October 2012
Understanding Carbon Budgets
Understanding Carbon Budgets
© WWF-SA
A carbon budget can be defined as a tolerable quantity of greenhouse gas emissions that can be emitted in total over a specified time. The budget needs to be in line with what is scientifically required to keep global warming and thus climate change “tolerable.” Carbon budgeting should not be confused with the use of targets, thresholds or caps to set emissions reduction goals.

According to the scientific Intergovernmental Panel on Climate Change, for the planet to have a 50% chance of avoiding a dangerous global average temperature rise of 2°C or more above pre-industrial levels, greenhouse gas concentrations must stabilise at 450 ppm CO2e. This will be very tough to achieve, but is still possible. As at April 2012, globally we are already at 396.18 ppm, so there is no time to lose. The average global temperature has already increased by 0.8°C over the past century, most of that since the 1970s.

Africa is set to get much hotter than the global average. If globally we continue emitting as we are, studies project that “by midcentury the South African coast will warm by around 1–2°C, and the interior by around 2–3°C; after 2050, warming is projected to reach around 3–4°C along the coast, and 6–7 °C in the interior”. The consequences of such temperature increases in South Africa can be found in government and independent research.

Many argue that aiming for 450 ppm is too high. WWF and other organisations say that humanity cannot allow our emissions to increase the average global temperature by more than 1.5 °C. Cooler would be better, but by now is unlikely to be possible. Hotter than that and the climate tips over into conditions that we will find it very hard to survive in, particularly people with few resources. The longer we delay cutting emissions, or if our cuts are insignificant, the more dramatic our actions will need to be and the heavier the price we pay – not only in conventional economic terms, but in human suffering, and destruction of the ecosystems which support life. 
Understanding Carbon Budgets
Understanding Carbon Budgets
© WWF-SA Enlarge