The Emissions Gap Report 2012

If action is delayed and emissions would remain high up to 2020, more rapid emission cuts would be required in subsequent years to have a ‘likely’ change of keeping global temperature rise below 2 °C. Such delayed-action pathways imply trade-offs, including higher overall costs, higher climate risks of overshooting the target as well as a heavier dependence on key mitigation technologies in the long term, such as bio-energy with carbon capture and storage.

If nations do not take swift action, emissions are likely to be around 58 gigatonnes of CO₂ equivalent (million tonnes, Gt) in eight years’ time. This will leave a gap that is bigger than it projected in earlier UNEP assessments, in 2010 and 2011, and would partly be the result of projected economic growth in key developing economies. Previous assessment reports have underlined that ‘early-action’ emission pathways that would be consistent with the 2 °C target, on average, would result in around 44 Gt by 2020 and would pave the way for the even larger reductions needed in subsequent years.

The Emissions Gap Report 2012 points out that even if the most ambitious level of pledges and commitments were to be implemented by all countries – and under the strictest set of rules – there would be an average gap of around 8 Gt of CO₂ equivalent by 2020, compared to that under the least-cost pathways towards 2 °C. This is 2 Gt higher than that of last year’s assessment.

Higher emissions by 2020 would lead to substantially higher mitigation costs for staying below 2 °C than under a least-cost pathway with immediate action. Preliminary economic assessments, highlighted in the new report, estimate that overall costs may increase by at least 10% to 15% if a substantial part of the required emission reductions would be delayed until after 2020.

Keeping Average Global Temperature Rise to Below 2 °C Still Doable

The report estimates that large emission reductions would be possible – with a mid-range of 17 Gt of CO₂ equivalents – for example, from the building, power generation and transport sectors, which could more than bridge the gap by 2020. Meanwhile, there are abundant examples of actions on a national level in areas ranging from improved building codes to fuel standards for vehicles, which, if scaled up and replicated, also could contribute.