In order to limit global temperature rise to 2oC and head off the worst impacts of climate change, global carbon neutrality should be attained by mid-to‐late century. This would also keep in check what the UN refers to as the global climate budget — or the maximum amount of carbon dioxide (CO2) that can be emitted into the atmosphere whilst staying within safe temperature limits beyond 2020, says a new report by the UN Environment Programme (UNEP). Exceeding an estimated budget of just 1000 gigatonnes of carbon dioxide would increase the risk of severe, pervasive and irreversible climate change impacts.Released days ahead of the UN Conference on Climate Change in Lima, Peru, UNEP’s Emissions Gap Report 2014 is the fifth in a series that examines whether the pledges made by countries are on track to meet the internationally agreed 2°C target. It is produced by 38 lead scientists from 22 research groups across 14 countries. Michel den Elzen of PBL Netherlands Environmental Agency was one of the lead authors.
According to the report, to achieve global climate neutrality between 2055 and 2070, annual anthropogenic CO2 emissions should hit net zero on the global scale to avoid exceeding the budget. Net zero implies that some remaining CO2 emissions could be compensated by the same amount of carbon dioxide uptake, or negative emissions, so long as the net input to the atmosphere due to human activity is zero, the report finds.
Taking into account non-‐CO2 greenhouse gases, including methane, nitrous oxide and hydrofluorocarbons, total global greenhouse gas emissions need to shrink to net zero between 2080 and 2100. Since 1990, global greenhouse gas emissions have grown by more than 45 per cent. To have a likely chance of staying below the 2oC limit, global greenhouse gas emissions should drop by about 15 per cent or more by 2030 compared to 2010, and be 50 per cent lower by 2050 on the way to net zero.
Past issues of the UNEP Emissions Gap Report focused on good practices across different sectors and their ability to stimulate economic activity and development, while reducing emissions. This year, the report also looks at how international development targets and corresponding policies at the national level can bring about multiple benefits, including climate change mitigation focusing in particular on energy efficiency.
Bridging the Gap
The 2014 Emissions Gap Report defines the emissions gap as the difference between emission levels in 2025 and 2030 consistent with meeting climate targets versus the levels expected if country pledges are met. The report examines whether the pledges made by countries are on track to meet the 2°C target. Despite the fact that the gap is not getting smaller, studies show that it could be closed if available global emissions reduction methodologies are fully exploited. Scientists estimate the gap in 2020 at up to 10 Gt CO2e and in 2030 at up to 17 Gt CO2e. The good news is that the report estimates that the emissions reduction potential in 2030 is around 29 Gt CO2e (relative to business-‐as-‐usual), so it remains feasible to close the gap.