UN warns against exceeding “Emissions Budget”

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The gap between what countires have pledged to achieve and what the IPCC has estimated is needed in order to stay within the 2°C target is estimated at 10 GT of CO₂e by 2020.

UNEP’s Emissions Gap Report 2014, published in November 2014, examines whether the pledges made by countries are on track to meet the internationally agreed 2°C target with a likely chance of greater than 66 per cent.

Climate Action Network International and more than a hundred countries are demanding that the global temperature increase compared with the pre-industrial level is kept below 1.5°C. Increasing the chance of staying within the 2°C target to 90 per cent or better would give around a 66 per cent chance of limiting warming to 1.5°C according to the new IPCC assessment report published by the IPCC in 2014.

In the UNEP Gap Report the global climate budget – or the maximum amount of carbon dioxide (CO₂) that can be emitted into the atmosphere to stay within a likely chance of 2°C – is estimated at 1000 gigatonnes of carbon dioxide. Exceeding the estimated budget of just 1000 Gton CO₂ would increase the risk of severe, pervasive and irreversible climate change impacts according to UNEP.

“An increase in global temperature is proportional to the build-up of long-lasting greenhouse gases in the atmosphere, especially CO₂. Taking more action now reduces the need for more extreme action later to stay within safe emission limits,” said Achim Steiner, UN Under-Secretary-General and Executive Director of UNEP. “In a business-as-usual scenario, where little progress is made in the development and implementation of global climate policies, global greenhouse gas emissions could rise to up to 87 Gton CO₂-eq by 2050, way beyond safe limits.”

“By introducing an emissions budget approach, the fifth Emissions Gap Report provides countries with a common platform to negotiate global targets for limiting global warming this century to 2°C beyond 2020, this is because countries are giving increasing attention to where they realistically need to be by 2025, 2030 and beyond,” added Mr. Steiner.

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 for 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.

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 Gton of CO₂-eq and in 2030 at up to 17 Gton of CO₂-eq.
In the case of a 1.5°C target the climate budget for a likely chance of staying within this target is 750 Gton of CO₂ according to the IPCC. In 2013 the world emitted 36 Gton of CO₂.

Global CO₂-eq emissions have to be between 70-95 per cent below 2010 emissions by 2050 to reach this target, says the IPCC.

Reinhold Pape

Source: UNEP Press release and IPCC 5AR. The Executive Summary of the report is available at: http://www.unep.org/pdf/UNEPEmissionsGapReport2014.pdf