UNEP and the Greenhouse Gas Emissions Gap

A new United Nations Environment Program (UNEP) Synthesis Report has assessed whether the pledges made by States in recent years at UNFCCC meetings are consistent with holding temperature increases to either 1.4 or 2C above pre-industrial levels; the study also suggests measures that could be taken to reach this objective. Among other purposes that this study could be used in climate change courses would be as a source of data for simulated negotiations or a “solutions” module. Among the take-aways of the report:

  1. Total anthropogenic emissions (fossil fuel and land use emissions) in 2009 were estimated at 49.5 GtCO2e;
  2. Carbon dioxide concentrations in 2010 were pegged at 388.5ppm, methane at 1870ppb and nitrous oxide at 323ppb;
  3. It is “likely” (greater than 66% probability) that limiting global emissions to 44 GtCO2e in 2020 would put the world on a path to limiting temperature increases to 2C during the 21st Century; in 2050, emissions would have had to drop to 21 GtCO2e to meet this objective;
  4. If countries implement their lower ambition pledges made at the Copenhagen and Cancun meetings of the UNFCCC, and are subject to “lenient” accounting rules (including LULUCF credits and surplus emission units), it will result in annual emissions of 55 GtCO2e in 2020, compared to 56 GtCO2e without the Copenhagen pledges; in the best case scenario, i.e. including all the conditional pledges of the Parties at Copenhagen and Cancun and strict accounting rules, emissions top out at an estimated 51 GtCO2e, still leaving a substantial gap in terms of the level of obligations necessary to avoid a 2C temperature increase. Expressed a different way, the reductions of Annex I States are now pegged at somewhere between a 4% reduction bellow 1990 levels up to 11% above those levels, for the least ambitious scenario, to 16-18% below 1990 levels for the most ambitious scenario. In either case, this is well below the 25-40% reductions that the IPCC has suggested are necessary to avoid more than a 2C temperature increase;
  5. Since the last assessment by UNEP of emissions pledges, countries have clarified their pledges in a manner that increases projected levels of emissions during this century;
  6. There are several measures that could help us close the “emissions gap”:
    • Renewable energy sources could contribute up to 38% of electricity production by 2020, resulting in an emission reduction potential of 1.5-25 GtCO2e;
    • Reductions from the industrial sector of 2.2-3.9 GtCO2e are possible, including use of best available technologies or practices, the use of fossil fuels as feedstocks in chemicals processing, etc.;
    • Reductions in the transportation sector could reach 1.4-2.0 GtCO2e by 2020;
    • Forestry practices could reduce emissions from 1.3-4.2 GtCO2e annually by 2020;
    • Opportunities exist to reduce non-carbon dioxide emissions, including methane production from landfill and wastewater, the source of 50% of anthropogenic methane emissions;
    • Potential reductions at the international level in the aviation and shipping sectors are in the order of 1.7-2.5 GtCO2e in 2020.

Noticeably absent in UNEP’s assessment of potential measures that can be taken to further reduce emissions are any discussion of the the costs of these interventions or their political viability. This could be a good starting point for class discussion. Also, one could try to tease out the assumptions that UNEP used to assess the impacts of lenient v. stringent implementation of emissions pledges.

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