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How Cities and Regions May Save One Fifth of Nations' Carbon Emissions

Cover of Climate Commitments of Subnational Actors and BusinessActions by cities and regions could save the lion's share of global greenhouse gas emissions not accounted for at the national level by 2020, according to a new study by the United Nations Environment Programme (UNEP). The total of these emissions includes also those from companies and sectors.

These savings altogether could complement national government efforts and save 1.8 Gt of greenhouse gas emissions (CO2-equivalent) by 2020. Of this total, action taken by cities could save 60% or 1.08 GtCO2e in 2020.

UN Under-Secretary-General and UNEP Executive Director Achim Steiner said, "Initiatives by cities, businesses and industrial sectors to cut emissions can contribute and support national emission commitments, bringing significant savings of CO2 equivalent."

Greenhouse gas emissions savings by type covered in the UNEP report

Above: Greenhouse gas emissions savings by type covered in the report, showing that regions and cities can save the vast majority.

Putting this in perspective, pledges by governments already made, if implemented, are expected to deliver five to seven GtCO2e by 2020, meaning that cities' actions could add a further 1/5 to 1/8 of that amount.

Steiner added: "As we prepare to conclude a new global climate agreement, it is important to keep our level of ambition alive. UNEP research shows that we need to move towards carbon neutrality by mid-to-late century to head to keep global temperature rise to below 2°C. Meeting this target cannot be reached through government action alone."

The UNEP report, 'Climate Commitments of Subnational Actors and Business', looks at 15 major initiatives in the areas of cities, regions, business and sectors - such as energy efficiency, methane, agriculture and finance.

Urban areas account for up to 76 per cent of energy-related CO2 emissions, while the world's cities produce almost half of all greenhouse gas emissions. Therefore, cities are central to tackling climate change.

The report looks at city and regional initiatives, such as the Covenant of Mayors - a group of 6,317 city mayors who committed to exceeding the European Union target of reducing CO2 emission by 20 per cent by 2020 compared to 1990 levels.

City and region-level initiatives to save green house gas emissions

Above: City and region-level initiatives to save greenhouse gas emissions. Click for a larger version.

The three city initiatives analyzed show the potential for a reduction of 1.08 GtCO2e in 2020, while the Climate Group's States and Regions Alliance could bring 0.76 GtCO2e of additional emissions reductions in the same year.

Phasing out inefficient lighting and replacing it with LEDs (under a UNEP-led en.lighten initiative) could save 0.05 GtCO2e.

Of the 180 initiatives identified, the vast majority are linked to specific sectors and industries. Areas showing untapped potential for specific action include energy efficiency, renewable energy, agriculture and forestry. Although many initiatives exist in these sectors, they often lack specific objectives, the means to deliver them, or scale.

The Detail

Sixteen major initiatives in the areas of cities and regions, companies and sectors such as energy efficiency, methane, agriculture, forestry and finance have been analyzed for the report on non-state climate mitigation action. The method used to quantify the emissions reductions that would result from the initiatives depends on the form of the commitments and the information available.

The reductions relative to a business-as-usual scenario that aims to take account of current government policies were calculated. In addition, the totals to account for overlaps between initiatives, both in the same sector and between sectors were adjusted. A final adjustment was made to calculate what is additional to government pledges for emissions reductions.

Networks and results

Cities work together through a number of networks to achieve greenhouse gas reduction and sustainable development.

Compact of Mayors 

The Compact of Mayors is an agreement by city networks, including ICLEI-Local Governments for Sustainability (ICLEI), C40 Climate Leadership Group (C40), United Cities and Local Governments (UCLG). They make Their emissions-reduction information publically available by reporting through a recognized city platform such as CDP Cities programme and carbonn Climate Registry

Compact of States and Regions 

The Compact of States and Regions represents a commitment by global state and regional government networks, including The Network of Regional Governments for Sustainable Development (nrg4SD), The R20 Regions for Climate Action and The Climate Group, and CDP, to provide an annual assessment of commitments (i.e. GHG reduction targets).

The Three City-level Initiatives Considered in the Report

  1. C40 initiative includes 36 cities with targets who recently reported their community emissions to the CDP, with base (or reference) years ranging from 2005 to 2013. The majority of targets were for 2020, 2025 or 2030.
  2. The  European Covenant of Mayors (CoM) programme reports a Baseline Emission Inventory (BEI), which is a quantification of the amount of CO2 emitted due to energy consumption in the territory of a Covenant signatory within a given period of time. It represents the emissions in the base year (1990) for all cities with a target (i.e. 0.69 GtCO2e) and the planned emission reductions, i.e. 0.188 GtCO2e by 2020, based on the Sustainable Energy Action Plans (SEAPs).
  3. cCR: The carbonn Climate Registry reports the total annual emissions of 422 member cities: 2.25 GtCO2e for 2013-2014. The average annual emission reduction commitment is 1.3%. Based on the reported emissions as of March 2014, the BAU based on the current policies scenario of the WEO for 422 cities is calculated. It is not possible to apply a regional approach here, because cities from a range of regions report to carbonn.


  • These three city level initiatives together, correcting for their overlap with each other, achieve 1.08 GtCO2e of additional emission reductions in 2020 as compared to a current policies scenario.
  • In addition there is the Climate Group's States and Regions Alliance. 20 of the 27 regions provided information on the Climate Group's website. They achieve 0.76 GtCO2e per year of additional emission reductions in 2020.
  • Altogether, 36 C40 cities have committed to reducing emissions from the base year by 0.2 GtCO2e by 2020.
  • The net effect of these commitments compared to business as usual (BAU) is 0.3 GtCO2e.
  • The Covenant of Mayors reports that its signatories have committed to a reduction of 0.2 GtCO2e by 2020 compared to the base emissions inventory.
  • The CoM has additional emission reductions of 0.5 GtCO2e by 2020 compared to the current policies scenario.
  • The 422 cities reporting to the carbonn Climate Registry will reduce emissions by 0.6 GtCO2e in 2020 compared to BAU.