Abstract

As of late 2014, international political consensus was shifting to acceptance that deep emission reductions were necessary to avoid dangerous climate change, exemplified by a 2015 G7 communiqué where all members committed to limiting the anthropogenic increase in global mean surface temperature to less than 2 degrees Celsius (°C) by 2050 relative to 19th century global temperatures, and full decarbonization by 2100. ¹ According to IPCC, to ensure a better than even chance of remaining below a 2°C average surface temperature rise global annual green-house gas (GHG) emissions will need to be reduced by 42–57% by 2050 relative to 2010, and 73–107% by 2100 in order to stay within a global carbon budget of 960–1,430 GtCO₂e. ² Achieving this target requires steep declines to near zero carbon intensity in all sectors.