Per capita emissions trended down from 2015 - 2018 mainly due to emissions reductions seen in the electricity sector.  Year to year variability is common due to the multitude of factors that influence the calculations.  With the establishment of the Global Warming Solutions Act (GWSA) and the subsequent deveopment and adoption of the Climate Action Plan (CAP) by the Vermont Climate Council, a number of greenhouse gas mitigation strategies are in the process of being implemented that are intended to reduce overall greenhouse gas emissions in the coming years.  Total emissions levels will also be significantly impacted by the COVID pandemic and post pandemic emissions levels will be very dependent on the rate and realities of economic and social recoveries and behaviors (e.g. travel behaviors, telework, etc.)

The Global Warming Solutions Act established mandatory statewide greenhouse gas emissions levels as opposed to aspirational targets for 2025, 2030, and 2050.  The 2025 requirement is based on the Paris goals and is 26% below 2005 levels.  The 2030 and 2050 goals are 40% and 80% below the 1990 baseline respectively.

Population values for 2018 are from the U.S. Census Bureau "Population, Population Change, and Estimated Components of Population Change: April 1, 2010 to July 1, 2019 (NST-EST2019-alldata)" tables.  The 2018 per capita value is derived from the latest VT GHG Emissions Update issued May 2021.  The data are for calendar year 2018, which is an annual value that was calculated with same complete methodology as the rest of the 1990 - 2017 data, and is the most current complete data that has been published.  Greenhouse gas emissions calculations are generally based on some sort of activity data (e.g. fuel sales) and fuel specific emissions factors.  The several year lag in emissions estimates is due to several factors, the main one being the inherent lag time in large federal datasets utilized in the calculations.