Which States are Leading with Lowest CO2 Emissions

Global warming and its causes have been under the spotlight recently, as climate change is becoming increasingly evident. CO2 emissions, as the result of human action, are responsible for 64% of global warming, so keeping an eye on local emission rates is a good way to monitor the situation at home. Using past rates as a comparison will also help indicate when changes in commercial, electrical power, residential, industrial and transportation emissions are effective, or not.

CO2 Emissions per Household

We researched the total residential CO2 emissions by state (in millions of tons), presented in the latest U.S. Energy Information Administration (EIA) report on Energy-Related Carbon Dioxide Emissions by State, for 2015-2016, released this year. Then, by dividing the figures by individual state’s  housing numbers, we created the above graph showing per household figures (in tons/housing unit -T/HU). CO2 emissions were calculated based on releases relating to the burning of fossil fuels in residential situations and do not account for emissions from commercial, electrical power generation, industrial or transportation emissions.

The states with the highest emissions per house are Alaska with 4.8T/HU, Connecticut with 4.2T/HU, Illinois and Michigan both came up with 4.1T/HU, and New Hampshire and Massachusetts both had 4.0T/HU.

14 states had emissions in the 3.0-3.9T/HU bracket. Maine, Vermont and Rhode Island all had 3.9, New Jersey had 3.8, New York had 3.7 and Utah 3.5T/HU. Minnesota and Wyoming both had 3.3T/HU, Wisconsin, Pennsylvania and Colorado all had 3.2T/HU, Ohio had 3.1 and Montana and Iowa 3.0T/HU.

The 2.0-2.9 bracket had a total of nine states, with Kansas leading at 2.7T/HU, Indiana, Nebraska and South Dakota all had 2.6T/HU, North Dakota had 2.4T/HU and Maryland, Idaho and New Mexico all had 2.3T/HU. The bracket ended off with Missouri at 2.0, though, interestingly, the U.S average fell into this bracket as well with 2.2T/HU.

The rest of the states had emissions below 2.0T/HU though Louisiana (0.9), Alabama and South Carolina (0.8), Arizona (0.7) and Florida and Hawaii(0.1) had the lowest emissions in the country.

Factors that Affect Emissions

As mentioned initially there are 5 sectors that are considered when calculating emissions:  commercial, electrical power, residential, industrial and transportation. According to the EIA report, total national emissions fell by 2% from 2015-2016. Also, 36 states saw an overall decrease in emissions, while 14 states had an increase.

When all factors are taken into account, for instance, New York came out with the lowest total emissions per household. High-density living led to residential efficiencies with heating; efficient, condensed public transport led to lower transport emissions; and its main economic driver is the financial sector (low energy, compared to e.g. manufacturing). So, despite New York accounting for about 6% of the population, it only used 1% of the country’s industrial energy.

Residential Emissions

When looking at one factor only, in this case, residential emissions, the picture is different. There are various factors that influence residential CO2 emissions by state, including population, climate, sources of energy, building standards, local economy and state policies. Thus, it is not easy to get a balanced picture of the reasons for emissions in each sector.

In this case, New York had the highest total emissions of 298.6 Million tons, but thanks to its rating of the 5th highest number of households, it lands in 11th place for average emissions per household.


Alaska is commonly known as the coldest state and added to the fact that it has the third lowest housing density, it had the highest per household residential emissions. Conversely, Hawaii had the lowest per household emissions, close to zero, thanks largely to its warm climate and low residential energy demands.


Wyoming had the lowest population density with just over 275,000 housing units. However, due to its cold climate, and high energy demands, Wyoming was the third highest energy producer in 2016, and had per capita emissions of 3.3T/HU. On the other hand, California had the highest number of households, so despite it having the second highest total residential emissions at 24.1Million tons, its average household emissions ended up at a low 1.7 T/HU.

Energy sources, building standards, economy and local policies are hard to separate from the shown data, as too many factors come into play to give a clear image. For instance, when considering energy sources, factors like whether the energy was produced in-state or imported from another state, and the origin of the energy will affect totals significantly.

The worst CO2 emitters

When looking at overall numbers it is easy to point fingers and say that one state is failing the emissions reduction battle, compared to another. However, when looking at emission by sector, we get a clearer more balanced image. On the whole, the country has managed to reduce emissions, so we are moving in the right direction, but changes need to be ramped up if we are to continue to make a difference and avoid the negative impact of continued global warming.

Looking at the graphic, it is clear that the east coast and northern central states hold the main culprits, with the west coast and south showing the lowest emissions. However, as stated this is not as simple as applying a face value. North and northeast have cold climates and so energy for heating is a factor, where the south and west coast have more temperate climates. That’s not even taking other factors like population density and energy supply etc, into account.

Everyone Needs to Get Involved

To reduce residential emissions there are several steps the average homeowner can take, including:

  • The most important step is to reduce your carbon footprint by buying and eating local, reducing consumption of meat and dairy.
  • Build wise, ensure spaces are well insulated and fit energy saving windows, roofing, and siding. Get an energy audit to check where you’re losing out.
  • Install some kind of energy supply device, from solar panels to air source heat pumps.
  • Avoid single-use and other plastics as much as possible. Petition big business to minimize the use of plastics in packaging.
  • Disconnect all electrical devices that are not in use, or on ‘standby’.
  • Switch all of your bulbs to LEDs, which use only 3% of the energy of incandescent bulbs.
  • Buy fewer, better-made clothes in natural sustainable fibers, avoid mass-produced synthetic items.
  • Travel by car less, move closer to work to cut your commute or opt for public transport.

Though it’s easy to expect government and industry to make the big changes, if everyone starts to reduce their own carbon footprint, a difference can be made. Finally, when in doubt, plant a tree; it’s literally the perfect choice for a ‘greener’ future.

Yuka Kato

Industry Analyst