Progress Through RGGI

Since the start of the program, RGGI member states have seen a GHG reduction 16% deeper than that of non-RGGI states during the same period.1 The potential emission reductions for Maryland from the RGGI program in 2020 are estimated to be 3.60 MMtCO2e. According to EPA's most recent social cost of carbon calculations (updated July 2015), this translates to an avoided cost of approximately $176 million in that year.2, 3 Assuming persistence of the program, the avoided emissions, and therefore savings would continue to accumulate in subsequent years. The social cost of carbon metric is intended to encompass a variety of damages due to climate change, including human health costs; however, as the IPCC fifth assessment report notes, there are limits to economic assessments of climate change risks based on an incomplete accounting and a number of assumptions involved in these and most models.4 Therefore, while cost-benefit analyses of climate impacts are useful, they should not be employed as a stand-alone evaluation of mitigation efforts.

Environmental Benefits

Maryland's current environment has evolved based on the conditions of a climate which had until recently been changing very slowly in the years since the last ice age. Relatively rapid changes can only be tolerated within a certain range, often referred to as the system's resiliency. Once this threshold is passed, the impacts are far more pervasive and likely irreversible. It is, therefore, crucial to take steps such as the RGGI program which reduce CO2 emissions and limit the extent of climate change, in addition to implementing adaptation strategies which increase our resiliency.

Some of the environmental benefits from reduced emissions will be measurable in the form of avoided damages and costs expected to permeate various sectors of Maryland's economy. Agriculture, fisheries, energy and certain types of tourism are all impacted by temperature and precipitation patterns, and therefore, are expected to be at high risk from climate change. Other damages to the environment, such as those at the ecosystem level or to the intrinsic value of nature, are inherently more difficult to quantify, though perhaps the most obvious and visible risks are those posed to the Chesapeake Bay. The Bay ecosystem is an invaluable and iconic part of Maryland and substantial time and effort has been dedicated to its protection and restoration. Some examples of risks to various sectors and segments of Maryland are highlighted below.

Examples of Risks from Climate Change


  • Heavy precipitation and extreme heat events can damage crops
  • Wet springs may delay planting
  • Long, dry summers reduce water availability and increase heat stress on plants
  • Warmer winters may increase pressure from weeds and pests


  • Warming habitats may shift commercial fish populations northward
  • Warming waters also bring new pests and increase damage from disease
  • Changes in acidity and water chemistry make it harder for crabs and oysters to build their shells


  • Regional tourism will face various impacts depending on the nature of the activity
  • Warmer winters make it more difficult for Maryland ski resorts to maintain adequate snow cover
  • Beaches are susceptible to more extreme weather events as well as sea- level rise


  • Hotter summer temperatures increase peak electricity demand, making it more difficult and possibly more expensive for utilities to provide electricity during these times
  • Electricity is more likely to fail precisely when it is most needed: when peak summer demand exceeds supply
Sun graphic

The Chesapeake Bay

  • Warmer waters mean lower dissolved oxygen content, exacerbating dead zones
  • Eelgrass, which provides food and shelter for fish, crabs and waterfowl, becomes stressed in warmer waters
  • Marsh and wetland habitat may be lost due to inundation from sea-level rise


Economic Benefits

Maryland invests auction revenue in the Strategic Energy Investment Fund (SEIF), which is administered by the Maryland Energy Administration (MEA). SEIF is comprised of a variety of funding sources, however, RGGI auction proceeds are the primary component. Investments include EmPower Maryland projects such as energy efficiency upgrades for low-to-moderate income families; direct bill assistance; and projects that promote affordable, reliable and clean energy across Maryland. Low-income households use a proportionally larger percentage of their total income to pay for electricity bills - on average more than three times the amount of higher income households.5 SEIF funding helps to alleviate the cost of monthly bills both immediately with bill-pay assistance, and in the long-term with energy efficiency upgrades. Additionally, energy efficiency measures decrease the total demand for electricity, placing downward pressure on electricity prices.6 SEIF's 2016 Report on Fund activities may be found here, and information on specific programs may be found on the websites of the Maryland Department of Housing and Community Development, the Office of Home Energy Programs and the Maryland Energy Administration

Health Benefits

Climate change is expected to have a broad range of consequences for human health, including indirect effects such a reduced agricultural yields contributing to food shortages. There are also more direct impacts on health and welfare from increased incidents of extreme heat and weather events, declining air quality and changes in the distribution of vector-borne-diseases. It is important to keep in mind that many of these frequently have a disproportionate impact on communities that are more vulnerable based on either the nature of the impact or the community's ability to adapt and respond to it.

The most immediate human health concern caused by the burning of fossil fuels is not the release of CO2, but the co-pollutants associated with combustion. For fossil-fuel-fired power plants, these include sulfur dioxide, carbon monoxide, hydrocarbons, and particulates. Some of these pollutants cause issues directly, while others undergo reactions in the atmosphere to create harmful secondary pollutants, such as ground-level ozone, acid rain, and photochemical smog. Several pollutants related to the production and combustion of fossil fuels7 are federally regulated as toxics under the Clean Air Act, including nine of the 30 pollutants identified as Urban Air Toxics.8 Polycyclic aromatic hydrocarbons (PAHs), a category of hydrocarbons that include known and probable human carcinogens, are formed primarily from the combustion of fossil fuels.9 In fact, of the EPA's six criteria pollutants regulated under the Clean Air Act, five are associated with the combustion of fossil fuels used in power plants. Reducing the prevalence of this method of electricity generation is therefore accompanied by the significant co-benefit of decreasing human health risks from hazardous air pollutants.

1 Arcadia Center, 2016. Regional Greenhouse Gas Initiative Status Report Part 1: Measuring Success
2EPA, 2015. "EPA Fact Sheet: Social Cost of Carbon".
3In 2016 dollars, using the average scenario and a 3% discount rate and assuming that all reductions occur in the year 2020 (although reductions have been occurring incrementally since the start of the program).
4 Intergovernmental Panel on Climate Change, 2014. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.
5 American Council for an Energy Efficient Economy, 2016. Lifting the High Energy Burden in America's Largest Cities: How Energy Efficiency Can Improve Low-Income and Underserved Communities
6 U.S. Energy Information Administration, 2016 Electricity Explained: Factors Affecting Electricity Prices.
7 Mainly coal and oil specifically, rather than natural gas.
8 National Center for Biotechnology Information, U.S. National Laboratory of Medicine. PubChem Database
9 U.S. EPA, "Hazardous Air Pollutants"

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