Maryland Climate and Energy FAQs

MIT Alumni for Climate Solutions

Climate Change — General Questions

Climate Change in Maryland

Maryland Energy Use and GHG Emissions

Pathways for Maryland to become carbon neutral

Climate Change — General Questions

What is the Greenhouse Effect and does it change climate?

Earth's atmosphere naturally moderates temperature by capturing sunlight energy as heat, in a manner similar to the way a greenhouse traps heat. Because of this Greenhouse Effect, Earth is warm enough for liquid water and is a comfortable place for humans and other life on the surface. The atmosphere naturally contains two main components that capture heat - the gas carbon dioxide and water vapor, the latter of which becomes precipitation when the air is saturated and then cools. As the atmosphere mixes, transfers, and balances water and heat energy between regions, its temperature, movement, and precipitation results in "weather," and the long-term weather is called "climate."

CO2 is produced by living cells when they chemically combine oxygen with food in a process called respiration. Plants and some bacteria also carry out the reverse process, converting CO2 in the atmosphere into biomass. These two opposing processes have been naturally balanced for thousands of years on Earth. However, when humans started burning fossilized biomass, the fossil fuels coal, oil and natural gas, for heat and electricity, more CO2 was generated and accumulated in the atmosphere, resulting in an increase in the greenhouse gas and enhancing the greenhouse effect. Other gases from a variety of human activities, including industrial and agricultural, also contribute to the greenhouse effect. The result in a slow but steady increase in the Earth's temperature, known as global warming or climate change.

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What is the connection between energy and climate?

Since the beginning of the Industrial Revolution 200 years ago, so much extra CO2 has been emitted from burning fossil fuels that it has substantially increased the concentrations of carbon dioxide and other heat trapping greenhouse gases (GHG) in the atmosphere. Since increasing the concentration of CO2 warms the Earth, climate change is dependent primarily on total emissions of extra CO2 and other GHGs. As a result, the US Climate Science Special Report indicates that global average temperature has increased 1.8° F between 1901 and 2016.

Although 1.8° F may seem like a small change, even a small increase in temperature increases the amount of water that the atmosphere can hold and decreases how much water can be frozen and stored in polar regions and on mountaintops. Over time, the effect of the extra heat and water in the atmosphere results in more intense mixing, more extreme weather and heavier precipitation. The effect of GHG emissions is cumulative, meaning that climate change will increase over time. In future, the rate of climate changes will increase even more since, at present, it is buffered by absorption of part of the the CO2 emissions by the oceans, and is expected to diminish over time.

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How significant is climate change in historical terms?

Scientists have found an excellent correlation between CO2 levels and climate over the history of the world. Natural carbon dioxide concentration in the atmosphere has varied only between 180-280 ppm, limited to a 100 ppm change, over hundreds of thousands of years. As a result, the Earth's water and carbon cycles have been relatively constant and the climate has been relatively stable over equally long periods.

In the 200 years since the industrial revolution, global human population has grown seven times larger. Increasing quantities of fossil fuels have been burned, and as a result, the average CO2 level rose above 300 ppm in 1950 and above 400 ppm  in 2016, almost double the pre-industrial level.. Most of us have seen the weather change in our lifetime. For example, 9 of the 10 hottest have happened since 2005 and the three hottest years on record were 2015, 2016, and 2017. With increasing CO2 concentrations, we are seeing more extreme storms, with intense flooding in some areas, and droughts in others regions.

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Climate Change in Maryland

What are the effects of climate change?

The effects of climate change on Maryland are similar to those in other temperate regions of the world. Temperature has increased about 1.8 °F (1 °C) since 1900, with the warmest years on record occurring recently. The increase in temperature by the end of the century is expected to be about 8 °F and a possible range of 6-11 °F. Climate change has modified the jet streams in the atmosphere, with the historic path near the US-Canadian border recently flowing much further south and closer toward the north pole than in the past. As a result, weather and seasonal patterns are changing in Maryland, as they are throughout the northeastern US.

Global warming is causing the polar ice caps to melt, including glaciers in Greenland and Antarctica, and contributing to sea level rise. Because of the unprecedented rate of changes taking place, scientist are not sure how fast Maryland's coast will see a rise, but predictions are at least two feet and as much as eight feet, according to the 2017 National Climate Assessment Climate Science Special Report. This compares to a rise of four inches between 1900 and 1993 and four more inches in the 25 years, indicating the increasing rate of change. The expected rise in the next decades will undoubtedly result in further inundation of Maryland's coastal regions, especially during high tides. Combined more intense thunderstorms, hurricanes and nor'easters, flooding will be a serious effect of climate change.

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What climate change effects will occur in Maryland?

Maryland's long coastline, both the Atlantic and Chesapeake Bay shores are vulnerable to flooding from climate change. Most of our cities are located along the coast, including Baltimore, Ocean City, and our capital, Annapolis, and will experience significant flooding due to sea level rise. The NOAA Sea Level Rise viewer can show which areas will be inundated by different sea level rise heights. Maps showing details of Maryland flooding are in the Maryland Sea Level Rise Projections, available on the web, and Scenarios.

Maryland temperature and heat records have been set in most of the years in the last decade – as of September 7, 2018, July 2018 was the wettest month on record in the state. The effects of extreme storms are shown on the Surging Seas Risk Zone Maps, including Annapolis. Both the Climate Science and Maryland reports rely on simulations (models) of weather effects from higher CO2 concentrations and temperatures. They show that reducing emissions would result in less flooding.

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What will the economic damage to Maryland be?

Increased tidal flooding affects our coastal property. The flooding and storm surges will both destroy structures and depress the value of property in the flood zone. A study of the economic impact of climate change by the American Association for the Advancement of Science reviewed conditions and trends in agriculture, crime, health, energy demand, labor, and coastal communities. It found that climate change will lower the Maryland Gross State Product by an estimated 5%, over $ 10 billion. With a six foot sea level rise, property value in Maryland may lose $19 billion, and more than 60,000 homes will be submerged, with first floors underwater. Flood damage is also likely further inland; for example, the 2016 flooding of Historic Ellicott City cost at least $ 22 million, with the 2018 flood resulting in loss to the same area.

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Can we reduce the threat to the state?

By joining with other states and the world, we can limit the damage to Maryland, by reducing CO2 and other GHG emissions through more efficient use of energy and using low or no-emission energy sources, like renewable solar and wind. However, the climate and temperature will not respond immediately. Using climate models that consider emissions and the physics of weather influences, such as trends in ocean and atmospheric currents and temperature, scientists predict that if our peak GHG emission year is 2020 and followed by significant reduction in the following decades, we will be able to limit warming to about 4 °F and prevent the greatest damage from climate change to our state. The longer we wait to start reducing our CO2 and other GHG emissions, the greater the threat of damages to our state.

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Maryland Energy Use and GHG Emissions

How much energy does Maryland use each year?

Maryland's main categories of energy use are electricity, heat for buildings, and transportation. Maryland consumes approximately 66 TWhs of electricity per year. 46 TWhs are generated from fossil fuels, primarily coal and natural gas. The remaining 20 TWhs come from nuclear, hydroelectric, solar, and other non-GHG-emitting sources. Maryland consumed about 219 billion cubic feet of natural gas in 2016. About 25 % of this was used to generate electricity and another 25 % was used for residential gas heating. Maryland burns about 3 billion gallons of gasoline per year.

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How much GHG does Maryland emit?

GHG emissions are measured as CO2, which calibrates the effect of different GHGs. For example, coal emits about twice as much CO2 per unit of energy as natural gas, and most of Maryland's electricity comes from coal-burning plants. Maryland's electricity generation is responsible for approximately 28 million metric tons of CO2e emissions per year. This number includes electricity that is generated out of state for in-state consumption. The fuel we burn for heat emits approximately 15 million metric tons of CO2 per year. Our cars emit approximately 30 million metric tons of CO2 per year.

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How much GHG can we absorb out of the atmosphere?

Maryland's largest sink for absorbing CO2 is our forests. Forests cover about 40% of the state's area, and absorb an estimated 12 million metric tons of CO2e per year. Farmland also has the potential to absorb significant amounts of CO2. With aggressive use of techniques such as cover-cropping, our 2 million acres of farmland could absorb an additional two million metric tons of CO2 per year.

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What is Maryland's net carbon budget?

If we tabulate Maryland's major GHG sources and sinks, we can estimate a state carbon budget:





Energy Use (CO2, CH4, N2O)



Electricity Use (Consumption)



Electricity Production (in-state)



Net Imported Electricity










Fossil Fuel Industry



Industrial Processes







Waste Management



Gross Emissions (Consumption Basis, Excludes Sinks)



Emissions Sinks




Net Emissions (Consumptions Basis) (Including forestry, land use, and ag sinks)



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Pathways for Maryland to become carbon neutral

What will Maryland have to do to become carbon neutral?

To be carbon neutral, we will have to limit greenhouse gas emissions to no more than we can absorb — reducing our emissions by approximately 95 million metric tons CO2e/yr. We will have to address emissions from not only electrical generation, but also heating, and the largest emitter, transportation. This goal is ambitious, but it is what we need to do — and by extension what the rest of the country needs to do — to reduce the threat of climate change to manageable levels.

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What's required to transition to renewable electricity?

Maryland consumes approximately 46 TWhs of electricity per year generated from fossil fuels, responsible for about 38% of our GHG emissions. To eliminate those emissions, we will have to build 46 TWhs of new, renewable generating capacity, such as wind and solar power, to replace our existing coal and gas-fired plants. Maryland's greatest energy resource is offshore wind power, with the potential to supply 600 TWhs per year, far more than our current needs. We will also need to make grid improvements, adding storage and power management systems to accommodate the distributed, variable nature of wind and solar power.

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What's required to transition to electric heating?

Burning fuel for heat is responsible for approximately 21% of our GHG emissions. To bring this number to zero, we will have to replace gas and oil-fuel furnaces with electric alternatives, such as high-efficiency heat pumps. For example, natural gas consumption was about 164 billion cubic feet in 2016, and this generated about 165 billion BTUs of energy. Replacing this with electrical energy will require an estimated 56 TWhs, almost double the current electricity production. Maryland will have to consider incentive programs and changes to building codes to drive the transition away from fossil-fueled heat.

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What's required to transition to low-carbon transportation?

Maryland burns about 3 billion gallons of gasoline per year, emitting about 30 million metric tons of CO2e (40% of our overall emissions). To eliminate this source of greenhouse gas, we will have to transition to electric vehicles and mass-transit (much of which is already electric.) In the near-term, we could incentivize the widespread transition to both electric and hybrid vehicles. Hybrids typically have twice the fuel economy of conventional cars and could cut our vehicle-related GHG emissions in half.

To make electric vehicles a more attractive option, we will need to build a charging infrastructure, and an additional 50 TWhs of renewable electrical capacity to charge these vehicles. Policies to encourage rooftop solar power on commercial buildings and homes, combined with policies to encourage businesses to provide charging stations, would enable car charging during sunlight hours. This would reduce the need for grid storage. Maryland should also expand its participation in the TCI, coalition of northeastern states working to develop low-carbon transportation solutions.

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Can we increase the amount of GHG we absorb from the atmosphere?

The most effective way to absorb GHG from the atmosphere is to plant more trees and increase forest area. Each acre of forest absorbs about 6 metric tons of carbon per year. Maryland's current reforestation law requires replanting forest land that has been cleared for state construction. Agricultural land also has the potential to absorb and sequester CO2 in the soil. Maryland has a program in place, but it should be expanded to the greatest extent possible. The HCA is dedicated to restoring the climate via active carbon-capture, using scalable machinery and other technologies.

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How do you put a price on carbon?

Carbon-pricing policies add a fee to the sale of fossil fuels (e.g. coal for power generation, natural gas for heating, and gasoline) in order to discourage consumption and encourage the transition to renewable energy. Revenues can be rebated to taxpayers based on income, and used to fund renewable energy projects. CXC and Citizens' Climate Lobby have promoted such legislation in Maryland. British Columbia has had a carbon tax policy since 2008, and the policy is credited with significantly reducing GHG emissions.

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What energy policies and programs has Maryland adopted to date?


Maryland's RPS requires utilities to buy 25% of their power from renewable sources by 2020.


Nine states along the eastern seaboard including Maryland collaborate in the RGGI. This program caps GHG emissions from large fossil-fuel generator plants. Plants can buy credits at auction to exceed their emissions cap, or they can sell credits if they stay under their cap. Each year the cap is reduced, This mechanism sets a price on GHG emissions that exceed the cap.

State Rebate Programs

Maryland offers rebates and state tax credits on a variety of GHG-reducing activities, such as installing solar panels and purchasing an electric vehicle.


Maryland is part of the TCI developing a cap and invest program for transportation fuels, which may be similar to RGGI.

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What can I do as an individual to reduce my GHG emissions?

Individuals and businesses can follow the same strategy we are proposing for the state. You should buy your electricity from a renewable source, switch to electric heat (with renewably-sourced electricity), and switch to an electric vehicle. The easiest, most impactful action is to switch to a "Green" electricity supplier. The Maryland Public Service Commission has a tool to find Green suppliers. There are also community solar programs, where you can buy electricity from a solar farm rather than putting panels on your roof. Joining one of these programs takes minutes, and requires no physical changes to your home wiring.

If you have a gas- or oil-fired furnace or hot water heater, you can replace it with a high-efficiency electric heat pump (make sure you are also getting your electricity from a renewable source). Weatherizing your home — sealing leaks and increasing the amount of insulation — can reduce your power consumption significantly. BGE and PEPCO have programs to audit your home and recommend improvements.

Installing solar panels on your home or business is more involved, but generally has a positive payback over time thanks to state and federal tax credits. And taking this step actually increases our capacity for generating renewable energy.  Also importantly, consider replacing your car with a hybrid or fully-electric vehicle. Hybrids can cut your gas consumption (and emissions) in half. Electric vehicles (charged by renewable electricity) will cut your transportation emissions to zero.

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Additional Resources

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