Atmospheric carbon dioxide levels continue to hit record levels. What can we do to decarbonize?

***Image Credit :*** ***https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide***

In 2022, the global average concentration of atmospheric carbon dioxide (CO2) hit a record high of 417 parts per million (ppm) and continues to rise at a rate of around 2 ppm per year. Atmospheric CO2 levels have been on the rise since the beginning of the Industrial Revolution; before industrialization, CO2 levels remained stable below 300 ppm for thousands of years. Today’s CO2 concentrations are the highest level in at least 800,000 years.

This rapid climb—largely due to human activities, primarily the burning of fossil fuels, deforestation, and industrial processes—has emerged as one of the most pressing challenges in modern history. Rising CO2levels contribute to climate change, causing detrimental impacts on ecosystems, weather patterns, and human health. It’s not too late to decarbonize, but successfully zeroing out new emissions and reducing atmospheric concentrations will require immediate action.

Rising greenhouse gas concentrations lead to global warming, sea-level rise, ocean acidification, and the intensification of extreme weather events, such as hurricanes, droughts, and heatwaves. The consequences of elevated CO2 levels are intersectional and impact communities disproportionately, exposing low income and black, Indigenous and people of color (BIPOC) to higher rates of environmental hazards. Designing equitable protection from the effects of rising CO2 levels is imperative to close existing racial gaps.

Among many promising solutions that, together, can reduce atmospheric CO2 here are five that are proven and are capable of addressing environmental justice concerns when designed appropriately:

1. Renewable energy paired with electrification:

Shifting away from fossil fuels in favor of renewable energy sources is crucial to decarbonize our energy sector. Solar, wind, hydro, and geothermal power have become increasingly affordable and accessible, offering cleaner alternatives to traditional coal, oil, and gas. When paired with battery storage and demand response technologies, these sources can sustainably power communities with minimal support from carbon emitting energy sources.

2. Energy efficiency:

Enhancing the energy performance of buildings, transportation systems, and industrial processes can significantly reduce energy consumption and associated CO2 emissions. Energy-efficient technologies, smart grid systems, and energy management practices can help optimize energy use while reducing carbon footprints. Incentive programs can ensure low-cost access to these services based on income or background.

3. Electrification of transportation:

Getting more people out of personal vehicles will reduce the energy consumption demands of transportation. Promoting and incentivizing public and active transportation (like biking and walking) in densely populated areas can reduce congestion while making transportation options more accessible to justice communities[LS1] . Paired with electric cars and greatly increasing the availability of charging stations, public and active transportation can decarbonize transportation without decreasing accessibility.

4. Reforestation and Land Management:

Forest ecosystems are natural carbon “sinks” that absorb CO2 from the atmosphere. Protecting existing forests and implementing large-scale reforestation initiatives through sustainable land management practices, including soil carbon sequestration and regenerative agriculture, can contribute to carbon removal and restore ecosystems. These restoration programs can be focused around low-income communities where green coverage tends to be more sparse.

5. Circular Economy and Sustainable Production:

Transitioning towards a circular economy—where resources are efficiently used, recycled, and waste is minimized—can significantly reduce CO2 emissions. Sustainable production processes, such as the use of renewable materials, eco-design principles, and recycling initiatives, are crucial for achieving carbon neutrality across all economic sectors, including manufacturing and construction.

Efforts to address climate change and decarbonization must go hand in hand with social and economic justice to ensure a just transition. By acknowledging and actively working to rectify the disproportionate impacts, we can build a more inclusive and sustainable future for all.

Eliandro Tavares

Assistant Researcher

This is a part of the AEC Blog series

An Update on Building Electrification in Boston

Boston’s pledge to become a carbon free city by 2050 will rely on significant emission reductions from buildings—the city’s largest source of greenhouse gas emissions—where utility gas, fuel oil, and electricity together account for almost 70 percent of total emissions. Research has supported electrification (the transition away from fossil fuels in favor of electric heating and cooling) as a critical step for building emission reductions, and although the city has begun to address this sector with a transition plan for all large buildings (>=35,000 square feet), there is no explicit plan for building electrification. Rather, Boston’s Climate Action Plan (CAP) calls for emission reductions from retrofitting and renewable energy investments including biofuels and hydrogen.

In July of 2021, Boston’s Air Pollution Control Commission passed a series of amendments to the Building Energy Reporting and Disclosure Ordinance (BERDO) setting the CAP’s decarbonization plan into motion. These amendments allow the city to track emissions from large buildings, which make up nearly half of the city’s total emissions, while also investing in equitable clean energy technology that prioritizes underserved communities. Moving forward, the city will use data collected from the BERDO amendments to develop a decarbonization program, meaning that Boston’s building decarbonization strategy is dependent on their findings in the coming years.

Large buildings are the focus of the city’s decarbonization strategy because of their disproportionate contribution to the city’s emissions, but research on small building electrification could serve as a promising example for Boston’s strategy for all buildings moving forward. Rocky Mountain Institute released an analysis on new single-family homes in Boston in which they compare the costs of all-electric versus mixed-fuel appliances and heating in new construction projects. They found an average Boston home could save nearly $1,600 in utility bills and 51 tons of carbon dioxide emissions over a 15-year period.

Electrification is an effective and affordable decarbonization strategy. Building electrification is not currently being emphasized by Boston city planners despite research that supports its cost effectiveness but a least-cost decarbonization plan for Boston requires this cost-effect option.

Eliandro Tavares
Assistant Researcher

This is a part of the AEC Blog series

What role does “renewable natural gas” have in a clean energy future?

“Renewable natural gas” (also known as RNG, methane gas, or biogas) is used as a strategy by gas utilities to avoid closure due to the state and local carbon neutrality goals. While landfill RNG collection projects are becoming more common across the United States, RNG is, at best, a temporary solution to achieving emission reductions, and at worst results in environmental harms that could offset the benefits of reduced fossil fuel use. The focus for emission reduction plans should be placed squarely on electrification paired with renewable electric generation.

RNG is a gaseous byproduct of decomposing organic matter and can be used to fuel vehicles or generate electricity and heat. For years RNG, primarily from landfills, livestock operations and wastewater treatment, has been used to produce small amounts of electricity. More recently, large-scale landfill RNG projects used to supplement conventional gas have become more prevalent.

Although RNG extracted from landfills has the potential to lower greenhouse gas emissions, landfill RNG potential isn’t sufficient to produce enough biofuels to substitute for fossil fuels. The technical potential for U.S. landfill gas is 1 Bcf per day (two-thirds of the total RNG potential in the United States), which is insignificant compared to the current U.S. gas consumption of 82.9 Bcf per day. Landfill RNG would need to be supplemented with RNG extracted from dedicated farmland. A paper published by Yale Economics concluded that the large-scale and destructive agricultural expansion needed to produce farmland RNG could negate its environmental benefits by endangering the forests it replaces. Farmland RNG production also requires a large amount of freshwater use, and a study published in Ecological Economics found that farmland RNG expansion would require freshwater needed for food production. These negative environmental impacts have the potential to offset the benefits of landfill and livestock RNG (preventing manure runoff into water supplies, reducing methane emissions). Despite these drawbacks, RNG is promoted by gas utilities as a viable alternative to electrification because of its purported ability to reduce emissions while keeping gas utilities’ business model alive.

The electric grid must transition to zero-emission sources like wind, solar, and hydro to reach 2050 emission targets without the negative land-use impacts that come with farmland RNG production expansion. A study from UC Davis found the total RNG potential in California could only provide 4.1 percent of the state’s conventional gas demand, meaning RNG cannot replace gas without importing substantial materials from out of state. A report from the Union of Concerned Scientists came to a similar conclusion for both California and the United States with regard to RNG transportation fuel..

Renewables like wind and solar are among the cheapest energy sources, making them the focal point of renewable energy infrastructure planning. There is little potential for RNG to reduce emissions at the same cost and scale as electrification resources.

Eliandro Tavares Assistant Researcher

This is a part of the AEC Blog series