Accelerating Decarbonization in the United States Technology, Policy, and Societal Dimensions (2024) / Chapter Skim
Currently Skimming:
8 Land Use
8 Land Use
Pages 417-464
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 417... ...
Funding from the Inflation Reduction Act (IRA) to incentivize terrestrial carbon sinks and non-CO2 emission reductions is technically capable of generating an annual land sink plus CH4 and N2O abatement of 211 Mt CO2e/y in 2030, and a total net emission (carbon sinks plus non-CO2 abatement)
|
From page 418... ...
from terrestrial ecosystems to the atmo sphere occur whenever photosynthetic uptake of atmospheric CO2 is smaller than emissions from plant respiration, biomass combustion, and microbial decomposition of dead biomass. Positive emissions cause an ecosystem to lose carbon mass because of a net transfer from terrestrial organic carbon to atmospheric CO2.1 Carbon dioxide emissions are net negative whenever losses are smaller than gains, which causes a net gain in ecosystem carbon stocks (a carbon sink)
|
From page 419... ...
, in which biomass is used to produce electricity, hydrogen, or a carbo hydrate fuel, with CO2 capture and geologic storage.3 However, mitigating agricultural emissions of non-CO2 GHGs were not covered in the 2019 report, and so here an analy sis is provided -- including available practices and magnitude of mitigation potential -- of N2O and CH4 reductions that play a key role in any net-zero GHG emissions pathway. The committee will not recapitulate everything in the 2019 report but will summarize and update its findings about terrestrial GHG mitigation.
|
From page 420... ...
to agricultural lands, but only as a frontier negative emissions technol ogy. These rocks react with CO2 from the atmosphere, yielding stable carbonate minerals and providing co-benefits by increasing soil pH, which improves the productivity of acidic soils (Beerling et al.
|
From page 421... ...
Next, the committee analyzes mitigation measures in the IRA that target agricultural-based emissions of methane and nitrous oxide. The committee offers specific recommen dations to the Secretary of Agriculture about the implementation of programs in the bill that target carbon sinks through forestry and agricultural soils, and through abatement of methane and nitrous oxide.
|
From page 422... ...
NOTE: BAU = business as usual; LULUCF = land use, land use change, and forestry; NCS = U.S. National Climate Strategy.
|
From page 423... ...
. It is possible to envision extreme scenarios in which the needed sink is much smaller because of curtailed energy demand or much larger because of more residual fossil fuel use and/or higher non CO2 GHG emissions.
|
From page 424... ...
. Because technological options like BECCS and DAC are unlikely to be deployed at levels that would materially affect 2030 emissions, carbon sinks in the United States through 2030 should be thought of as the "business as usual" (BAU)
|
From page 425... ...
(2021) , which combines optimistic assumptions about forestry and agricultural options, and assumptions about the decline of the BAU land sink.
|
From page 426... ...
Potential Size of Safe Terrestrial Carbon Sinks in the United States The National Academies (2019, p.
|
From page 427... ...
. The safe limit for agricultural C sequestration is less constrained by land use change concerns compared to forestry, in that most of the management practices to increase soil carbon stocks can be employed on agricultural lands that remain in production for 7 Baselines are benchmarks that represent a one-time fixed benefit.
|
From page 428... ...
. Reducing non-CO2 GHG emissions lessens the size of carbon sinks required to meet overall GHG mitigation targets, and thus potential reductions in agricultural CH4 and N2O emission are relevant to include.
|
From page 429... ...
Last, $0.3 billion of the $0.55 billion fund is for either climate mitigation or forest resilience. In addition, a fund of $0.1 billion for the hauling and use of material cleared for fire suppression may create a net carbon sink, but its magnitude and even its sign will depend on details of implementation.
|
From page 430... ...
This, could make them more resilient in case the 2023 or 2028 Farm Bills do not pass on time, as the conservation programs would still be in place. POTENTIAL TERRESTRIAL CARBON SINKS AND CH4 AND N2O ABATEMENT CREATED BY THE IRA Forestry The $2.15 billion for fire suppression may not create net carbon sinks.
|
From page 431... ...
. If all of this $2.75 billion is used effectively to create net carbon sinks at $20/tCO2, then it will sequester a total of 138 MtCO2 over 8 years.
|
From page 432... ...
report, forestry and agricultural carbon sinks were examined in detail, but the important non-CO2 greenhouses gases CH4 and N2O -- of which the agricultural sector is a major source -- were not covered. Hence, here the committee provides more background on the specific sources of these gases within agriculture, management practices to mitigate their emissions (see Box 8-1)
|
From page 433... ...
. Agricultural emissions of nitrous oxide and methane have been remarkably stable over the past 30 years (averaging 336 MtCO2e/y for N2O and 235 MtCO2e/y for meth ane)
|
From page 434... ...
for each approach, which they used to identify cumulative emissions reductions per year at different prices. For compatibility with the soil carbon calcula tions, abatement potentials are shown for methane and nitrous oxide at ≤$20/t CO2e, at $20–$50/t CO2e, and the total at ≤$50/t CO2e, as well as the percent reduction from 2020 emissions (EPA 2022)
|
From page 435... ...
. Copyright © 2023 Environmental Defense Fund.
|
From page 436... ...
Adding the expected forestry and agricultural carbon sinks plus N2O and CH4 reduc tions, the IRA could create a net 8-year net sink of 983 MtCO2e (138 + 845) and a 2030 net sink of 245 MtCO2e/y (34 + 211, assuming a linear ramp)
|
From page 437... ...
sinks and/or non-CO2 GHG reductions, from projects in which farmers/foresters adopt new management practices that increase C sinks and/or reduce GHG emissions. Currently, there are very few agriculture and forestry project types that are eligible for inclusion in compliance (cap-and-trade)
|
From page 438... ...
Forestry Carbon Sink Findings and Recommendations Finding 8-1: The $5 billion of forestry funding in the IRA is theoretically sufficient to create additional terrestrial carbon sinks as large as those in simple net-zero trajectories. There is sufficient land available to stay well within the safe limits pro posed by the National Academies (2019)
|
From page 439... ...
However, an important recent paper used remote sensing methods to compare 37 forest management projects in Califor nia designed to enhance carbon sinks with matched controls and found no additional carbon storage (Coffield et al.
|
From page 440... ...
Improved monitoring and GHG inventory capabilities will be crucial to track adoption rates and durability of carbon sequestering/GHG reducing practices and whether the projected C sinks and N2O and CH4 abatement are achieved. Different management practices to mitigate agricultural emissions of CH4 and N2O vary in their effectiveness.
|
From page 441... ...
This system would be analogous in function to the Forest Inventory and Analysis system for the nation's forests, which entails periodic measurement of forest biomass and soils, carbon, and forest condition. Measurements of soil carbon stocks and other key soil indications at agricultural NRI points would reflect actual on-farm conditions, and could be done on a rotating basis (e.g., 1,000 points per year, on a 10-year remea surement cycle)
|
From page 442... ...
In addition, economic and behavioral research need to investigate ap proaches to improve policy design and address inequities in participation of disadvantaged communities in conservation incentive programs. Recommendation 8-6: Incentivize the Abatement of CH4 and N2O Emissions and Improve Soil Carbon Sequestration.
|
From page 443... ...
Terrestrial Carbon Sinks Technically achievable "safe" totals from the National Academies (2019) are again 150 MtCO2/y from new forests, 100 MtCO2/y from changed forest management, 250 MtCO2/y from agricultural soils and 500 MtCO2/y from BECCS.
|
From page 444... ...
. Renewable Electricity There are a significant number of studies on the land required for the wind turbines, solar panels, transmission lines, and support infrastructure of a net-zero energy sys tem in the United States.
|
From page 445... ...
It separately estimated the land area that would be unavailable for joint use (i.e., the area actually occupied by the wind turbines and associated access roads) and the area that could also be used for other purposes (i.e., croplands beneath a windfarm)
|
From page 446... ...
. Corn ethanol production currently requires fossil energy and yields substantial N2O emissions from fertilizer 446 A00026 -- Accelerating Decarbonization in the United States_CH08.indd 446 3/29/24 7:55 PM
|
From page 447... ...
. With yields of 10–20 tons of perennial biomass per hectare per year on the 16 million hectares currently devoted to corn ethanol and 90 percent CO2 capture, BECCS would produce a carbon sink of 264–528 tCO2/y (assuming half the biomass is carbon)
|
From page 448... ...
, a $6.5 billion total invest ment mostly devoted to biofuels production. The IRA extends the current $1/gallon tax credit for biodiesel until 2024, and then replaces it with a credit of $0.2/gallon for bio fuels with 50 percent greenhouse efficiency, like current biodiesel (where greenhouse efficiency equals the percent of the GHG emissions of an energy-equivalent amount of fossil fuel)
|
From page 449... ...
However, there is not currently a sufficient comprehensive plan to develop BECCS. Finding 8-4: The need for carbon sinks and net-zero chemical fuels during 2030–2050 would likely cause a rush to biomass production that would decrease agricultural and forest land.
|
From page 450... ...
Finding 8-5: Reducing food waste could be an important way to reduce food sec tor GHG emissions more broadly. If food waste were halved, up to 10 percent of emissions from the food system could be mitigated.
|
From page 451... ...
. Animal agriculture specifically accounts for 5 percent of global carbon dioxide emissions, 37–44 percent of global methane emissions, 44 percent of nitrous oxide emissions, and 75–80 percent of total agricultural emissions (FAO et al.
|
From page 452... ...
. In addition to the emission profile of animal products, conventional meat supply chains pose other environmental and dietary health impacts, discussed in Chapter 3.
|
From page 453... ...
While the market for plant-based meat substitutes is projected to grow by 11 percent by 2029 (Fortune Business Insights 2022) , the much larger conventional meat market ($3 trillion, globally)
|
From page 454... ...
There is potentially more opportunity but less mitigation benefit with dairy substitutes. Despite the current animal protein–oriented food system's high GHG emissions, potential adverse health impacts, and high demand for arable land, research shows that a fundamental change in the food animal production system will be difficult, requiring technological innovation, policies that make sustainable food more acces sible and affordable, and buy-in from consumers.
|
From page 455... ...
. • Creating federal incentives for plant-based meat substitutes and cell-cultivated products that reflect their life-cycle GHG and land use benefits relative to conventional meat.
|
From page 456... ...
Transparent to Recommend reductions Analysis and Ways to Measure Reporting Additional Forest for Adaptive Sinks Management 8-2: Prioritize Secretary of • Land use • GHG A Broadened Ecosystem-Level Agriculture reductions Policy Portfolio Carbon Storage 8-3: Establish U.S. Department • Land use • GHG Rigorous and a Permanent, of Agriculture reductions Transparent National-Scale, (USDA)
|
From page 457... ...
Objective(s) Categories Short-Form Implementing Addressed by Addressed by Addressed by Recommendation Recommendation Recommendation Recommendation Recommendation 8-6: Incentivize USDA • Land use • GHG A Broadened the Abatement reductions Policy Portfolio of CH4 and • Equity N2O Emissions and Improve Soil Carbon Sequestration 8-7: Release a Department of • Land use • GHG Research, Comprehensive Energy reductions Development, and Research, Demonstration Development, Needs Demonstration, and Deployment Program for Biomass Energy with Carbon Capture and Storage 8-8: Convene Secretary of • Land use • GHG A Broadened an Expert Group Agriculture reductions Policy Portfolio to Recommend • Health Policies That Could Encourage Sustainable Diets 457 A00026 -- Accelerating Decarbonization in the United States_CH08.indd 457 3/29/24 7:55 PM
|
From page 458... ...
2023. "The Value of Low- and Negative-Carbon Fuels in the Transition to Net-Zero Emission Economies: Lifecycle Greenhouse Gas Emissions and Cost Assessments Across Multiple Fuel Types." Applied Energy 331:120388.
|
From page 459... ...
. "Biofuels and Greenhouse Gas Emissions: Myths Versus Facts." https://www.energy.gov/sites/prod/files/edg/ media/BiofuelsMythVFact.pdf.
|
From page 460... ...
2018. "Greenhouse Gas Emissions and Energy Use As sociated with Production of Individual Self-Selected US Diets." Environmental Research Letters 13(4)
|
From page 461... ...
2022. "Impact of Plant-Based Meat Alternatives on Cattle Invento ries and Greenhouse Gas Emissions." Environmental Research Letters, January.
|
From page 462... ...
2020. A National Strategy to Reduce Food Waste at the Consumer Level.
|
From page 463... ...
2021. "Carbon Intensity of Corn Ethanol in the United States: State of the Science." Environmental Research Letters 16(4)
|
From page 464... ...
2018. "Technical Opportunities to Reduce Global Anthropogenic Emissions of Nitrous Oxide." Environmental Research Letters 13(1)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.