@article {241, title = {Using Land To Mitigate Climate Change: Hitting the Target, Recognizing the Trade-offs}, journal = {Environmental Science \& Technology}, year = {2012}, month = {05/2012}, pages = {120518100539003}, abstract = {

Land can be used in several ways to mitigate climate change, but especially under changing environmental conditions there may be implications for food prices. Using an integrated global system model, we explore the roles that these land-use options can play in a global mitigation strategy to stabilize Earth{\textquoteright}s average temperature within 2 {\textdegree}C of the preindustrial level and their impacts on agriculture. We show that an ambitious global Energy-Only climate policy that includes biofuels would likely not achieve the 2 {\textdegree}C target. A thought-experiment where the world ideally prices land carbon fluxes combined with biofuels (Energy+Land policy) gets the world much closer. Land could become a large net carbon sink of about 178 Pg C over the 21st century with price incentives in the Energy+Land scenario. With land carbon pricing but without biofuels (a No-Biofuel scenario) the carbon sink is nearly identical to the case with biofuels, but emissions from energy are somewhat higher, thereby results in more warming. Absent such incentives, land is either a much smaller net carbon sink (+37 Pg C {\textendash} Energy-Only policy) or a net source (-21 Pg C {\textendash} No-Policy). The significant trade-off with this integrated land-use approach is that prices for agricultural products rise substantially because of mitigation costs borne by the sector and higher land prices. Share of income spent on food for wealthier regions continues to fall, but for the poorest regions, higher food prices lead to a rising share of income spent on food.

}, keywords = {climate, land use, mitigation}, issn = {1520-5851}, doi = {10.1021/es2034729}, author = {J. Reilly and Melillo, Jerry M. and Cai, Yongxia and Kicklighter, David W. and Gurgel, Angelo and Paltsev, Sergey and Timothy W. Cronin and Sokolov, Andrei and Schlosser, Adam} } @article {249, title = {Food, Fuel, Forests, and the Pricing of Ecosystem Services}, journal = {American Journal of Agricultural Economics}, year = {2011}, abstract = {


}, keywords = {ecosystem services, food, forests, fuel}, issn = {1467-8276}, doi = {10.1093/ajae/aaq087}, author = {Gurgel, Angelo and Timothy W. Cronin and J. Reilly and Paltsev, S. and Kicklighter, David W. and Melillo, Jerry M.} } @article {247, title = {Historical carbon emissions and uptake from the agricultural frontier of the Brazilian Amazon}, journal = {Ecological Applications}, volume = {21}, year = {2011}, month = {04/2011}, pages = {750 - 763}, abstract = {Tropical ecosystems play a large and complex role in the global carbon cycle. Clearing of natural ecosystems for agriculture leads to large pulses of CO2 to the atmosphere from terrestrial biomass. Concurrently, the remaining intact ecosystems, especially tropical forests, may be sequestering a large amount of carbon from the atmosphere in response to global environmental changes including climate changes and an increase in atmospheric CO2. Here we use an approach that integrates census-based historical land use reconstructions, remote-sensing-based contemporary land use change analyses, and simulation modeling of terrestrial biogeochemistry to estimate the net carbon balance over the period 1901{\textendash}2006 for the state of Mato Grosso, Brazil, which is one of the most rapidly changing agricultural frontiers in the world. By the end of this period, we estimate that of the state{\textquoteright}s 925 225 km2, 221 092 km2 have been converted to pastures and 89 533 km2 have been converted to croplands, with forest-to-pasture conversions being the dominant land use trajectory but with recent transitions to croplands increasing rapidly in the last decade. These conversions have led to a cumulative release of 4.8 Pg C to the atmosphere, with 80\% from forest clearing and 20\% from the clearing of cerrado. Over the same period, we estimate that the residual undisturbed ecosystems accumulated 0.3 Pg C in response to CO2 fertilization. Therefore, the net emissions of carbon from Mato Grosso over this period were 4.5 Pg C. Net carbon emissions from Mato Grosso since 2000 averaged 146 Tg C/yr, on the order of Brazil{\textquoteright}s fossil fuel emissions during this period. These emissions were associated with the expansion of croplands to grow soybeans. While alternative management regimes in croplands, including tillage, fertilization, and cropping patterns promote carbon storage in ecosystems, they remain a small portion of the net carbon balance for the region. This detailed accounting of a region{\textquoteright}s carbon balance is the type of foundation analysis needed by the new United Nations Collaborative Programmme for Reducing Emissions from Deforestation and Forest Degradation (REDD).}, keywords = {Amazon, Brazil, carbon emissions, cerrado, CO2 fertilization, crops, global warming, land cover and land use change, Mato Grosso, pasture, soils, terrestrial ecosystems model, United Nations Collaborative Programmme for Reducing Emissions from Deforestation and Forest Degradation (REDD)}, issn = {1051-0761}, doi = {10.1890/09-1957.1}, author = {Galford, Gillian L. and Melillo, Jerry M. and Kicklighter, David W. and Mustard, John F. and Timothy W. Cronin and Carlos C. Cerri and Carlos C. Cerri} } @article {245, title = {Nitrogen effect on carbon-water coupling in forests, grasslands, and shrublands in the arid western United States}, journal = {Journal of Geophysical Research}, volume = {116}, year = {2011}, month = {2011}, abstract = {As greenhouse gases, including CO2, accumulate in the atmosphere, the western United States is predicted to undergo large-scale climate warming and reduced summer precipitation in the coming decades. In this study we explore the role of these climate changes with elevated CO2 to determine the plant physiological response on primary productivity and associated feedbacks on evapotranspiration (ET) and runoff using a biogeochemistry model, TEM-Hydro, with downscaled climate data for the western United States from the NCAR CCSM3 A2 scenario. Net primary productivity increases by 32\% in forests due to feedbacks between warmer temperatures and enhanced nitrogen mineralization but decreases in shrublands by 24\% due to excessive drying and reduced nitrogen mineralization. Warming directly increases nitrogen mineralization rates but indirectly decreases them by reducing soil moisture, so the net effect is highly dependent on climatic conditions within each biome. Increased soil moisture resulting from larger water use efficiency from the elevated CO2 leads to more net nitrogen mineralization in forests, which reduces N-limiting conditions. The effect of CO2 on stomatal conductance is therefore enhanced because of its effect on reducing nitrogen limiting conditions. Runoff decreases over the 21st century by 22\% in forests, 58\% in grasslands, and 67\% in shrublands due to the reduced precipitation in each region but is modulated by the plant-induced changes in ET. The role of moisture limitation is therefore a crucial regulator of nitrogen limitation, which determines the future productivity and water availability in the West.}, keywords = {carbon-water coupling, climate, forests, GRASSLANDS, shrublands}, issn = {0148-0227}, doi = {10.1029/2010JG001621}, author = {Felzer, Benjamin S. and Timothy W. Cronin and Melillo, Jerry M. and Kicklighter, David W. and Schlosser, C. Adam and Dangal, Shree R. S.} } @article {74, title = {Importance of carbon-nitrogen interactions and ozone on ecosystem hydrology during the 21st century}, journal = {Journal of Geophysical Research}, volume = {114}, year = {2009}, month = {2009}, abstract = {There is evidence that increasing CO2 concentrations have reduced evapotranspiration and increased runoff through reductions in stomatal conductance during the twentieth century. While this process will continue to counteract increased evapotranspiration associated with future warming, it is highly dependent upon concurrent changes in photosynthesis, especially due to CO2 fertilization, nitrogen limitation, and ozone exposure. A new version of the Terrestrial Ecosystem Model (TEM-Hydro) was developed to examine the effects of carbon and nitrogen on the water cycle. We used two climate models (NCAR CCSM3 and DOE PCM) and two emissions scenarios (SRES B1 and A2) to examine the effects of climate, elevated CO2, nitrogen limitation, and ozone exposure on the hydrological cycle in the eastern United States. While the direction of future runoff changes is largely dependent upon predicted precipitation changes, the effects of elevated CO2 on ecosystem function (stomatal closure and CO2 fertilization) increase runoff by 3{\textendash}7\%, as compared to the effects of climate alone. Consideration of nitrogen limitation and ozone damage on photosynthesis increases runoff by a further 6{\textendash}11\%. Failure to consider the effects of the interactions among nitrogen, ozone, and elevated CO2 may lead to significant regional underestimates of future runoff.}, keywords = {AMBIENT OZONE, ATMOSPHERIC CO2, CLIMATE-CHANGE, ELEVATED CO2, Environmental Sciences, Geosciences, HARDWOOD FORESTS, Multidisciplinary, SOIL-MOISTURE, SOUTHERN APPALACHIAN FOREST, stomatal conductance, UNITED-STATES, WATER-USE}, author = {Felzer, Benjamin S. and Timothy W. Cronin and Melillo, Jerry M. and Kicklighter, David W. and Schlosser, C. Adam} } @article {79, title = {Indirect Emissions from Biofuels: How Important?}, journal = {Science}, volume = {326}, year = {2009}, month = {12/2009}, pages = {1397 - 1399}, abstract = {A global biofuels program will lead to intense pressures on land supply and can increase greenhouse gas emissions from land-use changes. Using linked economic and terrestrial biogeochemistry models, we examined direct and indirect effects of possible land-use changes from an expanded global cellulosic bioenergy program on greenhouse gas emissions over the 21st century. Our model predicts that indirect land use will be responsible for substantially more carbon loss (up to twice as much) than direct land use; however, because of predicted increases in fertilizer use, nitrous oxide emissions will be more important than carbon losses themselves in terms of warming potential. A global greenhouse gas emissions policy that protects forests and encourages best practices for nitrogen fertilizer use can dramatically reduce emissions associated with biofuels production.}, keywords = {biofuels, carbon loss, greenhouse gas emissions}, author = {Melillo, Jerry M. and J. Reilly and Kicklighter, David W. and Gurgel, Angelo and Timothy W. Cronin and Paltsev, S. and Felzer, Benjamin S. and Wang, X. and Sokolov, A. P. and Schlosser, C. Adam} }