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- Author or Editor: Jeffrey A. Hicke x
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Abstract
Croplands cover large areas of the globe and contribute significantly to the global carbon cycle. However, like other ecosystems, limited information exists on spatially explicit, ground-based estimates of carbon fluxes. In this study, county-level cropland area and harvest information reported in the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS) from 1972 to 2001 was utilized to calculate the temporal behavior of net primary production (NPP) for croplands across the United States. Production data for individual crops were converted to estimates of NPP using crop-specific factors. Because NASS does not include all crops of interest during all years, only a crop type in a county estimate was included if the entire time series was complete. Incomplete reporting occurred primarily with hay. Trends in crop area, NPP, and total production (area times NPP) exhibited significant spatial variation. The largest increases in production occurred in the Midwest, Great Plains, and Mississippi River Valley regions. Cropland area exhibited a range of trends from large percent increases in counties across the Great Plains and the West to decreases across the South. Generally, NPP increased in counties throughout the United States and for the country as a whole. It was estimated that total coterminous cropland production increased during 1972–2001 from 0.37 to 0.53 Pg C yr−1, a 40% increase over 1972 values. Since total cropland area changed little during the 30-yr period, production increases were driven primarily by gains in NPP.
Abstract
Croplands cover large areas of the globe and contribute significantly to the global carbon cycle. However, like other ecosystems, limited information exists on spatially explicit, ground-based estimates of carbon fluxes. In this study, county-level cropland area and harvest information reported in the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS) from 1972 to 2001 was utilized to calculate the temporal behavior of net primary production (NPP) for croplands across the United States. Production data for individual crops were converted to estimates of NPP using crop-specific factors. Because NASS does not include all crops of interest during all years, only a crop type in a county estimate was included if the entire time series was complete. Incomplete reporting occurred primarily with hay. Trends in crop area, NPP, and total production (area times NPP) exhibited significant spatial variation. The largest increases in production occurred in the Midwest, Great Plains, and Mississippi River Valley regions. Cropland area exhibited a range of trends from large percent increases in counties across the Great Plains and the West to decreases across the South. Generally, NPP increased in counties throughout the United States and for the country as a whole. It was estimated that total coterminous cropland production increased during 1972–2001 from 0.37 to 0.53 Pg C yr−1, a 40% increase over 1972 values. Since total cropland area changed little during the 30-yr period, production increases were driven primarily by gains in NPP.
Abstract
Climate change is often perceived as controversial in the public’s view. One meaningful way scientists can address this problem is to engage with the public to increase understanding of climate change. Attendees of scientific conferences address climate change within meetings yet rarely interact with the public as part of conference attendance. Here, we describe outreach (sending experts into the community) and inreach (bringing the public to a conference) activities at the 2015 Northwest Climate Conference in Idaho that were designed to increase the local community’s understanding of climate change and foster interaction between scientists and the public. Conference attendees volunteered to visit community schools and civic groups to give presentations and engage in a discussion on climate change. We designed a well-attended evening plenary session for the public that featured an experienced speaker who described local climate change impacts important to the community. Local high school students attended the conference, and several were mentored by conference attendees. We reached an estimated 1,000 students and 500 other members of the public in person and many others via advertising and newspaper articles. Keys to our success were local contacts with excellent connections to schools, civic organizations, local government officials, interest groups, and a pool of motivated, enthusiastic conference attendees who were already traveling to the area. We encourage other conference organizers to consider these activities in their future meetings to increase public knowledge of climate change, particularly given the urgency of action needed to limit future climate change and its impacts.
Abstract
Climate change is often perceived as controversial in the public’s view. One meaningful way scientists can address this problem is to engage with the public to increase understanding of climate change. Attendees of scientific conferences address climate change within meetings yet rarely interact with the public as part of conference attendance. Here, we describe outreach (sending experts into the community) and inreach (bringing the public to a conference) activities at the 2015 Northwest Climate Conference in Idaho that were designed to increase the local community’s understanding of climate change and foster interaction between scientists and the public. Conference attendees volunteered to visit community schools and civic groups to give presentations and engage in a discussion on climate change. We designed a well-attended evening plenary session for the public that featured an experienced speaker who described local climate change impacts important to the community. Local high school students attended the conference, and several were mentored by conference attendees. We reached an estimated 1,000 students and 500 other members of the public in person and many others via advertising and newspaper articles. Keys to our success were local contacts with excellent connections to schools, civic organizations, local government officials, interest groups, and a pool of motivated, enthusiastic conference attendees who were already traveling to the area. We encourage other conference organizers to consider these activities in their future meetings to increase public knowledge of climate change, particularly given the urgency of action needed to limit future climate change and its impacts.
Abstract
Bark beetle outbreaks have killed billions of trees and affected millions of hectares of forest during recent decades. The objective of this study was to quantify responses of surface energy and hydrologic fluxes 2–3 yr following a spruce beetle outbreak using measurements and modeling. The authors used observations at the Rocky Mountains Glacier Lakes Ecosystem Experiments Site (GLEES), where beetles killed 85% of the basal area of spruce from 2005–07 (prebeetle) to 2009/10 (postbeetle). Observations showed increased albedo following tree mortality, more reflected solar radiation, and less net radiation, but these postoutbreak radiation changes are smaller than or comparable to their annual preoutbreak variability. The dominant signals from observations were a large reduction (27%) in summer daytime evaporation and a large increase (25%) in sensible heat fluxes. Numerous Noah LSM with multiparameterization options (Noah-MP) simulations incorporating beetle-caused tree mortality effects were conducted to assess their impact on the surface hydrological cycle components that were not directly observed. Model results revealed substantial seasonal variations: more spring snowmelt and runoff, less spring–summer transpiration, and drier soil in summer and fall. This modeled trend is similar to observed runoff changes in harvested forests where reduced forest density resulted in more spring snowmelt and annual water yields. Model results showed that snow albedo changes due to increased litter cover beneath killed trees altered the seasonal pattern of simulated snowmelt and snow water equivalent, but these changes are small compared to the effect of leaf loss. This study highlights the need to include the transient effects of forest disturbances in modeling land–atmosphere interactions and their potential impacts on regional weather and climate.
Abstract
Bark beetle outbreaks have killed billions of trees and affected millions of hectares of forest during recent decades. The objective of this study was to quantify responses of surface energy and hydrologic fluxes 2–3 yr following a spruce beetle outbreak using measurements and modeling. The authors used observations at the Rocky Mountains Glacier Lakes Ecosystem Experiments Site (GLEES), where beetles killed 85% of the basal area of spruce from 2005–07 (prebeetle) to 2009/10 (postbeetle). Observations showed increased albedo following tree mortality, more reflected solar radiation, and less net radiation, but these postoutbreak radiation changes are smaller than or comparable to their annual preoutbreak variability. The dominant signals from observations were a large reduction (27%) in summer daytime evaporation and a large increase (25%) in sensible heat fluxes. Numerous Noah LSM with multiparameterization options (Noah-MP) simulations incorporating beetle-caused tree mortality effects were conducted to assess their impact on the surface hydrological cycle components that were not directly observed. Model results revealed substantial seasonal variations: more spring snowmelt and runoff, less spring–summer transpiration, and drier soil in summer and fall. This modeled trend is similar to observed runoff changes in harvested forests where reduced forest density resulted in more spring snowmelt and annual water yields. Model results showed that snow albedo changes due to increased litter cover beneath killed trees altered the seasonal pattern of simulated snowmelt and snow water equivalent, but these changes are small compared to the effect of leaf loss. This study highlights the need to include the transient effects of forest disturbances in modeling land–atmosphere interactions and their potential impacts on regional weather and climate.
