The tree line is a climatic boundary, however its ability to respond to changing climate seems to be constrained by the spatial distribution of trees at the leading edge; compared to abrupt or krummholz tree lines, diffuse tree lines are moving upslope much more readily in response to recent anthropogenic warming. Here we report on the micrometeorological processes that result from the diffuse leading edge of a moving tree line on Pikes Peak, Colorado, USA, and on the impacts these processes have on tree temperatures. We focus on the layering and movement of air in the lower 10m of the atmosphere including the height of the displacement of the zero velocity plane. Our experimental design consisted of 300m upslope transects through the tree line into the alpine tundra where we measured: (1) height of the zero plane displacement using handheld anemometers, (2) temperature of 10cm tall seedlings, 3-5m tall trees, and tundra grasses using an IR camera, (3) temperature and relative humidity at 2.5cm an 2m using Kestrel hand held weather stations, (4) the vertical atmospheric profiles using 10m towers equipped with 8 anemometers at 5 different elevations, (5) vertical movement of air using a bubble-blowing machine. Our results show that (1) the zero plane height decreased exponentially with increasing elevation (R2=0.432, N=57, p<0.0005) from approximately 25cm within the tree line to 2.5cm in the tundra above. The spatial variability of the zero plane height also decreased with elevation. (2) The temperature of small seedlings was (3) closely coupled to the ground vegetation (paired t-test t= 2.213, df=10, p=0.051),but seedlings were on average 3.88°C warmer than trees (paired t-test t= 5.808, df=10, p<0.0005), and trees were 6.1°C colder that the tundra (paired t-test t= 6.617, df=10, p<0.0005). (3) Compared to the air at 2m, the air layer at 2cm had higher temperature (+2.5°C, paired t-test t= 7.205, df=19, p<0.0005), and higher relative humidity higher (+29%, paired t-test t= 9.657, df=19, p<0.0005). (4) The vertical wind profile had a simple and smooth slow down to the zero plane at 2.5cm in the alpine tundra. However the profile was complex in all locations where trees were present: It showed an initial slow down to a very low speed at 3-4m, increase in velocity at 2m, and final slow down to the zero plane at 25cm. Qualitative and quantitative analysis of bubble movement (5) showed that the upper boundary layer was turbulent.
Part of the annual State of the Rockies Conference. Greg Zimmerman (CC class of 2006) discusses the results of the climate report card. Discussing "Climate Change in the Rockies: In Theory and On the Ground" are Roger A. Pielke, Sr., professor in the department of atmospheric science at Colorado State University; Roger Pielke, Jr., a professor in the environmental studies department at the University of Colorado; and Auden Schendler, director of environmental affairs at the Aspen Skiing Company. Recorded April 13, 2006.
The 2006 State of the Rockies Report Card continues the Rockies Project tradition of reporting key issues in this unique region of spectacular natural beauty, cultural wealth, abundant resources, and fragile environment. The Report Card includes analysis and discussion of some key issues that confront the Rockies: biodiversity, ranch economics, climate change, land conservation, and child development. Edited by Walter E. Hecox (CC professor of economics), Bryan Hurlbutt (CC class of 2004), and Caitlin O'Brady (CC class of 2005).
Program for the Colorado College State of the Rockies Conference held April 10 through April 13, 2006. Includes listings of presentations and speakers: Unveiling of the 2006 State of the Rockies Report Card, by Walter Hecox (CC professor of economics), Bryan Hurlbutt (CC class of 2004), Caitlin O'Brady (CC class of 2005); Land Conservation - Protecting Unique Landscapes and Habitats, with Tass Kelso (CC professor of biology), Jared Kapela (CC class of 2006), Bruce Runnels, Charles Bedford, Chris Pague; Preserving Biodiversity - Addressing Threatened, Endangered, and Invasive Species, with Walter Hecox, Joanna Prukop, Amanda Strauss (CC class of 2006), Randy Simmons, Anna Sher; Ranching in the Rockies - Threats and Signs of Hope, with Jack Wold (CC class of 1975), Andrew Yarbrough (CC class of 2006), Dan Dagget, Doc and Connie Hatfield, Dale Lasater, Brian Rohter, John Schiffer (CC class of 1967); Conservation in Action - Success Stories, with Caitlin O'Brady, John Fielder, Sydney Macy; Environmental Justice - Equally Protecting All Humans and the Environment, with Wade Roberts (CC professor of sociology), Angela Banfill (CC class of 2006), Jean Belille, William Snape III, Liam Downey, Kathryn Mutz, Sally L. Palmer; New Approaches to Governing the Rockies - Can Our Region's Political Voices Be Heard? with Tom Cronin (CC professor of political science), Chris Jackson (CC class of 2006), Daniel Kemmis, Michael Stratton, Sandy Buffett (CC class of 1991); Climate Change - What Happens in a Warmer Rockies, with Matthew Reuer, Gregory Zimmerman (CC class of 2006), Roger A. Pielke Sr., Roger Pielke, Jr., Auden Schendler; Rockies' History Comes Alive - John Wesley Powell Returns, with Anne Hyde (CC professor of history), Clay Jenkinson.
Presents list of lectures for the 2010-11 Colorado College State of the Rockies speaker series: Are the trees falling? How pine beetle and wildfire shape Rocky Mountain forests / Dave Theobald, Jason Sibold -- Big burn: the lasting legacy of the nation’s largest wildfire / Timothy Egan -- The White is turning red: case study of the White River National Forest / Tony Dixon, Jan Burke -- Colorado State Government & forests: controversy over health, climate and roads / Mike King, Nolan Doesken -- Environmental groups and public involvement in forest health decisions / Suzanne Jones, Sloan Shoemaker -- Private solutions: ownership, philosophy, management.
Human induced climate change is expected to increase temperatures in inter-continental regions of Northern America from 2˚ to 4.5˚C. This rapid change alters resource availability and places new stressors on vegetation. In this study I compare plastic avoidance and tolerance responses for two contrasting long-lived forb species (H. quinquenervis and E. speciosus). My experimental site was located in a Colorado subalpine meadow where overhead heaters have warmed vegetation and soil for the past 20 years to mimic expected climate changes. In warmed plots, H. quinquenervis has increased in abundance, size and flowering rate while E. speciosus has decreased in these parameters. Therefore, I expected to observe more tolerance responses in H. quinquenervis than in E. speciosus. To test this hypothesis I assessed photosynthetic CO2 assimilation rates, biochemical photosynthetic limitations and water use efficiency (WUE). Relative to control plots, CO2 assimilation rates were lower in heated plots for both species. However, there were no differences in the photosynthetic limitations derived from these A/Ci curves for treatment, species or their interaction. Lack of significance in these parameters is possibly related to the small sample size. WUE, or carbon gained per unit of water lost, had significantly greater values for E. speciosus than for H. quinquenervis. The ability of H. quinquenervis to maintain low WUE rates under potential water stress may be associated with its root structure as well as its ability to respond through tolerance mechanisms. This study reveals the importance of different stress responses as they relate to species success in a changing climate. By understanding the mechanisms behind differential species success, we can better predict and mitigate future climate changes.
Global climate change is quite possibly the most serious challenge that faces us today. Consumers and businesses alike are thinking more seriously about their environmental impact and what they can do to reduce their carbon footprint. One industry uniquely tied to the environment and concerned with its well-being is the ski industry and one way to achieve this reduction is through carbon offsets. Using data collected through a contingent valuation study regarding consumer behavior, this thesis analyzes the factors that affect consumers' willingness to pay (WTP) for carbon offsets in the ski industry. The study finds that age, gender, and climate knowledge are highly influential on WTP, and that the use of tax credits as an incentive provides the greatest increase in consumer WTP.
The United Nations negotiations on climate change have focused their attention on a set of policies for Reducing Emissions from Deforestation and Degradation (REDD+). This paper explores the potential of REDD+ to reduce CO2 emissions and protect tropical biodiversity. The study uses ArcGIS to model forest areas under threat of deforestation in 59 tropical developing countries. A constrained linear optimization model, implemented with linear optimization software, is used to construct a Conservation Possibilities Frontier (CPF). The CPF shows the potential of REDD+ to achieve emission reductions and species conservation under limited budgets. I use linear optimization to construct marginal abatement cost curves under various policy scenarios and estimate the costs of generating biodiversity co-benefits from REDD+. An international mechanism mainly designed to reduce emissions at least cost will provide low conservation benefits. Incorporating provisions for biodiversity co-benefits in the REDD+ framework can protect a high number of rare and threatened forest species at a relatively low cost.
With the growing concern about climate change, integrated impact assessment models (IAMs) have been developed to assess climate mitigation policies. Previous attempts to endogenize technology into regional climate policy models have assumed learning-by-doing or include a single energy sector. This study corrects for the previous limitations in a regional model of the United States and the rest of the world. A backstop technology and knowledge spillovers are added to the model to improve the model’s capacity to simulate a real policy. Each specification is then simulated under no policy (business as usual), an optimal policy, and restrictions of emissions back to 1995 levels. Since the United States has refused to ratify the Kyoto Protocol, it is particularly important to evaluate climate policies specific to the United States, like the Regional Greenhouse Gas Initiative (RGGI). This study also aims to evaluate the effectiveness the RGGI by modeling permit-funded R&D in the energy sector.
If, as many believe, the people of this world do little to address climate change and the average temperature of the world keeps rising, what will happen to our oceans, our weather, ecosystems and food supply? Cole Wilbur, Trustee and Past President of the David and Lucille Packard Foundation has been involved in venture philanthropy for over 33 years. He discusses why the Packard and Hewlett Foundations have pledged $1 billion and hope to have that matched to keep the Earth's temperature from rising no more than 2 degrees C by 2030. Part of Notable Lectures & Performances series, Colorado College. Recorded September 15, 2009.
The First Mondays Event Series is a campus-wide forum that aims to engage all members of the CC community, including students, staff, administrators and faculty. The series creates opportunities for the whole community to gather, encouraging everyone to be part of the intellectual life of the college, and facilitating discourse among students, faculty, and staff, across courses, disciplines, and divisions. This First Monday Event is titled Tourist to a Warm World: A glimpse in to the last great global greenhouse. A lecture by Kirk Johnson, PhD, vice president of research and collections and chief curator with the Denver Museum of Nature and Science. Dr Johnson studies fossil leaves to reconstruct ancient landscapes, using geological records to understand rapid contemporary trends of climate change. Earth’s climate has fluctuated between Icehouse and Greenhouse conditions, alternating between periods that sustained huge ice caps and times when there was almost no ice at all. During Greenhouse conditions, in the not-so-distance past, both Greenland and Antarctica were covered by forests! The state of Colorado preserves particularly rich records of the periods of lush vegetation and abundant water, providing a glimpse in an entirely different Planet Earth, with an environment that may help us to better understand temperature changes that are occurring in our own time. This event was sponsored by the Academic Events Committee. This lecture was presented at Colorado College, Shove Chapel, March 26, 2012.