AMS Climate Change Audio - Environmental Science Seminar Series (ESSS) - Impacts of Recent Climate Change: Current Responses and Future Projections for Wild Ecosystems

Impacts of Recent Climate Change: Current Responses and Future Projections for Wild Ecosystems

10/13/08 • 78 min

AMS Climate Change Audio - Environmental Science Seminar Series (ESSS)

Observed changes in natural systems, largely over the past century, indicate a clear global climate change signal. Even in the face of apparently dominating forces, such as direct, human-driven habitat destruction and alteration, this climate fingerprint implicates global climate change as a new and important driving force on wild plants and animals. Patterns across taxonomic groups are remarkably similar. Large poleward and upward range shifts associated with recent global climate change have been documented in a diversity of species. Likewise, significant trends towards earlier spring events have been documented in plants and animals across North America, Europe and Asia. These changes in species’ distributions and timing have been linked with regional climate warming for many species based on basic research and on long-term historical records. Our recent estimate is that about half of all wild species have responded to regional warming trends of 1-3° C over the past century, with strongest responses over the past 30 years. In the Third Assessment Report of IPCC (2001), we predicted that species restricted to extreme environments, such as mountaintops, the Arctic and Antarctic, would be most sensitive to small levels of warming and, indeed, these areas are showing the first signs of species declines and extinctions. Range-restricted species, particularly polar and mountaintop species, are showing severe range contractions in response to recent climate change. Tropical coral reefs and sea ice specialists have been most negatively affected, with indications that cloud forest amphibians are also highly vulnerable. New analyses indicate large differences in magnitude of spring advancement between major taxonomic groups, suggesting that normal interactions among species, such as flowers and the insects that pollinate them may become disrupted. Evolutionary adaptations to warmer conditions have occurred at the local, population level, but observed genetic shifts are limited. There is no indication that novel traits are appearing that would allow species to exist under more extreme climatic conditions than they currently live in. Dr. Parmesan’s early research spanned multiple aspects of the behavior, ecology and evolution of insect/plant interactions in natural systems. Since 1992, however, the focus of her work has been on biological impacts of anthropogenic climate change in natural systems. Her field work has focused on documenting continental-scale range shifts of butterfly species across both North America and Europe. Her more recent research has concentrated on global-scale syntheses of biological responses to climate change across all taxonomic groups. These syntheses have documented the global nature of climate change impacts, spanning all living organisms from microbes to charismatic animals in terrestrial, freshwater and marine systems. The intensification of global warming as an international issue led Dr. Parmesan into the interface of policy and science. She has given presentations for White House and Congressional representatives, has been involved in several U.S. and international assessments of climate change impacts, and has provided formal testimonies for the US House Select Committee on Energy Independence and Global Warming, as well as the Texas Senate Natural Resources Committee. She has also been active in climate change programs for many international conservation organizations, such as IUCN (the International Union for the Conservation of Nature), the WWF (World Wildlife Fund), and the National Wildlife Federation, and served on the Science Council of the Nature Conservancy. She was a Lead Author and Contributing author of the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (2001), as well as Reviewer and Co-author of the Uncertainty Guidance Report for the IPCC Fourth Assessment Report (2007). IPCC and its participants were awarded the Nobel Peace Prize in 2007.

Previous Episode

Accelerating Atmospheric CO2 Growth from Economic Activity, Carbon Intensity, and Efficiency of Natural Carbon Sinks

The increase in atmospheric carbon dioxide (CO2) is the single largest human perturbation of the climate system. Its rate of change reflects the balance between human-driven carbon emissions and the dynamics of a number of terrestrial and ocean processes that remove or emit CO2. It is the long term evolution of this balance that will determine to a large extent the speed and magnitude of climate change and the mitigation requirements to stabilize atmospheric CO2 concentrations at any given level. Dr. Canadell will present the most recent trends in global carbon sources and sinks, updated for the first time to the year 2007, with particularly focus on major shifts occurring since 2000. Dr. Canadell’s research indicates that the underlying drivers of changes in atmospheric CO2 growth include: i) increased human-induced carbon emissions, ii) stagnation of the carbon intensity of the global economy, and iii) decreased efficiency of natural carbon sinks. New Estimates of Carbon Storage in Arctic Soils and Implications in a Changing Environment The Arctic represents approximately 13% of the total land area of the Earth, and arctic tundra occupies roughly 5 million square kilometers. Arctic tundra soils represent a major storage pool for dead organic carbon, largely due to cold temperatures and saturated soils in many locations that prevent its decomposition. Prior estimates of carbon stored in tundra soils range from 20-29 kg of soil organic carbon (SOC) per square meter. These estimates however, were based on data collected from only the top 20-40 cm of soil, and were sometimes extrapolated to 100 cm. It is our understanding that large quantities of SOC are stored at greater depths, through the annual freezing and thawing motion of the soils (cryoturbation), and potentially frozen in the permafrost. Recent detailed analysis of Arctic soils by Dr. Epstein and his colleagues found that soil organic carbon values averaged 34.8 kg per square meter, representing an increase of approximately 40% over the prior estimates. Additionally, 38% of the total soil organic carbon was found in the permafrost. Past, Present and Future Changes in Permafrost and Implications for a Changing Carbon Budget Presence of permafrost is one of the major factors that turn northern ecosystems into an efficient natural carbon sink. Moreover, a significant amount of carbon is sequestered in the upper several meters to several tens of meters of permafrost. Because of that, the appearance and disappearance of permafrost within the northern landscapes have a direct impact on the efficiency of northern ecosystems to sequester carbon in soil, both near the ground surface and in deeper soil layers. Recent changes in permafrost may potentially transform the northern ecosystems from an effective carbon sink to a significant source of carbon for the Earth’s atmosphere. Additional emissions of carbon from thawing permafrost may be in the form of CO2 or methane depending upon specific local conditions. Dr. Romanovsky will present information on changes in terrestrial and subsea permafrost in the past during the last glacial-interglacial cycle and on the most recent trends in permafrost in the Northern Hemisphere. He will further discuss the potential impact of these changes in permafrost (including a short discussion on potential changes in methane gas clathrates) on the global carbon cycle. Dr. Romanovsky’s research suggests that permafrost in North America and Northern Eurasia shows a substantial warming during the last 20 to 30 years. The magnitude of warming varied with location, but was typically from 0.5 to 2°C at 15 meters depth. Thawing of the Little Ice Age permafrost is on-going at many locations. There are some indications that the late-Holocene permafrost started to thaw at some specific undisturbed locations in the European Northeast, in the Northwest and East Siberia, and in Alaska.

Next Episode

Two Engineering Measures to Reduce Global Warming: Injecting Particles into the Atmosphere and "Clean" Coal

Managing Incoming Solar Radiation Largely out of concern that society may fall short of taking large and rapid enough measures to effectively contain the problem of global warming, two prominent atmospheric scientists - Paul Crutzen, who won a Nobel Prize in chemistry in 1995, and Tom Wigley, a senior scientist at the National Center for Atmospheric Research - published papers in 2006, suggesting that society might consider using geoengineering schemes to identify a temporarily "fix" to the problem. The concept of geoengineering - deliberately using technology to modify Earth's environment - has been discussed in the context of climate change since at least 1960. Over the years, proposals have included everything from carbon sequestration through ocean fertilization to damming the oceans. Crutzen and Wigley argued that geoengineering schemes, if done continuously, could reduce global warming enough to buy society time to address mitigation. However, geoengineering schemes may not be the answer. And in fact, such measures have the potential to create more problems than they solve. In particular, Crutzen and Wigley focused on blocking incoming solar radiation, an idea that has generated much interest in the press and the scientific community. Nature offers an example of how to do this. Volcanic eruptions cool the climate for up to a couple of years by injecting precursors to sulfate aerosol particles into the stratosphere, which has the effect of temporarily blocking incoming sunlight. It is true that volcanic eruptions cool the climate, but their effects are not innocuous, and should serve as a warning to society to be very cautious about deploying such geoengineering “solutions” without careful and considered evaluation beforehand. Among other things, the particles from volcanic eruptions also cause ozone depletion. Clean Coal Technology and Future Prospects Clean coal technologies are real, commonly used in commercial industrial gasification and likely essential to reduce CO2 due to the fast growing use of coal worldwide, especially in China. Commercial example of clean coal technology in the USA is the 25 year-old coal to synthetic natural gas (SNG) plant in North Dakota where all of the CO2 is captured and most is geologically storage for use in enhanced oil recovery (EOR) in Canada. The key issue is expanding clean coal technologies into coal-based electric power generation. This expansion presents additional challenges - more technology options and higher cost of CO2 capture than for industrial gasification. This also requires large-scale demonstration of all three CO2 capture technology options: pre, post and oxygen combustion. In time, the CO2 capture and storage costs will be reduced by both “learning by doing” and developing advanced technologies already moving in to small-scale demonstrations. Biographies Dr. Alan Robock is a Distinguished Professor of atmospheric science in the Department of Environmental Sciences at Rutgers University and the associate director of its Center for Environmental Prediction. He also directs the Rutgers Undergraduate Meteorology Program. He graduated from the University of Wisconsin, Madison, in 1970 with a B.A. in Meteorology, and from the Massachusetts Institute of Technology with an S.M. in 1974 and Ph.D. in 1977 in Meteorology. Before graduate school, he served as a Peace Corps Volunteer in the Philippines. He was a professor at the University of Maryland, 1977-1997, and the State Climatologist of Maryland, 1991-1997, before coming to Rutgers. Dale Simbeck joined SFA Pacific in 1980 as a founding partner. His principal activities involve technical, economic and market assessments of energy and environmental technologies for the major international energy companies. This work includes electric power generation, heavy oil upgrading, emission controls and synthesis gas production plus utilization.