Climate Change Effects on Natural Resources FOR 797, Fall 2007 John Stella, [email protected] This seminar examined the evidence of global climate change, integrating scientific analyses and their perceptions in the media. Weekly class discussions focused on different physical, biological, Projected number of snow-covered days (Image: Union of Concerned Scientists) and social facets of the climate change story. Readings were drawn from primary climate change research (Nature, Science), global and regional analyses (IPCC 4th Assessment Report, New England Regional Assessment), news accounts, and the popular science literature (e.g. Tim Flannery’s The Weather Makers). For the final ‘White Paper’, students summarized the state of knowledge about a particular area, the perception of the issue in the media and popular literature, and the implications for policymakers. (Image: IPCC 2007) Muir Glacier, Alaska, 1941 and 2004 (Images: William Field, Bruce Molnia, USGS) FOR 797 Climate Change Effects on Natural Resources, Fall 2007 Final White Papers Table of Contents Chapter Subject Area Author Page 1 Overview: the physical science basis Katherina Searing 3 2 Paleoclimate and physical changes to the Matt Distler 10 atmosphere 3 Changes to the oceans Kacie Gehl 15 4 Changes to the cryosphere (snow, ice and frozen Brandon Murphy 19 ground) 5 Global and regional climate models Anna Lumsden 26 6 Impacts to freshwater resources Nidhi Pasi 31 7 Carbon sinks and sequestration Ken Hubbard 34 8 Impacts to coastal regions Juliette Smith 38 9 Effects on biodiversity and species ranges Lisa Giencke 43 10 Effects on species’ phenology Laura Heath 47 11 Human health, crop yields and food production Judy Crawford 52 12 Media perceptions of climate change: the Northeast Kristin Cleveland 57 case study 13 Mitigation measures Tony Eallonardo 62 INTRODUCTION Overview: the physical science Climate change is an extremely basis and expected impacts complex issue. Due to this complexity, policymakers required an objective and Katherina Searing comprehensive source of information regarding this topic. The Intergovernmental Panel on EXECUTIVE SUMMARY Climate Change (IPCC) was established by the The fourth assessment report (AR4) of World Meteorological Organization (WMO) and the Intergovernmental Panel on Climate Change the United Nations Environmental Programme (IPCC) is the most comprehensive report of (UNEP) in 1988. The stated goal of the IPCC is climate change science to date. This report states to assess the scientific, technical and socio- that there is clear evidence that global economic information pertaining to the temperatures have increased 0.74°C and sea understanding of the risks associated with levels have increased 17 cm in the 20th century. anthropogenic climate change, its potential By the end of the 21st century, global impacts and the mitigation strategies available. temperatures are predicted to increase between This international organization does not conduct 1.8 to 4.0°C and sea levels are expected to rise research nor does it collect climate related data. between 18 and 59 cm. Most importantly, this They rely on peer reviewed scientific and latest synthesis of climate change science reports, technical literature that has been published. The with 90% confidence, that human activities have IPCC also does not prescribe policy. caused a warming of the planet. The IPCC published their fourth This new report also highlights some of the assessment report (AR4) in 2007. Contributions likely impacts of increased temperatures and sea to this report were made by 1250 lead and level rise on six different sectors: freshwater contributing authors from more than 130 resources and their management; ecosystems, countries and the report was reviewed by more their properties, goods and services; food, fiber than 2500 scientific experts.1 This latest report and forest products; coastal systems and low includes several advancements over the previous lying areas; industry, settlement and society; and reports (most recently the third assessment report human health. Additionally, some regions of the [TAR] in 2001)2, such as tighter estimates and a world are identified as more vulnerable to the better understanding of uncertainties provided by effects of climate change, based on their substantial new data collection and research. 3 geographical location and adaptation capacity. The IPCC is currently divided it to three working The media plays an important role in the groups. Working Group I (WG I) reports on climate change arena by bringing the issue to “The Physical Basis of Climate Change,” people’s attention and by helping to shape public Working Group II (WG II) focuses on “Climate opinion. The release of the components of the Change: Impacts, Adaptation and Vulnerability,” AR4 earlier in 2007 and the publication of final and Working Group III deals with the version in November 2007, received a great deal “Mitigation of Climate Change.” The findings of media attention. of WGs I and II will be discussed here. Some scientists have expressed concerns about the findings of the IPCC due to the exclusion of some recent scientific data pertaining to the melting of glaciers and the ice sheets. The IPCC has been criticized for not 1 Chairman Pauchuri, Chairman of the IPCC Presentation: communicating these limitations clearly in the “IPCC Fourth Assessment Report: Synthesis Report” highly influential “Summary for Policymakers” Valencia, Spain. November 17, 2007. 2 documents that are utilized by decision makers. IPCC, 2001: Summary for Policymakers. In: Climate Aside from what is included in the AR4, Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the policymakers should consider the following Intergovernmental Panel on Climate Change [Houghton, when constructing policies concerning climate J.T.,Y. Ding, D.J. Griggs, M. Noguer, P.J. van der Linden, X. change: the spatial and temporal scale of climate Dai, K. Maskell, and C.A. Johnson (eds.)]. Cambridge change and its impacts, the economics of the University Press, Cambridge, United Kingdom and New prospective policies, and the security issues York, NY, USA. 3 regarding the effects of climate change. Chairman Pauchuri, Chairman of the IPCC Presentation: “Introduction to AR4” Bonn, Germany. May 12, 2007. SEARING OVERVIEW FOR 797 CLIMATE CHANGE EFFECTS ON NATURAL RESOURCES FALL 2007 STATE OF THE SCIENCE especially CO2 and CH4. A number of models have been constructed to predict how surface Working Group I: The Physical Science temperatures would change with a continued Basis increase in greenhouse gases. These models Perhaps the most important statement in project increases of about 0.2°C are over the next the recent report of WG I is that “warming of the two decades for a range of greenhouse gas climate system is unequivocal.” 4 , This emission scenarios. Projections for the year declaration is based on direct observations of 2100 range from increases of 1.8 to 4.0°C, increased global air and ocean temperatures, depending upon the concentration of greenhouse rising global sea level and reductions in snow gases released into the atmosphere. Sea level is and ice in the Northern hemisphere. The 100- projected to increase by 18 to 59 cm by the end year trend of increasing global average air of the 21st century. 6 The upper sea level temperature was approximately 0.74°C, up from projection has decreased since the TAR from 88 0.60°C, given in the TAR. This report also cm to 59 cm. Even if the greenhouse gas stated that the average ocean temperatures have concentrations could be stabilized, further increase to depths up to 3000 m. This heating warming and sea level rise would continue for leads to seawater expansion and consequently centuries due to the effects of the greenhouse sea level rise. Global average sea level rose on gases already present in the atmosphere. average 1.8 mm per year from 1861 to 2003 and there is some evidence that the rates of sea level Working Group II: Impacts, Adaptation rise are increasing.5 Sea levels increased a total and Vulnerability th of 17 cm during the 20 century. Reasons for the The major findings of WG II in the AR47, increased sea level include the melting of the are that the impacts of climate change are glaciers, ice caps and polar ice sheets. already occurring and they are now detectable at 8 Warming trends have not been uniform a global scale. Potential impacts of climate across the globe. Temperatures in the Arctic change were identified in six sectors: have increased at almost twice the global average 1) Freshwater resources and their management rate over the past century and the sea ice extent in the Arctic has shrunk by 2.7% per decade. Changes in average river runoff and The last time the Polar Regions were warmer water availability than at present, for an extended period of time Drought affected areas will expand (125,000 years ago), the melting of polar ice led to 4 to 6 m of sea level rise. Information gained Increased frequency of heavy from examining the paleoclimatic record informs precipitation events us that the warming that has occurred in the past Increased flood risk 50 years is unusual in the past 1,300 years. 2) Ecosystems, their properties, goods and This observed warming is due to both services natural and anthropogenic forces. Only climate models that incorporate both natural and Net carbon uptake will peak prior to anthropogenic factors can explain the changes in 2050 and then weaken or reverse surface temperatures over the past 100 years. Foremost among these anthropogenic factors is the increased concentration of greenhouses gases, 6 The predicted sea level rise is for the years 2090-2099 4 IPCC, 2007: Summary for Policymakers. In: Climate relative to 1980-1999. Ibid. p 13. Change 2007: The Physical Science Basis. Contribution of 7 IPCC, 2007: Summary for Policymakers.