VULNERABILITY AND ADAPTATION TO CLIMATE CHANGE An Assessment for the Texas Mid-Coast Arsum Pathak and Amanda Fuller Vulnerability and Adaptation to Climate Change: An Assessment for the Texas Mid-Coast National Wildlife Federation Texas Coast and Water Program PB Texas Mid-Coast Climate Assessment 1 CONTENTS Suggested Citation: Pathak, A., & Fuller, A. (2021). Vulnerability and Adaptation to Climate Change: An Assessment for the Texas Mid-Coast. Austin, TX: National Wildlife List of Tables and Figures 4 Federation. Executive Summary 5 1. INTRODUCTION: PURPOSE AND OBJECTIVES 10 Acknowledgements: The National Wildlife Federation would like to thank the Cynthia and George Mitchell Foundation for their financial support that made this work possible. State of Climate Science 11 We would also like to thank the following expert reviewers who provided comments Analytical Framework 12 and suggestions that helped improve this report: Dr. David Yoskowitz and Dr. Kateryna (Katya) Wowk (Harte Research Institute, Texas A&M University-Corpus Christi) and Management Needs and Opportunity 14 Myron Hess (Tributary Consulting). We thank Jonathan Seefeldt for the final design and 2. THE TEXAS MID-COAST 17 layout of this work. Overview of the Mid-Coast Region 17 Regional Environmental Assets 17 Cover image: A whooping crane in the Aransas National Wildlife Refuge along the Texas Mid-Coast. Photo by Kaila Drayton, National Wildlife Federation. Regional Socio-economic Assets 18 3. CLIMATE CHANGE PROJECTIONS FOR THE MID-COAST 20 All photos unless otherwise noted are by Kaila Drayton, National Wildlife Federation. Sea Level Rise and Inundation Regimes 20 Coastal Storms and Storm Surge 29 Extreme Temperature and Precipitation 32 4. ENVIRONMENTAL, SOCIAL, AND ECONOMIC IMPACTS 34 Projected Changes to Coastal Habitats 35 Implications for Whooping Cranes and Other Wildlife Species 40 Projected Changes to Water Quantity and Quality 42 Impacts on Key Economic Sectors 43 5. SOCIAL VULNERABILITY 46 Population Changes 48 Additional Social Vulnerability Considerations 48 6. ADAPTATION PLANNING 50 Advancing Ecosystem Restoration and Adaptation Goals 51 Adaptation Assessment Tools and Resources 53 7. FUTURE ACTION AND POLICY RECOMMENDATIONS 56 National Wildlife Federation References 59 Texas Coast and Water Program Appendices 64 LIST OF FIGURES EXECUTIVE SUMMARY Figure 1. A typical framework for vulnerability and adaptation assessments. 13 Figure 2. Geographic scope of this assessment. 14 In a time of increasing climate variability, local leaders and Figure 3. Overview of environmental assets. 19 decision-makers in the Mid-Coast need to account for emerging Figure 4. Inundation caused by four different scenarios of sea level rise. 22 environmental, social, and economic impacts. Figure 5. National Wildlife Refuges inundated by an intermediate low scenario of The purpose of this assessment is to equip local leaders and decision-makers in sea level rise. 24 the Texas Mid-Coast with locally relevant information about the area’s future Figure 6. Wildlife Management Areas inundated by an intermediate low scenario related to climate change impacts, enabling them to make greater investments in of sea level rise. 25 natural assets to shore up coastal environments for wildlife, local economies, and protection of their communities. The objectives of this assessment are threefold: Figure 7. Key areas inundated by an intermediate low scenario of sea level rise. 26 1) to provide the latest information regarding climate change-related risks to the Texas Mid-Coast, 2) to examine the impacts of climate change on key socio- Figure 8. Key areas inundated by an intermediate scenario of sea level rise. 27 economic and environmental assets in the region and, 3) to explore the adaptation planning, including funding mechanisms for nature-based projects, that can be Figure 9. Increase in inundation regimes in the Rockport-Fulton coastline with an increase in sea level rise. 28 utilized to address these risks. The Texas Mid-Coast is an ecologically unique transition zone with a combination Figure 10. Changes in storm surge caused by a Category 2 hurricane. 30 of fresh and salt wetlands surrounded by shallow bays and a low salinity Figure 11. Changes in storm surge caused by a Category 2 hurricane in environment. These productive ecosystems attract several critical species of Matagorda Bay. 31 aquatic and terrestrial wildlife such as whooping cranes, migratory waterfowl, Kemp’s Ridley sea turtles, among others. In addition to serving as habitats, these Figure 12. Days with min temperature below 32°F and max temperature above 95°F. 33 ecosystems in the Mid-Coast region also provide vital benefits to the surrounding coastal communities, including recreation, employment, flood protection, and Figure 13. Land use changes. 36 carbon sequestration, playing an integral role in the socio-economic development of these areas. The nearby coastal towns, with numerous recreational opportunities, Figure 14. Land use changes in Aransas NWR. 37 further enhance the economic and cultural importance of the Mid-Coast region. Figure 15. Land use changes in Guadalupe Delta WMA. 38 The Texas Mid-Coast, however, is highly vulnerable to coastal hazards that are Figure 16. Land use changes in Matagorda Bay. 39 expected to become more frequent and severe in the face of a changing climate. The region is expecting greater than the global average increase in sea level rise Figure 17. Social vulnerability rating for study area. 47 due to other non-climatic processes such as artificial groundwater and oil/gas extraction that enhance vertical land subsidence. Combined with an increase in LIST OF TABLES storm surge events, the coastal inundation and flooding pose direct challenges to the built and natural infrastructure of the region. The macroclimatic drivers Table 1. Examples of optimum temperature and salinity ranges for two common of changes in temperature and precipitation extremes further increase the estuary-dependent fishes in the Mid-Coast. 44 vulnerability of ecosystems with spillover effects on the dependent species and Table 2. Current and future population projections. 48 coastal communities. The expected future growth and development in the region, compounded with climate variability, will lead to changes in coastal habitats, Table 3. Social vulnerability indicators. 49 freshwater inflows, and other socio-economic implications. Table 4. Examples of projects funded from the Deepwater Horizon Oil Spill. 52 This assessment distills the larger context of coastal risks down to a localized understanding of the Mid-Coast region’s exposure for present and future threats Table 5. Examples of major federal and state level funding opportunities for nature-based projects. 55 posed by climate change to people and wildlife. It considers a full range of scientifically plausible outcomes using a combination of climate change modeling 4 Texas Mid-Coast Climate Assessment Executive Summary 5 tools, geospatial tools, literature reviews, and publicly available climate and non- climate related datasets to gain a comprehensive understanding of vulnerabilities of Socio-economic and the region. Some of the key findings from this assessment are as follows: Environmental Impacts Projected changes to coastal habitats and wildlife: As much as 21% of land Climate Change Projections in the Texas Mid-Coast is expected to be converted to open water by the end of the century, with the erosion of about 56% of freshwater and Exposure wetlands and conversion of tidal wetlands in Guadalupe Delta Sea level rise: An intermediate low sea level rise scenario (3 feet) will lead to to open water. Tidal wetlands in the barriers islands of widespread inundation to critical areas such as Matagorda Island unit of Aransas Aransas NWR are also expected to erode National Wildlife Refuge (NWR), half of the Big Boggy NWR, majority of San and convert to open water. The Bernard NWR, and Mad Island Wildlife Management Area (WMA). Roads resulting loss in crucial habitat and infrastructure at the coastal towns of Rockport and Aransas Pass will face will be consequential for whooping cranes and inundation. The shallow land between Guadalupe Bay and Hynes Bay will be lost, migratory waterfowls. Loss of saltwater wetlands at Big resulting in an intrusion of saltwater in the nearby lakes, bayous, and Guadalupe Boggy NWR will also lead to disruptions in birding and River streams that flows to the bay. In Jackson, an intermediate low sea level rise nesting sites for thousands of ducks and geese. will lead to the intrusion of saltwater into the lower Lavaca River basin and other Projected changes to water quantity and quality: Guadalupe, San Antonio, small creeks that empty in Lavaca Bay. Sea level rise at an intermediate level (5 Colorado, and Lavaca Rivers are already showing impaired water quality and feet) will also pose damages to the parts of Aransas NWR located in Calhoun, and declining 7-day minimum flows. Freshwater inflows from upstream rivers will infrastructure located on the coastal strip of Port Lavaca and Port O’Connor. Sea further impact the estuaries and bays in the Mid-Coast region. Long-term water level rise will also increase high tide flooding from seven flood days at present to quality trends in Matagorda Bay and Lavaca Bay indicate an increase in salinity by 60-160 per year by mid-century. an average 0.3/year in the last 20 years. Storm surge: Most of Matagorda Island WMA and Matagorda Peninsula and part Key economic sectors: About 44 critical