Climate Change Trends, Vulnerabilities, and Ecosystem Carbon in Channel Islands National Park, California

Gonzalez, Patrick

Greenhouse gas emissions from human activities have caused global climate change and widespread impacts on physical and ecological systems. To assist in resource management in Channel Islands National Park (NP) under climate change, this report presents results of original spatial analyses of historical and projected climate change trends and ecosystem carbon and a review of published research on impacts and vulnerabilities. Spatial analyses of historical temperature and precipitation at 800 m spatial resolution show the changes that the area within the boundaries of Channel Islands NP has experienced. Average annual temperature from 1950 to 2010 increased at a statistically significant rate of 1.4 ± 0.6ºC (2.5 ± 1.1ºF.) per century (mean ± standard error), with the greatest increase in spring. Total annual precipitation from 1950 to 2010 increased at a rate of 38 ± 28% per century, with the greatest increase in winter, but the rates were not statistically significant. Regional and global analyses of field data that includes data from southern California have detected ecological changes that have been attributed to human climate change. At Santa Monica, the tidal gauge closest to the park shows a rise in sea level at a statistically significant rate of 14 ± 3.4 cm (6 ± 1.3 in.) per century from 1933 to 2014. Analyses of ocean waters, including those of the Pacific Ocean off California, have shown increases in sea surface temperatures and acidity, both attributable to human climate change. Regional analyses of bird counts from across the United States (US), including southern California, show that climate change shifted winter bird ranges northward at a rate of 0.5 ± 0.3 km (0.3 ± 0.2 mi.) per year from 1974 to 2004. If the world does not reduce greenhouse gas emissions, projections under the four emissions scenarios of the Intergovernmental Panel on Climate Change (IPCC) indicate annual average temperature increases for the park of up to 3.5 ± 0.8ºC (6.3 ± 1.4º F.) (mean ± standard deviation) from 2000 to 2100. Model projections show possible increases of total annual precipitation of 5-7% for the four scenarios. Published analyses for the area including the national park indicate numerous vulnerabilities to future climate change, including inundation and erosion of coastal areas, changes to gray whales, sea stars, and mussels, and potential increased mortality of endangered plants such as soft-leaved paintbrush. Above ground vegetation in the park stores an amount of carbon equivalent to the annual emissions of 24 000 ± 17 000 Americans. From 2001 to 2010, ecosystem carbon increased on one-third of the area of Santa Rosa Island and the eastern end of Santa Cruz Island, coinciding with ecosystem restoration in those areas during that time period. As a whole, the national park did not experience a statistically significant change in above ground carbon.

Climate Change Trends, Vulnerabilities, and Ecosystem Carbon in Channel Islands National Park, California

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