From the heights of Mauna Kea on Hawaiʻi Island to the depths of the Mariana Trench, from densely populated cities to sparse rural indigenous communities and uninhabited sandy atolls, the Pacific region encompasses diverse associations of peoples and places that are directly affected by changes to the atmosphere, ocean, and land. The peoples of the Pacific are among the first to observe and experience the effects of global climatic changes.
Because the Pacific region is predominantly composed of vast ocean expanses punctuated only by small, isolated emergent islands and atolls, marine processes are critical factors in the region’s climate systems, and their impacts occur here to a greater degree than in continental regions. Rates of sea-level rise in the region during the modern altimetry period exceed the global rate, with the highest increases occurring in the western North Pacific (Cazenave and Llovel, 2010; Nerem and others, 2010; Timmermann and others, 2010). The ocean has also warmed during this period. Since the 1970s, sea-surface temperature has increased at a rate of 0.13 to 0.41 °F (0.07 to 0.23 °C) per decade, depending on the location (Keener and others, 2012a). Ocean chemistry has changed during this period as well, with surface pH having dropped by 0.1 pH units (Feely and others, 2009; Doney and others, 2012).
Over the past century, air temperature has increased throughout the Pacific region. In Hawaiʻi, average temperatures increased by 0.08 °F per decade during the period 1919 to 2006, and in recent years, the rate of increase has been accelerating, particularly at high elevations (Giambelluca and others, 2008). In the western North Pacific, temperatures also increased over the past 60 years (Lander and Guard, 2003; Lander, 2004; Lander and Khosrowpanah, 2004; Kruk and others, 2013), with a concurrent warming trend in the central South Pacific since the 1950s (Australian Bureau of Meteorology and CSIRO, 2011).
