Climate Change in the Pacific Islands
In the Pacific Islands, we are collaborating with the Hawai`i Conservation
Alliance and climate researchers at the University of Hawai`i’s International
Pacific Research Center, the Department of Geography and many other
Departments, NOAA, USGS, and many others. These collaborations are
aimed at assessing historic climate trends and promoting the development
of regional climate models that will aid in estimating future climate
conditions in the Pacific Islands.
The 17th annual Hawai‘i Conservation Conference attracted over 1,100
people in July, 2009, with its various lectures, symposia, and other
presentations focusing on the theme “Hawai‘i in a Changing Climate.”
Climate change presents Pacific Islands with unique challenges including
rising temperatures, sea-level rise, contamination of freshwater resources
with saltwater, coastal erosion, an increase in extreme weather events,
coral reef bleaching, and ocean acidification. Projections for the
rest of this century suggest continued increases in air and ocean
surface temperatures in the Pacific, increased frequency of extreme
weather events, and increased rainfall during the summer months and
a decrease in rainfall during the winter months.
El Niño-Southern Oscillation (ENSO), resulting from the large-scale global interaction of atmospheric and oceanic circulation, is an inter-annual climatic phenomenon (approximately 3-8 years) that creates temperature fluctuations in the tropical surface waters of the Pacific Ocean. ENSO events can have a significant impact on ecosystems due to changing surface winds, ocean currents, water temperatures, ocean nutrient availability, storm frequency and magnitude, etc. ENSO is a naturally occurring phenomenon, but there is uncertainty regarding how global warming and the associated climate changes will impact the frequency, magnitude, and the duration of this cycle and how that will in turn affect ecosystems. For example, changes to established ocean circulation patterns can have significant effects on biological connectivity for marine organisms, the distribution of species, biological productivity, and marine debris issues. Changes in storm events can impact corals directly from wave damage or more indirectly from runoff and sediment deposition. (Baker and Smith, 2008)
Most island communities in the Pacific have limited sources of freshwater. Many islands depend on freshwater lenses below the surface, which are recharged by precipitation. Changes in precipitation, such as the decreases currently observed in Hawai’i, are thus a cause of great concern. Sea-level rise also affects islands’ water supplies by causing saltwater to contaminate the freshwater lens and by causing an increased frequency of flooding during storm high tides. (United Global States Research Program, 2009)
The melting of mountain glaciers and the Greenland and Antarctic
ice sheets along with the thermal expansion of the oceans will likely
continue to increase sea level for many hundreds of years into the
future. The consensus estimate of sea level rise by 2100, published
in the Intergovernmental Panel on Climate Change’s Fourth Assessment,
was estimated at 0.6 to 2.0 ft. Improved estimates of the range of
sea level rise by 2100, which now include estimated effects of ice
dynamics, lie between 2.6 and 6.6 ft, a significantly higher estimate. (Pfeffer, W.T., et al., 2008)
In the Pacific Islands there are many low lying atolls, including
many that are part of the National Wildlife Refuge System. These atolls
are home to an estimated 10 million breeding-aged sea birds, and many
marine mammals, sea turtles, coral reef communities and other fish
Flooding will become more frequent and coastal land will be permanently lost as the sea inundates low-lying areas and as shorelines erode. Loss of land will affect living things in coastal ecosystems. For example, the Northwestern Hawaiian Islands, which are low-lying and therefore at great risk from rising sea level, have a high concentration of threatened and endangered species, some of which exist nowhere else. With further warming, hurricane and typhoon peak wind intensities and rainfall are likely to increase, which, combined with sea-level rise, would cause higher storm surge levels. (United Global States Research Program, 2009)
The ocean will eventually absorb most carbon dioxide released into
the atmosphere as a result of the burning of fossil fuels. Dissolving
of carbon dioxide into ocean surface waters will increase the acidity
of ocean surface waters. Oceanic absorption of CO2 from fossil fuels
may result in larger acidification changes over the next several centuries
than any inferred from the geological record of the past 300 million
years (with the possible exception of those resulting from rare, extreme
events such as meteor impacts).
supports more than 70% of the coral reefs in the United States with
additional extensive coral reefs in the Mariana Islands, American
Samoa, and National Wildlife Refuge islands and atolls throughout
the Pacific. Coral reefs are particularly sensitive to the impacts
of climate change as even small increases in water temperature can
cause coral bleaching. Rising sea surface temperature will place many
coral reefs into a temperature category that may be marginal for corals
and reef ecosystems, including much of the Indo-Pacific center of
reef biodiversity. Ocean acidification due to rising carbon dioxide
levels poses an additional threat to coral reefs and the rich ecosystems
they support. At the current rate of increase, atmospheric CO2 concentrations
will reduce the saturation state of carbonate minerals in the surface
ocean over the next 70 years until nearly all the locations of coral
reefs are at or beyond their normal environmental limits. This implies
the widespread loss of coral reefs worldwide if carbon dioxide emissions
In Hawai‘i, the seasonal and geographic distribution of rainfall and temperature has combined with steep, mountainous terrain to produce a wide array of island-scale climate regimes. These varying regimes in turn have supported the diversification of Hawai‘i native plants and animals. Increasing amounts of human-caused greenhouse gases will likely alter the archipelago’s terrestrial and marine environments by raising air and sea surface temperatures, changing the amount and distribution of precipitation, raising sea level, increasing ocean acidification, and exacerbating severe weather events.
Hawai‘ian climate has two main seasons: Ka‘u wela, the dry high sun season from May through October with warm, steady trade winds ; and Ho‘oilo, the cooler, wet season from November through April, with weaker and less frequent trade winds, and storms that bring rain across the islands. The atmospheric processes of these seasons are (1) the Hadley Cell climate that drives the trade winds and trade wind inversion, and (2) non-Hadley Cell climate that drives winter weather events such as Kona storms, the southern tails of mid-latitude cyclonic storms, and upper level atmospheric troughs. Other important climate features that affect Hawai‘i include El Niño drought events, hurricanes, and smaller scale weather processes.
Watch a video on Developing a Strategy to Address the Effects of Global Warming on Hawaii's Native Species by Stephen E. Miller, Science Advisor, U.S. Fish and Wildlife Service, Pacific Islands Office, Honolulu, HI. (July 30, 2008, 2008 Hawai'i Conservation Conference, Honolulu, HI.) Link to video (39 min-- please be patient while video loads)
Effects of Climate Change on Temperature in Hawai‘i: Overall, the daily temperature range in Hawai‘i is decreasing, resulting in a warmer environment, especially at higher elevations and at night. The average ambient temperature (at sea level) is projected to increase by about 4.1 (2.7 to 6.7)oF by 2100 (IPCC, 2007). These changes would increase the monthly average temperature to between 77oF to 86oF. Historically, temperature has been rising over the last 100 years with the greatest increase after 1975 (Giambelluca et al., 2008). The rate of increase at low elevation (0.16 oF per decade) is below the observed global temperature rise of 0.32oF per decade (IPCC, 2007). However, at high elevations, the rate of increase (0.48oF per decade) greatly exceeds the global rate.
Effects of Climate Change on Precipitation in Hawai‘i:
of Climate Change on Sea Level
Effects of Climate Change on Ocean Temperature
Ocean Acidity and the Effects of Increased Carbon Dioxide
Effects to Hawai`i’s Biodiversity
Avian Malaria Parasite and native Hawaiian birds: Climate change threatens to greatly expand the range and viability of avian malaria at higher elevations. Currently, at higher elevations, the transmission of avian malaria and the development of the malaria parasite are seasonal, both occurring during the warm summer and fall The cooler winter months are critical to the survival of Honeycreepers, when avian malaria development in suppressed by low temperatures.As global warming elevates air temperatures, seasonal, high-elevation avian malaria-free areas will shrink and eventually disappear entirely (Benning et al. 2002; Atkinson and LaPointe 2009). The spread of mosquitoes and avian malaria into the high elevations may eventually lead to the extinction of many, perhaps all, of the Honeycreepers that currently survive in these malaria-free areas.
This LCC includes Hawai’i, the northwest Hawaiian Islands, and other Pacific Islands within the United States' jurisdiction. The Pacific Islands Climate Change Cooperative (PICCC) is sponsored and partly supported by the USFWS and hosted by the Hawai`i Conservation Alliance (HCA). The PICCC steering committee is comprised of HCA members and other partners, forming a cooperative partnership of Federal, State, private, Hawaiian, and non-governmental conservation organizations and academic institutions. The goal of the partnership is to develop and maintain a strategic conservation response to the ecological changes induced by climate change. This can best be accomplished by collaboratively sharing expertise, knowledge, and resources.
Cooperative members include: the Office of Hawaiian Affairs, the Hawaii Department of Natural Resources, the University of Hawaii, National Oceanic and Atmospheric Administration, National Park Service, Natural Resources Conservation Service, U.S. Forest Service, The Nature Conservancy, the U.S. Geological Survey, U.S. Army and Kamehameha Schools.
Learn more about the Cooperative with this fact sheet (PDF 212 KB),or contact Deanna Spooner, PICCC Coordinator, at email@example.com or (808) 687-6175.
Atkinson, C.T. and D.A. LaPointe. 2009. Introduced avian diseases, climate change, and the future of Hawaiian Honeycreepers. J. Avian Medicine and Surgery Vol. 23: in press.
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Caldeira, Ken. 2007. What corals are dying to tell us about CO2 and ocean acidification. Oceanography. Vol. 20:188-195.
Chu, P.S. and H. Chen. 2005. Interannual and interdecadal rainfall variations in the Hawaiian Islands. Journal of Climate. Vol.18:4796-4813.
Diaz, Henry F., Pao-Shin Chu, and Jon K. Eischeid. 2005. Rainfall changes in Hawai`i during the last century. 16th Conference on Climate Variability and Change, American Meteorological Society, Boston, MA.
Fletcher, Charles. 2009. How high is sea level likely to rise by the end of the 21st century? A Review of Research. In press at Shore and Beach.
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Guinotte, J.M., Buddemeier, R.W., Kleypas, J.A., October 2003. Future Coral Reef Habitat Marginality: Temporal and Spatial Effects of Climate Change in the PacificBasin. Coral Reefs (2003) 22: 551–558.
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Jokiel, P.L., K. S. Rodgers, I. B. Kuffner, A. J. Andersson, E. F. Cox, F. T. Mackenzie. 2008. Ocean acidification and calcifying reef organisms: a mesocosm investigation. Coral Reefs (2008) 27:473–483.
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Oki, D.S. 2004. Trends in Streamflow Characteristics at Long-Term Gaging Stations, Hawaii: U.S. Geological Survey Scientific Investigations Report 2004-5080, 120 p.
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United Global Change Research Program. May 2009. http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts/regional-climate-change-impacts/islands