A century of spatial and temporal patterns of drought in Hawai'i across
hydrological, ecological, and socioeconomic scales
Abstract
Drought is a prominent feature of Hawaii’s climate, however, the
biological, ecological, cultural, and socioeconomic impacts of drought
in Hawaii are not well understood. This paper provides a comprehensive
synthesis of impacts of past droughts in Hawaii that we integrate with a
geospatial analysis of drought characteristics (duration, frequency,
severity, and geographic extent) using a newly developed 93-year
(1920-2012) gridded Standardized Precipitation Index (SPI) dataset. The
synthesis examines past droughts classified into five categories:
meteorological, agricultural, hydrological, ecological, and
socioeconomic drought. Results show that drought duration, magnitude,
and frequency have all increased significantly, consistent with trends
found in other Pacific Islands. Most droughts, though not all, were
associated with El Nino events, and the two worst droughts in the past
century were 1998-2002 and 2007-2012. The most severe drought in the
record (2007-2012) had the greatest impacts on Hawaii Island, whereas
the islands of Oahu and Kauai experienced more severe drought conditions
during the 1998-2002 event. Both droughts exerted a large and
quantifiable impact on the agricultural sector, and although anecdotal
evidence points to strong impacts on ecological and socioeconomic
sectors, more research is needed to understand drought impacts to these
sectors. This synthesis is an example of how coupling quantitative SPI
analysis with economic and ecological impacts can provide the historical
context needed to better understand future drought projections, and will
contribute to more effective policy and management of natural, cultural,
hydrological, and agricultural resources.