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This paper considers key drivers to climate policy development with an emphasis on the role of a jurisdiction's underlying energy resource. The states of Hawaii in the United States and Victoria in Australia provide an insightful comparative case study given their differing energy resources: Hawaii has no native fossil fuel resources but abundant renewable energy options while Victoria has an economy traditionally reliant on cheap, plentiful coal. The Advocacy Coalition Framework is applied to analyze why the two states, despite the different incentives provided by their energy resources, developed similar climate policies in the earlier period of policy response to global warming. Analysis finds the stable parameter of energy resources is counterbalanced by other policy drivers including public opinion, leadership and, in particular, features of policy-making particular to the subnational level that provide a different context for climate policy development to that offered at the national level. [ABSTRACT FROM AUTHOR]

Natural climate variability poses a limit to the confidence in regional climate projections, particularly for the near‐term. Therefore, the next decades are of importance for regional impact studies and the development of regional adaptation plans. This article presents results from an ensemble of regional climate model simulations (years 1996–2005 and 2026–2035) that are used to examine the effects of both anthropogenic forcing and natural variability associated with the Pacific Decadal Oscillation (PDO) on near‐term climate projections for the Hawaiian Islands. The Community Earth System Model Large Ensemble (CESM‐LE) is used in conjunction with the Weather Research and Forecasting (WRF) model for downscaling. The climate responses to the PDO and anthropogenic forcing are isolated and analyzed separately. In response to anthropogenic forcing, significant increases in surface air temperature, of ∼0.8 K, are projected at low elevations. Stronger warming, of up to 1.3 K, is seen at higher elevation areas. Future climate simulations show significant increases in wet season rainfall, of ∼10%–20%, along the windward slopes of Big Island and Maui. Rainfall patterns during the positive PDO phase are projected to reverse in sign, leading to drier conditions, by ∼10%–30%, at many locations. Future climate simulations show daily rainfall extremes will increase, by up to ∼10%–15%, at many locations. Daily temperature extremes are also projected to increase significantly, by up to 1.4 K. Overall, results indicate that natural variability will continue to contribute to uncertainty in near‐term rainfall projections for the Hawaiian Islands, masking the forced signal. Plain Language Summary: This project studies how temperature and precipitation will change across the Hawaiian Islands in the near future due to human‐induced causes (e.g., burning coal and other fossil fuels). This is done by comparing climate model simulations for two 10‐year periods (1996–2005 vs. 2026–2035). Further, this research evaluates how natural climate variations affect Hawaiian climate. The main analysis concentrates on an important type of natural climate variability in the North Pacific, the Pacific Decadal Oscillation. This research implements dynamical downscaling, that is, a regional climate model is used to refine global climate model simulations in order to better capture the local weather patterns in Hawai'i. We find that land and ocean temperatures across the Hawaiian Islands region will become warmer due to human‐induced causes. We also find that rainfall will likely increase for some areas of Hawai'i, particularly the mountain slopes, posing an increased risk for flooding. The simulations reveal that natural climate variability will continue to contribute to near‐term climate variations in this region. While the natural climate variability limits our confidence in the projected rainfall changes, it is hoped that our findings will assist decision makers across the State of Hawai'i in creating climate adaptation plans. Key Points: Significant increases in near‐surface temperature and sea surface temperature are projected across the Hawaiian Islands regionSignificant increases in mean and extreme rainfall are projected for some areas of the islandsNatural decadal variability will continue to mask the forced signal in near‐term rainfall projections for the Hawaiian Islands [ABSTRACT FROM AUTHOR]

Changes in the intra-annual cycle of atmospheric CO2 at Mauna Loa, Hawaii, are investigated by comparing monthly observations to the mean value of each year’s waxing and waning phase of the cycle. Results identify a previously unnoticed change between 1965 and 2004 during October in which October concentrations declined relative to the cycle’s mean value. Results confirm a previously noted change in spring (April), but unlike previous analyses, this result indicates that between 1965 and 2004 April concentrations rose relative to the cycle’s mean value. The timing of these changes is not caused by commonly recognized patterns of atmospheric circulation, such as ENSO events. Instead, these changes may be generated by asymmetric effects of warming. Warming in early spring may increase heterotrophic respiration relative to net primary production while warming in late summer/early fall may enhance net primary production relative to heterotrophic respiration. [ABSTRACT FROM AUTHOR]

Complex socio-ecological issues, such as climate change have historically been addressed through technical problem solving methods. Yet today, climate science approaches are increasingly accounting for the roles of diverse social perceptions, experiences, cultural norms, and worldviews. In support of this shift, we developed a research program on Hawaiʻi Island that utilizes knowledge coproduction to integrate the diverse worldviews of natural and cultural resource managers, policy professionals, and researchers within actionable science products. Through their work, local field managers regularly experience discrete land and waterscapes. Additionally, in highly interconnected rural communities, such as Hawaiʻi Island, managers often participate in the social norms and values of communities that utilize these ecosystems. Such local manager networks offer powerful frameworks within which to co-develop and implement actionable science. We interviewed a diverse set of local managers with the aim of incorporating their perspectives into the development of a collaborative climate change research agenda that builds upon existing professional networks utilized by managers and scientists while developing new research products. We report our manager needs assessment, the development process of our climate change program, our interactive forums, and our ongoing research products. Our needs assessment showed that the managers’ primary source of information were other professional colleagues, and our in-person forums informed us that local managers are very interested in interacting with a wider range of networks to build upon their management capacities. Our initial programmatic progress suggests that co-created research products and in-person forums strengthen the capacities of local managers to adapt to change. [ABSTRACT FROM AUTHOR]

ABSTRACT Trends of annual maximum 1-day precipitation in three major Hawaiian Islands are investigated using a nonparametric Mann-Kendall method and Sen's test ( MKS). The records are from 24 stations on Oahu, Maui, and Hawaii, and the period of analysis ranges from 1960 to 2009. To complement the MKS method, a non-stationary three-parameter generalized extreme value ( GEV) distribution is also used to detect trends in precipitation extremes. Both methods demonstrate that negative trends prevail for Oahu and Maui but positive trends dominate the Island of Hawaii. The influence of the location and the scale parameter in the GEV model on different return levels (2-year, 20-year, and 100-year) are explicitly described. The return-level threshold values are found to change with time considerably. As a result, a rare storm with daily precipitation of 300 mm (20-year return period) in 1960 has become a rather common storm event (3-5-year return period) in 2009 on the Island of Hawaii. The opposite trend behavior in extreme events is observed on Oahu and Maui, where rainfall extremes have become less frequent in the last five decades. A positive relationship is found between the precipitation extremes and Southern Oscillation Index ( SOI), implying greater extreme events during La Niña years and the opposite for El Niño years. [ABSTRACT FROM AUTHOR]