“There is a human perspective to climate change that goes far beyond temperature and sea levels. It is about the overall impact to human health and the need to protect natural resources for future generations. By transforming climate science into practical knowledge we can reduce vulnerabilities and enhance the resiliency of communities and ecosystems to adapt to change,” said Thomas Giambelluca, acting associate director of the Social Science Research Institute in the College of Social Sciences and a climatologist and hydrologist in the UH Mānoa Department of Geography.
For more than 30 years, Giambelluca has led a team of interdisciplinary researchers utilizing state-of-the-art techniques to study the interaction between climate and terrestrial ecosystems. Together this group forms the nexus of the university’s Ecohydrology Lab, which also is involved in research on the regional manifestations of global climate change, the effects of climate change on regional hydrological and ecological processes, and the impacts of changing vegetation on regional climates and hydrological cycles.
Invasive species are one of the greatest threats to a healthy, functioning native ecosystem in Hawai‘i. With climate change expected to further exacerbate this situation, the team is currently monitoring two field sites – one a native Hawaiian forest, the other is a nearby forest invaded by strawberry guava. In-depth field studies regarding water flux into, out of, and within the vegetative layer are being conducted to better understand the sensitivity of the two ecosystems and how both respond to changes in climate. Supported by funding from the Department of Interior Pacific Islands Climate Science Center and the United States Geological Survey (USGS) Pacific Islands Ecosystem Research Center, the project provides local resource managers with critical data necessary to devise appropriate long-term land-management strategies.
How much water do rubber plantations use? How strong of a carbon sink is rubber? These are just a few questions the Ecohydrology Lab addressed with its Ecosystems Fluxes in Southeast Asia Rubber Plantations study. Conducted as a cooperative project between the University of Hawai‘i at Mānoa, Kyushu and Nagoya Universities in Japan, and the Cambodian Rubber Research Institute, with support from a variety of awards including grants from the National Aeronautics and Space Administration (NASA), the project examined the sustainability of this rapidly expanding industry in Southeast Asia with regard to environmental issues such as water usage and carbon recycling. The results will provide leaders in the region with valuable information regarding the possible environmental effects of increased rubber cultivation on ecosystem services.
Ecohydrology Lab researchers also maintain numerous microclimate stations within the state. The most established is HaleNet, which has been in operation on Haleakala since 1988. HaleNet allows scientists to investigate climate-vegetation interactions, alien plant and animal invasions, local climate shifts associated with global warming, and historical changes. The information collected enables researchers to project future climate changes in the area.
Giambelluca’s team also launched an interactive water resource management website on evapotranspiration (http://evapotranspiration.geography.hawaii.edu/) that, when added to the group’s existing Rainfall Atlas of Hawai‘i (maps of spatial patterns of rainfall), Climate of Hawai‘i (maps of spatial patterns of climate), and Solar Radiation (maps of spatial patterns of solar radiation) websites, forms a family of products providing critical information on the state’s average climate and water processes.
In building the site, the team collected, analyzed and mapped a range of variables including rainfall, evapotranspiration, wet canopy evaporation, transpiration, soil evaporation, potential evapotranspiration, solar radiation, clear sky solar radiation, cloud frequency, albedo, net radiation, air temperature, relative humidity, vapor pressure deficit, wind speed and soil moisture. More than 12,000 data maps were created, covering each hour of the average 24-hour cycle for each month and each hour of the average 24-hour cycle for the year. Average values for each month and the annual average were also mapped.
The websites include interactive maps that allow users to see the spatial patterns for each variable. Individuals may also zoom in on areas of particular interest, navigate to specific locations using different base maps, and click on a location to obtain the mean value of the selected variable, graphs of the mean monthly and hourly values, and obtain tables with mean hourly, monthly and annual values of all variables for a selected location.
“Understanding and quantifying the movement of moisture within the atmosphere is critical to the management of Hawaii’s water resources and the protection of its natural environment. It is a key component in the analysis of how climate change, land development and species invasion will affect the islands’ natural ecosystems, agriculture and domestic water availability. As we work to address the growing challenges Hawai‘i faces due to climate change, the practical applications of this data, beyond climate modeling and resource management, are far reaching. For example, evapotranspiration rate predictions may help the agriculture sector estimate potential water demands for crops and determine the optimum time for irrigation. Similarly, the solar industry may find the solar radiation data useful in developing projections for photovoltaic needs,” said Giambelluca.
Whether it is studying the effects of tropical deforestation on regional climate and hydrology or whether the expansions of roads in Thailand accelerate soil erosion, one thing is certain – Giambelluca and his group of Ecohydrology Lab researchers are making significant contributions to our understanding of climate change, its overall impact to human health and the need to protect and manage our natural resources for future generations.
