Hilo’s future: Wetter, warmer

Hilo’s famous rain storms could get even heavier over the next 100 years. And that’s the good news.

Hawaii Island and the rest of the state are expected to see major and irrevocable impacts to their fragile ecosystems, infrastructure, water supplies, and more as a result of global climate change, according to a White House report released this week.

The U.S. Global Change Research Program on Tuesday released its Third National Climate Assessment, a comprehensive look at current and future impacts on the various regions of the U.S. as a result of continuing climate change.

Fifteen Hawaii scientists were listed as contributing directly to the report’s section on Hawaii and U.S.-affiliated Pacific islands, but many more played roles in providing data for the report, said John Marra, Pacific Regional Climate Services director for the National Oceanic and Atmospheric Administration. He served as a lead author on the report.

“Each chapter got culled down to just the basic information from much larger studies. Reports that were 300-400 pages were cut down to 50, then down to eight, down to a sentence or three words,” he said. “So, some of the finer details may not be in the report. … But the main idea is, the air is getting warmer. The ocean’s getting warmer and becoming more acidic. The sea level is rising, and it’s going to continue to do that. We’ve already seen impacts from these changes, and we’re going to continue seeing impacts that are going to get more severe, including impacts to our communities, our habitats and our cultures.”

The section focuses on five key — and ominous — messages concerning impacts in Hawaii and the Pacific:

• Ocean warming and acidification will lead to bleaching or death of coral reefs and impede their future growth, which will in turn impact the fish and other sea life that rely on coral reefs, as well as impact businesses that rely on fisheries;

• Freshwater supplies will be severely limited due to salt water intrusion, increased evaporation due to higher temperatures, and increased demand for water in drier areas;

• Increasing temperatures and decreasing rainfall in some areas will stress native plants and animals, especially in high-elevation ecosystems such as Mauna Loa and Mauna Kea, with increasing exposure to invasive species and increased risk of extinctions;

• Rising sea levels, coupled with high water levels caused by storms, will increase coastal flooding and erosion, damaging coastal ecosystems, infrastructure and agriculture, while negatively affecting tourism;

• Mounting threats to food and water security, infrastructure, health and safety are expected to lead to increasing human migration, making it increasingly difficult for Pacific Islanders to sustain the region’s many unique customs, beliefs and languages.

As introduction, the report explains that “Hawaii and the U.S. affiliated Pacific islands are at risk from climate changes that will affect nearly every aspect of life. Rising air and ocean temperatures, shifting rainfall patterns, changing frequencies and intensities of storms and drought, decreasing baseflow in streams, rising sea levels, and changing ocean chemistry will affect ecosystems on land and in the oceans, as well as local communities, livelihoods and cultures.”

According to Thomas Giambelluca, a professor of geography at the University of Hawaii at Manoa who also served as an author on the report, perhaps one of the most interesting findings in the climate assessment is that precipitation will follow a pattern in some locations where dry areas will become even drier in the next 50-100 years, while wet areas will become even wetter.

“Using statistical downscaling of the larger models, we have a new projection for mid- and late-century. For all islands except Kauai, winter rainfall in the future will, under various scenarios, decrease in all the dry areas, significantly, while in the wet areas, we don’t see any indication of a decrease, and we may even see an increase,” he said. “It raises big concerns about future increases in demand for water. … Unlike Hilo residents, most everybody who lives in dry areas like Kona, all those water users are going to need more water.”

As for how Hawaii is prepared to confront such daunting statistics, Marra offered a more upbeat outlook.

“Hawaii needs to be lauded for its efforts (in confronting climate change),” he said. “Hawaii’s already got some policies with respect to climate change. I think the folks in this region are relatively enlightened to climate change, especially since the impacts are in the Pacific region are writ large. They see the impacts, impacts which are arguably more severe compared to those seen on the mainland, for instance. There’s also a culture of collaboration here that’s a neat thing, and it’s going to be vital to making progress.”

Email Colin M. Stewart at cstewart@hawaiitribune- herald.com.