Climate Change Hawaii
Climate Change in Hawaii: Caught Between A Rock And A Big Wave
Crop failure and drought in Africa, loss of biodiversity in the Amazon and extreme flooding and heat waves in Europe all prove that, if nothing else, climate change is successfully uniting the world in a collective state of imperilment.
Now add to the list Hawaii.
As the only US state located in the tropics, and the only one surrounded entirely by water, scientists expect climate change to affect the Hawaiian Islands in ways unlike anywhere else in the country.
Speaking at a global climate change conference last month on the island of Kauai, scientists from the University of Hawaii (UH) and the US Geological Survey sketched a potential profile of a near-future Hawaii that is expected to be warmer, drier and more susceptible to dramatic rain events and severe coastal erosion.
Dr. Thomas Giambelluca, a climatologist and ecohydrologist with the UH Geography Department, said that while the overall global surface temperatures have been warming since at least 1860, Hawaii is in an area of slower warming, about half the global rate. He noted that records since the mid-1970s show that, although Hawaii's daytime temperatures are remaining constant or climbing slowly, nighttime temperatures are rising at a high rate, especially at higher elevations where the warming rate has been about 0.44 degrees Celsius since the mid-70s. Warmer nights have implications for not only greater energy use, but also biological impacts such as slower growth of crops and natural vegetation.
As overall global rainfall has increased during the last century, Hawaii's recorded precipitation has experienced a 5 percent to 20 percent decrease between 1901-2005. According to Giambelluca, this downward trend isn't limited to Hawaii, but can be seen across the same band of latitude (19 degrees N - 28 degrees N) around the world.
Giambelluca pointed to a decrease in precipitation during Hawaii's winter months (November to April) over the last century, with a more dramatic decline (27 percent) since 1970. Research also shows that Hawaii's summer rainfall is increasing slightly, with trends pointing to a drier archipelago with a potentially shrinking cloud zone around Hawaii's high volcanic peaks in the zone where rising moist tropical air creates the rain that makes the islands lush and green.
Giambelluca said Hawaii could start to experience more frequent droughts punctuated by periodic extreme heavy downpours. "It is possible we will have less rainfall, but still have more big rain events," Giambelluca said.
Between February 2006 and April 2006, parts of Hawaii had six weeks of nearly continuous heavy rainfall during which time the Kaloko Dam on Kauai was breached, sending hundreds of millions of gallons of water racing toward the sea, killing seven residents who were swept out of their own homes.
Last month, an extreme rain event on Kauai flooded the Hanalei Valley, home to the bulk of Hawaii's taro crop and a wildlife refuge for rare and endangered Hawaiian birds. Biologists on Kauai have since reported an increase in bird deaths as they move from flooded areas into the flow of automobile traffic.
Today, Hawaii relies on about 50 stream gauges to measure stream flow, down from a high of around 200 in the 1960s, said Dr. Gordon Tribble, director of the Pacific Islands Water Science Center for the US Geological Survey. The reduced capacity to measure stream flow, Tribble said, is reflective of reduced state and federal funding.
Hawaii, which has traditionally been made up of communities arranged around watershed systems, still relies on aquifers and groundwater replenished by trade wind-introduced rainfall for the bulk of its fresh water. Reduced rainfall and the decline of dry-weather flow in Hawaii's streams, Tribble said, has major implications for not only Hawaii's 1.3 million people, but also its flora and fauna, including about one-quarter of all federally listed threatened and endangered species in the US.
The impact climate change may have on Hawaii's unique flora and fauna are of particular interest to botanists and biologists. Chipper Wichman, director of the National Tropical Botanical Garden, speaking from the organization's headquarters on Kauai, said that because 90 percent of Hawaii's native plants (even higher for invertebrates and birds) are found only in Hawaii, often confined to a single mountain or valley, they are especially vulnerable as climate change alters their ecosystems.
Wichman pointed to shifting rainfall patterns and higher temperatures as having direct and indirect consequences for plants and animals. As wet forests become mesic and mesic forests become dry, it is unlikely all native species will be able to evolve or migrate fast enough to keep up with climate change, Wichman said.
Hawaii's native bird population, already decimated by avian malaria and avian pox, could suffer final death blows if even a slight rise in ambient temperature increases the territory of mosquitoes, allowing them to move beyond their current range of up to 3,500 feet. Because native Hawaiian birds serve as pollinators and are essential for seed dispersal, their loss severely affects plants too.
"Biodiversity is the fabric of life," Wichman said. "As we lose what some perceive to be insignificant species, we are actually breaking the threads of this fabric. When enough threads are broken, the very integrity of our ecosystem will unravel."
Speaking at the climate change conference, Dr. Charles Fletcher, chair of the UH Geology and Geophysics Department said, "scientists are not doing a good job of communicating the facts of global warming to policy makers and the public." He was referring to what he called "climate change deniers," particularly in the United States. "You don't see that in other countries," Fletcher said.
Citing the example of the Federated States of Micronesia, Fletcher spoke of how low-lying islands in the Pacific are being threatened right now by increasingly high tides and the accompanying salt water, which destroys the soil and aquifers, making food production and obtaining drinking water difficult, if not impossible.
Global sea level rise averages about 3.3 millimeters per year. In Micronesia, the rise is 8 mm to10 mm per year, the result, in part, of ocean heating and wind patterns. In Hawaii, Fletcher said, sea levels are rising more slowly, around 1.5 mm a year. If and when Hawaii sees accelerated rates of sea level rise as in Micronesia, Hawaii's current problems will seem small by comparison, Fletcher said.
Fletcher noted that the ocean absorbs about 80 percent of the heat in the earth's climate system and, as such, buffers us from the major impacts of global warming. Taking 1/100th of one degree from the ocean and releasing it into the atmosphere would raise the atmospheric temperature by 18 degrees Fahrenheit. Fletcher called the ocean the "800-pound gorilla in the climate system that absorbs excess heat."
Whether a one meter sea level rise occurs by 2100 or whether it happens later (Fletcher said that carbon released into the atmosphere already ensures this will happen), forecasts indicate a number of dramatic changes for Kauai, and consequently all the Hawaiian Islands in relatively similar ways.
The majority of Hawaii's population live in coastal plains where large ocean waves are going to increasingly "punch further into the islands." At just over half a meter sea level rise, Fletcher said flooding will become an annual event. Worsening drainage and high tides means the water will have no place to go. With higher sea levels, it will take less rainfall intensity to cause the same amount of flooding.
"Eventually, you will be wondering if it's fresh water or salt water that is coming into your living room," he said.
Sea level rise, flooding and the greater impact of waves may also effectively transform many coastal communities in Hawaii into a series of barrier islands. "We're going to be saying 'aloha' (farewell) to a lot of our beaches," Fletcher said.
On Kauai, Fletcher said, nearly three-quarters (72 percent) of the sandy coastline is eroding at rate of about one foot (0.3 meters) per year.
Fletcher suggested planning for a possible sea level rise of one meter (3.2 feet) over the next 90 years. It's high time to carefully reconsider what crops will be grown, where and how buildings and infrastructure are built and how people in Hawaii conduct their daily affairs, according to the UH professor.
"Climate-proofing our infrastructure and towns now could buy us a few generations of use for many of our communities," Fletcher said. "We should be building up (from ground level) and back (from the shoreline)."
Here Today, Gone Tomorrow
One of the earliest ecosystems to show evidence of climate change are coral reefs. Like other reef systems around the world, Hawaii's corals are bearing the brunt of rising temperatures, accelerated erosion and greater terrestrial runoff, although to a lesser degree than other regions. UH research scientist with the Hawaii Institute of Marine Biology Dr. Paul Jokiel has studied coral ecosystems since the early 1970s. He said that climate change would adversely affect Hawaiian corals and all life that depends on them for survival.
"Dry areas will get drier, wet areas wetter and greater storm activity will bring more sediment onto the reefs," Jokiel said, adding that increased severe storms, rising sea levels and greater ocean acidification can all lead to mass coral bleaching (the result of stress conditions) and mortality. Two significant coral bleachings in Hawaii occurred in 1996 and 2002.
"If we work real hard, we can probably hold temperature increases to 2 degrees Celsius. If we go much beyond that, the projections get pretty grim," Jokiel said. "At an increase of 5 degrees Celsius, we're talking about projections of a 90 percent decrease in crop production in Africa."
Still, Jokiel said that even a 2 degrees Celsius increase will result in massive loss of coral reefs. Quoting a colleague, he noted that coral reef biologists may lose their own subject of study, but could at least provide a warning for the rest of the world as to the seriousness of climate change.
"Eventually, if we keep doing what we're doing with the atmosphere and the oceans, we'll reach a place where nothing will calcify and we may see an entire ecosystem go belly-up," Jokiel said.
Pointing to a PowerPoint projection of a mass of sharply downward sloping lines from 50 research models tracking coral reef viability, Jokiel's message is stark: "Everything is crashing."
A warmer, more acidic ocean not only affects coral reefs, but also fish populations, mammals, zooplankton and algae. In Hawaiian waters, for example, scientists are reporting drops in the production of spiny lobster and monk seal pups that seem to be linked to documented increases in ocean temperature and a decrease in oceanic productivity.
Jokiel said the goal right now should be to limit temperature rise to 2 degrees Celsius through 2100. Rising 6 degrees Celsius would bring changes which, according to Jokiel, "you don't want to see."
Continuing, he said, "the CO2 we put in the atmosphere stays there unless part of it goes in the ocean. It doesn't go away. The stuff we put in the air remains with us for thousands of years. On a geologic scale it doesn't mean much, but for humans it means a great deal."
As these and other Hawaii-based scientists continue their research and amass more data, the forecasts are growing increasingly consistent, all pointing to an immediate future in which Kauai and the other Hawaiian Islands are warmer, drier and more vulnerable to extreme weather events like torrential rains and drought. Coastal inundation, severe disruptions of ecosystems, the loss of biodiversity from the coral reefs to cloud forests, now the last refuge of countless plants and animals found nowhere else on earth, are all indicative of a paradise literally lost.
Ask anyone in Hawaii today and they'll tell you the place remains drop-dead gorgeous. Travel magazines still gush about Kauai and rank it among the world's best tropical islands. But as climate change accelerates, it ushers in new conditions that force even the most die-hard skeptics to re-examine the evidence, consider the consequences and starting today, plan for a different tomorrow.
**Jon Letman is a freelance writer in Hawaii. He writes about politics, society, culture and conservation on the island of Kauai. You can read the original article here.