Climate change – Big Island Style – Hawai’i
It’s always winter in paradise. And—it’s always summer. Actually, it’s generally everything in between as well. Hawaiian weather contradicts convention. This may sound strange but only because on most of the Earth, it’s possible to predict likely weather and climate based on latitude. In the high northern and southern latitudes, we get cold snowfall and tundra regions. At around 50 degrees (north and south) we find temperate forests. The desert and arid 30-degree latitudes are generally dry and hot, while the equator is home to the tropics.
But Hawai’i defies this logic. The main Hawaiian Islands, sitting at 20 degrees’ latitude, contain all of these climate zones and more, on just a few specs of land hidden amidst one of the most isolated island chains in the entire world. Unique to this blue planet, the Hawaiian archipelago blasted forth from deep beneath the Pacific, creating the towering volcanoes of Mauna Kea and Haleakala, the rolling fields of Waimea, the tropical beaches of Waikiki and Makalawena, and the ancient forests of Kohala and Kaua`i—each with unique climate patterns, creatures, topography, and character.
Hawai’i became no ordinary place, particularly as weather and climate microcosms gave breath to countless divergent species. The ancient process of metamorphic birth and renewal has forged one of the most unique evolutionary powerhouses anywhere on Earth. Changing climates, topography, and temperatures are nature’s playground. Offer Mother Nature a flat expanse and she will give you a limited number of trees and animals that fit and flourish in such a uniform environment. Offer her towering mountains from sea to sky in that same expanse, and she will create countless creatures that thrive and subside in every nook and cranny of the changing landscape. This is essentially the story of Hawai’i.
Long before humans were even a twinkle in the evolutionary eyesight of Mother Nature, the forces that would govern our lives here on the Big Island were already taking hold. The Hawaiian-Emperor Seamount Chain first emerged as a crumbling mass of molten lava thousands of feet below the surface of the ocean around 70-80 million years ago. As the enormous Pacific Plate began to drift northwest at a lumbering pace of only a few inches per year, a “hot spot” of seeping magma from the Asthenosph ere under the plate began the slow, laborious formation of the Emperor Seamounts and the Hawaiian Ridge. At that time, the northernmost atolls in the Hawaiian chain, Kure and Midway, were situated in the present-day location of the Big Island and were much larger than the flat eroded islands slowly sinking beneath the waves that we see today.
Fast forward to present-day. The southernmost end of this chain, the Big Island, gives daily reminders of this arduous birthing process—the constant explosive flows of Pele’s wrath and the quiet daily rumblings from deep below as the island’s ever-growing mass settles onto the Pacific Plate. Laid out over thousands of miles of endless ocean, it is apparent to the inquisitive observer that the southern islands, such as Hawai’i, form towering volcanoes cresting high above sea level. Slowly moving northwest, the height and topography of the islands are torn away by time and the erosive processes of wind, water, and gravity. Eventually, the islands become atolls until they reach the Darwin Point (so named for it was he who first described the life and death of atolls), when the sea reclaims the land that once broke free of it.
Each of the 130 Hawaiian Islands, which include atolls and islets, has passed through this gauntlet of climate and weather. Even the eight main Hawaiian Islands are at slightly different stages in this journey today. Therefore we find so many climates spread across such a small geographical area. As the youngest member of the chain, the Big Island is exposed to the most primitive throes of this ancient cycle. The changing landscapes and climates have also created the breeding ground for a multitude of unique creatures to evolve and occupy all the varying conditions that can be found on this one small island. The Big Island is home to 4 of the 5 main climate zones and 8 of the 13 sub-zones (more on this later). Considering that these zones represent the major climates found throughout every region and habitat on Earth, that is nothing short of amazing. Where else can you go skiing in the morning, diving at midday, explore a rainforest before dinner, and watch the stars from a grassy pasture at night?
Unquestionably, even to the casual observer, dramatic shifts in weather, topography, and climate are only a short drive away from anywhere on the island. Which has created much debate over exactly how many climate zones and classifications can be found on the Big Island. You may have heard over the coconut wireless that Hawai`i has 8, 9, 10, 11, or 12 of the 13 climate zones? Or is it 12 of the 30 sub-zones? It’s hard to keep track, mainly because there are so many different systems used to classify climate. There is the Aridity index, Koppen climate classification, and the Holdridge life zone classification system, to name a few. Scientists have developed differing systems based on air mass types, plant hardiness, evapotranspiration (whatever that is), biomes, and many other criteria. Even Aristotle got into the climate naming game. So, depending on which classification you choose and how you define it, the results will be different. Complicating the matter is that systems change over time as scientists refine their methods. So, what is a budding climatologist to do? Easy, just pick the most common and simple system.
Most scientists, scholars, sorcerers, and snowmen consider the Koppen climate classification system the most widely accepted and accurate method for sorting out the wet from the dry. Using this system, based mainly on average annual and monthly values of temperature and precipitation, the Big Island has 4 of the 5 main climate zones and 8 of the 13 sub-zones, as previously noted.
Now we could get really deep and dorky into how these zones are laid out on the island (see map), but the real wonder of this phenomena is how these varying climate zones commixed within unique landscapes and lit the spark that ignited a process evolutionary biologists love to discuss—adaptive radiation (sticking with the dorky bit here). Darwin’s famous example of finches on the Galapagos is a well-documented example of how fragmented landscapes and climate can encourage evolutionary diversification or adaptive radiation. It was these finches, as well as the diversity of life throughout the rest of the Galapagos that would inspire and inform his groundbreaking theories on natural selection and evolution.
Too bad Darwin never made it to Hawai`i. He would have been enveloped by an even more profound diversity of climate and creatures. His finches diverged from just one or two into 14 distinct species. Impressive, but the Hawaiian equivalent, honeycreepers, have metamorphosed into at least 56 species from just two distinct finch-like birds who accidentally landed on these remote, birdless islands 4-8 million years ago. But birds are just the tip of the iceberg. Hawai`i is home to over 5,000 endemic species of insects including carnivorous caterpillars (Eupithecia mphoreas), giant dragonflies (giant Hawaiian darner), and more than a quarter of the world’s endemic flies. There are up to 70 distinct species of coral, a quarter of which are native, and over 450 species of reef fish, like the ‘a`awa (Hawaiian hogfish) and mamo (sergeant major). Hawaii has about 9,000 endemic species. These include some of the smaller, less thought about creatures like the 1,200 native land snails that evolved from between 22-24 original snail immigrants. And keep in mind Hawaii occupies about .01% of the world’s terra firma.
All of these evolutionary exploits are made possible by the countless environmental niches created by the multitude of climate zones clashing with the varying altitudes, valleys, streams, wet and dry sides, emerald bays, exposed coastlines, currents, weather patterns, and on and on. Perhaps one of the most unique and unlikely zones is Hawaii’s polar tundra region high above the clouds of mighty Mauna Kea and Mauna Loa. Divided by Saddle Road, atop the tallest volcano in the world (Mauna Kea) and the most massive (Mauna Loa), resides two of the most sacred locations in all of Hawaiian culture.
“White Mountain,” as the native Hawaiians called Mauna Kea, was so named for the snow-covered summit that can usually be seen throughout the winter months. Mauna Loa, or “Long Mountain,” is often capped by snow and has a base larger than some states. The Hawaiians believe that the fire goddess Pele thrust her (digging stick) into Mauna Loa’s summit and created the fiery lava chambers and fearsome forces we still feel today. Pele was chased to Mauna Loa by her sister Namakaokaha`i, goddess of water and the sea, after seducing her husband. Hawaiians considered these regions the origin of space, a place of creation where the sky and earth separated to form the heavens. Adopted into the scientific community, these heavenly gates have gained prominence as one of the premier astronomical observatories on Earth. A distinction often at odds with the spiritual and sacred value they hold for many Hawaiians.
Home to 13 of the most powerful telescopes in the world, Mauna Kea’s peak rises above 40% of the Earth’s atmosphere. The ground consists of permanently frozen soil and, in most months, the average temperature is below 32° F (0° C), The unique and special characteristics of this high altitude, polar tundra region are perfect for a modern-day form of sky worship—astronomy. The air above Mauna Kea is very low in turbulence and extremely dry—two important requirements for measuring infrared and submillimeter radiation in far away galaxies. The number of clear, cloud-free nights is among the highest in the world due to its unique geography and height. Water vapor and air pollution are held well below the summit observatories by a tropical inversion layer about 600 meters thick that isolates the upper atmosphere from the lower. But that is not to say it’s always clear above the summit. In the winter months, it’s not uncommon for the National Weather Service to order blizzard warnings for the summit regions!
But the Big Island is not unique among the Hawaiian Islands for distinct and diverse weather, climate, and creatures. From desert and semi-arid plains to mountain forests, pastoral plains, and rainforests, Kaua’i possesses more climate variations than many countries. The four major islands (O`ahu, Molokal, Maui, Lanal) lying in between Kaua’i and the Big Island also have varying climactic zones relative to their sizes and levels of erosion. Hawai’i’s unique weather patterns are intrinsically tied to its geology as the size and mass of each island’s volcanic peaks and mountains create the stage for a breathtaking natural play where the forces of nature act like dueling antagonists.
Most of the Hawaiian Islands have a leeward side, to the south and west, and a windward side, to the north and east. The former is much drier and the latter is much wetter (often called the dry and wet sides). The northeast trade winds gather moisture as they run uninhibited over miles of the endless Pacific. Once the trades have the Hawaiian Islands in their sights, the monumental natural forces of rock and wind crash violently into one another. The windward side pushes weather and moisture up into the atmosphere causing it to then fall as rain, creating the lush, tropical rainforest conditions of the east and northern shores of many of the Hawaiian Islands.
This “orographic” rainfall often carves lush, breathtaking valleys (like Waipi`o and Pololu on the Big Island), as it winds its way back towards the ocean, eroding the eastern flanks on its journey back to the sea. As the relentless forces of wind and water are cleaved by the presence of the mighty islands, they have left windward coastlines characteristic of this ancient struggle, such as the 3,315-ft high sea cliffs on Molokal (the world’s highest) or Maui’s famous Pali Coast. The wind, of course, carries on to the leeward side of most the islands, but lacking moisture it creates the arid and semi-arid zones characteristic of the areas in south and-west Kaual and the Big Island. Therefore, the valleys and landscape of the leeward sides tend to be less dramatically eroded and not as steep. Sheltered by the windward flanks, they have been spared the worst erosive effects of Mother Nature and instead we are blessed with calmer beaches and sandy shorelines, like Hapuna Beach on the Kohala Coast, consistently voted as one of the world’s best!
The Hawaiians had perhaps the simplest system to describe these varying climates and weather. They believed in two seasons: Kau—the fruitful season when the sun was overhead from May to October, the trade winds blew consistently, and the waters were calmer. And ho`oilo—when the sun fell into the south from November to April, the weather cooled, and the trades became less predictable. Perhaps more so than modern people, they also recognized not just the diversity of life that the abundance of climates created within the bountiful islands, but also its sanctity. Although certainly they had some negative impacts on species and habitats, they created and adopted a community-based structure of ecosystem management from mauka (mountain) to makai (sea) for the ‘aina (land), thepo`e (people), and the holoholona (creatures).
Sadly, the influence of subsequent colonization would eventually create an extinction catastrophe, reversing millions of years of nature’s work in barely an evolutionary blink. Today, over half of all endemic birds in Hawai’i are extinct, with 31 of the remaining 42 native species threatened with extinction. Nearly 25% of US endangered species are found in Hawaii, even though it occupies only a fraction of the country and receives a tiny percent of endangered species funding. But the many (spiritual power) and biological power plant that created these islands still rumbles deep within the belly of Pele’s fiery home.
The one constant in Hawai’i is rebirth and renewal. The ancient evolutionary forces that forged the climates and creatures into this vibrant paradise the world has come to know still simmer in the mists of its hidden forests, lush valleys, lofty peaks, and countless clouded corners. Hawai’i continues to be a refuge for travelers and locals alike to find community, to gain deeper understandings of our place in time among the stars, to witness the brilliance of nature’s creativity, and to experience the massive forces shaping our climate, culture, and creature’s destiny. So, toss on a raincoat, don a pair of slippers, bundle up in winter gear, slip into some hiking boots, light the fireplace, or kick on the air conditioner because Hawaii is no ordinary place.