In an amazing feat involving time, location, and tectonic uplift, UCSB scientists pulled up a core sample from below the Santa Barbara Channel that gives the first detailed look at an ancient period of significant global climatic change, one that holds parallels to today's warming oceans. Methane bubbling up from defrosting methane hydrates under the sea — with an ability to warm the atmosphere 86 times as much as carbon dioxide — likely played a significant role in this climate warming in millennia past, posits their paper, published in Paleoceanography recently. Among the core samples recovered by UCSB geo-scientists James Kennett, Craig Nicholson, Christopher Sorlien, and their colleagues — taken from a very deep and old piece of the Earth brought upward by tectonic uplift — was one that held distinct layers from an important period of transition in the global climate cycle. And it could be dated accurately — no mean feat for pieces of earth hundreds of thousands of years old.
Using arcane methods understood only by scientists like Kennett — a professor emeritus of marine geology, paleoceanography, stratigraphy, micropaleontology, and paleobiology — Nicholson — a research geophysicist at the Marine Science Institute — and Sorlien — a structural evolution geologist with the Earth Research Institute — that involved identifying and comparing carbon and oxygen isotopes in the microfossils embedded in the core sample, the researchers found that the ocean warmed more quickly than previously surmised, possibly when methane plumes would surface after methane hydrates (or methane frozen solid) buried on the ocean margins destabilized into methane gas as sea levels lowered, underwater pressures decreased, and the ocean started to warm.
As well as fascinating details like the fact that the four-meter core sample happened to contain ash from a well-documented volcanic eruption in Yellowstone (which allowed accurate dating of this core) and that it recorded a 4,000-year period during the first warming swing in what would become a 100,000-year-long cycle back to glaciation (the periods had been shifting from 41,000-year cycles for a half-million years or so), this chunk of sea bottom showed that an ocean as vast as the Pacific could warm by 4-5°C in fewer than 50 years. Climate scientists have assumed such a phenomenon could only be accomplished over thousands of years. Instead, the core sample showed that temperature jumps occurred several times, and rapidly, over less than 700 years.