Kvenvolden K A
U.S. Geological Survey, 345 Middlefield Road, MS999, Menlo Park, CA 94025, USA.
Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3420-6. doi: 10.1073/pnas.96.7.3420.
For almost 30 years. serious interest has been directed toward natural gas hydrate, a crystalline solid composed of water and methane, as a potential (i) energy resource, (ii) factor in global climate change, and (iii) submarine geohazard. Although each of these issues can affect human welfare, only (iii) is considered to be of immediate importance. Assessments of gas hydrate as an energy resource have often been overly optimistic, based in part on its very high methane content and on its worldwide occurrence in continental margins. Although these attributes are attractive, geologic settings, reservoir properties, and phase-equilibria considerations diminish the energy resource potential of natural gas hydrate. The possible role of gas hydrate in global climate change has been often overstated. Although methane is a "greenhouse" gas in the atmosphere, much methane from dissociated gas hydrate may never reach the atmosphere, but rather may be converted to carbon dioxide and sequestered by the hydrosphere/biosphere before reaching the atmosphere. Thus, methane from gas hydrate may have little opportunity to affect global climate change. However, submarine geohazards (such as sediment instabilities and slope failures on local and regional scales, leading to debris flows, slumps, slides, and possible tsunamis) caused by gas-hydrate dissociation are of immediate and increasing importance as humankind moves to exploit seabed resources in ever-deepening waters of coastal oceans. The vulnerability of gas hydrate to temperature and sea level changes enhances the instability of deep-water oceanic sediments, and thus human activities and installations in this setting can be affected.
近30年来，人们一直密切关注天然气水合物，它是一种由水和甲烷组成的结晶固体，被视为一种潜在的（i）能源资源、（ii）全球气候变化因素以及（iii）海底地质灾害。尽管这些问题中的每一个都可能影响人类福祉，但只有（iii）被认为具有直接重要性。对天然气水合物作为能源资源的评估往往过于乐观，部分原因在于其极高的甲烷含量以及在全球大陆边缘的广泛分布。尽管这些特性很有吸引力，但地质环境、储层性质和相平衡因素降低了天然气水合物的能源资源潜力。天然气水合物在全球气候变化中可能扮演的角色常常被夸大。尽管甲烷是大气中的一种“温室”气体，但许多从分解的天然气水合物中释放出的甲烷可能永远无法到达大气，而是在到达大气之前可能被水圈/生物圈转化为二氧化碳并封存起来。因此，来自天然气水合物的甲烷对全球气候变化的影响可能很小。然而，随着人类在沿海海洋不断加深的水域中开发海底资源，由天然气水合物分解引发的海底地质灾害（如局部和区域尺度上的沉积物不稳定和边坡失稳，导致泥石流、滑坡、坍塌以及可能引发海啸）正变得越来越重要且迫在眉睫。天然气水合物对温度和海平面变化的敏感性加剧了深水海洋沉积物的不稳定性，因此在这种环境下的人类活动和设施可能会受到影响。
