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On 26 July 2017, supplement and paranoia peddling website NaturalNews.com made a sweeping conclusion about climate change based on a portion of a single chart they found. The post, by Mike Health Ranger Adams, uses a time series of satellite sea level data from the National Aeronautics and Space Administration to argue that climate change is no big deal and that the mainstream media is ignoring data that proves him right: To prove this, Adams points to NASA’s satellite altimetry data — used by scientists to precisely measure global average sea level change since 1993 — which he says busts the whole global warming thing wide open, despite its fairly unambiguous long-term upward trend: The region of the chart — around the last two years of the record — that allegedly proves global warming is a lie is highlighted above. It shows a period of generally flat sea level rise. Astute chart readers, however, may note that there have been a number of times throughout the record in which sea level rise has been flat, or even briefly reversed, before continuing the more dominant rising trend. According to University of New South Wales climatologist and sea level expert John Church, this is the reason the media is silent on the issue; in fact, it is in no way newsworthy: To understand why the event is not noteworthy, one needs to understand both the short- and long-term drivers of sea level change. From a long-term global perspective, there are two primary drivers of sea level rise: the first is the balance between water trapped in ice and water contained within the ocean itself. Simply put, when ice that is trapped on land melts, it increases the volume of water in the ocean, causing sea level to rise. The second major driver is known as thermal expansion — when water gets warmer it expands, increasing its volume. Research suggests that these two contributors alone explain 75 percent of the observed sea level rise since 1971. These larger trends, however, can be dampened (or enhanced) by shorter term weather patterns. The most important factors to consider on this time-scale are the El Niño-La Niña cycle (which affects both water temperature, as well as evaporation and precipitation of moisture) and the hydrological issues associated with where rainwater falls on land. The best illustration of these factors combining to alter the overall trend of sea level rise is the 2010-2011 drop in sea level mentioned above. In this instance, the confluence of La Niña and a number of other atmospheric circulation patterns forced an anomalously large amount of rain to fall over the uniquely bowl-shaped continent of Australia, as described by Scientific American: Eventually, of course, this water evaporates and returns to the ocean, where it joins the expanding and increasing global ocean reservoir. We spoke to Fasullo — the lead author on the study that documented the cause of the 2010-2011 drop in sea level — about this current hiatus, and he told us it in no way conflicts with our understanding of the connection between global warming and sea level rise: Ultimately, the story published by Adams attempts to disguise a weather as a climatological trend, University of California, Santa Cruz Climatologist Gary Griggs told us: Using two years of data to make sweeping claims about trends in the global climate system, especially when such fluctuations are known and understood by science, is misleading and inaccurate, and as such we rank this claim as false.
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