Warming oceans could melt ice faster than expected
Ice sheets simmering in warmer ocean waters could melt much quicker than realized. New research is suggesting that as oceans heat up they could erode away the ice sheets much faster than warmer air alone, and this interaction needs to be accounted for in climate change models.
"Ocean warming is very important compared to atmospheric warming, because water has a much larger heat capacity than air," study researcher Jianjun Yin of the University of Arizona said in a statement. "If you put an ice cube in a warm room, it will melt in several hours. But if you put an ice cube in a cup of warm water, it will disappear in just minutes."
The researchers studied 19 state-of-the-art climate models and saw that subsurface ocean warming could accelerate ice-sheet melting over the next century, resulting in greater sea level rise that could exceed 3 feet (1 meter). Glaciers in Greenland and Antarctica will melt at different rates, though. [ In Photos: Glaciers Before and After ]
Different strokes for different coasts Given a midlevel increase in greenhouse gases, the ocean layer about 650 to 1,650 feet (200 to 500 meters) below the surface would warm , on average, about 1.8 degrees Fahrenheit (1 degree Celsius) by 2100, the researchers found.
The actual warming in different regions could differ significantly, though. They found that temperatures of subsurface oceans along the Greenland coast could increase as much as 3.6 degrees F (2 degrees C) by 2100, but along Antarctica would warm less, only 0.9 degrees F (0.5 degrees C).
"No one has noticed this discrepancy before — that the subsurface oceans surrounding Greenland and Antarctica warm very differently," Yin said. The discrepancy is caused by different currents in the ocean: The Gulf Stream will send warmer waters toward Greenland, while the Antarctic Circumpolar Current blocks some of the warmer waters from reaching Antarctica.
Warmer waters = melting ice "This does mean that both Greenland and Antarctica are probably going melt faster than the scientific community previously thought," study researcher Jonathan Overpeck, also of the University of Arizona, said in a statement. "We could have sea level rise by the end of this century of around 1 meter [more than 3 feet] and a good deal more in succeeding centuries." Previous estimates had projected sea levels to rise by anywhere between 1.5 and 6.5 feet (0.56 and 2 meters), and in 2011 a study by Eric Rignot, of the University of California at Irvine, and others projected that sea level rise would reach 12.6 inches (32 centimeters) by 2050 alone. Overpeck and Yin's study adds to the evidence that sea level rise by the end of the century will be near the high end of these projects.
Global Average Temperature Updated - News
That recent temperature trend was enough to drag the three-decade moving average, from 1981 to 2010, up by half a degree Fahrenheit from the 1971 to 2000 period, according to the report by NOAA. The 30-year baseline is used by scientists to understand
They found that temperatures of subsurface oceans along the Greenland coast could increase as much as 3.6 degrees F (2 degrees C) by 2100, but along Antarctica would warm less, only 0.9 degrees F (0.5 degrees C). "No one has noticed this discrepancy
Seven locations and your current GPS location can be stored with nicknaming capability. Current weather conditions displayed with location name and time, temperature, wind speed, wind gust speed, and wind direction; humidity, visibility, UV Index,
Every state's annual maximum and minimum temperatures increased on average, the National Oceanic and Atmospheric Administration's National Climatic Center said. The 30-year averages, known as normals, are used to gain an understanding of how current
Phoenix hit a high temperature of 118 degrees on Saturday, topping a 10-year-old record of 116 degrees for the date. The National Weather Service say clouds from monsoon activity likely kept the area from reaching 120 degrees, but they say it's still
Average Temperature July 1, 2011 | Chaos Manor - Jerry Pournelle
I saw where you stated that you haven’t found a good reference for the method of how they make the Global Mean Temperature Anomaly. The first thing to realize is that there is no one method used. The three major surface air temperature datasets; National Climatic Data Center (NCDC), NASA GISS (GISS) and the Hadley/CRU (HadCRUT) all use different methods. However there is some basic similarities across them. For one they all divide the globe into 5° x 5° grid squares. Second they find an average for each grid square. Since the grid squares closet to the poles are smaller area wise compared to the ones closer to the equator when combining the grid they use a weighting system so that the larger squares do not become statistically dominant in the resulting Global Temperature Anomaly. To see how each dataset takes the quality controlled raw data and makes the grid averages you need to read the papers they are based on.
Thank you. I am having trouble following some of the links, but that may be due to where I am. I still have seen no discussion of how these methods are chosen and how and why the weights are assigned to the various cells, nor have I seen any discussion of what methods are used to compensate for the loss of some of the data, such as when all of Siberia didn’t report for a month. By discussion I mean an explanation at the level of “scientifically educated tax payer who is expected to go without some discretionary luxury in order to pay for this” – ie, an explanation of why certain procedures are used, and why the results are often contrary to intuition.
For example, it may be obvious to NASA that last year was the second hottest year ever, but to the outside observer this is more a function of where you measured what, and what weights are given to the various measurements. It was pretty cold in many places. It was cold and wet in others. Surely out of the billions we pay for these models, they could spare a bright graduate student who can explain just what we are paying for? But perhaps I ask for too much.
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