[Coral-List] FW: NASA Study Finds Earth's Lakes Are Warming
GJ at fishion.eu
Tue Dec 7 15:43:54 EST 2010
Please see below a study by NASA showing warming of lakes all around the globe.
I am fully aware that there is not a single coral living in a freshwater lake. Aside from squeezing the term coral in to get this message through ;-), the relevance to coral reefs is that these findings show a global phenomenon and that it is the result of many actual measurements. As I see no reason why seawater would not warm when freshwater does, I am inclined to believe the authors that this is evidence of global warming. Clearly something is happening.
Question though is how relevant a period of 25 years is. Is there any other explanation than GW for this warming in the past 2.5 decades? I guess that plant material and seeds in a lake bottom should give a record of past temperatures and that such studies have been done. Is anyone on the list aware of those and could someone shed light for us on the relevance of this study? Geologists, sceptics, please...
A full degree C in a decade seems pretty impressive. That is 10 degrees in a century... imagine that on a reef... ecological changes would be enormous..
Regarding the recent debate on the content of the coral-list 2 issues that got sort of mixed up: issues and how we communicate.
I really prefer to see the list open to discussion such as climate change directly related to reefs or not. After all it is considered one of the major threats to reefs and must be within the scope of this list. The more we know, the better we can judge and ask the next scientific question.
But I fully agree with anonymous that all the personal bantering is annoying and embarrassing. We're all human and have emotions. That's what we are and is fine. But a global broadcast of first moment feelings doesn't serve any purpose and only takes the focus away from the real message and issue. When I am in doubt, I often find it helpful to write a response, save it and amend it the next day before I send it. Maybe this could help. Or else if you feel the need to vent your feelings, please communicate with each other directly and save good old Jim the headache.
Don't sarcasm, personal attacks, etc usual tell us more about the sender than the receiver...
As to questioning the motives of governments, isn't this exactly what democracy is about?
Warm wishes, GJ
Dr Gert Jan Gast - Fishion Consultancy
Koningin Wilhelminakade 227, 1975GL IJmuiden, the Netherlands
Ph +316 5424 0126, Fax +31255 521546, Skype gjgast
NASA Study Finds Earth's Lakes Are Warming
by Staff Writers
Pasadena CA (JPL) Nov 24, 2010
In the first comprehensive global survey of temperature trends in major lakes, NASA researchers determined Earth's largest lakes have warmed during the past 25 years in response to climate change.
Researchers Philipp Schneider and Simon Hook of NASA's Jet Propulsion Laboratory in Pasadena, Calif., used satellite data to measure the surface temperatures of 167 large lakes worldwide.
They reported an average warming rate of 0.45 degrees Celsius (0.81 degrees Fahrenheit) per decade, with some lakes warming as much as 1 degree Celsius (1.8 degrees Fahrenheit) per decade. The warming trend was global, and the greatest increases were in the mid- to high-latitudes of the Northern Hemisphere.
"Our analysis provides a new, independent data source for assessing the impact of climate change over land around the world," said Schneider, lead author of the study published this week in the journal Geophysical Research Letters. "The results have implications for lake ecosystems, which can be adversely affected by even small water temperature changes."
Small changes in water temperature can result in algal blooms that can make a lake toxic to fish or result in the introduction of non-native species that change the lake's natural ecosystem.
Scientists have long used air temperature measurements taken near Earth's surface to compute warming trends. More recently, scientists have supplemented these measurements with thermal infrared satellite data that can be used to provide a comprehensive, accurate view of how surface temperatures are changing worldwide.
The NASA researchers used thermal infrared imagery from National Oceanic and Atmospheric Administration and European Space Agency satellites.
They focused on summer temperatures (July to September in the Northern Hemisphere and January to March in the Southern Hemisphere) because of the difficulty in collecting data in seasons when lakes are ice-covered and/or often hidden by clouds. Only nighttime data were used in the study.
The bodies studied were selected from a global database of lakes and wetlands based on size (typically at least 500 square kilometers - 193 square miles - or larger) or other unique characteristics of scientific merit.
The selected lakes also had to have large surface areas located away from shorelines, so land influences did not interfere with the measurements. Satellite lake data were collected from the point farthest from any shoreline.
The largest and most consistent area of warming was northern Europe. The warming trend was slightly weaker in southeastern Europe, around the Black and Caspian seas and Kazakhstan. The trends increased slightly farther east in Siberia, Mongolia and northern China.
In North America, trends were slightly higher in the southwest United States than in the Great Lakes region. Warming was weaker in the tropics and in the mid-latitudes of the Southern Hemisphere. The results were consistent with the expected changes associated with global warming.
The satellite temperature trends largely agreed with trends measured by nine buoys in the Great Lakes, Earth's largest group of freshwater lakes in terms of total surface area and volume.
The lake temperature trends were also in agreement with independent surface air temperature data from NASA's Goddard Institute for Space Studies in New York. In certain regions, such as the Great Lakes and northern Europe, water bodies appear to be warming more quickly than surrounding air temperature.
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