While we were trying (unsuccessfully) to find the criminals who hacked the e-mails of scientists, and trying (unsuccessfully for the most part) to point out that being victims of a crime does not mean a group’s research is faulty, and watching the disastrous results of the cynical assault on American politics by e-mail thieves and modern enemies of Hypatia, the world continues to spin. Galileo so aptly described the news: Eppur si muove!
Lake Tahoe, seen here from Emerald Bay, was one of the primary validation sites for the global lake study. The lake, which straddles the borders of California and Nevada, is the largest alpine lake in North America. Image credit: NASA-JPL
Against those religiously inclined to ignore the facts, a modern Galileo could say: Eppure, lei si scalda!
Just a few months ago critics of science told us that the Copenhagen conference on climate change was unnecessary, because the world is cooling, and not warming. Eleven months ago, supporters of the theft of e-mails from the Hadley Climate Research Unit in Britain claimed that researchers had goofed about global warming, and then covered it up. The sad old Earth kept turning and orbiting . . .
Comes now this news from NASA:
November 23, 2010
Jet Propulsion Laboratory, Pasadena, Calif.
RELEASE : 10-308
NASA Study Finds Earth’s Lakes Are Warming
WASHINGTON — 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 0.81 degrees Fahrenheit per decade, with some lakes warming as much as 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-September in the Northern Hemisphere and January-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 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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Global trends in seasonal nighttime lake surface temperatures, 1985-2009. Image credit: NASA/JPL-Caltec
World wide, a few lakes show not a great deal of warming, but none of the lakes sampled showed any cooling over the past two-and-a-half decades.