NASA study finds Earth's lakes are warming

Nov 23, 2010
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.

(PhysOrg.com) -- 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 . "The results have implications for , which can be adversely affected by even small water temperature changes."

Small changes in water temperature can result in that can make a toxic to fish or result in the introduction of non-native species that change the lake's natural ecosystem.

Global trends in seasonal nighttime lake surface temperatures, 1985-2009. Image credit: NASA/JPL-Caltech

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 data that can be used to provide a comprehensive, accurate view of how surface temperatures are changing worldwide.

The NASA researchers used thermal from National Oceanic and Atmospheric Administration and European Space Agency satellites. They focused on summer temperatures (July-September in the and January-March in the ) 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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omatumr
1.7 / 5 (6) Nov 24, 2010
Really? NASA isn't manipulating the data this time?

Since Climategate, many of us are aware of President Eisenhower's 1961 warning that government research funds might produce a "scientific-technological elite" that would seize control of public policy.

www.youtube.com/w...=related

Our once proud space agency has lost a lot of credibility.
ekim
4 / 5 (4) Nov 27, 2010
Really? NASA isn't manipulating the data this time?

Do you have evidence?
It seems that "climate gate" isn't the conspiracy you think it is. You would think a global conspiracy would provide more evidence of it's existence.
http://www.indepe...222.html
Ethelred
3.7 / 5 (3) Dec 04, 2010
Oliver's evidence consists of the vast global conspiracy to hide from all mankind his idea that the Sun has an iron core and that neutrons repel each other.

Clearly now YOU have joined me in this vast conspiracy even though we have yet to learn the secret handshake.

In other words don't hold your breath waiting for Oliver to do more than give a One in reply. Oh, he did say Bull to one of my posts this week. That is the best reply he seems to be able to manage.

Requests for evidence all point to his own papers which don't have actual evidence that support his conclusions.

Ethelred