This natural-color satellite image shows small blue and green lakes in northern Siberia, near the Gulf of Ob. 
 
 Until now, no one knew for sure how many lakes exist on Earth. 
 
 Blame geography — most of the world's lakes are in places where humans don't live, said David Seekell, an environmental scientist at Umea University in Sweden. "This is something one would have assumed had been done long ago, and was in a textbook somewhere," Seekell said. 
 
 Lake size was a liability, too. Millions of lakes are too small for mapmakers to bother charting. 
 
 Instead of counting lake by lake, earlier estimates were statistical guesses, based on the number of lakes in a parcel of land or on average lake size. One widely cited study from 2006 estimated the lake total at 304 million. [5 Surprising Facts About Lakes ] 
 
 A new study published Sept. 16 in the journal Geophysical Research Letters sidesteps these problems. With high-resolution satellite data and supercomputers to check every cloudless pixel, researchers now have the best count yet of lakes on Earth. The result? There are 117 million lakes in the world. 
 
 Yet the bodies of water cover more land (3.7 percent of Earth's surface) than previous studies had predicted. This is because quite a few medium- to large-size lakes were missing from older databases, said Cory McDonald, a research scientist with the Wisconsin Department of Natural Resources, who was not involved in the study. 
 
 "I was surprised that the total surface area they measured was much greater than previous estimates," said Cory McDonald, a research scientist with the Wisconsin Department of Natural Resources, who was not involved in the study. "We knew there problems with the extrapolation methods used to fill the data gap for the small lakes, but previous estimates assumed we had a pretty good handle on the medium- to larged-sized ones," he told Live Science in an email interview. "This study largely puts to rest the long-debated questions of 'How many lakes there are in the world and how much surface area do they cover?'" 
 
 About 90 million of the lakes fall in the smallest size category, measuring 0.5 to 2.5 acres (0.2 to 1 hectare), the study reports. That's equal to a country house lot, a large farm pond or 1.9 American football fields. 
 
 "Most lakes are in the far North, and there's actually quite a few of them," said Seekell, a co-author of the new study. "Even if they're small and no one sees them, they are potentially important for global-scale environmental issues like the carbon budget," he told Live Science. 
 
 Climate scientists believe lakes influence greenhouse gas levels in the atmosphere. Lakes pump out carbon dioxide and methane — both greenhouse gases — but they can also lock away carbon for centuries by trapping it in their cool bottom muds. Without an accurate count, the role of lakes is difficult to assess, Seekell said. 
 
 According to the new results, the world's lakes cover about 2 million square miles (5 million square kilometers), which is 3.7 percent of the land uncapped by glaciers. 
 
 Most lakes are in the Northern Hemisphere between 45 degrees north latitude and 75 degrees north latitude. (Think about Canada, Russia, Alaska, Northern Europe and the Great Lakes.) This results from the tectonic scattering of continental landmasses and the past positions of glaciers, the researchers said. There is less land in the southern high latitudes, and the North's sizable plains were scraped by ice age glaciers, leaving behind millions of pothole lakes. 
 
 The majority (85 percent) of Earth's millions of lakes are at low altitudes, found at elevations less than 1,600 feet (500 meters) above sea level. 
 
 The study excluded the Caspian Sea, the world's largest lake, which covers an area of about 143,000 square miles (371,000 square km). Antarctica and Greenland were also left out of the study. (Antarctica has about 400 lakes buried by ice.) 
 
 The researchers plan to freely release the lake database, Seekell said. They also intend to update the count with higher-resolution data from the Landsat 8 satellite. 
 
 "Lakes are not static on the landscape, and in some parts of the world, they are disappearing quite quickly," Seekell said. 
 
 In certain regions of Russia and Alaska, higher temperatures are causing what was once permanently"frozen ground, called permafrost, to thaw, causing small lakes to dry up. Melting permafrost under a lake is like a cracked tub liner — the lakes drain out from their bottoms. Drought and overuse are also shrinking lakes. In northern China, for instance, more than 100 lakes disappeared during the 2000s from these causes. 
 
 Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science. ||||| Several Russian news outlets are reporting that Russian scientists have successfully drilled to Antarctica's Lake Vostok, a massive liquid lake cut off from daylight for 14 million years and buried beneath 2 miles (3.7 kilometers) of ice. 
 
 The lake is the object of a years-long project to study its waters, which may house life forms new to science. 
 
 The news appears to have originated from Ria Novosti, a state-run news agency, which ran the following quote from an unnamed source with no affiliation: "Yesterday, our scientists stopped drilling at the depth of 3,768 meters [12,362 feet] and reached the surface of the sub-glacial lake." 
 
 The same news report went on to discuss an old theory that Nazis built a secret base at Lake Vostok in the 1930s, and that German submarines brought Hitler and Eva Braun's remains to Antarctica for cloning purposes following the German surrender in World War II. 
 
 "There are a lot of rumors going around about penetrating the lake, and we need the Russian program to make the official announcement," said John Priscu, a University of Montana microbiologist and veteran Antarctic researcher who has been involved in Lake Vostok investigations for years 
 
 "If they were successful, their efforts will transform the way we do science in Antarctica and provide us with an entirely new view of what exists under the vast Antarctic ice sheet," Priscu told OurAmazingPlanet in an email. 
 
 It appears there has been no official confirmation of the team's success. There are no press releases on the website of Russia's Arctic and Antarctic Research Institute, the government agency that oversees the country's polar science expeditions. 
 
 Possible cold-loving life 
 
 Lake Vostok, about the size of Lake Ontario, is the largest lake on the icy continent. Scientists estimate the lake itself is roughly 14 million years old — the age of the ice sheet that covers it — and that the water currently in the lake is roughly 1 million years old. 
 
 Scientists believe the lake could be home to cold-loving microbial life adapted to living in total darkness. The organisms likely survive using mechanisms similar to the ever-increasing parade of creatures that have been discovered living in the total darkness of hydrothermal vents at the bottom of the ocean, deriving energy from minerals in seafloor rocks. 
 
 Today's news follows on the heels of other unsourced reporting from American news outlets last week, which claimed the scientists were lost, and that something sinister was afoot at Vostok Station. Priscu, who has been in contact with Russian science headquarters in St. Petersburg over the course of the 2011-2012 field season, has firmly refuted such reports. 
 
 The Vostok team has been racing against the approach of Antarctica's brutal winter weather. Extreme cold can prevent aircraft from operating, and could maroon the team at the station during the total darkness and bitter temperatures of austral winter. 
 
 Temperatures have already plunged below minus 49 degrees Fahrenheit (minus 45 degrees Celsius), and Priscu said it was likely the team would need to leave by this week at the latest. [The Coldest Places on Earth] 
 
 Race to test for life 
 
 Even if the Russian team has reached the lake, they will be forced to wait until next season to actually sample the water because of the type of drill they're using, which can bring back only ice — not liquid water — from the deep borehole. The water must freeze over the Antarctic winter before researchers can lay hands on it, to see what organisms might be living in Lake Vostok. 
 
 Two other nations are mounting projects to drill into ancient Antarctic lakes hidden beneath miles of ice, and with drill technology that can fetch liquid water samples for analysis in the space of days. Both lakes are in West Antarctica, in conditions slightly less brutal than those at Vostok Station, which holds the record for coldest temperature ever recorded on Earth: minus 129 degrees F (minus 89 degrees C), in July 1983. 
 
 The British are positioned to start drilling at Antarctica's Lake Ellsworth in autumn 2012, and an American team hopes to begin drilling to the Whillans Ice Stream, a network of subglacial waterways, in January 2013. 
 
 If the Russians have indeed reached Lake Vostok this week, it could be a close contest to see who will be first to test whether life can go on in the cold darkness beneath Antarctica's ice. 
 
 Reach Andrea Mustain at amustain@techmedianetwork.com. Follow her on Twitter @AndreaMustain. Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet and on Facebook.
– Eight years ago, a much-discussed study estimated that there were 304 million lakes on Earth—but a careful count reveals that the number is closer to a third of that. The planet holds 117 million lakes, researchers find in what LiveScience calls the "best count yet." And while they may be fewer in number, they take up more of the Earth's surface than scientists had thought: some 3.7% of it, it turns out. Experts used computers to count the bodies of water using high-resolution satellite images. "This is something one would have assumed had been done long ago, and was in a textbook somewhere," says a researcher. One reason it wasn't: Most lakes are far from human residences, and millions are so small they haven't appeared on maps, LiveScience reports. Indeed, 90 million of the lakes counted were between 0.5 to 2.5 acres, or less than two football fields. The new figure measures the lakes around today, a number that can easily change; indeed, the Aral Sea, once the fourth-biggest lake on Earth, is now almost dry, the Independent reports. So what's the point of all this counting? "If we are to be able to make realistic estimates of the collected effects of the different processes in lakes, for example their contribution to global warming, we first need a good map," a researcher says in a press release. (Of course, we're not the only planet with lakes.)