http___metro-portal.hr_koliko-ima-vode-na-zemlji_58133_1.xml
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If Earth was the size of a basketball, all of its water would fit into a ping pong ball. How much water is that? It's roughly 326 million cubic miles (1.332 billion cubic kilometers), according to a recent study from the U.S. Geological Survey. Some 72 percent of Earth is covered in water, but 97 percent of that is salty ocean water and not suitable for drinking. "There's not a lot of water on Earth at all," said David Gallo, an oceanographer at the Woods Hole Oceanographic Institution (WHOI) in Massachusetts. Oceans create a water layer spanning 15,000 miles (24,000 kilometers) across the planet at an average depth of more than 2 miles (3.2 km). If you poured all of the world's water on the United States and could contain it, you'd create a lake 90 miles (145 km) deep. This seems, and looks, like a lot of water, Gallo told Life's Little Mysteries, but looks can be deceiving. If the Earth was an apple, Gallo said, the water layer would be thinner than the fruit's skin. The Earth's freshwater is even rarer. "For humanity to thrive, or even exist, we need to sprinkle that teeny bit of fresh water in the right places, at the right times and in just the right amounts," Gallo said. Here's how Earth's freshwater is spread around the globe: - 70 percent of freshwater is locked in ice caps - Less than 1 percent of the world's freshwater is readily accessible - 6 countries (Brazil, Russia, Canada, Indonesia, China and Colombia) have 50 percent of the world's freshwater reserves - One-third of the world's population lives in "water-stressed" countries, defined as a country's ratio of water consumption to water availability. Countries labeled as moderate to high stress consume 20 percent more water than their available supply. There is much more freshwater stored in the ground than there is in liquid form on the surface, according to the USGS. This article was provided by Life's Little Mysteries, a sister site to OurAmazingPlanet.
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Koliko ima vode na Zemlji Oko 72 posto površine Zemlje je pokriveno vodom, a 97 posto te vode otpada na slanu morsku varijantu koja nije pogodna za piće Kad bi Zemlja bila veličine košarkaške lopte, sva voda koje se nalazi na njoj stala bi u jednu lopticu za stolni tenis. Preciznijim jezikom, vode na Zemlji ima oko 1,3 milijardi kubičnih kilometara, uvjeravaju američki geološki stručnjaci iz USGS-a (United States Geological Survey) koji su proveli istraživanje na tu temu. Oko 72 posto površine Zemlje je pokriveno vodom, a 97 posto te vode otpada na slanu morsku varijantu koja nije pogodna za piće. Drugim riječima, na Zemlji baš i nema mnogo vode, uvjerava David Gallo, oceanograf iz WHOI-ja (Woods Hole Oceanographic Institution) iz Massachusettsa, a citira ga portal LLM. Oceani i mora čine vodeni sloj koji se prostire oko 24.000 kilometara duž Zemlje, a prosječne je dubine 3,2 kilometra: kad biste svu vodu svijeta ulili u Sjedinjene Američke Države (pod pretpostavkom da imaju oblik posude), dobili biste jezero duboko oko 145 kilometara. To se čini kao velika količina vode, ali u izgled vara. Da je Zemlja jabuka, kaže Gallo, sloj vode bio bi tanji od jabučne kože. A slatke i pitke vode je još manje. Da bi ljudi uspjeli preživjeti, potrebno je da pitku vodu rasporede na prava mjesta u pravo vrijeme i u pravoj količini. Evo kako je slatka voda raspoređena: - 70 posto slatke pitke vode zarobljeno je u ledenjacima - manje od 1 posto svjetske pitke slatke vode je dostupno izravno - šest država (Brazil, Kanada, Rusija, Indonezija, Kina i Kolumbija) imaju oko 50 posto svjetskih rezervi pitke vode - jedna trećina svjetske populacije živi u takozvanim „vodostresnim" zemljama koje se definiraju kao zemlje čija je potrošnja vode 20+ posto veća od onoga koliko im je trenutno dostupna u zalihama i izvorima - više je pitke i slatke vode u zemlji nego što je ima u tekućem obliku na površini planeta (tvrde iz USGS-a)