Freshwater use and conservation

0:00(footsteps crunching) - [Narrator] It's a beautiful warm day, and I'm taking my dog, Rumble Thunder Paws, for a walk. As we finish our usual hike, coming down a rocky slope in Eastern Tennessee, I give him some water to drink from a water bottle, but how do I know that my water is safe for him to drink?

0:18After all, only 2.5 percent of all the water on Earth is freshwater and only a portion of that is safe to drink. The rest is saltwater and isn't safe for us to drink. So with only a tiny portion of all of our water on Earth being freshwater, how do we use it? Where does it go?

0:36And is it disappearing? And can we make more? So first, let's think about how we use freshwater. You and I use freshwater every day. Whenever you brew a cup of tea or take a shower, you're using freshwater. Surprisingly, only eight percent of our freshwater use goes to domestic purposes, like cooking, cleaning, bathing, and drinking, or in the case, when I fill my water bottle with tap water for a hike with good old Rumble Thunder Paws.

1:05In contrast, though, the great majority, or about 70 percent of global freshwater use goes to agriculture. And while that seems like a lot of water, and it is, this makes a bit of sense too. We need to eat and we need water to grow food. And as populations increase, that means more people that need food, and more food that we need to grow.

1:29And, of course, more water that we need to use. Finally, about 22 percent of all freshwater worldwide goes to industrial uses, which includes electricity production, fossil fuel extraction, and manufacturing. Industries tend to use mainly freshwater because saltwater corrodes the metal parts used in machinery.

1:51Even though we use a lot of water, the amount of freshwater on Earth now is the same as there always has been. The only difference is that the population of humans has increased by leaps and bounds, meaning that there's more of us, and more demand for freshwater.

2:06This figure shows how the human population has increased over time, in particular from the 1950s onwards. And this part of the figure shows estimates for the future human population. Keep in mind that as there's more of us, more people need freshwater, but with increased demand, there's just less available freshwater that's been treated, and is safe to use.

2:30In many parts of the world in particular, in drier areas, freshwater sources are being used and drained faster than they are being replenished by rainwater, or other sources. And there are other threats to freshwater, including pollution, agricultural runoff, habitat loss, and climate change.

2:47Let's take a closer look at one of these. Agricultural runoff puts excessive nutrients into surface waters that can cause harmful algal blooms. This just goes to show just because water isn't salty doesn't mean it's fresh enough, or clean enough for consumption.

3:03So if we have such a small amount of freshwater, why don't we treat saltwater so we can drink it? Well, that's definitely possible. You can actually make freshwater from saltwater through desalination, which removes the dissolved salts in saltwater. Unfortunately, desalination processes are expensive, energy-intensive and involve large-scale facilities, so it's not a very accessible option right now.

3:31So what else then, can we do to conserve freshwater on Earth? Well, there's lots of things we can do. You can take shorter showers, or turn off the tap while you're brushing your teeth. You can also get involved in your local community and check if there are initiatives or practices that reduce water use by businesses, industries, agriculture, and government.

3:52Let's do a quick summary. Freshwater is an incredibly important but limited resource. We use it for all kinds of things from bathing and drinking to growing food and producing electricity. Although we're not losing freshwater, sometimes we use freshwater faster than it is able to be replenished, but we can all do our part to conserve freshwater by making small changes to our everyday habits.

4:16What do you think Rumble? (dog softly whining) Me too. I know that you'd like shorter showers and baths, for sure, buddy. And with that, I think I'll take Rumble out for a quick stroll around the neighborhood.