Question: Currently only 3% of the water on earth is drinkable and most of this water is found in glaciers. How can we increase this percentage so that more people can access water easily and prevent them from gaining diseases?

Harriet Aitken answered on 18 Jun 2014:

Hi Lillymiss,

That’s a difficult one, water is in a cycle called the hydrological cycle constantly moving between the groundwater, oceans, the atmosphere and back to the surface as rain/snow. Water in glaciers, although not appearing to be in this continuous cycle is in a relatively delicate balance so if we upset this balance we have to think about the consequences. Does a glacial provide a habitat for creatures? What will happen to the sea level – if we remove the glacial volume, it ultimately end up back in the water cycle which could be disastrous!

In some ways, we are getting better at reusing the water we have – there are many different types of water purification available like filtration, or chemical methods like coagulation (unwanted chemicals clumping together) and sedimentation (those clumps then settling out of water). But with an increasing demand for water, not only drinking water but water for farms and production, we will for sure have to try to increase the percentage of fresh (and clean!) water available.

The biggest source of water is by far the oceans and there are currently methods to purify salt water. One of the oldest ones is just to heat salty water, if you collect evaporated water the salt is left behind and you are left with clean water. Unfortunately, heating is expensive so it doesn’t make for a very cost effective solution. A second way is using a membrane, salt ions are actually quite large so my using a small filter (membrane) we can get rid of the salt leaving us again with clean water. Unfortunately this has its own downfall – although not as expensive filters can often become blocked and the by product is very very salty water – you have to think about what you will do with this, if you were to just put it back in the ocean you might end up harming plan and/or sea life in the area.

There are pros and cons to any technology, but something has to be done. I think that membrane filtration would be the most successful way to increase the availability of fresh water on earth but it’s a tough area of research with lots of great scientists working on this!