in addition to sand, glass usually requires two other main components: sodium carbonate and calcium carbonate. as with most industrial processes, the availability of these ingredients is changing dramatically due to climate change and human production methods. 

sodium carbonate as a flux lowers the melting point by about 250° c. after extraction in salt lakes, it is manufactured using the solvay process, which requires a high level of water and energy as well as quicklime: rare limestone heated to 1000° c.

on top of that, many natural salt lakes are shrinking rapidly due to global warming. “since 1847, the volume of water level has dropped nearly 50 percent. more recently, the change has been so dramatic, you can see it from space.”

limestone is removed in large mines to get calcium carbonate. the material is used in all possible areas of our everyday life, but it is limited. limestone was formed over hundreds of millions of years and there is an annual usage of 5000 million tons of limestone.

potassium carbonate can be extracted from wood ash. a forgotten flux that was used in previous years. seashells consist largely of calcium carbonate and once formed some of the limestones. finely ground they give glass the well-known durability.

the increasingly scarce material quartz sand has not yet been replaced. in contrast to concrete and other high consumers, glass can be recycled endlessly. it can even be ground to sand again, which means that the material is in a closed cycle if the additives are harmless. unfortunately, many glasses are not.