Chalk - specifically magnesium carbonate - was first introduced into rock climbing in the 1950s for the purposes of being able to achieve more dynamic, gymnastic moves on the rock by helping to dry sweat on the hands and improve grip.
In the years since, it became a commonly accepted practice within climbing around the world.
Depending on the rock, chalk can be highly visible and this can be a cause for concern to land managers and Traditional Owners.
On different rock types and over the years, it can also have subtle physical effects. Sandstone and limestone will absorb chalk over time and gradually become smoother and blemished.
Overhanging routes and boulder problems that are sheltered from the elements allow for chalk to build up if we do not clean as we go.
What we can do
Consider taking a more mindful approach to chalk and limiting use to when it is needed.
Be aware of the terrain - are you using chalk in an area that will receive rain?
Bring a brush - climbing stores usually stock the correct type for the right rock. Soft boar hair brushes are great for sandstone, whereas wire brushes are damaging.
Try to avoid creating tick marks or patting the rock with chalk. Encourage a clean approach to brush tick marks off regularly. For many climbers these marks can also be a spoiler or even bad beta for their onsight attempt.
The less evidence that we leave of our presence in the outdoors, the more likely the next person is to enjoy the same experience.