Micah I respect you and your posts, but that article (although it has some good points) screams the dreaded word "new age" and so does many parts of the rest of the website.
To answer the original poster. Since we as magickal practioners use the energy within all of nature, and work from the inside (spiritual) out (physical) to produce a change/influence, it is possible to effect the elements as we may effect anything (IE: people, situations, etc). But something never comes from nothing. You can provoke a physical spark into a flame, but not cause an element to manifest out of nowhere. In another example, we can produce an effect of healing in the body/mind because our physical bodies have a natural ability to heal themselves, we merely help it along in the right direction with magick.
When working with nature we must understand how it works in order to know how to produce the effect we desire. And not just how it works spiritually but physically as well. After that, it's a matter of determination, patience, practice, practice, and more practice.