Forces of Change was commissioned by Jacob Swanson, saxophone, on the theme of climate change. The piece is a loose concerto construction, in three movements:
I. Extreme Weather Events (fast)
II. Sea Ice Melts (slow)
III. Sea Levels Rise (building, fast)

The music in each movement is directly related to climate change data, researched from the National Center for Atmospheric Research and climatologist Jeff Weber of Boulder, Colorado. Despite the doomsday forecasts, many climatologists are hopeful that humanity will be able to survive ourselves, and live in a more resilient way in cooperation, not competition, with nature.

I. Extreme Weather Events

In the first movement the saxophone’s melodies are derived from the number of extreme weather events in the US from 1910-present (graphed here). The orchestra evokes the spirit of these events, such as hurricanes, droughts, and floods. The movement ends with uncertainty, but within that is a glimmer of hope.

II. Sea Ice Melts

In the second movement, the orchestra floats calmly on a “sea” of chords, while the saxophone drifts in arc-like melodies like an arctic tern. The sax’s range very slowly reduces as the ice melts. Each chord in the orchestra derives from climate data--low sea ice levels means fewer and lower notes, and high sea ice levels means more full, wide-ranging chords.

III. Sea Levels Rise

In the third and final movement, the orchestra carries two main melody lines, representing the temperature of the Earth and the rising levels of the sea. Many times one line trails right behind the other as it rises in pitch and rhythm. The sax highlights the increasing rates of the data. The piece ends with the racing ahead of the “temperature” melody line, as we await our uncertain future.