At 8:30 p.m. local time on March 23, perhaps two billion people will recognize Earth Hour by turning off lights. It will be a time to consider our obligation to the earth’s environment in light of the responsibilities assigned to humanity in the biblical story of creation.

For most of human history, we relied on our own muscles for the energy we needed to survive. We worked fields with simple tools, fished with lines and small nets that we could handle, and foraged on foot for food and fuel. A fit human could maintain an energy output equal to 70-80 watts.

Today, the farmer works his fields in the air conditioned cab of a tractor with more than 100,000 watts. We fish from big trawlers hauling nets which can stretch for a mile, and remove whole species from the sea. The office worker arrives at his building in a powerful car and is carried up many stories in an electric powered elevator.

As William Catton put it in his pioneering work “Overshoot,” we are no longer mere homo sapiens, with little impact on the earth’s environment. We are now homo colossus, each of us having the energy impact of the hundreds of slaves once controlled only by lords and kings. We can clear large forests, dam great rivers and bulldoze mountain tops to reach mineral resources.

As we recognize Earth Hour, let us remember to take seriously the responsibility that came with God’s grant of dominion over the earth and its inhabitants.