"By" is the preposition we use to tell the listener who or what is responsible for something existing or happening. Example: This poem was written by Edgar Allen Poe. That house was designed by Frank Lloyd Wright. He owns a painting by Picasso. There is a salt lake in southern Chile that was formed by a tsunami. The shovel was used by Henry for 20 years before it broke. I heard someone say that pink sunsets are caused by pollution..... I hope this helps.

Which storm are you talking about? The threat of global warming is real and eminent and we have been witnessing some of the drastic changes in global temperature, floodings, melting of polar ice, sea level rise and droughts. The situation may worsen unless some concrete steps is taken to mitigate the adverse effect of climate change.