Climate Matters: Warmer and drier climate dulls fall foliage

Fall colors are behind schedule this year and may not be as brilliant as in the past, thanks to a warming and changing climate.

This year was a good example of how different fall looks and feels as summer heat stretches longer and the fall cooldown hits more abruptly later in the season.

Temperatures have been much warmer than normal in recent months, over 2 degrees above average for September. Rainfall has also been much lower than normal; it was the second driest August ever recorded in Columbia.

Bob Rives, a forester with the Missouri Department of Conservation, says we need the opposite to see good colors in the fall. "The things that we look for that traditionally people have associated with good fall color would be increased levels of moisture or good moisture throughout the whole growing season," Bob says. But it is rarely so cut and dry.

Climate change is making an already complicated task even more difficult as the environmental triggers for fall foliage are changing. "If we have a warming, drying climate, it's going to extend our growing season, so the timing of fall color may gradually go further into October and into November," Bob says.

He also predicts that fall colors will be delayed and staggered, with trees changing at different times. "We associate drier weather with poorer fall color, or maybe a sequence where the different species don't all change at the same time, which makes for less of a colorful peak."