"What the heck is it with all the floods?" Is a common question I've received from many of you recently. Just in the last few years alone, monsoons sparked catastrophic floods that have displaced millions of people in India. England and Wales saw their wettest summers ever recorded in more than two centuries of record keeping. China's heavy rains recently killed 120 in flooding and landslides. The horrific flash flood in Southwest Arkansas earlier this month. That's not all Mozambique, Uruguay and Sudan suffered remarkable floods, while climate experts warned that more extreme weather is likely to come if global warming continues unabated.
Of course, we'll never forget how bad the flooding has been the last couple of years locally with southern West Virginia and Eastern Kentucky hit hard by devastating flash floods.
I know Global Warming is a topic up for debate and many of you may not think the climate is changing and I'll be the first to admit, we still need more data over a longer period of time to see if these weather extremes are in fact due to a globally warmed planet.
Here's some information I've found.
The United Nations calls extreme weather a sign of global warming and it blamed the 2007 record hot average global temperature for spawning flooding, deadly heat waves and wildfires.
There's a 90 percent chance we'll see more frequent heavy rainfalls and heat waves this century, according to a worldwide consortium of scientists and government officials known as the Intergovernmental Panel on Climate Change. Already, it reports, "the frequency of heavy precipitation events has increased over most land areas."
What gives? First, there's a simple principle. Warm air holds more moisture than colder air. So as the planet warms, more moisture is suspended in air... then periodically falls to the ground.
Then there are societal issues compounding matters: people like to build in floodplains, that nice relatively flat land that unfortunately historically served as an overflow basin for when rivers breached their banks. Asphalt and concrete and just about any kind of development, even adding a deck or patio exacerbate matters. When rain falls, it can't soak into the ground. Water flows down roads and into streams at rates far faster than historically, scouring out the banks and flushing away fish. Porous pavement and other green advances in development can alleviate these problems somewhat.
Perhaps one of the most unexpected results of climate change for the general public is this flooding. It seems counter-intuitive with warming. If the Earth is warmer, we should have droughts and less water, right? Well, because of increased evaporation and altered weather patterns, you indeed can get bigger floods and drier droughts, all in the same place.