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Des Moines Register: Iowa View--Record Shows Planet will Keep Warming Unless We Act
Wednesday, August 22, 2012
ABOUT THE AUTHOR
JERRY SCHNOOR is a professor at the University of Iowa and co-director of the Center for Global and Regional Environmental Research there. He chaired the Iowa Climate Change Advisory Council . Contact: Jerry Schnoor email@example.com
Can we learn from the drought of 2012? Is this truly the “new normal” climate for which we need to plan? Let’s consider the following.
Weather is what we experience on a day-to-day basis at any location. But climate is the long-term manifestation of weather recorded over decades to centuries and longer.
One indication of decadal climate change lies in long-term trends of daily high temperature records set at weather stations throughout the world compared to the number of record daily low temperatures. In a variable climate system, there will always be new extremes experienced as the record grows longer. But the ratio of record highs to lows should average 1:1. However, on a warming planet, the number of record highs should significantly exceed the number of lows.
That’s exactly what’s occurring — the United States recorded about two new daily highs for every record low temperature in recent years. But by mid-century, climatologists project that the ratio of record highs to lows will increase to 20:1 and by the end of the century it will be 50:1.
While there will always be record cold settings, they will occur much less frequently relative to maximum temperatures over the long run. In July 2012, the U.S. experienced 3,740 record daily high temperatures compared with just 211 record lows, according to Weather Channel meteorologist Guy Walton. Indeed, the drought of 2012 was a rare meteorological event, but we can expect it to occur more frequently in the future because we are “forcing” the climate with accumulated greenhouse gases (GHG) that warm the Earth. When conditions become dry, the air becomes hot relatively easily, like we experienced in Iowa this summer.
Iowa’s past 50 years have been warmer (due to warmer nights and winters) and wetter compared to the early 1900s. Extrapolating from the recent past, we might expect flood years like 1965, 1993, 2008, 2010, and 2011 to become more frequent. On the other hand, climate models predict Iowa will become warmer and somewhat dryer in the 21st century, more consistent with the drought years of 1936, 1956, 1988 and 2012. So there is a fair amount of uncertainty surrounding our future precipitation.
The only thing that we know with some certainty is that it will be warmer overall. Extremes in weather are likely to increase based on the increasing variability seen over the past 30 years. If fossil fuel emissions continue unabated, the planet will grow continuously much warmer for decades and centuries to come.
However, humans can reverse climate change by acting now. Iowa can be part of a global action network, a coalition of the willing, to constrain GHG emissions by 2020 and achieve steep cuts by 2050. Iowans can build a new green economy from wind energy and solar power and biomass resources. As chair of the Iowa Climate Change Advisory Council in 2007 and 2008, I saw a consensus emerge among committee members on policies to save energy, create jobs and curb our greenhouse gas emissions.
It’s a teachable moment. The tendency by some to dismiss the current drought as just another manifestation of variable weather is unfortunate. It fails to acknowledge the clear and present danger of accumulating greenhouse gases and the changing climate it will cause.
The lesson from the drought of 2012 is to act now to create a better future. We should plan for and adapt to extremes — both floods and droughts — while transitioning to renewable resources to mitigate climate change. Investing now in the state’s renewables, energy efficiency and infrastructure will be expensive.
But it’s a future that provides clean air, a vibrant economy and improved resilience to extremes like the drought of 2012.