“Extreme summer climate anomalies in Texas in 2011, in Moscow in 2010, and in France in 2003 almost certainly would not have occurred in the absence of global warming with its resulting shift of the anomaly distribution. In other words, we can say with high confidence that such extreme anomalies would not have occurred in the absence of global warming.”
This quote is from a new scientific paper in Proceedings of the National Academy of Sciences. The paper will be freely available online Monday August 6 as article #12-05276: Proc. Natl. Acad. Sci., "Perception of climate change", Hansen, J., Mki. Sato, and R. Ruedy. A draft copy can be downloaded here.
I often hear people state that we need to reduce our emissions of heat trapping carbon dioxide for our children and grandchildren’s sake. Unfortunately, human-caused global warming has already caused large increases in extreme heat waves. Global warming-caused extremes are happening now.
Figure one shows June-July-August temperature anomalies for three years within the base period 1951-1980 as compared to the temperature anomalies for the previous six years 2005-2011. (Anomalies measure how much warmer or cooler a value is from normal. For example, body T is normally 98.6 degrees. If you had a fever and your body T was 101.6 degrees, your T anomaly would be +3 degrees.) Colors toward the right such as yellow, red, and brown represent above normal temperatures while colors toward the left such as aqua and blue represent below normal temperatures.
In 1955, 1965, and 1975 the warmer vs. cooler regions mostly cancelled each other out which is what one would expect due to natural weather patterns. However, one can quickly see that the most recent years reveal many more locations with well above normal temperatures. Notice the large brown region of very hot T in Europe in 2010 (Russian Heat Wave) and the brown region of very hot T in the US in 2011 (Texas/Oklahoma drought). Extreme hot T is winning out and the pattern does not match that of “normal weather”.
The authors then determined just how extreme the past six years were by using a mathematical term called standard deviation denoted by the symbol sigma. A three sigma value means one should expect to see that temperature only 0.1 to 0.2% of the time (1 or 2 times per thousand chances). See figure two for a visual of standard deviation.
Figure three shows that the previous six years had these rare three sigma events covering between 4% and 13% of the world. In the absence of human caused global warming, one would expect the brown areas to cover only 0.1–0.2% of the planet.
So what we can expect in the future?
If humans keep dumping billions and billions of tons of heat-trapping CO2 into the year each year the extreme heat appearing now will appear mild to what is coming. Figures four and five (IPCC, 2007) show what is expected to happen to global air T depending on which carbon emission scenario the world chooses to follow. Unfortunately, we are following the worst-case scenario right now with no sign that we will choose to exit the carbon highway to hell.
According to Synthesis Report from the Climate Change Congress - University of Copenhagen (Richardson et al., 2009):
"Recent observations show that societies and ecosystems are highly vulnerable to even modest levels of climate change, with poor nations and communities, ecosystem services and biodiversity particularly at risk. Temperature rises above 2oC will be difficult for contemporary societies to cope with, and are likely to cause major societal and environmental disruptions through the rest of the century and beyond."
Look where we are by the end of the century if we do not take action now to reduce our carbon emissions. The US is covered by values that have blown past the safe level of 2C. A simple way to think about climate change is this: Human body T is very sensitive to even small changes in T. If your body T rises three degrees you know you are very sick and you need to do something. Climate change is no different. The values appearing in the moderate to high growth scenarios are killers. The planet has a fever and we must act to avoid it getting too high.
In my blog post I showed how I was able to reduce my energy bill by more than half. Energy efficiency is something you can do right now to avoid Mother Nature from getting a really high fever and it pays you $$$.
Unfortunately, we need to do much more than just being energy efficient. We need to begin shifting away from dirty, expensive fossil fuels such as coal and oil, and begin to add cleaner, cheaper technologies such as solar, wind, hydro, and geothermal to the grid. I also think we need to have an intelligent, adult conversation about using more nuclear power. Think these are too difficult? Think again. I invite you to watch three excellent videos that show how people around the world, including in the US, are tackling their energy needs by going green and how they are prospering. See Earth: The Operator's Manual where Dr. Richard Alley explains climate change and energy choices. View Episode #1, Episode #2, and Episode #3.
Finally, being an election year, we must decide if addressing climate change is an issue that will determine how we vote. Only through government support will the US be able to shift to clean green technologies thus securing better health, improved national security, economic competitiveness, and energy independence from the Middle East.
As a group, the Republican Party of the United States of America does not accept the overwhelming scientific understanding that humans are causing climate change. Make your voice count. Vote this November.
