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Summertime – When the Livin’ is HOT and DRY
The summers of 2011 and 2012 were the hottest summer on record in the past 60 years. Steven A. Root, Certified Consulting Meteorologist, has been examining hourly and daily temperatures in 59 hub cities dating back to January 1, 1950. Root computes the cooling degree days (CDD) for each city, each day of the year. Cooling degree days are the number of degrees that a day's average temperature is above 65 degrees. The hottest summer in Root's records was 2011 with 60,402 CDDs. “The summer of 2012 is on pace to finish third hottest on the list of 62 summers since 1950, with an estimated 59,484 CDDs, but is still in the running for number two or one on the list,” Root said. The second hottest summer, according to Root was 1951 with 60,078 CDDs.
NOAA’s National Climatic Data Center also rates the summer of 2012 as the third-warmest summer for the contiguous U.S. on record. The summer of 2012 also ranked18th driest among all summers since 1895, with the drought in the nation’s mid-section marking the driest year for eight states. That summer marked the first time since 1957 that over half the country had been in drought for three consecutive months. And the severe drought covered 39% of the lower 48 states.
National Geographic reported that temperatures across the continental U.S. soared in 2012 to an all-time high. “2012 marks the warmest year on record for the contiguous U.S., with the year consisting of a record warm spring, the second warmest summer, the fourth warmest winter, and a warmer than average autumn,” said Jake Crouch, a climate scientist at the National Climatic Data Center at the U.S. National Oceanic and Atmospheric Administration (NOAA).
National Geographic also reported: 2012 was also the 15th driest year on record for the nation. The average precipitation total for the contiguous U.S. was 26.57 inches (67.5 centimeters), 2.57 inches (6.5 centimeters) below average. Moreover, every one of the lower 48 states had above average temperatures. Nineteen states had their warmest year on record and an additional 26 states experienced one of their top ten warmest years on record.
So what factors account for these drastic rises in temperatures and decreases in rainfall across the nation? One reason is the concentration of carbon dioxide in the atmosphere, which acts as insulation for the Earth, holding in the heat created by the sun’s warming of the planet and contributing to fluctuating changes in weather patterns.
Since 1958, scientists from the Scripps Institution for Oceanography have been using an instrument on the top of the Mauna Loa volcano in Hawaii to measure CO2 in the atmosphere. Charles David Keeling, a geochemist affiliated with the Scripps Institution of Oceanography at the University of California, San Diego, started measuring carbon dioxide levels from Mauna Loa in 1958. The troposphere is where the bulk of Earth's atmosphere resides. It's the buildup of carbon dioxide in the troposphere that has climate scientists concerned. Atmospheric carbon dioxide has been rising steadily since measurements began in 1958.
The level of carbon dioxide in the atmosphere has now reached a new level – 400 parts per million (ppm), highest that it’s ever been in Earth’s history. Keeling’s first measurements showed carbon dioxide levels at 313 ppm. The 400 ppm is a reminder of just how rapidly our atmosphere is changing - taking only 55 years, half a person’s lifetime. Ralph Keeling, who took over the monitoring project at Scripps after his father died in 2005, says a daily reading of 400 ppm really marks the beginning of a transition that will play out over several years.
Out of a million air molecules, 400 are carbon dioxide. That's 0.04 percent. “Lots of things that are present in small amounts can have big impacts,” Keeling said. “These are not small changes in percent terms. Two or 3 million years ago was the last time we had concentrations in this range, so we're moving into territory that's almost outside the scope of human existence on the planet at this point.”
The majority of the increase is attributed to burning fossil fuels, such as coal in power plants, petroleum products, and gasoline in automobiles. Half of the carbon dioxide that we've put into the air by burning fossil fuels has actually stayed in the air, and will remain there for centuries. The other half has been soaked up by the oceans, trees, soils, vegetation and so on. But Richard Houghton of the Woods Hole Research Center says we shouldn't assume that nature will be able to keep this up forever. For one thing, as the oceans warm, their ability to soak up carbon dioxide will slow.
“Climate change is primarily a consequence of the addition of carbon dioxide into the atmosphere. We emit carbon dioxide, through burning fossil fuels or forests, and some of that carbon stays in the atmosphere, intensifying the heat-trapping greenhouse effect and warming the climate. What kind of global warming we’ll see in the future will largely be due to how much carbon dioxide—and to a lesser extent, other greenhouse gases like methane—we add to the atmosphere. And to fully understand the future, we need to understand the present and the past, and track the concentration of CO2 in the Earth’s atmosphere,” wrote Bryan Walsh, senior editor of Time magazine’s Science & Space section, May 2.
To see historical carbon dioxide levels on the hundred- or thousand-year scale, researchers can study ice core samples. Air gets trapped in ice as it freezes, so sampling ice from increasing depths allows scientists to chart carbon dioxide levels far into the past. Data for this 2,000-year history come from ice core samples taken from the Law Dome in Antarctica.
Air data from the Mauna Loa observatory, added to data collected from 2,000 years in history from ice and snow measurements, show stark trends in atmospheric carbon dioxide. Data show carbon dioxide levels fairly steady, hovering around 275 ppm from 2,000 years ago to the early 1900s, when a steep increase began that continues to the present.
Since 1896, scientists have been trying to the question: What will happen to the temperature of the earth if the amount of carbon dioxide in the atmosphere doubles?
Climate scientist Michael Mann, distinguished Professor of Meteorology at Penn State University and author of the book, The Hockey Stick and the Climate Wars: Dispatches from the Front Lines, believes we may already be experiencing some of the effects. “If we look at the past year here in the U.S., last summer, the record heat, the record drought, the record wildfire that destroyed large forest areas in Colorado, New Mexico. We saw tremendous damage to our crops in the breadbasket of the country. We saw Arctic sea ice diminish to the lowest level we've ever seen, and it's on a trajectory where there will be no ice in the Arctic at the end of the summer in perhaps a matter of 10 years or so. We also saw the devastation of Superstorm Sandy. Now, we can't say directly that Hurricane Sandy was caused by climate change, but many of its characteristics are precisely the kinds of characteristics that we predict tropical storms and hurricanes will have if we continue to warm the planet. We will see more destructive tropical storms. We'll see more flooding,” he said in an interview May 14, 2013.
What can be done about the problem? Mann recommends: “We need to find a way to transition away from fossil fuel energy that we know is degrading the climate. We have to find a way to level the playing field so that the marketplace will allow renewable energy sources to compete with fossil fuel energy.”
“CO2 levels will not likely stop at 400 ppm—barring an immediate turn away from fossil fuels, CO2 emissions will keep growing globally, and CO2 concentrations will keep rising,” Walsh concluded. “The U.N.’s official goal is to keep CO2 levels below 450 ppm, and as Ralph Keeling has indicated, we’re rapidly running out of time to make that happen. CO2 can stay in the atmosphere for centuries, which means that we’ve already locked in far more warming than we’ve yet experienced. The Keeling Curve (data from Mauna Loa) tells us our past, but it’s also a roadmap for our future—a future that will almost certainly be hotter.”
NOAA: Carbon Dioxide Levels Reach Milestone at Arctic Sites
Third Hottest Summer on Record for U.S.
Summer of 2012 in running for Hottest Summer on Record
2012: Hottest Year on Record for Continental U.S.
A Change in Temperature
Greenhouse Effect: CO2 Concentrations Hit Record High of 400 PPM
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