Arizona's Climate Change Induced Agricultural Crisis?

In an article from the Arizona Daily Star newspaper, environment reporter Tony Davis discusses the predictions of the Bloomberg, Steyer, and Paulson collaboration on climate change impacts for the United States (aka, the Risky Business Project). According to Davis' article,

"Crop yields for staples such as wheat, cotton, soybeans and corn could take a big hit in Arizona by 2099, dropping by 25.9 to 51 percent from current levels, the report says."

First off, Arizona produces only tiny quantities of these "staples." Arizona's corn acreage makes up only  0.09 percent of the US total, and its production is only 0.07 percent of the national harvest. Wheat production in Arizona is only 0.4 percent of the national total, cotton is 3.6 percent, and soybean production in the state appears to be so inconsequential that the USDA doesn't report it in either its 2013 crop summary or its online statistical database.

We've long been hearing that Arizona is going to turn into an unbearable oven because of anthropogenic climate change and increasing maximum temperatures. Some scientists (notably, James Hansen) have postulated that the southern states will become almost uninhabitable.

July is the hottest month in Arizona. Here are the statewide maximum temperatures since 1930. See any trend, especially a man-made climate change signature? Nope, because there isn't any trend.

No trend in Arizona's maximum temperature during the hottest month for more than eight decades. There were three anomalously hot years in the 2000s, but 1999 was tied with 1950 for the lowest maximum over this period, the last two years have been below normal -- as have three of the last six. The same lack of trend since 1930 is also found in each of the state's seven individual climate divisions.

There hasn't been a hint of a significant trend in annual precipitation for Arizona since 1895. No significant trend in summertime precipitation, either, over the past 120 years. Even the normally hot and dry southern regions of the state have no significant trends since 1895 in either their annual or summertime precipitation.

Average temperatures throughout the state did increase from the 1970s up to the mid-1990s, but then they stopped flat and haven't gone anywhere at all since then. Two decades of no warming -- meanwhile, atmospheric greenhouse gas concentrations have kept skyrocketing. Summertime average temperatures also have no significant trend since the mid-1990s, including in the southern regions of the state.

The absence of significant trends in all these variables over time periods ranging from the last couple decades up to well over a century should lead to far more caution in apocalyptic modeling predictions.

Which leads us back to crop yields in Arizona. Despite the hysteria over the current decade-long drought, 2010 saw the highest ever yields of corn and wheat since records in the state began way back in 1882, while 2011 set a record yield for cotton dating back to the start of its records in 1912. There are absolutely no signs of declining trends in yields for any of these crops over the past decade, and over the past two decades the trends are all upwards.

The 18 highest corn yields in Arizona's history have taken place during the last 20 years. The 9 highest cotton yields have all occurred during the past decade, and the one outlier -- 2005 -- was the 13th highest on record.

Over at the Smithsonian Magazine, Colin Schultz has recently claimed that "Arizona is bone dry, desiccated by the worst drought ever seen in the state's 110-year long observational record. The Grand Canyon State has been in drought conditions for a decade, and researchers think the dry spell could hold out for another 20 to 30 years."

Worst drought ever? The cumulative statewide precipitation over the past decade isn't the worst ever. There were worse periods in the 1950s and early 1900s. The current 60-month precipitation index for the state is nowhere near as low as in the early 1900s, and effectively equivalent to what it was during the 1950s.

The drought index for May -- the latest month available -- is only the six worst on record, not the worst, and the drought index for the past year is only the 15th worst since 1895. The 60-month drought index was far worse in the early 1900s than at anytime since the most recent drought began. In the southwest climate division -- by far the driest portion of the state -- the 60-month precipitation index is currently only 10 percent below normal, and ranked only 43rd worst out of 115 periods (i.e., it is about average).

Facts such as these may not be as entertaining as reading the over-the-top end-of-the-world activism that passes for "science journalism" nowadays, and this is the fundamental problem that confronts the climate realists. As long as science journalism fails to uncritically examine and present the realities of our climate, the further away from reality much of the public moves.