Anyone who's turned on the TV or read a newspaper in the last two months knows that there's a big drought on in the eastern United States, especially strong from northern Virginia to Southern New England. Ominously, the epicenter lies along the Washington–New York's Interstate 95 axis—and thus it is fated to be a drought more important than any other weather event in world history.

Figure 1. Drought severity for the eastern United States. Source: Drought Monitor, www.cpc.noaa.gov.

The media seems to think that whatever weather happens in its Vatican—I-95 from the Washington Monument to the Statue of Liberty—is somehow indicative of national and global trends. Perhaps they accrued this knowledge from the recently published U.S. National Assessment of global warming, which takes global climate models and erroneously applies them to regions like this one. (That little bit of junky science may land the Assessment in the garbage heap—see your previous issue of WCR).

The last I-95 weather whopper was the huge snowstorm of early January 1996, which prompted a Newsweek with the headline "Blizzards, Floods and Hurricanes: Blame Global Warming." The analogous cover for this drought, we predict, will grace Time's cover within the next two months. And given that magazine's previous track record on this issue, you can bet that Time will be sure to conflate a dry Baltimore with a hot planet.

In fact, this is a very bad drought. New York's reservoirs are way down, during a time of year in which they should be brimful. If conditions do not change in the next two months (and there's no real reason to expect them to), 2002 will rival 1930, which is the drought of record for the last century. (There are spotty records showing a much more extensive drought of four years' duration in the early 1850s in portions of the East).

If that comes to fruition, a tremendous amount of eastern forest is likely to go up in smoke this summer. In 1930, 300,000 Virginia acres burned, a figure that has never even been approached in the succeeding seven decades. Much of the Appalachian region was heavily logged in the late 19th century, so the trees in 1930 were a lot younger than they are now.

Which means there's much more to burn this time, in part because of the increasingly old trees we continue to hug. Large tracts of this senescent vegetation were damaged in the big ice storms of the 1990s, which has left a huge amount of seasoned fuel on the forest floor. Much of Shenandoah National Park's woods look like hell about to break loose, just given enough heat and drought.

It was so dry in 1930 that the normally moist surface layer turned to powder, allowing the sun's energy to concentrate exclusively on raising the temperature rather than evaporating water. As a result, many of the all-time-hot records hail from that summer. Given an extreme drought, along with the extreme pavement growth of the Washington and Baltimore areas, a temperature of 110°F will not be at all out of the question in 2002, nor would 107°F, farther north in very urban New Jersey. The rural record in Virginia, by the way, was set in July, 1930, at 109°F.

As an antidote to what will certainly be overhype of an already bad situation, perhaps a look at long-term trends in record high and low temperatures over the United States is in order. The reference for this is a 2001 paper in the journal Climate Research, published by our research group at the University of Virginia, which we describe in detail in WCR, Vol. 7, No. 1.

There are really three epochs of climate in the United States for the last 100 years. Temperatures increased rapidly in the first third of the 20th century, decreased somewhat in the second third, and then rose again in the last third. For what it's worth, there's no significant net change in the last 90 years. What "warming" trend there is in the overall record was induced in the first decade of the 20th century, 100 years ago.

We do live in an era of climate extremes—which is to say, extreme journalism about climate. But will the temperature extremes we are boldly forecasting (assuming the drought continues) merit the lurid coverage we forecast with equal confidence?

Hardly. When we look at the early 20th-century warming period, we find that, more than anything else, it was the hottest days of the year that were getting hotter. That's a climate tending toward more extreme temperature 70 to 100 years ago. When we look at the mid-century cooling, we find that, more than anything else, the coldest days got colder. That's a climate also tending toward more extreme temperature 40 to 70 years ago.

The picture during the recent warming is completely different. By far, the biggest change is that the coldest days of winter are warming up. That's a tendency toward a climate with fewer temperature extremes.

What about precipitation? Over the last 100 years, U.S. rainfall has gone up about 10 percent. As are result, there is more water available for all. This is borne out by examining records of long-term soil moisture, which shows a slight but statistically significant increase in the last 100 years. That we show no real net warming in the last 70 years means there is simply more water available now, everything else being equal. Nor is it being evaporated away at an increasing rate that compensates for the increase in rainfall, which is a mainstay of the apocalyptic argument.

More than anything, this information makes the current severe drought and expected extreme temperatures in the East doubly anomalous. Both conditions will occur in spite of an overall tendency for increased rainfall and soil moisture, and in a regime dominated by moderating annual temperatures, where the coldest air of winter is showing the greatest change, rather than the hot air of summer.

But all of this won't stop a lot more hot air from escaping from the television this summer, when Washington is likely to be dry-roasted, New York will sizzle, and climate hysteria will be thermonuclear.

Reference:

Knappenberger, P.C., P.J. Michaels, and R.E. Davis. 2001. Nature of observed temperature changes across the United States during the 20th century. Climate Research, 17, 45–53.