October 24, 2011

Natural Variability Still Plays Large Role in Winter Climate

Filed under: Climate Forcings, Solar

The last couple of winters across the central and eastern United States as well as much of Europe were on the cold and snowy-side of things, to say the least. And of course, anytime there is some type of weather misery, a particular segment of the population likes to trot out global warming as the culprit. Cold, snowy, winters are no exception (despite your apparent (mis)conception as to what global “warming” would entail). Ironically, a subset of this same segment of folks was fingering global warming as the reason for the string of warmer-than-normal winters immediately preceding our past two shiverers (Figure1).

Now comes word that things other than global warming can lead to winter weather extremes. While that may come as shocker to some, it should be a snoozer to the vast majority.


October 17, 2011

No Change in Storminess

As we enter the winter season, we all realize that if a large snow storm forms anywhere on the planet, someone will immediately appear and claim we are witnessing the effect of global warming. However, winter storms (aka extratropical cyclones) are tough to sell to the public given the images of cold, snow, wind, and misery at the low end of the temperature scale. So if winter storms are a hard sell, hurricanes (aka tropical cyclones) are nothing short of ideal – warm water, heavy rain, wind, and misery in already warm parts of the world.

But, it turns out that in either case, new research reported in the scientific literature finds little in the way of changes that are unusual in today’s climate of “global warming.”


October 11, 2011

IPCC Mischaracterizes Precipitation Changes

Filed under: Precipitation

It it’s 2007 Fourth Assessment Report (AR4), the Intergovernmental Panel on Climate Change (IPCC) investigated the character of the changes in precipitation that have been observed across the world over the past half-century or so. In doing so, they concluded:

Observed changes in intense precipitation (with geographically varying thresholds between the 90th and 99.9th percentile of daily precipitation events) for more than one half of the global land area indicate an increasing probability of intense precipitation events beyond that expected from changes in the mean for many extratropical regions (Groisman et al., 2005; Figure 3.39, bottom panel). This finding supports the disproportionate changes in the precipitation extremes described in the majority of regional studies above, in particular for the mid-latitudes since about 1950.

Here’s the graphic mentioned in the quote above:

Figure 1. Bottom panel of IPCC AR4 Figure 3.39 showing “regions where disproportionate changes in heavy and very heavy precipitation during the past decades were documented as either an increase (+) or decrease (–) compared to the change in the annual and/or seasonal precipitation” (from IPCC AR4, 2007).

The problem is, is that the methodology that the IPCC relied upon was insufficient to base such a conclusion.

Over those regions where a more appropriate methodology has been employed, contrary to IPCC proclamations, the changes in intense precipitation events have proven to be very much proportionate to the observed changes in total annual precipitation. And even though the IPCC knew that this was the case for at least one of these major land areas (the United States), they nevertheless chose to forward the mischaracterization.

Chalk up another addition to the list of IPCC errors.


October 3, 2011

Malaria Declines Despite Local Warming

Filed under: Adaptation

“Spreading tropical disease” is high on the list of bad things that are going to happen as the world warms—if you believe the doomsayers. And topping their list of spreading tropical diseases is malaria.

But, as we have on many past occasions pointed out, malaria is neither “tropical” nor is it “spreading.”

In fact, back in the late 19th century, malaria was thought to be endemic in most regions east of the Rocky Mountains—brought to the U.S. in the 16th and 17th century by European colonists and African slaves and spreading across the country with the migration of those populations (Zucker, 1996).

Figure 1. Region of the U.S. where malaria was thought to be endemic in 1882 (source: Zucher, 1996).

Malaria transmission was still a problem in some parts of the U.S. into the mid-20th century, and, in 1946, when the CDC was established (back then it was known as the Communicable Disease Center) its primary goal was to eradicate malaria from the U.S.—which it successful achieved within a few years (with the help of DDT).

All the while, the average temperature in the U.S. was on the rise, increasing by some 1 to 2 degrees between 1882 and the early 1950s.

Clearly, a warming climate did not leading to an expansion of malaria in the U.S.

Nor does it appear to be doing so elsewhere.


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