Some wonder if the record snow in places such as Des Moines, and bonebreaking cold temps, mean the climate change theory is wrong. No, it doesn’t, mainstream climate scientists say. In fact, extreme weather can be an indicator of global warming and climate change. It’s the global average temperature over time that is the issue. Read an analysis by James Hansen of NASA

An Essay on Regional Cold Anomalies within Near Record Global Temperature

James Hansen, Reto Ruedy, Makiko Sato, Ken Lo

Overview. Public skepticism about global warming was reinforced by the extreme cold

of December 2009 in the contiguous 48 United States and in much of Eurasia. The summer of

2009 was also unusually cool in the United States. But when a cold spell hits, we need to ask:

* Cold compared to what. Our memory of the past few winters? Winters of our

childhood? Winters earlier in the 20th century?

* Cold where and for how long? Regional cold snaps are expected even with large

global warming. Weather fluctuations can be 10, 20 or 30 degrees, much larger than average

global warming.

* The reality of seasons. As the plot of Earth we live on turns away from the sun, in

winter or at night, it cools off. That’s true even with global warming, albeit not quite so much.

Before addressing these matters, we note that scientists reporting global warming have come

under attack for a supposed conspiracy to manufacture evidence of global warming. Perhaps because

some members of the public accept these charges as reality, vicious personal messages are sent to the

principal scientists almost daily.

The spiral into an almost surrealistic situation with ad hominem attacks on scientists may have

originated in part with vested interests who do not want society to address climate change. But there is

more than that – including honest, wishful thinking that climate change is not really happening. But

wishing does not alter facts.

The scientific method practically defines integrity. [Albert Einstein: “The right to search for truth

implies also a duty; one must not conceal any part of what one has recognized to be true.” Richard

Feynman: “The first principle is that you must not fool yourself – and you are the easiest person to

fool.”] All scientists make honest mistakes, but the scientific method is designed to correct them. The

skeptical nature of the scientific method causes conclusions to be reexamined as new data appears.

Cases of deliberate fudging of data, of scientific fraud, are so rare that these infrequent episodes live in

infamy for decades and even centuries.

We know of no cases of fraud in analyses of global temperature measurements. Despite

unfounded accusations, we believe that our best approach is simply to continue to report our scientific

results as clearly as possible. Most of the public continue to respect scientists for what they do and how

they do it. We presume that most of the public can separate science from political commentary.

Our data show that 2009 was tied for the second warmest year in the 130 years of near‐global

instrumental measurements – and the Southern Hemisphere had its warmest year in that entire period.

Before discussing these data, and their reconciliation with regional cold anomalies, we must consider

the time frame of comparison.

If we look back a century, we find cold anomalies that dwarf current ones. Figure 1 shows

photos of people walking on Niagara Falls in 1911. Such an extreme cold snap is unimaginable today.

About a decade earlier, in February 1899, temperature fell to ‐2°F in Tallahassee, Florida, ‐9°F in Atlanta,

Georgia ‐30°F in Erasmus, Tennessee, ‐47°F in Camp Clark, Nebraska, and ‐61°F in Fort Logan, Montana.

The Mississippi River froze all the way to New Orleans, discharging ice into the Gulf of Mexico.

As we will show, climate is changing, especially during the past 30 years. The changes are

perceptible, even though average temperature change is smaller than weather fluctuations. The answer

to the simple question: “How come it’s so damned cold” turns out to be simple: “Because it’s winter.”

full 14page report can be found here