Friday, January 14, 2011

But - but - but - there's snow!

There's snow! On the ground! In 49 states! Global warming is a lie! Gotcha!

Um, except of course, it isn't.
Last year equaled 2005 as the warmest year on record, government climate experts reported Wednesday. ...

"The warmth this year reinforces the notion that we are seeing climate change," said David Easterling, chief of scientific services at the climatic data center. Nine of the 10 warmest years on record have occurred since 2000, he noted. The exception was 1998, which is the third warmest year on record going back to 1880.

Easterling said the data "unequivocally" disproves claims that climate warming ended in 2005.
Those claims themselves were a case of stepping down from the earlier claims that warming ended in 1998. Even so, despite being demonstrably wrong about 1998 and again about 2005, if we don't see yet another "all-time" (i.e., since 1880) record set by say 2012, you can be sure we'll be hearing from the same quarters claims that "global warming ended in 2010." The concept of "long-term trend" just refuses to register with them even when it's this clear:

The "anomaly" is the difference between the temperature and the average of the 20th century as a whole. The 132-month (11-year) running mean is perhaps the most significant line because using an 11-year span smooths out the natural variation in the Sun's irradiance. While recent research offers a hint that the relationship between solar activity and the Earth's climate may be even more complex than was thought, the fact that the 11-year running mean tracks so closely to the five-year running mean indicates rather strongly that the Sun's overall contribution to the global warming being seen now is minor. Which should - but probably won't - be the final nail in the coffin of the nanny-nanny naysayer chant that "it's all the Sun's doing."

(The charts were found at this link at RedGreen&Blue.org.)

Speaking of things that should make other things clear, the report, which came out of NOAA, said it was the 34th consecutive year with worldwide temperatures above the 20th century average and that for the US in particular, while it was only the 23rd warmest year on record, it was also the 14th year in a row with an annual temperature above that long-term average. Just how many years are there in a "not a coincidence?"

One point that struck me was that average ocean temperature was the third warmest on record (average land temp was the highest ever recorded) despite the fact that 2010 was a La NiƱa year, during which tropical Pacific Ocean temperatures are below normal. Which means if it had been a normal year, the ocean (and therefore the overall average) temperature would have been even higher.

Another point was that 2010 was tied for the warmest year ever despite the fact that it
saw record cold and snow in January and February in the Northern Hemisphere, particularly eastern North America,
and December was unusually cool. This simply emphasizes that, as I have said many times, one cold winter no more disproves global warming than one hot summer proves it. It's that overall trend that matters. At the same time, it's worth reminding ourselves that more severe weather patterns are a prediction of global warming models and that the effects of such warming in one area, particularly the polar regions, can actually cause colder weather somewhere else.

All of which means that
[t]hough you can't make a direct link between Australia's killer floods and climate change, they do hold a warning for the future: Scientists predict such extreme weather events will increase both in intensity and frequency as the planet warms. ...

The flooding follows a spate of severe natural disasters in the past year. While the most deadly was Haiti's earthquake, extreme weather also killed thousands of people across the globe, including a scorching heat wave that choked Russia in the summer and devastating floods that engulfed more than 60,000 square miles (150,000 square kilometers) in Pakistan.

"The Earth is delivering a message to us. And the message is that more extreme weather is becoming the norm rather than the exception," said John Magrath, a climate change researcher at British charity Oxfam.
How can that be? A very simple explanation would start by reminding is that heat is a form of energy. At the air and the oceans warm, more energy is being pumped into weather systems. At the same time, warmer air can hold more moisture.

(Which, parenthetically and in case you're interested in a sidebar but if you're not skip to the next paragraph, is why weather forecasts refer to "relative" humidity. It's a measure of how much moisture is in the air compared to how much it could hold at that temperature, expressed as a percentage. So a relative humidity of 50% means there is half the moisture in the air that there could be at that temperature but how much actual moisture is represented by that figure varies with temperature. Which in turn is why you rarely hear the term in weather forecasts except in the summer: At other times of year, the amount of moisture in the air is generally too low to be of concern. Which in turn in turn is why your nose runs in cold weather: It's your body trying to compensate for the dryness of the air. End of sidebar.)

So with global warming you've got more energetic systems with most available moisture, leading to more severe storms and potential floods. At the same time, that tendency to dump more moisture "here" can leave less moisture available "there," leading to droughts. Alternatively, that pattern could play out in one area, so that instead of a pattern of rain mixed with dry spells you get severe storms punctuating extended droughts.

At the same time,
[s]cientists caution against drawing conclusions about climate change from a single storm, flood, cold snap or heat wave. Natural variability is and will always be a factor when it comes to extreme weather.
Which is absolutely true. Which is why, yet again, you look at the overall pattern, the long-term trend. The more you do that, the more the nanny-nanny naysayers look like either fools or liars. Or, more exactly, they look like fools who are being fooled by being lied to by liars.

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