Last Three Years the Quietest For Tornadoes Ever

schwit1 writes The uncertainty of science: 2014 caps the quietest three year period for tornadoes on record, and scientists really don't understand why. "Harold Brooks, a meteorologist with the National Severe Storms Laboratory in Norman, Okla., said there's no consistent reason for the three-year lull — the calmest stretch since a similar quiet period in the late 1980s — because weather patterns have varied significantly from year to year. While 2012 tornado activity was likely suppressed by the warm, dry conditions in the spring, 2013 was on the cool side for much of the prime storm season before cranking up briefly in late May, especially in Oklahoma, SPC meteorologist Greg Carbin said. Then, activity quickly quieted for the summer of 2013."

Comments

And where are all the hurricanes?

[Anonymous Coward]

It's been a while since a cat 3 made landfall on a US shore, hasn't it?

Re:And where are all the hurricanes?

[Geoffrey.landis]

More storms, more violent storms, the coasts scoured down to bedrock by hurricanes, the interior a hell of violent weather.

I don't recall anybody ever predicting "the coasts scoured down to bedrock by hurricanes, the interior a hell of violent weather".

It's worth summarizing what we actually know (minus the idiotic alarmism), what we have some models for but still need details, and what is simply speculation.

Here is what we do know: greenhouse gasses added to the atmosphere increases the average temperature of the planet, and this includes the greenhouse gasses added by human activity. The physics of this seems to be sound, large numbers of measurements bear out the fundamentals, and so far all the alternative theories that say greenhouse gasses don't increase average temperature have been failed; they've been ruled out by evidence.

There is still quite a large set of error bars on how much warming to expect from anthropogenic greenhouse gasses. A hundred different groups have studied this problem (this is not one or two climate scientists) with models using different assumptions. The best estimate is 3 degrees kelvin per doubling, with error bars of about plus or minus 1.5. The amount by which the planet has so far warmed due to anthropogenic effects is slightly over a half degree-- call it about one degree Fahrenheit. Let me point out how small that is-- you probably wouldn't feel the difference between, say, a fall day with a high of 54 F or one that's 55. However, on a global scale, this has an effect, and it's worth noting that the warming is cumulative-- the average will go up from there, not down.

However, it's also important to not that this is an average. It's not what you see in one particular location, or one particular day, or even any particular year. This is summarized by the motto "climate is not weather." Any location--any region-- might be warmer of cooler than the average in any given year.

The effect of this warming on weather--extreme storms-- is less well known. This is a much harder problem to model. The best models suggest that warming will increase extremes of weather, but this is not a robustly confirmed result, and exactly which extremes of weather-- hurricanes? typhoons? Arctic storms? Tornados? Droughts? Floods?-- needs a lot of work to model well.

In general, these predictions of increases of extreme weather are long term predictions. So far, the warming is still relatively small. If we keep increasing the amount of greenhouse gasses in the atmosphere, the effect (assuming that better models confirm that there is an effect) will be larger. This is a long term effect, not a short term one-- we're talking effect of warming of several degrees, not the current half degree. Not next year, but in decades in the future. And even then, predicting an average increase in large storms doesn't necessarily say large storms hitting the continental US will increase-- we are discussing the world, not the few percent of the world that is called the U.S.

But in general, detailed effects are much harder to model than global averages.

And of course, any given storm cannot be ascribed to global warming. All the people who said "Hurricane Sandy is an example of global warming!" were simply off base. Climate is not weather.

Re:Time to openly admit...

[itzly]

Climate is not weather. The chaotic variations in weather tend to cancel out when measured over longer time frames, and wider area. There is no doubt that the total energy contained in the Earth's oceans and atmosphere is rising, even if we can't predict year to year exactly what's going to happen.