2010 Ties as Warmest Year, Brings Extreme Weather

NASA and NOAA both are reporting that 2010 has tied with 2005 as the warmest year on record.  A plot of the NASA data:

It was also the wettest year on record.

The link between warmer and wetter is pretty straightforward: warmer air holds more water (about 7% per degree C of warming).  A warmer atmosphere also circulates more vigorously.  You might think of the atmosphere as a sponge which has gotten larger and gets wrung out more thoroughly.

Ironically, the same things that cause the atmosphere to become more heavily loaded with water (to oversimplify: enhanced evaporation) also can cause soils and plants to dry out much more quickly.

Climate Progress has interviewed climate scientist Kevin Trenberth, who had this to say:

I find it systematically tends to get underplayed and it often gets underplayed by my fellow scientists. Because one of the opening statements, which I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.

Trenberth has written a paper, Changes in precipitation with climate change (PDF), which gets into the gory details.

Perhaps more worrying is this Climate Progress quote from meteorologist Dr. Jeff Masters, discussing the huge increase in extreme weather events in 2010: 

In my thirty years as a meteorologist, I’ve never seen global weather patterns as strange as those we had in 2010. The stunning extremes we witnessed gives me concern that our climate is showing the early signs of instability. Natural variability probably did play a significant role in the wild weather of 2010, and 2011 will likely not be nearly as extreme. However, I suspect that crazy weather years like 2010 will become the norm a decade from now, as the climate continues to adjust to the steady build-up of heat-trapping gases we are pumping into the air. Forty years from now, the crazy weather of 2010 will seem pretty tame. We’ve bequeathed to our children a future with a radically changed climate that will regularly bring unprecedented weather events–many of them extremely destructive–to every corner of the globe. This year’s wild ride was just the beginning.

Emphasis mine.  (More on that later.)

The increase in rainfall presents a huge problem for infrastructure, not only because existing infrastructure is unable to handle the associated increases in runoff, but also because engineers have no good way to decide what to design for.

For example, a normal design criterion is to make the design (a road or drain system or bridge or whatever) able to withstand a "100-year" storm, i.e., a storm which has a 1 in 100 chance of happening in any one year.  But now many areas are having 100-year storms about every 5 years.

What to do?

I saw one very sophisticated and elaborate study that went to great efforts to get data for the last 150 years.  They did a fabulous analysis on that data and published beautiful color maps of 100-year (and 5-year, 10-year, etc.) storms for use in engineering design.

That's nice, but our climate started on its present path in the mid-1970s.  Anything before that reflects a climate which no longer exists.

There is a saying in shooting: "You cannot miss hard enough."