The link between strange and extreme weather and climate change. Does it matter?

The powerful killer tornados that blasted across the Southeast on Tuesday were - according to Dr. Jeff Masters, the most deadly mid-winter tornados in recorded history with the exception of a storm in January, 1949. The drought that continues to plague northern Georgia, Alabama and the Carolinas is equally unusual in that region's history.

Scientists and responsible science writers (such as Chris Mooney) are admitting that in both cases - and in general - they must be very cautious about attributing these oddball extremes to climate change.

Fair enough. That's how science should and must be. But really, does it matter? If we are witnessing hundreds of broken records for temperature, rainfall and drought in the course of a year, there's a gut level instinct that tells you something is changing in the world. No one has yet defined how we'll mark the official, scientifically sanctioned and approved beginning of Climate Change. No one has described how we will someday look back on history and set a pushpin on a timeline and declare, "This is when the climate began to change."

We certainly can't say that just because over 50 people were killed in February tornados this year, we can expect to see such patterns repeated from now on. The most certain thing we can say about climate change is that its behavior will be uncertain. Our weather patterns may change, but they may not settle into any patterns at all.

I think it's fair to say that having the Arctic ice cover disappear, having countless glaciers retreat, having severe flooding in England, catastrophic drought in Australia and shrinking snowpack in the Rockies all represent changes in...something. We can studiously avoid blaming these facts on global warming, but not if it means denying that they are happening.

From record heat to record early snow?

Southern California - swimmin' pools, movie stars.....and some mighty weird weather.

Two weeks ago they were baking in the midst of triple-digit temperatures as drought conditions pushed the water managers to the brink of imposing restrictions. Now, the National Weather Service is predicting the possibility of snow in mid-September.

"This system will be almost unprecedented in terms of cold weather and snow levels for September in southwestern California," the NWS said.

"Many locations may well set record low maximum temperatures on Friday, with temperatures more typical of January rather than September," forecasters said.

Here in the San Francisco suburbs, we've had a day of cooling temperatures and steady winds that forced the Alameda/San Francisco ferry to curtail service. Feels like autumn back East.

So much for simplifying your wardrobe to fit the warming climate.

Drought and its list of woes

If it stops raining where you live and stays that way for long enough, your life must change. Unless you can find water from other sources - drilling new wells, importing it from a distance, desalination of ocean water - you'll be forced at least to ration your uses of water, as will everyone in the affected region. No more watering the lawn or washing the car. No more filling the pool and taking those long showers. The cost to you of whatever water is left may rise to cover the expenses of importing, manufacturing or preserving it.

I've subscribed to Google Alerts for "drought," which gets me a daily email of stories containing that word. I get a lot of sports stories describing baseball players and their "hitting droughts." But there are plenty of places in the world currently suffering prolonged lack of water. The impacts range from ranchers destroying livestock to starving elephants raiding villages to recreational lakes drying up and leaving boats sitting in the mud. Of course, drought dries up agricultural land and raises the risk of fires. Drought indirectly raises the prices of agricultural products. It stresses trees, making them vulnerable to bugs and disease.

Farmers are the most directly affected by drought. They will seek relief from the government if their crops can't grow. Those whose businesses are indirectly affected by the drought - markets that sell fruits, vegetables, dairy and meat products - don't get that kind of relief. They seek other sources and raise their prices accordingly. The consumers bear the brunt of the passed-along costs.

Extended drought, which can go on for years and even decades, can not only drive farmers and ranchers out of business, but can lead to whole communities being uprooted and whole regions becoming dustbowls. Water tables drop and wells dry up. Rivers shrink. Water rationing becomes so severe that residents move to other moister climes. Vegetative cover dies off, leaving the soil vulnerable to severe erosion if and when a good rain storm happens.

In areas subject to flooding, you can move to higher ground. In an area going through a long period of drought, there's no refuge.

Here's the constantly updated U.S. Drought Monitor map, provided by the National Drought Mitigation Center in Lincoln, Nebraska. Note the "exceptional" drought conditions in the Southeast.

Extreme Weather Tabulation for Early 2007

The most informative and persuasive book I've yet read about climate change and the risks we face is Hell and High Water by Joe Romm. Joe blogs at Climate Progress, one of my favorite feeds and sources for factual information about the effects of human-produced carbon emissions on our environment. So, read the book and bookmark Joe's blog.

I'm pointing to his latest article here because it does a great job of presenting the essentials of a just-released report by the World Meteorological Organization that confirms what the news stream has implied - records for different kinds of extreme weather were broken all over the place in the first four months of this year. Other news reports since April have noted more examples of unprecedented rain, flooding, drought and major storms landing in new locations.

What this should say to people who understand risk aversion is that the models for human-influenced global warming are proving to be valid, that the impacts can no longer be regarded as might happen or even gonna happen. They are happening and where they will happen next is the most important uncertainty. A population roughly the size of California's (36 million) has been rendered homeless or displaced by flooding over the past 3 months.

The task is huge and tricky, but it's time for more public consideration of contingency planning.
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