It was a glorious Independence Day in Minnesota. A high of 84F and a decent breeze to take the edge off the sun made the perfect backdrop to pick up the aroma of grilling meat. It’s all any of us could ever hope for. But it was in blinding contrast to the soggy wet June that made a mud puddle out of huge swatches of southern Minnesota and brought nasty storms that at one point had over a million people without power. What is up with this weather?
The same strange patterns that brought us a drought last year have been equally unkind in the opposite way this year, meaning we are in a kind of long-term trend towards more extreme weather in every and all direction. Exactly why is unclear, but we can expect this to continue. At least when everyone talks about the weather but no one does anything we can call it a reasonable response, yes?
The problem is the same one as last year – the Northern Jet Stream is nonexistent. To call it “broken” would be an understatement, as there is no sign of a ribbon of air dashing around the planet. Instead, there are thin ribbons of upper-level winds running almost at random. And they are bringing the bizarre weather with them.
Typically, the middle of the continent is dominated by a strong western flow that balances out the equatorial tradewinds which are caused by the drag against the atmosphere as we spin through the heavens. The process loops around from the topics and brings water from the warm oceans towards the pole, falling as life giving rain. Last year, it was simply dead and dry. This year, the flow is almost entirely north and water is being dumped in stagnant bands that keep the water flowing, even where it doesn’t normally go. Heavy flooding in central Europe and Alberta was caused by this problem. Tornado fuel in the form of water from the Gulf of Mexico has poured into Oklahoma.
Even when the Jet Stream is flowing, it’s 14% slower than it should be. It’s as if the great circulation of the planet has simply broken. But why is up for debate.
To simply say that this is tied to global warming is a bit of a cop-out. We can expect that as the atmosphere heats up there will be changes in circulation, but exactly what will change is hard to predict. This has not been a part of any model for warming, and reasonably so – it’s far too complex. What we can do is look at other effects that relate to this immediate problem and see if we can make some predictions.
The great anomaly that is often tied to this problem is the intense melting over the Arctic last summer. There’s little doubt that the two are related, but exactly how is not known. What we can say is that the record loss of ice in 2012 was met with a rebuild back to essentially normal winters, even as other zonal flows to the south remained very odd. The track of Hurricane Sandy was considered a once in 700 year event that is clearly related to the busted Jet Stream, but the arctic did manage to recover over that period. The relation remains sketchy at best.
Sunspot activity has been at a 100 year plus low since 2008, running very close to zero over the last 5 years. Some have long believed that solar activity has a lot to do with the temperature of the planet, especially with a strong historical correlation between sunspot decline and distinct periods of cooling. Why hasn’t the planet cooled down in the last 5 years? It’s hard to say what the heat capacity of Earth is, but if this theory is going to pan out we had better see some cooling soon. It is possible, however, that a lack of mixing from the tropics is the first stage of a longer term cooling. We will have to see.
No matter what, this trend has been in place for over a year now. It’s not going away any time soon. If this means that farming in the grain belt is going to be disrupted in just about every way possible, too little water one year and too much the next, there will be serious food shortages in our future.
All we can do is watch the Jet Stream to see if it gets itself together. Perhaps one or more other things will happen that might explain just why this failed so badly for so long. Until then, we can only hope that we have more days like today and a reasonably normal summer. It’s nice to have a good 4th of July, but the farmers need a lot more than that to keep the great riches of the US flowing.