7 August 2018

The Right Answer To The Wrong Question

Posted by Dan Satterfield

You’re standing at the South Pole marker at Amundsen-Scott Station, and someone asks “which direction is the South Pole Telescope from here?”  “Go north!”, is a correct answer to the wrong question! Here is another wrong question: Did climate change cause the recent Europe-wide heat wave? Did climate change cause Death Valley to have the hottest month ever reliably recorded on Earth? How about the California fires that are still burning (and now the worst on record)?

The right question is how much of a role did climate change play in these events and over the coming months, we will have some answers. They will come in the form of  “fingerprint studies“, which estimate how much more likely such an extreme event was to occur, based on the warming we’ve already seen. The easiest correct answer is that climate change plays a role in EVERY weather event now. It must, because the planet is around .8C warmer than 150 years ago.

Want To Dig Deeper?

 Let’s talk about how the warming planet is changing the wind flow pattern several kilometers above the surface. This is crucial because the wind flow up high controls the weather at the ground below. If that pattern gets stuck, then the weather below it will become stagnant. If it’s a heat wave, it will continue and likely get hotter. If it’s a drought or a wet and rainy weather pattern, the same applies. If climate change is causing a traffic jam in the wind flow pattern aloft, then climate change is holding the smoking gun at the site of extreme weather events.

Here’s where I buried the lead: There is growing evidence that this is indeed happening.

This chart below shows the winds at what meteorologists call the 250 millibar pressure level. Note the wavy ridges and troughs. These are called Rossby waves and they are caused by two things: Unequal heating of the planet and the Earth’s rotation.  They slowly move and change around the planet and they bring the day to day weather changes we all experience. 

An important paper that looks into the physics behind this was published in Nature’s Scientific Reports last May by Michael E. Mann, Stefan Rahmstorf and others. This paper may be a difficult read for non-geeks (I read it three times myself, and then asked Dr Mann to make sure I wasn’t getting something wrong!). 

First, watch this video:

Rossby waves are caused by temperature differences between the Poles and Equator, but guess what? That temperature difference is getting smaller because the poles are warming much faster due to the increasing greenhouse gases. This is called Arctic amplification and when conditions are right, these Rossby waves become trapped and amplify over an area. Enter heat wave stage left, and drought stage right!

A very good explanation of the paper I linked above is available here. Michael Mann put it this way: “Arctic warming projects onto a meridional temperature pattern that favors (through the thermal wind) a double zonal jet profile (peak in upper tropospheric westerlies in sub-polar and lower mid-latitudes with a minimum in between) which, in turn, supports the phenomenon of planetary wave resonance.”

Final Note

Synoptic meteorologists (like myself) started noticing these atmospheric blocking events seem to be more common, but are they really? Science teaches you that the truth is in the data, not the mind. One of the first to tackle this was Dr. Jennifer Francis at Rutgers University and I’ve done a few posts about her research. The reason this latest research is important is that it takes the earlier research and shows a physical explanation for how it’s happening.

Here is what you should worry about: Is this summer’s widespread extreme weather a climate surprise? Is this what happens when we warm the planet by .8ºC?? If so, what happens when we reach 1.5º C in 30-40 years or two degrees after that??  

Here is the bad news: That 1.5 C is happening no matter what. It’s already baked into the system. It’s unlikely we can even hold below 2ºC.

We could have if we’d acted 30 years ago, but too many people listened to politicians telling them what they wanted to hear. Those that stood up and told the truth, were thrown out. Just ask former Congressman Bob Inglis how that works.

We are pulling the tail of a sleeping climate lion, and this summer may just be his half-awake “leave me alone” twitch. What happens in 30 years when we kick him in the side? I won’t be around, but your grandchildren will.