There is a horrible disaster going on right now in Alberta, Canada where a powerful forest fire is raging, threatening to destroy whole towns including forest. This fire, according to experts was likely caused by man made activities given the location of where the fire started and a lack of lightning strikes.
Naturally, on cue, several journalist and some more, shall we say aggressively supportive me Anthropogenic Global Warming theory meteorologist immediately claim this fire was due to climate change before even one flame could be contained. You know what they say, never miss an opportunity to exploit a disaster.
So what caused this fire? Well, we know experts believe that this fire was caused by a man made activity. Perhaps someone was camping and did not put out the fire correctly. Perhaps even a simple flick of a cigar could have caused this disaster. However, there was a cause from the weather.
Above is the Sea Surface Temperature Map as of May 5th. For the past several weeks we have seen a rapid collapse of El Nino, which was very strong but despite the hype, was not the strongest ever (1998 still is the champ). However, while the Tropical Pacific is changing, the Northern Pacific has not changed all that much while the northern Atlantic continues to cool. What we have in place is called a positive PDO in the Pacific and a weakening positive AMO in the Atlantic.
The Pacific Decadal Oscillation (PDO) is a completely natural oscillation which lasts for 20 to 30 years. We are currently in a warm PDO phase which naturally explains many of the elevated temperatures over the past 20 years (shhh, you weren’t supposed to know that). For more information on the PDO, go here!
So why is the PDO important? Okay, so I’m going to explain this in general terms but unlike others, I will show you a direct link to this Sea Surface Temperature Anomalies (SSTA) and this fire. So let’s get this cracking.
1. Note the cold water in the central Pacific and the warm water along the west coast of North America. This thermal gradient (text book +PDO) leads to air mass clashes over the northern Pacific and what we call a sustained trough. Sometimes these troughs become cut off and become powerful upper level lows.
2. With the upper level low intensifying in the northern Pacific, a ridge becomes sustained over western North America. The ridge is a direct result of the trough in the northern Pacific. While air rises in association with a trough, air sinks under a strong ridge. The sinking air warms and with strong 500 MB heights (that’s how we measure upper level ridges) that sinking air gets very hot. Thus you end up with a dry, hot weather pattern over western Canada, the northern Rockies, and the Northern Plains in the United States.
3. Now, remember the SSTA in the Atlantic? Again, we are dealing with thermal dynamics. We have very warm water in the western Atlantic and very cold water in the northeastern Atlantic. This clash of air masses is leading to a trough over the northwestern Atlantic which acts like a block. Think of this block like a traffic jam. So, the result of this, combined with a ridge in the West is a sustained trough and/or upper level low over the Eastern United States. This is why the Philadelphia and New York City metropolitan areas have seen plenty of rainfall of late.
4. So, think back to your high school physics class and remember Conservation of Mass. You must have a thermal and mass balance in the atmosphere. This is why we have storms. The upper level lows in the Pacific and over the Eastern United States balance the ridge over western North America. The ridge intensifies and as a result, so too the two troughs/upper level lows, which leads to a feed back loop until the block is broken.
So you take this pattern with what was already a warm winter due to the combination of El Nino and the positive PDO, and you end up with a low level environment in Alberta, Canada that is supportive for forest fires. I should note, that this very same pattern was shifted east last month and lead to some fire concerns in New Jersey a few weeks back.
This process is not unusual. In fact, there are several cases of these dangerous fires throughout western North America. If you want to research past fire events in Canada, go here.
Carbon Dioxide did not cause this fire at all. There is no proof to support that claim. What caused this pattern is the combination of natural conditions in the atmosphere combining together to produce a dry boundary layer in western and central Canada. Combine this factor with someone who was careless who started the fire. Then add a strong pressure gradient between a low over the Upper Mid West of the United States and a high pressure system over western Canada leading to strong winds and you have yourself a dangerous forest fire.
This pattern has happened before and will happen again. It is not outside the bounds of our normal climate and I can promise you that sadly we will see these fires again like we have in the past. This is part of a natural process for forests, which at times gets the aid of a careless individual. In reality, due to our better understanding of these forest fires and control burns, we have seen a marked reduction in these types of dangerous forest fires over the years. Still, they still can and do happen, just like in California last year.
Over the next several decades we will see the Atlantic continue to cool significantly as we go into a negative AMO phase and the northern Pacific is expected to follow suit as well. When this happens, the patterns will flip and you’ll noticed marked changes in surface temperatures and weather pattern as a result. The last time we saw a combination of a negative AMO/PDO was back in the 1950’s which ironically (I say this sarcastically) was when global temperatures were much cooler (but you didn’t hear that).
As you can see after reading this, this fire has nothing to do with climate change but is in fact part of the current climate and has been for centuries.